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Home My WebLink AboutReports - Erosion Control - 04/01/2025 EROSION CONTROL REPORT Pederson Toyota Fort Collins, Colorado Prepared for: Pedersen Properties 4455 S Mason Street Fort Collins, CO 80525 Prepared by: Kimley-Horn and Associates, Inc. 3325 South Timberline Road - Suite 130 Fort Collins, Colorado 80525 (970) 462-9320 Kimley))) Horn Project#:296073000 Prepared:April 2025 Kimley>Morn April 2025 City of Fort Collins Stormwater Engineering 281 N. College Ave. Fort Collins, CO 80524 RE: Pederson Toyota Erosion Control Report To Whom it May Concern, Kimley-Horn and Associates, Inc. is pleased to submit this Erosion Control Report for your review as part of the Basic Development Review (BDR) submittal for the above referenced project. The report outlines Best Management Practices (BMPs) to be implemented with the proposed construction to minimize potential pollutants in stormwater discharge. This report and attached drainage plans have been prepared in accordance with the Fort Collins Stormwater Criteria Manual ("FCSCM") and the latest Mile High Flood District Urban Storm Drainage Criteria Manual ("USDCM"). This report also accompanies the Colorado Department of Public Health and Environment General Permit for Stormwater Discharge Associated with Construction Activities (aka, Stormwater Discharge Permit or SDP). The General Permit No. for this SDP is (to be filled-in by permittee), and the Certification No. for this SDP is (to be filled-in by permittee). The Permit Certification is effective beginning (to be filled-in by permittee), and initial certification expires (to be filled-in by permittee). Please note this Stormwater Management plan (including the Site Maps) is not a static document. It is a dynamic device that should be kept current and logged as construction occurs. As such, this version was prepared to facilitate initial plan approvals and permits but does not necessarily reflect the final version or the transitions throughout the construction process. As the site develops and changes, the contractor is expected and encouraged to change the content, so the Erosion Control Report works as effectively and efficiently as possible. Please contact us with any questions or concerns. Thank You, KIMLEY-HORN AND ASSOCIATES, INC. Emily Felton, P.E. -. Suite 130, Fort Collins, CO :0 � . Erosion Control Report Pederson Toyota — Fort Collins, Colorado TABLE OF CONTENTS I. PROJECT DESCRIPTION AND NATURE OF CONSTRUCTION ................................1 SITELOCATION ................................................................................................................1 EXISTING SITE CONDITION................................................................................................1 PROPOSED CONSTRUCTION ACTIVITIES ............................................................................2 II. POTENTIAL POLLUTANT SOURCES.........................................................................2 ALL DISTURBED AND STORED SOILS.................................................................................2 VEHICLE TRACKING OF SEDIMENTS...................................................................................2 MANAGEMENT OF CONTAMINATED SOILS ..........................................................................3 LOADING AND UNLOADING OPERATIONS ...........................................................................3 OUTDOOR STORAGE OF CONSTRUCTION SITE MATERIALS, BUILDING MATERIALS, FERTILIZERS, AND CHEMICALS..........................................................................................3 BULK STORAGE OF MATERIALS.........................................................................................4 VEHICLE AND EQUIPMENT MAINTENANCE AND FUELING.....................................................4 SIGNIFICANT DUST OR PARTICULATE GENERATING PROCESSES........................................4 ROUTINE MAINTENANCE ACTIVITIES INVOLVING FERTILIZERS, PESTICIDES, DETERGENTS, FUELS, SOLVENTS, AND OILS............................................................................................4 ON-SITE WASTE MANAGEMENT PRACTICES ......................................................................5 CONCRETE TRUCK/EQUIPMENT WASHING, INCLUDING THE CONCRETE TRUCK CHUTE AND ASSOCIATED FIXTURES AND EQUIPMENT...........................................................................5 DEDICATED ASPHALT AND CONCRETE BATCH PLANTS.......................................................6 NON-INDUSTRIAL WASTE SOURCES SUCH AS WORKER TRASH AND PORTABLE TOILETS.....6 SAW CUTTING AND GRINDING...........................................................................................6 OTHER NON-STORMWATER DISCHARGES INCLUDING CONSTRUCTION DEWATERING NOT COVERED UNDER THE CONSTRUCTION DEWATERING DISCHARGES GENERAL PERMIT AND WASH WATER THAT MAY CONTRIBUTE POLLUTANTS TO THE MS4......................................7 III. CONSTRUCTION CONTROL MEASURES.................................................................7 IV. INSTALLATION AND REMOVAL SEQUENCE OF CONSTRUCTION MEASURES.8 V. MAINTENANCE AND INSPECTION REQUIREMENTS..............................................9 VI. FINAL VEGETATION AND STABILIZATION .............................................................9 X. REFERENCES............................................................................................................10 XI. LIST OF APPENDICES .............................................................................................10 APPENDIX A—SITE REFERENCES APPENDIX B— EROSION CONTROL PLANS APPENDIX C—EROSION CONTROL DETAILS APPENDIX D—LANDSCAPE PLANS APPENDIX E— PERMITS/APPLICATIONS APPENDIX F— INSPECTION LOGS APPENDIX G—CONTRACTOR INSERTS kimley-horn.com 3325 S Timberline '• Suite 130, Fort Collins, • 80525 • 1 • Erosion Control Report Pederson Toyota — Fort Collins, Colorado I. PROJECT DESCRIPTION AND NATURE OF CONSTRUCTION Site Location Pederson Toyota (the "Project') is located in the southeast quarter of Section 35, Township 07 North, Range 69 West, of the Sixth Principal Meridian, City of Fort Collins, Larimer County, State of Colorado. The property is bounded by South Mason Street to the West, Kensington Drive to the South, a Target department store to the North, and South College Avenue to the East. A Vicinity Map is shown below in Figure 1. LEI I Cl _ W. TROUTMAN 13KVVY. - LJ1J L7.L.LJ UJ ® 0 R U3 SITE ? W.HARMONY RD. W.HARMONY RD. d 4 w C7 w J J U U G3 Figure 1: Vicinity Map Existing Site Condition The property currently consists of an existing car dealership and a paved parking lot. The Project site is located within the General Commercial (CG) Zone District. Soil Properties A Natural Resource Conservation Service (NRCS) Web Soil Survey for the project area was obtained to determine the soil characteristics of the site. The results of this study show that the majority of the site consists of hydrologic soil group (HSG) Type B with soil that includes Altvan-Santana Loam. The northeast corner of the site consists of hydrologic soil group (HSG) Type C with soils that include Nunn Clay soil. Therefore, HSG Type C soils were assumed for the entirety of the. A copy of the Custom Soil Resource Report is provided in Appendix A. kimley-horn.com •- -. Suite 130, Fort Collins, CO 80525 • 1 Erosion Control Report Pederson Toyota — Fort Collins, Colorado Pathway to Nearest State Water The Project is located within the Mail Creek Basin, see copy of the City of Fort Collins Drainage Basins image included in Appendix A. The existing site is split into two basins. The east basin drains from the south to the northeast to storm inlets located on-site, ultimately draining to the storm sewer system along S College Ave. The western basin drains south to north to storm inlets locate on- site, ultimately draining to a storm sewer system located along S College Ave via the Target parcel. While they are split into two basins on site, both storm lines ultimately drain to the storm system along College to the Poudre River. Existing Vegetative Area to Impervious Area The site currently consists of 90% impervious area, and around 10% pervious lawn and clayey soils. Existing Groundwater Depth A Preliminary Geotechnical Investigation dated February 13, 2014, was prepared by Earth Engineering Consultants, LLC. There are no known significant geologic features at this site. Groundwater was encountered at depths ranging from 15 to 20.5 feet below the existing ground surface in the boring test holes. Groundwater levels will not likely affect planned development at this site. Additional information for the Geotechnical report can be found within Appendix A. Proposed Construction Activities The Project is proposing to remove some of the existing building, storage structures, pavement, and utilities. To develop the site, building additions, pavement and utility improvements, and increased landscape area will proposed. Sawcuts will be used in adjacent roadways for utility installations. The project will provide LID and water quality treatment for the site. II. POTENTIAL POLLUTANT SOURCES All Disturbed and Stored Soils Most of the site will be disturbed during demolition and grading of the site. Once soils have been disturbed, they do not retain the same compaction as in their native state, therefore surface runoff can cause more soil erosion than was historically observed. Based upon the site design this site should not disturb all areas of construction until it is required to as part of the Construction Activities (phasing). Once exposed those areas of exposed soils should be kept in a roughened condition (surface roughening). Around the perimeter, construction fence with rock wattles should be used to ensure sediment does not leave the site. Soil that is transported onto adjacent roadways should be swept or scraped (street sweeping) to prevent the migration of sediment. Curb inlet protection should be placed at all downstream inlets to limit suspended runoff bring transported downstream in stormwater runoff(rock sock style inlet protection). Stockpiles in the same respect do not retain the same compaction and are more susceptible to soil erosion. Stockpiles on this site shall be placed in or near the center of the site and away from any drainage swales to not require perimeter run off controls (Materials/Site Management Control). The stockpile should be kept loose, not -. Suite 130, Fort Collins, CO :0 � . Erosion Control Report Pederson Toyota — Fort Collins, Colorado compacted, and watered as needed to prevent dust issues (site watering). The stockpile should be monitored for signs of erosion displacement and sediment accumulation and if conditions warrant it, the stockpile should be structurally covered or if it is going to sit a long while will be reseeded (temporary seeding). Vehicle Tracking of Sediments Vehicle tracking of sediment may occur throughout the construction process and along all areas where the pavement meets the disturbed dirt. This occurs most often after any melt off or rain conditions when mud collects on vehicles tires and is tracked out onto the road consequently leaving site. This increases the possibility of sediment discharging to the storm system. To prevent tracking, construction fence (site barrier/site management control) should be used site wide to limit the access by the contractor and their subs to only three construction entrances (vehicle tracking pads to be installed) on the east of the site, north of the site, and south of the site. There will be a gate at the entrance that will be closed before contractors come on site during the muddy days (site management control) and should only be opened to let larger deliveries drop off, otherwise subcontractor parking should be kept to the street. All contractors have signed contracts that should have them clean the streets if they are found to be tracking dirt onto the street. (site management control). The tracking pad should be monitored visually every day and if track-out becomes a significant problem a larger or more robust tracking pad may be installed. Otherwise, all track-out that reaches the street should be scraped and swept (street sweeping). Secondary controls at the closest affected combination inlets should have protection (drop inlet protection) to capture sediment not swept up in a timely manner. Management of Contaminated Soils There are no known contaminated soils on the site. If encountered, the contractor should have the material stored in a covered area (materials management control) as to not mix with the stormwater until the material can be identified and proper classification and disposal methods can be determined in accordance with the various waste laws and with good construction safety and practices. Loading and Unloading Operations This project will have diverse loading and unloading. There should be a significant amount of export leaving the site, the foundation workers should have to deliver forms to the site and deliver premixed concrete. Building materials should have to be staged around the site and Landscapers should need to pile the materials on site to complete the landscape work. It is anticipated that the loading and loading vehicles will be contributing to material being tracked out onto adjacent roadways. Depending on the type of material delivered to the site they may have a significant spill potential. In addition to the vehicle tracking of sediments section of this report, (VTC, Sweeping, etc.) contractors should require subcontractors to park offsite or on stabilized areas with lower potential for tracking debris (site management control). Where the project is mostly dirt, and not stable contractors should encourage semi-trailers to pull alongside the project and site loaders should be used to off load the trailers. Where the site parking lot and private drives have been installed materials should be placed in piles along the hardscape the use of site forklifts should be more heavily used. When loading and unloading is occurring, depending on the materials, there may be an increased problem of containers being dropped, punctured, or broken. These off-loading activities should be done under roofs or awnings where possible and be located away from storm drains and -. Suite 130, Fort Collins, CO :0 � . Erosion Control Report Pederson Toyota — Fort Collins, Colorado where nearby spill kits are accessible. Spills on site should be addressed using spill prevention and response procedures. Outdoor Storage of Construction Site Materials, Building Materials, Fertilizers, and Chemicals It is anticipated that inert material like wood, shingles, tiles, siding insulation and stone should be stored on site and outside in the elements. It is also anticipated that materials that do not weather well (cement, mortar, etc.) should also be located outside. Chemicals are not anticipated to be left outside. The contractor should monitor as the inert materials have a lower potential to leave the site to make sure they are not being impacted by the exposure to the elements (site management control). The materials that should need added attention are the cements and mortars as they quickly mix with water and cause pollution issues. When not stored inside the contractor should place these materials on pallets to get above potential surface runoff and covered with tarps or plastic to prevent mixing with stormwater (materials management control). Very small quantities of chemical are needed to contaminate stormwater so the fertilizers, paints, form oils, petroleum products, and other typical chemicals, should be stored in the construction conex box, trailers, vehicles, or the like out of contact with precipitation (materials management control). If not stored in a location as described, secondary containment will be required. Bulk Storage of Materials No structures will be built on site at this time and no liquid chemicals above 55 gallons are expected. Vehicle and Equipment Maintenance and Fueling In the case that vehicle and equipment maintenance and fueling is needed on site, the contractor should monitor these activities carefully to avoid contamination from small spills of petroleum. Some grading companies will employee a fuel truck to fill the heavy equipment on site or require the maintenance of a broken machine. In those cases where the vehicle is not able to be maintained off site, these activities will be done in the least detrimental way possible. The maintenance and fueling should be located as far from stormwater features as possible and at least 50 feet from a stormwater feature (site management/materials management). Spill materials should be nearby, and a bucket or other container and shovel located nearby to hang a hose after filling to catch drips, and to scoop up any dirt that inadvertently mixed with the soil (materials management). That container should have a lid and be disposed of when the activity is completed. The contractor should require maintenance work to be done on a tarp or other material to prevent the residual oils and greases from mixing with the dirt (materials management). Significant Dust or Particulate Generating Processes This project will result in earth moving activities, street sweeping, and track-out and carry out, bulk materials transport and saw cutting. As these activities result in offsite transport of atmospheric pollution reasonable precautions shall be taken. The contractor should follow all required "BMPs" articulated in the Fugitive Dust Manual and a least one additional BMP included during each of the identified activities in accordance with City Ordinance No. 044,2016. Also, a copy of the Dust Control Manual should be kept in the trailer during construction for reference. Such activities will include but not limited to watering the site, covering trucks, slower site speeds and vehicle tracking mentioned above. kimley-horn.com •- -• Suite 130, Fort Collins, CO 80525 • 1 Erosion Control Report Pederson Toyota — Fort Collins, Colorado Routine Maintenance Activities Involving Fertilizers, Pesticides, Detergents, Fuels, Solvents, and Oils Fertilizers and Pesticides should be used during the later phases of the project when trying to establish a healthy vegetation. These chemicals are highly water soluble and are easily and unnoticeably carried in the stormwater. Proper application rates and recommended timing of application should be strictly followed and not on days, or the next day, where the weather is calling for precipitation (materials management control). As most of these types of chemicals will be brought on by the Landscaper, the contractor should require them to keep these products in their vehicles until time of application and they should not be allowed to leave these materials on the site (site management control). If these materials are stored on site, they shall be kept inside or outside covered and above the ground to prevent the materials from mixing with water and runoff (materials management control). If any detergents, paints, acids, cement, grout, and solvents are used, they could be mixed with water and cause the water to be discolored, cloudy, or sudsy. The contractor should keep an eye out for water that is discolored, cloudy, or sudsy around the site (site management control). When these materials are to be handled, operated, and cleaned up all within the inside of the structure, where external use is concerned these materials will be stored in the construction conex box, trailers, vehicles, or the like out of contact with precipitation (materials management). If not stored in a location as described secondary containment will be required (materials management). Fuels and oils might be associated with the smaller equipment used on site, chainsaws, pumps, generators, etc. As petroleum products are easily suspended in water and are spread across the top of the water surface. These products when located in water have rainbow sheen on them. The contractor should also monitor during construction (site management controls). These products will be stored in the construction conex box, trailers, vehicles, or similar structure that will minimize contact with precipitation (materials maintenance controls). If not stored in a location as described secondary containment will be required (materials maintenance). Any untreated runoff from these activities can be detrimental to wildlife if not cleaned up. On-site Waste Management Practices All large and heavy weighted waste piles (concrete chunks, excavated pipes, etc.) should be kept in a neat, grouped pile until the material is to be disposed of properly. The contractor should only store these piles for a short duration 5-10 days and should keep them 50 feet from any drainage course or inlet (Administrative Control). All dry wastes should be maintained through dumpsters and monthly hauler removal (hauler should be notified if dumpster becomes full and hauled off as needed). Where available by the hauling company the dumpster will be covered. If not practical or available by the haul company, the contractor should require an increased removal schedule where the "Max fill line" on the dumpster should be strictly followed. Corners of the dumpsters should be monitored for"Dumpster Juice" leaking into the soil in dry conditions and rain/melt off conditions looking for it mixing with the runoff. Dumpsters, like the waste piles, should be located at least 50 feet from any drainage course or inlet. Contractors should require workers to collect trash at the end of the day to prevent trash being left out overnight. No construction debris (including broken concrete) should be buried on site. Erosion Control Report Pederson Toyota — Fort Collins, Colorado Concrete Truck/Equipment Washing, Including the Concrete Truck Chute and Associated Fixtures and Equipment Concrete will be a large portion of this project. It is anticipated that it should be used with the joints around the manholes, pour in place inlets, curb and gutter installation, sidewalks, and foundations. Premixed concrete trucks should be used in this process and should be delivered to the site and when pouring the foundation, a pump truck should be used all of which will need to be maintained through the washing of their chutes and pump arms to prevent the concrete from hardening and ruining the equipment. This concrete wash water has a high alkaline content which is hazardous material to terrestrial and aquatic wildlife. The contractor should designate a section of dirt near the entrance to be excavated and compacted around the sides formed to retain the concrete wash water on site (as an acceptable practice by the State) so long as the wash water is kept in the washout (concrete washout). There should be a rock pad for the truck to park on while washing as to prevent tracking from this washout (VTC). The placement of this washout should be located at least 50 feet from any drainage course or inlet. Later in the project after the parking lots curb and gutter has been poured the use of a mobile washout facility can be used on site in a similar location and after the ground has been leveled (concrete washout— mobile). The contractor (including all masonry and concrete tradesmen) shall clean out equipment within the washout area so that the runoff is not allowed to leave the washout. The only exception would be for them to wash in the next day's pour location. All concrete workers should be made aware of the where they are to wash (site management controls & education)., If there is a significant amount of spillage when the transfer from concrete truck to pump truck occurs, a tarp or other ground cloth should be used to collect spillage. (ground cover control). Dedicated Asphalt and Concrete Batch Plants There will be no dedicated asphalt or concrete batch plants erected onsite for this project. Premixed concrete and paving materials should be delivered to the site and placed. Non-industrial Waste Sources such as Worker Trash and Portable Toilets Since facilities are not located nearby for workers to use, trash and sanitary facilities should be required on the site. Worker trash will be comingled with the industrial trash and should follow the same controls with the caveat that a trashcan should be located near the entrance of the site as the contractor will need to dump their trash from lunch, etc. and this will be emptied weekly or more frequently, if needed. If tipped over and when being cleaned, portable toilet facilities become a potential discharge if not cleaned up. If human waste is spilled, the contractor should require it be treated as a biological hazard of untreated sewage, and it should need to be cleaned up in accordance with Larimer County Health Department Guidance. The toilets should be staked in a way to prevent tipping on a dirt surface and located at least 50 feet from a drainage course or inlet. If the site cannot accommodate a portable toilet on dirt, a containment pan or other secondary containment should be provided. They should also be anchored prevent from tipping. All materials shall be properly disposed of in accordance with the law. Saw Cutting and Grinding The street connections will require cutting into the city street. This project should need the use of hardened saws. These saws generate a significant amount of dust. The kimley-horn.com •- -• Suite 130, Fort Collins, CO 80525 • 1 Erosion Control Report Pederson Toyota — Fort Collins, Colorado contractor should require the watering the cutting surface to prevent airborne particulates (BMP in the City's Fugitive Dust Manual). The cutting slurry has a high content of fine particulates (Silica Dust, Metals, etc.) that is not allowed to discharge as runoff from the site. To prevent slurry from discharging offsite, contractors should use the minimum amount of water needed to prevent dust and blades from overheating (site management control). Cutting slurry should be collected via vacuum or allowed to dry out and be scraped and swept up after the cutting has finished (saw cutting). Other Non-Stormwater Discharges Including Construction Dewatering not Covered under the Construction Dewatering Discharges General Permit and Wash Water that may Contribute Pollutants to the MS4 Based upon the geotechnical data, ground water levels indicate that it will be significantly lower (15 to 20'/2 feet) than the bottom of the deepest excavation. However, if encountered, dewatering activities may be required. Groundwater has in most excavations mixed with the dirt and as they are pumped, they will add an increased velocity coming out of the out flow end contributing to erosion and speeding the transport of the suspended sediment particles. Also, construction dewatering activities must be identified in the Erosion Control Report if they are to be infiltrated on site. If the material is anticipated to be pumped to a stormwater conveyance the proper Construction Dewatering Permit must be pulled from the State of Colorado. If pumping activities are to occur on the site, the use of rock packs on the intake end of the pump should be used and a silt bag should be used on the outflow end of the pump to reduce the silt and sediment from leaving the activity (dewatering Control Measure). If this will be under a Dewatering Permit water samples should be collected in accordance with that permit. III. CONSTRUCTION CONTROL MEASURES Throughout the entire construction of the project, erosion control devices shall be installed to ensure minimal pollutant migration. These erosion control measures may be installed in phases, or not at all, depending on actual conditions encountered at the site. It is the responsibility of the Contractor to make the determination as to what measures should be employed and when. In the event that a review agency deems BMPs to be insufficient, it shall be the responsibility of the contractor to implement modifications as directed. Best Management Practices (BMPs) are loosely defined as a method, activity, maintenance procedure, or other management practice for reducing the amount of pollution entering a water body. The term originated from rules and regulations in Section 208 of the Clean Water Act. Details for Structural and Non-Structural BMPs have been included in Appendix B. These details should be used for additional information on installation and maintenance of BMPs specified in this report. It is also intended to serve as a resource for additional BMPs that may be appropriate for the site that have not specifically been mentioned in the report. Construction Fence (CF) A construction fence restricts site access to designated entrances and exits, delineates construction site boundaries and keeps construction out of sensitive areas. Fencing should be used in combination with other perimeter control BMPs such as rock wattles or silt fence. Fencing should be inspected daily. kimley-horn.com •- -. Suite 130, Fort Collins, CO 80525 • 1 Erosion Control Report Pederson Toyota — Fort Collins, Colorado Rock Wattle (RW) Rock wattles is made of rock or gravel wrapped in a geotextile having a long cylindrical shape. They are used as a part of perimeter and sediment control. Rock wattles are often placed along the base of construction fence around the entire perimeter of a site. Inlet Protection OP) Inlet Protection consists of permeable barriers installed around inlets to filter runoff and keep sediment from entering a storm drain inlet. Existing and proposed inlets should be covered with inlet protection during construction. Rock Sock (RS) Rock sock is a constructed of gravel wrapped in wire mesh or another geotextile formed into a long cylindrical filter. They are used usually as a part of perimeter control or to aid in inlet protection. When placed along a curb line they are called curb socks. They are placed to trap sediment from stormwater runoff that flows onto roadways because of construction activities. Concrete Washout (CWA) Concrete Washout area involves designating and properly managing a specific area for concrete washout. It can be created using one of several approached designed to receive wash water from washing tools, dump trucks, mobile batch mixers or pump trucks. Vehicle Tracking Control (VTC) Vehicle tracking controls provide stabilized construction site access where vehicles can enter and exit the site on to paved public roads. It is used to remove sediment (mud or dirt) from vehicles to limit tracking onto the paved surface. Stockpile Management (SP) Stockpile management included measures to minimize erosion and sediment transport from soil stockpiles. Stabilized Staging Area (SSA) A stabilized staging area is a clearly designated area where construction equipment and vehicles, stockpiles, waste bins, and other construction related materials are stored. The office trailer may also be located in this area. Depending on size of site multiple staging area may be necessary. Surface Roughening (SR) Surface Roughening involves tracking, scarifying, imprinting, or tilling a disturbed area to provide temporary stabilization of disturbed areas. Surface roughening created variations in the soil surface to minimize wind and water erosion. IV. INSTALLATION AND REMOVAL SEQUENCE OF CONSTRUCTION MEASURES Prior to construction a construction fence, vehicle tracking control, and concrete washout areas should be installed to ensure limited access to the site and to control sediment being transported on and off site. Inlet protection at any existing inlets should also be put in place. As demolition is occurring surface roughening should be completed on the empty lots to limit runoff occurring on site. Following demolition and as the site and roadways are being constructed curb socks should be added along the flowlines, a stabilized staging area and stockpile management area should be created to hold construction equipment and materials. Inlet protection should be added to proposed inlets as they are constructed. kimley-horn.com 3325 S Timberline Rd, Suite 130, Fort Collins, • :0 � : • Erosion Control Report Pederson Toyota — Fort Collins, Colorado Finally temporary vegetation should be added to the empty lots to stabilize them prior to future development being added. Street sweeping should take place to ensure sediment does not enter storm network. These erosion control measures may be installed in phases, or not at all, depending on actual conditions encountered at the site. It is the responsibility of the Contractor to make the determination as to what measures should be employed and when. In the event that a review agency deems BMPs to be insufficient, it shall be the responsibility of the contractor to implement modifications as directed. V. MAINTENANCE AND INSPECTION REQUIREMENTS All temporary erosion control facilities shall be inspected at a minimum of once every two (2) weeks and after each significant storm event or snowmelt. Repairs or reconstruction of BMPs, as necessary, shall occur as soon as possible to ensure the continued performance of their intended function. The construction site perimeter, disturbed areas, all applicable/installed erosion and sediment control measures, and areas used for material storage exposed to precipitation shall be inspected for evidence of, or the potential for, pollutants entering the drainage system. Attention should be paid to areas with a significant potential for stormwater pollution, such as demolition areas, concrete washout locations, and vehicle entries to the site. The inspection must be documented to ensure compliance with the permit requirements. Any BMPs not operating in correctly must be addressed as soon as possible, immediately in most cases, to prevent the discharge of pollutants. If modifications are necessary, such modifications shall be documented in the inspection logs found in Appendix F. Uncontrolled releases of mud, muddy water, or measurable amounts of sediment found offsite will be recorded with a brief explanation of the measures taken to clean up the sediment that has left the site, as well as the measures taken to prevent future releases. This record shall be made available to the appropriate public agencies (Colorado Department of Public Health and Environment, Water Quality Control Division; Environmental Protection Agency; City of Fort Collins; etc.) upon request. Preventative maintenance of all temporary and permanent erosion control BMPs shall be provided to ensure the continued performance of their intended function. Temporary erosion control measures are to be removed after the site has been sufficiently stabilized, as determined by the City of Fort Collins. Maintenance activities and actions to correct problems shall be noted and recorded during inspections. Details have also been included in Appendix B. VI. FINAL VEGETATION AND STABILIZATION Final stabilization of the site will be achieved by either leaving a paved surface in place or by reseeding. All areas to be seeded as outlined in the Final Landscape Plan, or required by the City in the disturbance of other properties, will have the area amended in accordance with section 12-132 of City Municipal Code and be seeded based upon the specs called out in the landscape plan. A copy of the Landscape plans can be found in Appendix D. All seeded areas will be crimped and mulched same day or next day after seeding in accordance with the Temporary and Permanent Seeding Details associated kimley-horn.com 3325 S Timberline Rd, Suite 130, Fort Collins, • :0 � : Erosion Control Report Pederson Toyota — Fort Collins, Colorado with this project, and in accordance with the City of Fort Collins Erosion Control Criteria. Once installed there will be no temporary irrigation system so all seeding will be monitored until the site has reached a vegetative cover (density) of 70%. Non- seed stabilization is expected to be completed soon after hardscape construction is complete. Seeded areas will require more time to establish and may need irrigation to establish growth. As defined by the Colorado Department of Public Health and Environment (CDPHE) in the General Permit Application for Stormwater Discharges, "Final stabilization is reached when all soil disturbing activities at the site have been completed, and uniform vegetative cover has been established with a density of at least 70 percent of pre- disturbance levels or equivalent permanent, physical erosion reduction methods have been employed." Establishment of 70 percent is required for a determination for project closure by the City of Fort Collins. K REFERENCES City of Fort Collins Flood Maps, City of Fort Collins GIS, Accessed January 20, 2025, at <https://gisweb.fcgov.com/HTML5Viewer/Index.htmI?viewer=FCMaps&LayerTheme=flo odplains> Custom Soil Resource Report, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. November 5, 2024. Fort Collins Stormwater Criteria Manual, City of Fort Collins, December 2018. Urban Storm Drainage Criteria Manual, Volumes 1-3, Mile High Flood District, Updated March 2024. -. Suite 130, Fort Collins, CO :0 � . Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix A - Site References Kimley>Morn It f Y i. r.. t Williams - a .', [DRAM �D Lake n , 1 rL ALLY M a 'I I Creek VC M Rftn - Master Plan - � - . , i 9 Y o ' 6 = _ ,w Water Quality PI n a yp Nelson - 'r_ . . .� ..� t _. :-:.,,m, , . . . • - Reservoir � �1• f 1- •. i P t.y S , :sax.F s.. \ r r XX k Ate' 1 1 f` ♦ { F r ! 1 f f' Troutman Pond y19�'. ' ri : • Retrofit Existing Pond to a 17 , � ,• .f Steve r accommodate Water Quality ' , ' Volume t , ?` - - p tra► } . ' y s �#' s1'1 ,,:r - _ •�mot• . dr . : _ �,�� h- Larkborou h Pond Woodridge Pond r .s � a.: y irt .:�, ;. 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' •e and Habitat Improvements 0 500 1,000 2,000 rit WSW nS ABCs t £' I % `d , , Feet ffm S € ASSOCIATES ' � NAIP Image-2009 USDA United States A product of the National Custom Soil Resource Department of Cooperative Soil Survey, Agriculture a joint effort of the United Report for N �� States Department of Agriculture and other Larimer County Federal agencies, State Natural agencies including the Resources Agricultural Experiment Area, Colorado Conservation Stations, and local Service participants s � or I M r I 0 200 ft '- February 17, 2025 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nres.usda.gov/wps/ portal/nres/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nres)or your NRCS State Soil Scientist (http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/? cid=nres142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.)should contact USDA's TARGET Center at(202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice)or(202)720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 SoilMap.................................................................................................................. 8 SoilMap................................................................................................................9 Legend................................................................................................................10 MapUnit Legend................................................................................................ 11 MapUnit Descriptions.........................................................................................11 Larimer County Area, Colorado...................................................................... 13 3—Altvan-Satanta loams, 0 to 3 percent slopes......................................... 13 4—Altvan-Satanta loams, 3 to 9 percent slopes......................................... 15 74—Nunn clay loam, 1 to 3 percent slopes.................................................17 References............................................................................................................19 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 Custom Soil Resource Report scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and 6 Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 Custom Soil Resource Report Soil Map M 0 493230 493260 493290 493320 493350 493380 493410 493440 493470 493500 40°31'35'N e•�. — � I — I4 40°31'35"N r t � d I 8 t 8 Is q- i �19 t sr r. 287 Soil M:a'ip may not b= u�lid,'at this scaale., "� , 40°31 29 N � I r 40°31 29 N 493230 493260 493290 493320 493350 493380 493410 493440 493470 4935M 3: 3 F io v Map Scale:1:1,270 if printed on A landscape(11"x 8.5")sheet c Meters N ° 0 15 30 60 90 Feet 0 50 100 200 300 Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 13N WGS84 9 Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest(AOI) Spoil Area The soil surveys that comprise your AOI were mapped at Area of Interest(AOI) 1:24,000. Q Stony Spot Soils Very Stony Spot Soil Map Unit Polygons Warning:Soil Map may not be valid at this scale. Wet Spot �i Soil Map Unit Lines Enlargement of maps beyond the scale of mapping can cause Other misunderstanding of the detail of mapping and accuracy of soil 0 Soil Map Unit Points g pp g y .- Special Line Features line placement.The maps do not show the small areas of Special Point Features contrasting soils that could have been shown at a more detailed V Blowout Water Features scale. Streams and Canals Borrow Pit Clay Spot Transportation Please rely on the bar scale on each map sheet for map .+. Rails measurements. J Closed Depression ti Interstate Highways Gravel Pit Source of Map: Natural Resources Conservation Service US Routes Web Soil Survey URL: Gravelly Spot Major Roads Coordinate System: Web Mercator(EPSG:3857) O Landfill Local Roads Maps from the Web Soil Survey are based on the Web Mercator A Lava Flow Background projection,which preserves direction and shape but distorts distance and area.A projection that preserves area,such as the Marsh or swamp Aerial Photography Albers equal-area conic projection,should be used if more Mine or Quarry accurate calculations of distance or area are required. O Miscellaneous Water This product is generated from the USDA-NRCS certified data as O Perennial Water of the version date(s)listed below. V Rock Outcrop Soil Survey Area: Larimer County Area,Colorado + Saline Spot Survey Area Data: Version 19,Aug 29,2024 Sandy Spot Soil map units are labeled(as space allows)for map scales 4W Severely Eroded Spot 1:50,000 or larger. 0 Sinkhole Date(s)aerial images were photographed: Jul 2,2021—Aug 25, 3) Slide or Slip 2021 Sodic Spot The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps.As a result,some minor shifting of map unit boundaries may be evident. 10 Custom Soil Resource Report Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3 Altvan-Satanta loams,0 to 3 1.1 17.9% percent slopes 4 Altvan-Satanta foams,3 to 9 3.9 61.9% percent slopes 74 Nunn clay loam, 1 to 3 percent 1.3 20.2% slopes Totals for Area of Interest 6.3 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or 11 Custom Soil Resource Report landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 12 Custom Soil Resource Report Larimer County Area, Colorado 3—Altvan-Satanta loams, 0 to 3 percent slopes Map Unit Setting National map unit symbol: jpw2 Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Altvan and similar soils:45 percent Satanta and similar soils: 30 percent Minor components:25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform:Terraces, benches Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 -0 to 10 inches: loam H2- 10 to 18 inches: clay loam H3- 18 to 30 inches: loam H4 -30 to 60 inches: gravelly sand Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 10 percent Available water supply, 0 to 60 inches: Low(about 5.4 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No 13 Custom Soil Resource Report Description of Satanta Setting Landform: Structural benches, terraces Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 -0 to 9 inches: loam H2-9 to 18 inches: loam H3- 18 to 60 inches: loam Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 10 percent Available water supply, 0 to 60 inches: High (about 10.1 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Minor Components Nunn Percent of map unit: 10 percent Ecological site: R067BY002CO- Loamy Plains Hydric soil rating: No Larim Percent of map unit: 10 percent Ecological site: R067BY063CO- Gravel Breaks Hydric soil rating: No Stoneham Percent of map unit: 5 percent Ecological site: R067BY002CO- Loamy Plains Hydric soil rating: No 14 Custom Soil Resource Report 4—Altvan-Satanta loams, 3 to 9 percent slopes Map Unit Setting National map unit symbol: jpwf Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Farmland of statewide importance Map Unit Composition Altvan and similar soils: 55 percent Satanta and similar soils:35 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform:Terraces, benches, fans Landform position (three-dimensional): Side slope, base slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 9 inches: loam H2- 9 to 16 inches: clay loam H3- 16 to 31 inches: loam H4-31 to 60 inches: gravelly sand Properties and qualities Slope: 6 to 9 percent Depth to restrictive feature: More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 10 percent Available water supply, 0 to 60 inches: Low(about 5.5 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: R067BY008CO - Loamy Slopes 15 Custom Soil Resource Report Hydric soil rating: No Description of Satanta Setting Landform:Terraces, structural benches Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 -0 to 9 inches: loam H2-9 to 14 inches: loam H3- 14 to 60 inches: loam Properties and qualities Slope: 3 to 6 percent Depth to restrictive feature: More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 10 percent Available water supply, 0 to 60 inches: High (about 10.1 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Minor Components Nunn Percent of map unit: 6 percent Ecological site: R067BY002CO- Loamy Plains Hydric soil rating: No Larimer Percent of map unit:4 percent Ecological site: R067BY002CO- Loamy Plains Hydric soil rating: No 16 Custom Soil Resource Report 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlpl Elevation: 3,900 to 5,840 feet Mean annual precipitation: 13 to 17 inches Mean annual air temperature: 50 to 54 degrees F Frost-free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform:Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 9 inches: clay loam Bt-9 to 13 inches: clay loam Btk- 13 to 25 inches: clay loam Bk1 -25 to 38 inches: clay loam Bk2-38 to 80 inches: clay loam Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water(Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 7 percent Maximum salinity: Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum: 0.5 Available water supply, 0 to 60 inches: High (about 9.9 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e 17 Custom Soil Resource Report Hydrologic Soil Group: C Ecological site: R067BY042CO - Clayey Plains Hydric soil rating: No Minor Components Heldt Percent of map unit: 10 percent Landform:Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY042CO- Clayey Plains Hydric soil rating: No Satanta Percent of map unit: 5 percent Landform:Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY002CO- Loamy Plains Hydric soil rating: No 18 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal/ nres/detail/national/soils/?cid=nres142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nresl42p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/ home/?cid=nres142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 19 Custom Soil Resource Report United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nres.usda.gov/wps/portal/ nres/detail/soils/scientists/?cid=nres142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/? cid=n res 142 p 2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/lnternet/FSE—DOCUMENTS/nrcsl42p2_052290.pdf 20 SUBSURFACE EXPLORATION REPORT PEDERSEN TOYOTA DEALERSHIP—ADDITION &RENOVATION 4455 SOUTH COLLEGE AVENUE FORT COLLINS, COLORADO EEC PROJECT NO. 1142002 Prepared for: Heath Construction PO Drawer H 141 Racquette Drive Fort Collins, Colorado 80522 Attn: Mr. Rodney Rogers (rodne�rogersgheathconstruction.com) Prepared by: Earth Engineering Consultants, LLC 4396 Greenfield Drive Windsor, Colorado 80550 February 13, 2014 EARTH ENGINEERING Heath Construction CONSULTANTS, LLC PO Drawer H 141 Racquette Drive Fort Collins, Colorado 80522 Attn: Mr. Rodney Rogers (rdney.rogersgheathconstruction.com) Re: Subsurface Exploration Report Pederson Toyota Dealership—Addition&Renovation Fort Collins, Colorado EEC Project No. 1142002 Mr. Rogers: Enclosed, herewith, are the results of the geotechnical subsurface exploration completed by Earth Engineering Consultants, LLC (EEC) personnel for the proposed expansion at the existing Pedersen Toyota Dealership located at 4455 South College Avenue in Fort Collins, Colorado. For this exploration, seven (7) soil borings were completed at the site to obtain information on existing subsurface conditions. This exploration was completed in general accordance with our proposal dated December 23, 2013. In summary, existing asphalt pavement and aggregate base course was encountered at the surface of each boring and was underlain by apparent fill and/or native sandy lean clay subsoils, granular sands and gravels, and sandstone bedrock. The in-situ cohesive materials were generally classified as sandy lean clay, were soft to medium stiff, and exhibited low swell potential, as measured in laboratory testing at current in-situ moisture contents and dry densities. The granular soils were generally medium dense and the bedrock consisted of highly weathered sandstone that became less weathered and more competent with depth. Groundwater was encountered in four of the borings at depths ranging from approximately fifteen (15) to twenty (20) feet during the initial drilling operations. The borings were backfilled upon completion of the drilling operations; therefore subsequent groundwater measurements were not obtained. Based on materials observed within the site-specific soil borings, and the anticipated foundation loads, we recommend the proposed three-story, slab-on-grade parking garage addition be supported on a grade beam and straight shaft drilled pier/caisson foundation 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 www.earth•engineering.com Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 2 system. We also recommend the interior slab-on-grades by supported on two (2) feet of structural fill. This will require the cohesive soils to be excavated to a depth of two (2) feet below the slab bearing elevation prior to placing and compacting two (2) feet of structural fill. In the pavement areas, the near surface cohesive soils should be scarified, moisture conditioned, and recompacted, as described within the attached report. Care will also be needed at the time of construction to evaluate likely previously placed backfill soils adjacent to the existing building and within the razed building footprints of adjacent storage facility. Geotechnical recommendations concerning design and construction of the proposed site improvements are provided within the attached report. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed report, or if we can be of further service to you in any other way,please do not hesitate to contact us. Very truly yours, Earth gn 'veering Consultants,LLC � Dot C to Ai''••yJ' � t .eJ�Q `�sSlpNAI Ryan M. Laird, P.E. Project Engineer Reviewed by: David A. Richer, P.E. Senior Geotechnical Engineer SUBSURFACE EXPLORATION REPORT PEDERSEN TOYOTA DEALERSHIP—ADDITION &RENOVATION 4455 SOUTH COLLEGE AVENUE FORT COLLINS, COLORADO EEC PROJECT NO. 1142002 February 13, 2014 INTRODUCTION The subsurface exploration for the proposed expansion at the existing Pedersen Toyota Dealership located at 4455 South College Avenue in Fort Collins, Colorado has been completed. For this exploration,seven(7)soil borings were completed to approximate depths of 10 to 35 feet below existing site grades to obtain information on existing subsurface conditions. Individual boring logs and a site diagram indicating the approximate boring locations are provided with this report. We understand this project will include an addition to the existing 2-story building,consisting of a 3-story parking garage, an on-site park area and on-site pavement improvements. The majority of the proposed expansion along the west side of the existing dealership is planned on the grounds of an existing storage yard. We understand the storage facility building will be razed to accommodate the proposed expansion. The first story of the proposed parking garage will include areas for service bays, storage, retail, and a car wash, as shown on the site diagrams provided to us by the project architect. The third story of the proposed parking garage will not be constructed immediately,but will allow for future expansion. At this time, we have had the opportunity to review the 50%schematic design dated October 10,2013,but we do not know the depth of the existing building's foundation system or the wall/column loads of the proposed expansion. Foundation loads for the proposed parking garage are estimated to be moderate/heavy with maximum column loads in the range of 400 kips and maximum wall loads in the range of 4 kl£ Floor loads are expected to be moderate/heavy. Small grade changes are expected to develop final site grades for the expansion project. The purpose of this report is to describe the subsurface conditions encountered in the completed test borings, analyze and evaluate the test data, and provide geotechnical engineering recommendations concerning design and construction of the foundations and support of floor slabs and pavements. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 2 EXPLORATION AND TESTING PROCEDURES The boring locations were established in the field by Earth Engineering Consultants, LLC (EEC) personnel by pacing and estimating angles from identifiable site references. The approximate locations of the test borings are indicated on the attached boring location diagram. The locations of the test borings should be considered accurate only to the degree implied by the methods used to make the field measurements. The test borings were drilled using a truck mounted, CME-55 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch nominal diameter continuous flight augers. Samples of the subsurface materials encountered were obtained using split barrel and California barrel sampling procedures in general accordance with ASTM Specifications D1586 and D3550, respectively. In the split barrel and California barrel sampling procedures, standard sampling spoons are driven into the ground by means of a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the split barrel and California barrel samplers is recorded and is used to estimate the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. In the California barrel sampling procedure, relatively undisturbed samples are obtained in removable brass liners. All samples obtained in the field were sealed and returned to the laboratory for further examination, classification, and testing. Laboratory moisture content tests and visual classifications were completed on each of the recovered samples. In addition,the unconfined strength of appropriate samples was estimated using a calibrated hand penetrometer. Atterberg limits and washed sieve analysis tests were completed to evaluate the quantity and plasticity of fines in the subgrade samples. Swell/consolidation tests were completed on selected samples to evaluate the potential for the subgrade and foundation bearing materials to change volume with variation in moisture and load. Results of the outlined tests are indicated on the attached boring logs and summary sheets. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 3 As part of the testing program, all samples were examined in the laboratory and classified in accordance with the attached General Notes and the Unified Soil Classification System,based on the soil's texture and plasticity. The estimated group symbol for the Unified Soil Classification System is indicated on the boring logs and a brief description of that classification system is included with this report. SITE AND SUBSURFACE CONDITIONS The existing dealership is located at 4455 South College Avenue in Fort Collins, Colorado. The area for the proposed 3-story parking garage expansion to the west of the existing building is currently a self-storage facility consisting of rows of 1-story units and asphalt pavement, as shown in the attached site photos. An EEC field engineer was on site during drilling to evaluate the subsurface conditions encountered and direct the drilling activities. Borings B-1 through B-6 were completed to obtain subsurface information for the building expansion while boring B-7 was completed to obtain subsurface information for the pavement area on the west. Field logs prepared by EEC site personnel were based on visual and tactual observation of disturbed samples and auger cuttings. The final boring logs included with this report may contain modifications to the field logs based on the results of laboratory testing and evaluation. Based on the results of the field borings and laboratory evaluation, subsurface conditions can be generalized as follows. In summary, approximately 3 inches of existing asphalt pavement and 5 inches of aggregate base course (ABC) were encountered at the surface of the borings. The subsurface soils generally consisted of cohesive soils classified as sandy lean clay with varying amounts of sand underlain by granular sands and gravels. Borings B-4,B-5,and B-6 encountered bedrock at depths of approximately 21, 27, and 17.5 feet, respectively. The cohesive soils were generally soft to medium stiff and showed low swell potential. The granular soils were generally medium dense and contained varying amounts of clay. Bedrock consisted of highly weathered sandstone that transitioned from soft to moderately hard/cemented with depth.The bedrock formation was weathered nearer to the surface and became less weathered and more competent with depth, exhibiting moderate to high load bearing capabilities. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 4 The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil and rock types. In-situ, the transition of materials may be gradual and indistinct. GROUNDWATER CONDITIONS Observations were made while drilling and after completion of the borings, to detect the presence and depth to hydrostatic groundwater. At the time of our field exploration, groundwater was encountered in four of the borings at depths ranging from approximately 15 to 20.5 feet below existing site grades. The borings were backfilled upon completion of the drilling operations; subsequent groundwater measurements were not obtained. Fluctuations in groundwater levels can occur over time depending on variations in hydrologic conditions, and other conditions not apparent at the time of this report. Monitoring in cased borings,sealed from the influence of surface infiltration,would be required to more accurately evaluate groundwater levels and fluctuations in the groundwater levels over time. Zones of perched and/or trapped groundwater may occur at times in the subsurface soils overlying bedrock,on top of the bedrock surface or within permeable fractures in the bedrock materials. The location and amount of perched water is dependent upon several factors, including hydrologic conditions,type of site development,irrigation demands on or adjacent to the site, and seasonal and weather conditions. The observations provided in this report represent groundwater conditions at the time of the field exploration, and may not be indicative of other times, or at other locations. ANALYSIS AND RECOMMENDATIONS Swell—Consolidation Test Results The swell-consolidation test is performed to evaluate the swell or collapse potential of soils to help determine foundation, floor slab and pavement design criteria. In this test, relatively undisturbed samples obtained directly from the California sampler are placed in a laboratory apparatus and inundated with water under a predetermined load. The swell-index is the resulting Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 5 amount of swell or collapse after the inundation period expressed as a percent of the sample's preload/initial thickness. After the inundation period,additional incremental loads are applied to evaluate the swell pressure and/or consolidation. For this assessment, we conducted seven (7) swell-consolidation tests on relatively undisturbed soil samples obtained at various intervals/depths and loading schemes throughout the site. The swell index values for the in-situ soil samples analyzed revealed generally low swell characteristics and a slightly tendency to consolidate with increased loads as indicated on the attached swell test summaries. The following table summarizes the swell-consolidation laboratory test results for samples obtained during our field explorations for the subject site. Swell Consolidation Test Results Boring Depth, Material Type In-Situ Dry Inundation Swell No. ft. Moisture Density, Pressure, Index,% Content,% PCF psf W-) B-1 4.0 Red Sandy LEAN CLAY(CL) 15.4 109.7 500 (-)0.2% B-2 4.0 Reddish Brown Sandy LEAN CLAY(CL) 19.1 106.8 500 (-)0.4% B-3 9.0 Red Clayey SAND(SC) 13.3 104.6 1000 (-)0.2% B-4 4.0 Red Sandy LEAN CLAY(CL) 12.0 113.1 500 (-)0.4% B-5 4.0 Red Clayey SAND(SC) 12.6 119.3 500 (-)0.1% B-6 9.0 Brown Sandy LEAN CLAY(CL) 12.4 115.2 1000 (-)0.2% B-7 2.0 Red Clayey SAND(SC) 18.1 110.6 150 (-)0.2% Colorado Association of Geotechnical Engineers (CAGE) uses the following information to provide uniformity in terminology between geotechnical engineers to provide a relative correlation of slab performance risk to measured swell. "The representative percent swell values are not necessarily measured values; rather,they are a judgment of the swell of the soil and/or bedrock profile likely to influence slab performance." Geotechnical engineers use this information to also evaluate the swell potential risks for foundation performance based on the risk categories. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 6 Recommended Representative Swell Potential Descriptions and Corresponding Slab Performance Risk Categories Slab Performance Risk Category Representative Percent Swell Representative Percent Swell (500 psf Surcharge) (1000 psf Surcharge) Low 0to<3 0<2 Moderate 3 to<5 2 to<4 High 5to<8 4to<6 Very High >8 >6 Based on the laboratory test results,the in-situ samples analyzed for this project were within the low range. Site Preparation The existing one-story self-storage structures, which are located to the west of the existing building and the associated foundations, we assume will be demolished and removed. In addition, the existing pavement, vegetation including tree root growth from the existing deciduous trees, and topsoil should be removed from the parking garage and pavement improvement areas. After removal of all deleterious materials,as well as completing all cuts and over-excavations,and prior to fill placement and/or site improvements,the exposed soils should be scarified to a minimum depth of 9 inches,adjusted in moisture content to within+/- 2% of standard Proctor optimum moisture content and compacted to at least 95% of the material's standard Proctor maximum dry density as determined in accordance with ASTM Specification D698. Final site grades were not available at the time of this report; however, based on our understanding of the proposed development,we expect small fill depths may be necessary to achieve design grades in the improvement areas. Fill soils required for developing the pavement area subgrades, after the initial zone has been moisture conditioned/stabilized, should consist of approved,low-volume-change materials,which are free from organic matter and debris. Based on the testing completed, it appears the on-site cohesive type materials could be used as general site fill below the pavement area subgrades provided adequate moisture treatment and compaction procedures are followed. Those procedures would include placement in loose lifts not to exceed 9 inches thick,adjustment in moisture content to+/-2%o Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 7 of optimum moisture content for cohesive type soils, and compaction to at least 95% of the materials maximum dry density as determined in accordance with ASTM Specification D698, the standard Proctor procedure. If the site's existing cohesive fill subsoils are used as general site fill,care will be needed to maintain the recommended moisture content prior to and during construction of overlying improvements. Care will be needed after preparation of the subgrades to avoid disturbing the subgrade materials. Positive drainage should be developed away from site structures and pavements to avoid wetting of subgrade materials. Subgrade materials becoming wet subsequent to construction of the site improvements can result in unacceptable performance. Foundation System Based on the subsurface conditions observed in the test borings and on the anticipated foundation loads,we recommend supporting the proposed building addition/parking garage on a grade beam and straight shaft drilled pier/caisson foundation system extending into the underlying bedrock formation. Particular attention will be required in the construction of the drilled piers due to the depth of bedrock and presence of groundwater. For axial compression loads,the drilled piers could be designed using a maximum end bearing pressure of 40,000 pounds per square foot(psf), along with a skin-friction of 4,000 psf for the portion of the pier extended into the harder underlying bedrock formation. Straight shaft piers should be drilled a minimum of 8 feet into competent or harder bedrock. Lower values may be appropriate for pier "groupings" depending on the pier diameters and spacing. Pier groups should be evaluated individually. To satisfy forces in the horizontal direction, piers may be designed for lateral loads using a modulus of 50 tons per cubic foot(tcf)for the portion of the pier in native cohesive soils,75 tcf for native granular materials or engineered fill,and 400 tcf in bedrock for a pier diameter of 12 inches. The coefficient of subgrade reaction for varying pier diameters is as follows: Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 8 Coefficient of Subgrade Reaction(tons/ft) Pier Diameter(inches) Engineered Fill or Cohesive Soils Bedrock Granular Soils 18 33 50 267 24 25 38 200 30 20 1 30 160 36 17 125 1133 When the lateral capacity of drilled piers is evaluated by the L-Pile (COM 624) computer program,we recommend that internally generated load-deformation(P-Y)curves be used. The following parameters may be used for the design of laterally loaded piers, using the L-Pile (COM 624) computer program: 1[- Parameters Native Granular Soils or On-Site Overburden Bedrock Structural Fill Cohesive Soils Unit Weight of Soil(pcf) 130(i) 115(') 125(') Cohesion(psf) 0 200 5000 Angle of Internal Friction 0(degrees) 35 25 20 Strain Corresponding to '/z Max. Principal --- 0.02 0.015 Stress Difference.50 *Notes: 1) Reduce by 64 PCF below the water table Drilling caissons to design depth should be possible with conventional heavy-duty single flight power augers equipped with rock teeth on the majority of the site. However, areas of well- cemented sandstone bedrock lenses may be encountered throughout the site at various depths where specialized drilling equipment and/or rock excavating equipment may be required. Varying zones of cobbles may also be encountered in the granular soils above the bedrock. Excavation penetrating the well-cemented sandstone bedrock may require the use of specialized heavy-duty equipment,together with rock augers and/or core barrels. Consideration should be given to obtaining a unit price for difficult caisson excavation in the contract documents for the project. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 9 Due to the presence of granular soils and groundwater at approximate depths ranging from 10 to 20 feet below current site grades in the parking garage area, maintaining open shafts may be difficult without stabilizing measures. Groundwater was encountered at approximate depths of 15 to 20.5 feet below site grades; we expect temporary casing will be required to adequately/properly drill and clean piers prior to concrete placement. Difficulty can be encountered in "sealing" temporary casing into the surface of the sandstone bedrock. Groundwater should be removed from each drilled pier hole prior to concrete placement. Pier concrete should be placed immediately after completion of drilling and cleaning. A maximum 3-inch depth of groundwater is acceptable in each drilled pier prior to concrete placement. If pier concrete cannot be placed in dry conditions,a tremie pipe should be used for concrete placement. Due to potential sloughing and raveling,foundation concrete quantities may exceed calculated geometric volumes. Pier concrete with slump in the range of 6 to 8 inches is recommended. Casing used for pier construction should be withdrawn in a slow continuous manner maintaining a sufficient head of concrete to prevent infiltration of water or the creation of voids in pier concrete. Foundation excavations should be observed by the geotechnical engineer. A representative of the geotechnical engineer should inspect the bearing surface and pier configuration. If the soil conditions encountered differ from those presented in this report, supplemental recommendations may be required. We estimate the long-term settlement of drilled pier foundations designed and constructed as outlined above would be less than 1-inch. Floor Slab Design and Construction All existing vegetation and/or topsoil should be removed from beneath the new floor slabs. Additionally,the floor slab subgrades should be over-excavated to allow for at least 2 feet of approved fill below the floor slabs. Soft or loose in-place fill/backfill associated with prior building or utility construction,and any wet and softened or dry and desiccated soils should be removed as encountered. Close evaluation of the existing on-site fill material within the building floor slab areas will be required during the construction phase. A proof roll should be Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 10 performed to evaluate the integrity and/or stability of the material prior to floor slab preparation. After stripping, completing all cuts and removal of any unacceptable materials and prior to placement of any new fill, the in-place soils should be scarified to a minimum depth of 9 inches,adjusted in moisture content and compacted to at least 95%o of maximum dry density as determined in accordance with ASTM Specification D-698,the standard Proctor procedure. The moisture content of the scarified materials should be adjusted to be within the range of ±2% of standard Proctor optimum moisture at the time of compaction. Fill materials required to develop the floor slab subgrade should be an approved imported structural fill,which should consist of inorganic,non-plastic,granular soil containing less than 10 percent material passing the No.200 mesh sieve with a 2-inch maximum particle size. Structural fill procedures would include placement in loose lifts not to exceed 9 inches thick, adjustment in moisture content to+/-2%of optimum moisture content, and compaction to at least 95% of the materials maximum dry density as determined in accordance with ASTM Specification D698, the standard Proctor procedure. After preparation of the subgrades, care should be taken to avoid disturbing the subgrade materials. Materials which are loosened or disturbed by the construction activities will require removal and replacement or reworking in place prior to placement of the overlying floor slabs. Positive drainage should be developed away from the proposed building addition to avoid wetting the subgrade or bearing materials. Subgrade or bearing materials allowed to become wetted subsequent to construction can result in unacceptable performance of the improvements. Seismic Conditions The site soil conditions consist of approximately 20 feet of medium stiff to medium dense overburden soils. For those site conditions,the 2009 International Building Code indicates a Seismic Site Classification of D. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 11 Pavements—Design and Construction Recommendations We expect the site pavements will include areas designated for automobile traffic and areas of heavier truck traffic. For heavy-duty truck areas we are using an assumed equivalent daily load axle (EDLA) rating of 25 and in automobile areas we are using an EDLA of 10. Proofrolling and recompacting the subgrade is recommended immediately prior to placement of the aggregate road base section. Soft or weak areas delineated by the proofrolling operations should be undercut or stabilized in-place to achieve the appropriate subgrade support. It should be noted that the clay subgrade soils are subject to pumping at high moisture contents. It is possible or even likely that pumping of the subgrades will occur during construction and stabilization of the subgrades will be required to allow for placement of the overlying pavements. Based on the subsurface conditions encountered at the site and the laboratory test results,it is recommended the on-site parking areas be designed using an R- value of 10. If instability is observed during proofroll observations,we suggest subgrade stabilization may be considered to mitigate for unstable subgrade soils. The stabilization could include incorporation of Class "C" fly ash to enhance the subgrade integrity by incorporating at least 13 percent by weight, Class "C"fly ash, into the upper 12-inches of subgrade. An alternate would be to use granular import to develop the pavement subgrades after removal of the cohesive subgrade soils. The granular soils would be less likely to show instability and could result in reduced pavement sections. We would be pleased to evaluate planned import materials and provide appropriate pavement design sections placed on the proposed subgrade fill. Pavement design methods are intended to provide structural sections with adequate thickness over a particular subgrade such that wheel loads are reduced to a level the subgrade can support. The support characteristics of the subgrade for pavement design do not account for shrink/swell movements of an expansive clay subgrade or consolidation of a wetted subgrade. Thus, the pavement may be adequate from a structural standpoint, yet still experience cracking and deformation due to shrink/swell related movement of the subgrade. It is, therefore, important to minimize moisture changes in the subgrade to reduce shrink/swell movements. Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 12 Recommended pavement sections are provided below in Table T. The hot bituminous pavement(HBP) could be grading SX(75) or S (75)with PG 58-28 oil. The aggregate base should be Class 5 or Class 6 base. Portland cement concrete should be an exterior pavement mix with a minimum 28-day compressive strength of 4200 psi and should be air entrained. HBP pavements may show rutting and distress in truck loading and turning areas. Concrete pavements should be considered in those areas. TABLE I—RECOMMENDED PAVEMENT SECTIONS Automobile Parking Heavy Duty Areas EDLA 10 25 18-Kip ESAL's 73,000 182,500 Reliability 75% 85% Resilient Modulus—(based on assumed R-Value of 10) 3562 3562 PSI Loss 2.5 2.0 Design Structure Number 2.60 3.25 Composite Section—Option A Hot Bituminous Pavement 4"x 0.44= 1.76 5"x 0.44=2.20 Aggregate Base 8"x 0.11 =0.88 10"x 0.11=1.10 Design Structure Number (2.64) (3.30) Composite Section with Fly Ash-Option B Hot Bituminous Pavement 3-1/2"x 0.44= 1.54 4-1/2"x 0.44= 1.98 Aggregate Base 6"x 0.11 =0.66 8"x 0.11 =0.88 Fly Ash Treated Subgrade 12"x 0.05=.60 12"x 0.05=0.60 Design Structure Number (2.80) (3.46) PCC(Non-reinforced) 5" 7" The recommended pavement sections are minimums and periodic maintenance should be expected. Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation. The location and extent of joints should be based upon the final pavement geometry. Sawed joints should be cut as recommended by PCA guidelines. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. Since the cohesive soils on the site have some shrink/swell potential,pavements could crack in the future primarily because of the volume change of the soils when subjected to an increase in Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 13 moisture content to the subgrade. The cracking, while not desirable, does not necessarily constitute structural failure of the pavement. The collection and diversion of surface drainage away from paved areas is critical to the satisfactory performance of the pavement. Drainage design should provide for the removal of water from paved areas in order to reduce the potential for wetting of the subgrade soils. Long-term pavement performance will be dependent upon several factors, including maintaining subgrade moisture levels and providing for preventive maintenance. The following recommendations should be considered the minimum: • The subgrade and the pavement surface should be adequately sloped to promote proper surface drainage. • Install pavement drainage surrounding areas anticipated for frequent wetting (e.g. garden centers,wash racks) • Install joint sealant and seal cracks immediately, • Seal all landscaped areas in, or adjacent to pavements to minimize or prevent moisture migration to subgrade soils; • Placing compacted,low permeability backfill against the exterior side of curb and gutter; and, • Placing curb,gutter,and/or sidewalk directly on approved proof rolled subgrade soils with the use of base course materials. Preventive maintenance should be planned and provided for through an on-going pavement management program. Preventive maintenance activities are intended to slow the rate of pavement deterioration, and to preserve the pavement investment. Preventive maintenance consists of both localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface sealing). Preventive maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Prior to implementing any maintenance, additional engineering observation is recommended to determine the type and extent of preventive maintenance. Site grading is generally accomplished early in the construction phase. However as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 14 desiccation, or rainfall. As a result, the pavement subgrade may not be suitable for pavement construction and corrective action will be required.The subgrade should be carefully evaluated at the time of pavement construction for signs of disturbance, such as but not limited to drying, or excessive rutting. If disturbance has occurred,pavement subgrade areas should be reworked, moisture conditioned, and properly compacted to the recommendations in this report immediately prior to paving. Please note that if during or after placement of the stabilization or initial lift of pavement, the area is observed to be yielding under vehicle traffic or construction equipment, it is recommended that EEC be contacted for additional alternative methods of stabilization, or a change in the pavement section. Other Considerations Positive drainage should be developed away from the structure and pavement areas with a minimum slope of 1 inch per foot for the first 10 feet away from the improvements in landscape areas. Care should be taken in planning of landscaping adjacent to the building and parking and drive areas to avoid features which would pond water adjacent to the pavement, foundations or stemwalls. Placement of plants which require irrigation systems or could result in fluctuations of the moisture content of the subgrade material should be avoided adjacent to site improvements. Lawn watering systems should not be placed within 5 feet of the perimeter of the building and parking areas. Spray heads should be designed not to spray water on or immediately adjacent to the structure or site pavements. Roof drains should be designed to discharge at least 5 feet away from the structure and away from the pavement areas. GENERAL COMMENTS The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations,which may occur between borings or across the site. The nature and extent of such variations may not become evident Earth Engineering Consultants,LLC EEC Project No. 1142002 February 13,2014 Page 15 until construction. If variations appear evident, it will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical engineer be retained for testing and observations during earthwork and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of Heath Construction for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty,express or implied,is made. In the event that any changes in the nature,design,or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by the geotechnical engineer. DRILLING AND EXPLORATION DRILLING&SAMPLING SYMBOLS: SS: Split Spoon- 13/8"I.D.,2"O.D.,unless otherwise noted PS: Piston Sample ST: Thin-Walled Tube-2"O.D.,unless otherwise noted WS: Wash Sample R: Ring Barrel Sampler-2.42"I.D.,3"O.D.unless otherwise noted PA: Power Auger FT: Fish Tail Bit HA: Hand Auger RB: Rock Bit DB: Diamond Bit=4",N,B BS: Bulk Sample AS: Auger Sample PM: Pressure Meter HS: Hollow Stem Auger WB: Wash Bore Standard"N Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D.split spoon,except where noted. WATER LEVEL MEASUREMENT SYMBOLS: WL : Water Level WS While Sampling WCL• Wet Cave in WD : While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB : After Boring ACR: After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils,the indicated levels may reflect the location of ground water. In low permeability soils,the accurate determination of ground water levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION DEGREE OF WEATHERING: Soil Classification is based on the Unified Soil Classification Slight Slight decomposition of parent material on system and the ASTM Designations D-2488. Coarse Grained joints. May be color change. Soils have move than 50%of their dry weight retained on a#200 Moderate Some decomposition and color change sieve;they are described as: boulders,cobbles,gravel or sand. throughout. Fine Grained Soils have less than 50% of their dry weight High Rock highly decomposed,may be extremely retained on a#200 sieve;they are described as : clays, if they broken. are plastic, and silts if they are slightly plastic or non-plastic. HARDNESS AND DEGREE OF CEMENTATION: Major constituents may be added as modifiers and minor Limestone and Dolomite: constituents may be added according to the relative proportions Hard Di icu t to scratch with knife. based on grain size. In addition to gradation, coarse grained Moderately Can be scratched easily with knife. soils are defined on the basis of their relative in-place density and fine grained soils on the basis of their consistency. Hard Cannot be scratched with fingernail. Example: Lean clay with sand, trace gravel, stiff(CL); silty Soft Can be scratched with fingernail. sand,trace gravel,medium dense(SM). Shale. Siltstone and Cla, sue: CONSISTENCY OF FINE-GRAINED SOILS Hard Can be scratched easily with knife,cannot be scratched with fingernail. Unconfined Compressive Moderately Can be scratched with fingernail. Strength,Qu,psf Consistency Hard Soft Can be easily dented but not molded with < 500 Very Soft fingers. 500- 1,000 Soft Sandstone and Conglomerate: 1,001 - 2,000 Medium Well Capable of scratching a knife blade. 2,001 - 4,000 Stiff Cemented 4,001 - 8,000 Very Stiff Cemented Can be scratched with knife. 8,001 - 16,000 Very Hard Poorly Can be broken apart easily with fingers. RELATIVE DENSITY OF COARSE-GRAINED SOILS: Cemented N-Blows/ft Relative Density 0-3 Very Loose 4-9 Loose 10-29 Medium Dense 30-49 Dense 50-80 Very Dense 80+ Extremely Dense PHYSICAL PROPERTIES OF BEDROCK UNI= SOIL CLASSIFICATION SYSTEM Soil Classification Group Group Name Criteria for Assigning Group Symbols and Group names Using Laboratory Tests Symbol Coarse—Grained Gravels more than Clean Grovels Less Sails more than 50% of coarse than 5% fines Cu>4 and «c<3r GIN Well—graded gravel` 50% retained on fraction retained No. 200 sieve on No. 4 sieve CU<4 and/or 1>Cc>3r GP Poorly—graded gravel` Gravels with Fines Fines classify as ML or MH GM Silty gravel, G,H more than 12% fines Fines classify as CL or CH GC Clayey Gravel°•G•" Sands 50% or Clean Sands Less Cu>§ and 1<G.G< SW Well—graded sand) more coarse than 5% Fines fraction passes Cu<6 and/or 1>Cc>3° SP Poorly—graded sand' No. 4 sieve Sands with Fines Fines classify as ML or MH SM Silty sand°'"'' more than 12% fines Fines classify as CL or CH SC Clayey sand e Fine—Groined Silts and Clays inorganic PI>7 and plots on or above "A'Line' CL Lean clay'•`•" Soils 50% or Liquid Limit less more passes the than 50 PI<4 or plats. below "A"Line' ML Silt R4° No. 200 sieve organic, Liquid Limit — oven dried <OJS OL Organic clay KuMN Liquid Limit — not dried Organic silt'"m Silts and Clays inorganic PI plots on or above "A"Line CH Fat clay e11 Liquid Limit 50 or more PI plots below "A"Line MH Elastic Silt`'"' organic Liquid Limit — oven dried Organic cloy°i'"'P <0.75 OH Liquid Limit — not dried Organic silt"' ' Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat ''Bused on Nt m"tenvl pvssing the 3-in, (75- ° (D",) _dt all contains 15 !0 299if1us No. 200, add Cu=D /D Cc= '�-` mm) slew °° with sand' or "with growl, whichever Is °If Field sample con faired cobbles or boulders, pnsd.mirunt or both, odd "with dabbles or boulders, or bath" Llf sal contains 2 30" plus No. 200 to group namt predaminvnUy sand, odd "sandy to group aGmvels with 5 tv I= fines required dual °If sa0 contains 215% sand, vdcrwl h-sar "tp name. s dais group name. -If so0 eontolns 2 30% plus No. 200 GW GM well graded revel with silt -If Mee classify os CL-ML, des duel symbol predominantly grovel, add "gravely" to group 9 9 GW-GC well-gm GC-cM, or sC-SM.ded grovel with day IF Rase ore Ic, add"wIth a onic Fines to name. GP-GM peony-graded gr. d with sill organ rg xp124 and plots on or "bow "A" line GP-GC vod coded ravel with de. group name op15pl or plats below A" I{lin °Sands with 5 to 12%f Fes require dual If sa0 contains >15%grwel, odd"with grovel" °PI plots on or "bole A" Ilne symbols: 'o group e, opt plots below. "A" {re. SW-SM well-gmded sand with silt If AttML. Iltyerg limits plots shaded ore", sv0 is o SW-50 well-gmded sand with clay -ML, cilty clay. SP-51A poorly graded sand with silt SP-SC peony graded send with cloy °o For aoagOc°ibn of Me-gmincd A. and Ilne-gruhnl seellen of mmee- "Ined mill ` 50 Ev°otbn of W-11n" Halmntd et Fl-I to 1-M5, w� ` then Pl-0.73(LL-20)id then z Al U v2 a2n MH OH • 10 c ML ML aIx OL I' 0 0 10 7a ao <a se. so 70 eo se. 100 110 LIQUID LIMIT (ILL) r 1 i : - - p�0�0 PEDERSEN TOYOTA EXPANSION FORT COLLINS,COLORADO EEC PROJECT No. 1142002 JANUARY 2014 f, EARTH ENGINEERING CONSULTANTS, LL[ r�� •:••!%.�::�Tiddi°ddi'i«`i�!♦'i'i'i'i'�.,: �:�r�;:;,,14�.:s,. r�r -xiX iiiiiii°i�iiiisii♦i`ii4'iiiiiii i-:Ss�:?��:;•s,♦.•:;:�e�,•:;:y: L\\ © ...•«•:Oi'♦••'i'!i'i'Oi'i'i ii'i'i`ira:�}:•:;:•:•.':4 s t:$;::4� >. ..1 :1.111♦1••1♦ ♦•. • ♦ ........ .... .. :•.«�i««««O'Oi'i i�W. •'i••i'i'i ii`i'i•�•=v:was•': O:•00:•::❖: :�:sS;::��:•�`rf::3i .i1 i iiY c-�_�•♦♦1♦♦_�•_.:::::..:..:♦i�'::C.:.Q.1•.••.O•':-g «« `:'i a i i<�ii« •i •Oi?i�i 0:.'.7.':::'::!i i:•:;:•:•:•':v'<e♦��•'•<••'1 �•'� .rJ�'i♦i i.•�!i•<• i ..........•iYi'i r i i i•�!J♦•i i� . .. 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Legend HIM: rK4111 ■u■ �GApproximate Boring Locations OlSite Photos lPhotos taken in approximate location, d1rection ofarl-owJ IFigure 2: Boring Location Diagram Pedersen Toyota - Remodel Expansion Fort Collins, ProjectNo I rth EEC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B-1 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 1 WATER DEPTH FOREMAN: DG START DATE 1/24/2014 WHILE DRILLING 20.5' AUGER TYPE: 4"CFA FINISH DATE 1/24/2014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5035 24 HOUR N/A SOIL DESCRIPTION D N QU MC DD -LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-3" BASE-5.5" 1 SANDY LEAN CLAY(CL) 2 red _ medium stiff to stiff 3 with traces of gavel _ 4 Fc—s 5 5 1 6000 15.4 107.4 1 31 1 18 54.8 1 <500 psf None 6 7 8 9 __ sand seam ESS 10 11 6.5 11 gravel seam _ 12 13 14 CLAYEY GRAVEL(GC) CS 15 21 1000 4.3 121.9 red _ medium dense 16 17 18 19 brown/red SS 20 21 6000 14.4 BOTTOM OF BORING DEPTH 2O.5' 21 22 23 24 25 Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B-2 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 1 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING 15.0' AUGER TYPE: 4"CFA FINISH DATE 1/2412014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5031 24 HOUR N/A SOIL DESCRIPTION D N QU MC DD -LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-3" BASE-3" 1 SANDY LEAN CLAY(CL) 2 dark brown _ stiff to very stiff 3 with calcareous deposits _ 4 Fc—s 5 10 1 9000 19.1 107.3 1 1 <500 PSf None 6 7 8 9 CLAYEY SAND&GRAVELS(SC/GC) SS 10 16 6000 7.0 red/brown _ medium dense 11 12 13 14 SAND&GRAVEL(SP/GP) CS 15 31 9000 6.6 119.7 31.4 dense to medium dense with clayey zones 16 17 18 19 20 SS _ 14 5000 21.1 1)See Note 1 below 21 BOTTOM OF BORING DEPTH 21.0' 22 1)Encountered 3 inches of sandy LEAN CLAY with brown/gray/rust interbedded layers 23 24 25 Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B.3 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 1 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING None AUGER TYPE: 4"CFA FINISH DATE 1/2412014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5035 24 HOUR N/A SOIL DESCRIPTION D N QU MC DD -LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-2" BASE-7" 1 SANDY LEAN CLAY(CL) 2 brown/red _ medium stiff to stiff CS 3 9 3000 21.6 101.0 mottled _ 4 brown/red ESS 5 6 4000 14.1 6 7 8 SAND&GRAVEL(SP/GP) 9 red _ %@ 1000 Psf medium dense to dense CS 10 10 2000 13.3 111.7 s1000 psf None 11 12 13 14 __ ESS 15 19 5.5 16 17 18 19 CS 20 30 5.3 134.7 BOTTOM OF BORING DEPTH 2O.0' 21 22 23 24 25 Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B-4 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 1 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING 19.5' AUGER TYPE: 4"CFA FINISH DATE 1/2412014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5035 24 HOUR N/A SOIL DESCRIPTION D N QU MC DD -LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-3" BASE-13" 1 SANDY LEAN CLAY(CL) 2 red _ stiff 3 4 Fc_s 5 14 1 8000 12.0 111.E 1 1 1 <500 psf None 6 7 8 9 SAND&GRAVEL(SP/GP) SS 10 22 5.6 red _ medium dense 11 12 13 14 SILTY SAND(SM) CS 15 9 8000 10.5 red _ loose 16 17 18 19 GRAVEL _ medium dense SS 20 27 1000 10.9 112.9 with clay seams 21 BEDROCK:SANDSTONE weathered/poorly cemented to cemented CS 22 50/6" 5000 17.2 107.7 BOTTOM OF BORING DEPTH 22.0' 23 24 25 Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B 5 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 2 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING 17.0' AUGER TYPE: 4"CFA FINISH DATE 1/2412014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5035 24 HOUR N/A SOIL DESCRIPTION D N QU MC DD -LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-3" BASE-5" 1 SANDY LEAN CLAY/CLAYEY SAND(CL/SC) 2 red _ very stiff to stiff/medium dense 3 4 Fc_s 5 11 1 5000 12.6 114.1 1 29 1 16 36.6 1 <500 Psf None 6 7 8 9 __ sand seams ESS 10 11 3000 13.7 11 12 13 14 SANDY LEAN CLAY(CL) CS 15 8 4000 22.2 101.5 stiff with gravel seams 16 17 18 19 CLAYEY SAND(SC) SS 20 6 20.8 40.2 loose to medium dense 21 22 23 CLAYEY SAND(SC) medium dense 24 decomposed,poorly cemented sandstone at 25' _ CS 25 28 5000 21.7 116.4 Continued on Sheet 2 of 2 Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS, COLORADO PROJECT NO: 1142002 LOG OF BORING B-5 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 2 OF 2 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING 17.0' AUGER TYPE: 4"CFA FINISH DATE 1/2412014 AFTER DRILLING NIA SPT HAMMER: AUTOMATIC SURFACE ELEV 5035 24 HOUR NIA SOIL DESCRIPTION D N QU MC DD A-LIMITS -200 SWELL TYPE (FEET) (BLOWS/FT) (PSI) (%) (PCF) LL PI I%) PRESSURE %@ 500 PSF Continued from Sheet 1 of 2 26 27 BEDROCK:SANDSTONE 28 poorly cemented to cemented with increased depths _ 29 Ess 30 50/4" 4000 17.2 __ 31 32 33 34 brown/rust CS 35 Bounce BOTTOM OF BORING DEPTH 35.0' 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B-6 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 1 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING None AUGER TYPE: 4"CFA FINISH DATE 1/24/2014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5035.5 24 HOUR N/A SOIL DESCRIPTION D N QU MC DO A•LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-3" BASE-6.5" 1 SANDY LEAN CLAY(CL) 2 red _ stiff to very stiff CS 3 8 3000 10.9 118.8 with traces of gravel _ 4 Ess 5 9 6000 16.3 6 7 8 9 1000 psf brown Fc_s 10 11 7000 12.4 118.4 <1000 psf None 11 12 13 14 SILTY SAND(SM) SS 15 50 15.7 dense _ brown/grey/rust 16 poorly cemented sandstone/siltstone _ 17 18 BEDROCK:SANDSTONE AND SILTSTONE poorly cemented to cemented with depth 19 brown/grey/rust Fc—s 20 Bounce 4000 8.2 21 22 23 24 SS 25 50/1" 5000 13.3 BOTTOM OF BORING DEPTH 25.5' _ _ Earth Engineering Consultants, LLC PEDERSEN TOYOTA-REMODEL EXPANSION FORT COLLINS,COLORADO PROJECT NO: 1142002 LOG OF BORING B-7 DATE: JANUARY 2014 RIG TYPE: CME55 SHEET 1 OF 1 WATER DEPTH FOREMAN: DG START DATE 1/2412014 WHILE DRILLING None AUGER TYPE: 4"CFA FINISH DATE 1/2412014 AFTER DRILLING N/A SPT HAMMER: AUTOMATIC SURFACE ELEV 5035 24 HOUR N/A SOIL DESCRIPTION D N QU MC DD -LIMITS -200 SWELL TYPE (FEET) (BLOWSIFT) (PSF) (%) (PCE) LL PI (%) PRESSURE %@.500 PSF ASPHALT-3" BASE-5.5" 1 SANDY LEAN CLAY/CLAYEY SAND(CL/SC) 2 red %@ 150 Psf medium stiff to stiff/medium dense C _S 3 8 4000 18.1 110.5 25 11 39.8 <150 psf None 4 ESS 5 5 5000 10.4 6 SAND(SP) 7 medium dense with fine gravel 8 9 __ FSS 10 15 5.5 BOTTOM OF BORING DEPTH 10.5' 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Earth Engineering Consultants, LLC SWELL / CONSOLIDATION TEST RESULTS Material Description: Red Sandy LEAN CLAY(CL) Sample Location: Boring 1, Sample 1, Depth 4' Liquid Limit: 31 IPlasticity Index: 18 % Passing#200: 54.8% Beginning Moisture: 15.4% JDry Density: 109.7 pcf JEnding Moisture: 16.9% Swell Pressure: <500 psf %Swell @ 500: None 10.0 8.0 6.0 a� 3 e7 4.0 2.0 c m E d g 0.0 c m m (L -2.0 Water Added 0 -4.0 0 U) o -6.0 U -8.0 -10.0 0.01 0.1 1 10 Load(TSF) Project: Pedersen Toyota- Remodel Expansion Location: Fort Collins, Colorado Project#: 1142002 EEC Date: February 2014 6bL SWELL / CONSOLIDATION TEST RESULTS Material Description: Reddish Brown Sandy LEAN CLAY(CL) Sample Location: Boring 2, Sample 1, Depth 4' Liquid Limit: -- IPlasticity Index: -- % Passing#200: -- Beginning Moisture: 19.1% JDry Density: 106.8 pcf JEnding Moisture: 18.3% Swell Pressure: <500 psf %Swell @ 500: None 10.0 8.0 6.0 a� 3 U) 4.0 2.0 c m E d 0.0 c m L d a Water Added -2.0 -4.0 0 0 Cn a -6.0 U -8.0 -10.0 0.01 0.1 10 Load(TSF) 1 Project: Pedersen Toyota- Remodel Expansion Location: Fort Collins, Colorado Project#: 1142002 Date: February 2014 SWELL / CONSOLIDATION TEST RESULTS Material Description: Red Clayey Sand (SC) Sample Location: Boring 3, Sample 3, Depth 9' Liquid Limit: -- IPlasticity Index: -- % Passing#200: -- Beginning Moisture: 13.3% JDry Density: 104.6 pcf JEnding Moisture: 21.2% Swell Pressure: <1000 psf %Swell @ 1000: None 10.0 8.0 6.0 a� 3 U) 4.0 2.0 c m E d 0.0 c m L d a -2.0 Water Added -4.0 0 0 Cn a -6.0 U -8.0 -10.0 0.01 0.1 10 Load(TSF) 1 Project: Pedersen Toyota- Remodel Expansion Location: Fort Collins, Colorado Project#: 1142002 Date: February 2014 SWELL / CONSOLIDATION TEST RESULTS Material Description: Red Sandy LEAN CLAY(CL) Sample Location: Boring 4, Sample 1, Depth 4' Liquid Limit: -- IPlasticity Index: -- % Passing#200: -- Beginning Moisture: 12.0% JDry Density: 113.1 pcf JEnding Moisture: 15.6% Swell Pressure: <500 psf %Swell @ 500: None 10.0 8.0 6.0 a� 3 U) 4.0 2.0 c m E d 0.0 c m L d a -2.0 Water Added -4.0 0 0 Cn a -6.0 U -8.0 -10.0 0.01 0.1 10 Load(TSF) 1 Project: Pedersen Toyota- Remodel Expansion Location: Fort Collins, Colorado Project#: 1142002 Date: February 2014 SWELL / CONSOLIDATION TEST RESULTS Material Description: Red Clayey SAND (SC) Sample Location: Boring 5, Sample 1, Depth 4' Liquid Limit: 29 IPlasticity Index: 16 % Passing#200: 36.6% Beginning Moisture: 12.6% JDry Density: 119.3 pcf JEnding Moisture: 15.8% Swell Pressure: <500 psf %Swell @ 500: None 10.0 8.0 6.0 a� 3 U) 4.0 2.0 c m E d 0.0 c m L d a Water Added -2.0 -4.0 0 0 Cn a -6.0 U -8.0 -10.0 0.01 0.1 10 Load(TSF) 1 Project: Pedersen Toyota- Remodel Expansion Location: Fort Collins, Colorado Project#: 1142002 Date: February 2014 SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Sandy LEAN CLAY(CL) Sample Location: Boring 6, Sample 3, Depth 9' Liquid Limit: -- IPlasticity Index: -- % Passing#200: -- Beginning Moisture: 12.4% JDry Density: 115.2 pcf JEnding Moisture: 15.7% Swell Pressure: <1000 psf %Swell @ 1000: None 4.0 2.0 0.0 a, -2.0 3 U) Water Added -4.0 -6.0 m E d -8.0 c m L a -10.0 -12.0 O 14.0 0 Cn C O U -16.0 -18.0 -20.0 0.01 0.1 10 Load(TSF) 1 Project: Pedersen Toyota- Remodel ExpansionPM NON Location: Fort Collins, Colorado Project#: 1142002 :�E E C Date: February 2014 SWELL / CONSOLIDATION TEST RESULTS Material Description: Red Clayey Sand (SC) Sample Location: Boring 7, Sample 1, Depth 2' Liquid Limit: 25 1 Plasticity Index: 11 % Passing#200: 39.8% Beginning Moisture: 18.1% JDry Density: 110.6 pcf JEnding Moisture: 14.9% Swell Pressure: <500 psf %Swell @ 150: None 10.0 8.0 6.0 a� 3 U) 4.0 2.0 c m E d 0.0 c m L a Water Added -2.0 -4.0 0 0 Cn a -6.0 U -8.0 -10.0 0.01 0.1 10 Load(TSF) 1 Project: Pedersen Toyota- Remodel Expansion Location: Fort Collins, Colorado Project#: 1142002 Date: February 2014 EARTH ENGINEERING CONSULTANTS, LLC SUMMARY OF LABORATORY TEST RESULTS Sieve Analysis(AASHTO T 11&T 27/ASTM C 117&C 136) Sieve Size Percent Passing 3/8" (9.5 mm) 100 No.4 (4.75 mm) 95 No.8 (2.36 mm) 85 No.10 (2 mm) 82 No.16 (1.18 mm) 72 No.30 (0.6 mm) 60 No.40 (0.425 ram) 54 No.50 (0.3 mm) 48 No.100 (0.15 mm) 39 No.200 (0.075 mm) 31.4 Project: Pedersen Toyota-Remodel Expansion-4455 S.College Avenue Location: Fort Collins,Colorado Project No: 1142002 Sample ID: B-2,S-3, 14 Sample Desc.: Sand&Gravel(SP/GP) 400 Date: February 2014 EARTH ENGINEERING CONSULTANTS, LLC Summary of Washed Sieve Analysis Tests (ASTM C117 & C136) Standard Sieve Size 5" 3" 2" 1" 1/2" No.4 No.10 No.30 No.50 No.200 6" 4" 2.5" 1.5" 3/4" 3/8" No.8 No.16 No.40 No.100 100 90 80 70 60 0 50 40 N c LL 30 20 10 0 1000 100 10 1 0.1 0.01 Grain Size (mm) Gravel Sand Cobble Silt or Clay Coarse Fine Coarse Medium Fine Project: Pedersen Toyota-Remodel Expansion-4455 S. College Avenue Location: Fort Collins,Colorado a Project No: 1142002 4 Sample ID: B-2,S-3, 14 i. Sample Desc.: Sand&Gravel(SP/GP) Date: February 2014 EARTH ENGINEERING CONSULTANTS, LLC SUMMARY OF LABORATORY TEST RESULTS Sieve Analysis(AASHTO T 11&T 27/ASTM C 117&C 136) Sieve Size Percent Passing 3/8" (9.5 mm) 100 No.4 (4.75 mm) 98 No.8 (2.36 mm) 94 No.10 (2 mm) 93 No.16 (1.18 mm) 89 No.30 (0.6 mm) 81 No.40 (0.425 ram) 76 No.50 (0.3 mm) 70 No.100 (0.15 mm) 57 No.200 (0.075 mm) 40.2 Project: Pedersen Toyota-Remodel Expansion-4455 S.College Avenue Location: Fort Collins,Colorado Project No: 1142002 Sample ID: B-5,S-4, 19 Sample Desc.: Clayey SAND(SC) 400 Date: February 2014 EARTH ENGINEERING CONSULTANTS, LLC Summary of Washed Sieve Analysis Tests (ASTM C117 & C136) Standard Sieve Size 5" 3" 2" 1" 1/2" No.4 No.10 No.30 No.50 No.200 6" 4" 2.5" 1.5" 3/4" 3/8" No.8 No.16 No.40 No.100 100 90 80 70 60 0 50 40 L 30 20 10 0 1000 100 10 1 0.1 0.01 Grain Size (mm) Gravel Sand Cobble Silt or Clay Coarse Fine Coarse Medium Fine Project: Pedersen Toyota-Remodel Expansion-4455 S. College Avenue Location: Fort Collins,Colorado a Project No: 1142002 4 Sample ID: B-5,S-4, 19 i. Sample Desc.: Clayey SAND(SC) Date: February 2014 Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix B- Erosion Control Plans Kimley>>) Horn w Q 0 r m LEGEND ' I I 4301 S.COLLEGE AVE. I PROPERTY LINE LOT 2,FOSSIL CREEK COMMERCIAL 20'ACCESS EASEMENT 6'UTILITY EASEMENT PLAZA 1ST REPLAT / I EXISTING EASEMENT REC. NO.297855 REC.NO.278737 / LOD PROPOSED LIMITS OF DISTURBANCE z O cF CF PROPOSED CONSTRUCTION FENCE w z PROPOSED SEDIMENT CONTROL LOG 1 \ M�`� s Lu __ _ I x x TP PROPOSED TREE PROTECTION FENCE � � 'I•� :e _h�,r�h�v� �. ��'�. 0 s�3q W N co c, — -- --.cn oa °a °° � i' j M O 0DG 0 ® � z o w o�0h c; SSA STABILIZED STAGING AREA '�•� w - J �n --� O 4J C O \ LU r 1— LU �� I O . . Tp r X TP w TP Q SP TEMPORARY SOIL STOCKPILE z • W W VTC VEHICLE TRACKING PAD gQr- S� �F SF w o CF SFV TP TP �. TP Tp CF z TP . .W. W Z0. TP .�.TP.,. 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Lu \ \ \ ° G • ---• • • . • • • • • • • • • • • • oil I Q 3. NO TRACKING OF MUD OR DEBRIS PERMITTED ON SURROUNDING o \ s '� GW G ° �',',' ' G O Y ° I PROPERTY OR STREETS. IF TRACKING DOES OCCUR, CONTRACTOR OG� :: W W\ W W . . . . . . . ° G G G G . . . ° 4455 S.COLLEGE AVE. a ° SCL h ¢ SHALL CLEAN IMMEDIATELY. y a G ° ° �. G EXISTING PE BUILDING 4. PROTECT UNDERGROUND TREATMENT SYSTEMS DURING t<` / 'li \ ''` .I" \ ° ° TOYOTA BUILDING 20, 90 SS ' v v GW \. . . . . . . G 19,792 SF INSTALLATION. �� TPLu ° G aG., ss I SITE DATA: U Q aJ �� <, G.. \. . . . . . . ° ° a . . . . . . . . . � G . . . ° �. ° w. ° AREA OF DISTURBANCE: Vi ^ . .w ° 1 ONSITE IMPROVEMENTS: ±4.77 ACRES Z LL W .� OFFSITE IMPROVEMENTS: ±0.27 ACRES o O \ 1 ° G G ff ° TP TOTAL ±5.04 ACRES J z x W \ . G W W ° � I. . . . . J \ \ G 0 4 o ' y TP W G° . . . . ° G ° ° ° r! I 0 J �/ W \ Wv . . . . . . . . . ° . . . . . . . . . . . . . . . . . . . . . w a o \ . . . . . . . . . . . . . . . . . . . . . . . I EARTHWORK: O U L.L c P. G G . . . . . . ° CUT 10451 CY CY Z FILL 2726 CY CY ° �. . . . . . . ° a ° NET 7725 CY CUT O � 0 G / CF I 0 4455 S.MASON ST. ° .. °4? G � .• G •° IP 0 LOT 1,PEDERSEN AUTO PLAZA W W W° W G G . . . . . G '� U U SUBDIVISION 2ND FILING • • • • • • • • ° ° v G z z ;' W v �. . . . . . . . G . . . . . . . G . . . . . . . . . . . . . . . . . . . . . . . \ . . . . . . . Z Z W \JJ W . . . . . . . . . . . . . . . . . . . . ° O \ -` G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . r a G ° ° Q \�Y EPSE ° ° ° � ) Q I-- O Lu SS I v o8 U��C.NO'56� I G°G ° G . . . . . . . . . . . W \ . .� . . . . . . . . . . . . ,p, . . . . . . . Y. . . . . . . . . . . I � v a W1 . _ � . .�. 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W construction completed AT HARMONT ROAD LOT 1, KENSINGTON COMMONS o P.U.D.3RD FILING o� Vegetative PROJECT NO. CO w Temporary Seeding/Planting Anytime Site will be inactive for more than 30 days 296073000 CD F W Mulcing/Sealant Anytime Site will be inactive for more than 30 days N o SHEET Permanent Seeding/Planting ® -> Know what's b@IOW. ulz W Sod Installation Call before you dig. 0 Rolled Products Anytime Site will be inactive for more than 30 days u C7 .0 O Z Ln Y17 w Q 0 r m LEGEND ' I I 4301 S.COLLEGE AVE. I PROPERTY LINE LOT 2,FOSSIL CREEK COMMERCIAL 20'ACCESS EASEMENT 6'UTILITY EASEMENT PLAZA 1ST REPLAT / I EXISTING EASEMENT REC. 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IF ADJACENT W / I \ {� v _ASPHALT HAS ALSO BE REMOVED,APPLY /� v SS STREET SWEEPING 1W v 1 v v / CONSTRUCTION FENCING WITH ROCK SOCKS DURING INSTALLATION,CONTRACTOR TO T +'• �1 n� AT THE BOTTOM TO LIMIT DEBRIS THAT WILL / PROVIDE TEMPORARY PROTECTION FOR PERMANENT SEEDING AND U o SS W W GET INTO THE EXCAVATED AREA. UNDERGROUND DETENTION. IF ADJACENT PS ' 00 ,; �1 $� / 5035 ASPHALT HAS ALSO BE REMOVED,APPLY \ v 16'RIGHT-OF WAY I O MULCHING o 36 / CONSTRUCTION FENCING WITH ROCK SOCKS REC. NO.88032686 W W o I y W TP W —� — AT THE BOTTOM TO LIMIT DEBRIS THAT WILL EX./PROP. FLOW ARROW 1-- W GET INTO THE EXCAVATED AREA.W W ^ Q z to �W w j D w Apo w \ ow 5036 >% < Q ao VARIABLE WIDTH R.O.W. 0 U W V" W W W W T W V" W 0 o \ \ 9 STATE HIGHWAY 287 z W Q co a Q z SS zip a \ \ �' W W v DRAINAGE EASEMENT 5036 W W W J o (WIDTH VARIES) m REC.NO.565864 / 1 1 2 w . �� \ CF I W . z g \S o S S S 00 0 0 J ~ J � W 8— 5037 W W W 5037 Y � O Y O © \ W � W W \ � 1 o ■ � SOU Q \ �W W W W W W W I CV a v \� w \ w w I N N a O I TP CO O U \z • •.y W �W \ W SSA �� DESIGNED RJP .. .•A .y \ .y .y 4 .y \ TP DRAWN BYBY: ANP \ \ I �., CHECKED BY: EPF w Z \ W\ W , W \ \ z } w NOTES: DATE: 4/16/2025 \ ?: "�, "C Q OfI 1. REFERENCE LANDSCAPE PLANS FOR FINAL CONDITION OF \ �•\,W \ \ W \ \ RS r w = LANDSCAPE AREAS. o W W W W CF W W w = 2. SURFACE ROUGHENING REQUIRED UNTIL AREA IS PAVED OR a, 00_ CF d HARDSCAPED, OR BUILDING FLOOR IS POURED. INSTALL CURB SOCK w �\ �\ •� W W IF, I I-I SP III W �� - J IN PAVED AREAS UNTIL LANDSCAPE OR VEGETATION IS INSTALLED. • W W �N N Z) q 3. NO TRACKING OF MUD OR DEBRIS PERMITTED ON SURROUNDING \ .:: .\ �W W W \ �, BUILDING EXPANSION o s 11,347 SF a Y ° PROPERTY OR STREETS. IF TRACKING DOES OCCUR, CONTRACTOR OG �� \ \ \ RS W I 4455 S.COLLEGE AVE. SCL PEDERSEN TOYOTA I i SHALL CLEAN IMMEDIATELY. A ` "' ,, W W W W 4. PROTECT UNDERGROUND TREATMENT SYSTEMS DURING W SS\ \, \ I BUILDING ��9 O' 44,075 SF TOTAL BUILDING EXPANSION INSTALLATION. z 2 O2 W W W 20,485 SF 0W Q `/�J. BSc W �� TP 1011 SS I SITE DATA: U J ` \ I AREA OF DISTURBANCE: V) o ` `� W \ W W W W W I I ONSITE IMPROVEMENTS: ±4.77 ACRES z J c 6 I x OFFSITE IMPROVEMENTS: ±0.27 ACRES J o O \ f. W W \ pW o I TP TOTAL ±5.04 ACRES Q J z O x O J �of 031° W Sp3 I — EARTHWORK: Lu e \\ \W cr W v�o 6 CUT 10451 CY CY z z W ow� ."'-' I FILL 2726 CY CY \ NET 7725 CY CUT �_ M O J� 1 0 4455 S LL .MASON ST. \ ,�� W W W \ \ \ I / so h CF IP I O 00 LOT 1,PEDERSEN AUTO PLAZA \ ;:r. W \ W \ \ M 'l O SUBDIVISION 2ND FILING ,W W\ W \ 0 1 S� 1 -- z Z) z W Lu --- ---_-- w > O E M I-- z r E PS 1 E 5037 � Q SS \U�Y 586A W I' V J ^^ ' Lu 0 1O 8 REc.NO'5 � 1 1 \ I W vJ V J a I P RS Z .� .� a \ r III c� o O \ 1 W 1 W � \ W LL NORTH 0 J U W \ \ •�9 W 1 W \ W W W RS W \ \ �Vj W W Uj J —j W SCL I GRAPHIC SCALE IN FEET LL 5 o \ ,�: p 0 15 30 60uj rn L— Z o 1 •r� �� RS RS SS N d'� IW W RS RS RS 35 I SCALE: 1" = 30' cwi , W p 5�3� 5� I .' 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Iw construction completed AT HARMONT ROAD LOT 1, KENSINGTON COMMONS o � P.U.D.3RD FILING o� Vegetative PROJECT NO. CO w Temporary Seeding/Planting Anytime Site will be inactive for more than 30 days 296073000 0)F w Mulcing/Sealant Anytime Site will be inactive for more than 30 days N o . Permanent ng/Planting ® SHEET > � below. Ulz Sod Installation Call before you dig. 0 c7i Rolled Products Anytime Site will be inactive for more than 30 days u C7. 1 O z W Q 0 r m LEGEND ' I I 4301 S.COLLEGE AVE. I PROPERTY LINE LOT 2,FOSSIL CREEK COMMERCIAL 20'ACCESS EASEMENT 6'UTILITY EASEMENT PLAZA 1ST REPLAT / I EXISTING EASEMENT REC. 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IF ADJACENT W >- I .v I I _ASPHALT HAS ALSO BE REMOVED,APPLY / v I L 1 I L ASS STREET SWEEPING \ �'. 1W v v v / CONSTRUCTION FENCING WITH ROCK SOCKS DURING INSTALLATION,CONTRACTOR TO v +'• 1 n� AT THE BOTTOM TO LIMIT DEBRIS THAT WILL / PROVIDE TEMPORARY PROTECTION FOR PERMANENT SEEDING AND U o � SS GET INTO THE EXCAVATED AREA. UNDERGROUND DETENTION. IF ADJACENT , '� PS ' �1 $� / 5035 ASPHALT HAS ALSO BE REMOVED,APPLY \ v 16'RIGHT-OF WAY 1 O MULCHING ? o 36 / CONSTRUCTION FENCING WITH ROCK SOCKS REC. NO.88032686 W W o I y W TP W — AT THE BOTTOM TO LIMIT DEBRIS THAT WILL EX./PROP. FLOW ARROW W GET INTO THE EXCAVATED AREA.W W ^ Q TFv v v 1 v v U (n N n \ PS D PS O q w \ `sow PS PS PS 5036 W Vj Q � a \ \ W W W I VARIABLE WIDTH R.O.W. 1 � O O a W W W W W W T W V" W 0 \ \ STATE HIGHWAY 287 Z W Q co -- � 1 PSW QZ � 4, L — SS zJp a \ \ W v DRAINAGE EASEMENT 5036 W J o �a ;, , �\ (WIDTH VARIES) m REC.NO.565864 / 2 CF 1 w Z PS / J = J o J Z 8— 5037 5037 ■ Y 0 O •. .i� W ° W W W W O U Q \ �W W W W W W W I CV F— a v \� w w I N N a �� `� PS 1 TP Z z .�W W ° DESIGNED 1 RJP DRAWN BY BY: ANP o \ CHECKED BY: EPF W Z W\ W , W z } w NOTES: DATE: 4/16/2025 \ ?: "�V 1. REFERENCE LANDSCAPE PLANS FOR FINAL CONDITION OF � \ !'\,W \ \ W \ RS r w = LANDSCAPE AREAS. 151 W W W W CF W W w = 6 2. SURFACE ROUGHENING REQUIRED UNTIL AREA IS PAVED OR IF, �, �� o M CF a HARDSCAPED, OR BUILDING FLOOR IS POURED. INSTALL CURB SOCK Z \ W W W �, o = J IN PAVED AREAS UNTIL LANDSCAPE OR VEGETATION IS INSTALLED. U \\ \,\ '.?' �W W W W W so �, BUILDING EXPANSION N Y 3. NO TRACKING OF MUD OR DEBRIS PERMITTED ON SURROUNDING o s :• �� 11,347 SF a 1 PROPERTY OR STREETS. IF TRACKING DOES OCCUR, CONTRACTOR 0 0 W \ PS RS PS I 4455 S.COLLEGE AVE. SCL h ¢ v SHALL CLEAN IMMEDIATELY. G� , \ PEDERSEN TOYOTA A ` °' ,, 4. PROTECT UNDERGROUND TREATMENT SYSTEMS DURING t<` / 'li I BUILDING 44,075 SF TOTAL BUILDING EXPANSION INSTALLATION. 2 OO 4, 4 20,485 SF lO 2 W W W of Wj �J � TP \ W I ss I SITE DATA:Lu U I .. ` I AREA OF DISTURBANCE: U) ONSITE IMPROVEMENTS: ±4.77 ACRES z G W� W W pg W co I x OFFSITE IMPROVEMENTS: ±0.27 ACRES o f LO II I ,i TP TOTAL ±5.04 ACRES J z W \ x W W W TPof Lu 030 I O J O W 5�3 I — EARTHWORK: U L.L \ .� s 6 CUT 10451 CY CY a W vO� Q \ WA. � FILL 2726 CY CY NET 7725 CY CUT O 0 Z ' M O4455 S.MASON ST. \ •.,�� W � � PS \ I / I, w so h � CF I IP I � O LOT 1,PEDERSEN AUTO PLAZA \ ; o MID ' o SUBDIVISION 2ND FILING W W W C' 1' U _ z z ® w v v w 11 O, � \ —Lu I I I W E M �' r E Q SS \�\�Y EPS 5g64 W 5037 I, v J < ^ O u, O U� N 56 \ I W v) o 8 REG. O• !�� IF, RS Z a I.J.J LL PS I I NORTH 0 W U O O w W S RS PS \ W W W w J J L.L 5p36 0 \ 0- � ° \ \ SCL I GRAPHIC SCALE IN FEET O w W W W I 0 15 30 60 U J IW W W W \ p U RS SS z o 1 •r RS RS RS T 7 N d'� IW W W W RS ,SO 5635 B B I SCALE: 1" = 30' Z 1 1 W � PS `8 PS I � LL K I .' W 1 V" W �W �Y W V" W I p W LL w (I W W W •Y W W W W •Y / W •Y W Y o I C CF W W Sp39 1 W W 5035 RS W W W W W W V" V" W W W W V" �Y W W W Z ¢ M CF SCL SCL ,� CF TABLE OF CONSTRUCTION SEQUENCE AND BMP APPLICATION O a UTILITIES FLATWORK �W N z CONSTRUCTION PHASE MOBILIZATION DEMOLITION GRADING LANDSCAPE DEMOBILIZATION O SS (n w INSTALLATION INSTALLATION S+S+ SS \ N = BEST MANAGEMENT PRACTICE(BMP) o O W Z d W STRUCTURAL INSTALLATION - - - Lu Silt Fence Barriers* M Q Cl) 7 Q V °' 3�- 36 36 U a Contour Furrows(Ripping/Discing) p N n 50 g0 W .60 z Vehicle Pad* § \ NOT FOR g o FOR REVIEW ONLY >+w Flow Barriers(Wattles)* 0o pW m � z Inlet Filter Bags* Existing Downstream Inlets CONSTRUCTION NRock Bags* Existing Downstream Inlets cal N 0 Riprap 4512 S.MASON ST. do *Temporary BMP to be removed when LOT 1,THE GATEWAY 103 KENSINGTON DR. Kimley-Horn and Associates,Inc. Iw construction completed AT HARMONT ROAD LOT 1, KENSINGTON COMMONS o � P.U.D.3RD FILING o� Vegetative PROJECT NO. CO w Temporary Seeding/Planting Anytime Site will be inactive for more than 30 days 296073000 �F 0 w Mulcing/Sealant Anytime Site will be inactive for more than 30 days N o SHEET Pod Installation nation Seeding/Planting ® Call before you dig. C7.2 Know what's b@IOW. Sod Installation0 Rolled Products Anytime Site will be inactive for more than 30 days O Z Ln Y � Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix C- Erosion Control Details Kimley>>) Horn Chapter 7 Construction BMPs Pre-Construction 7= ■ Develop Site Plan 0 Obtain Stormwater Construction Permits • Obtain Site Survey,Hydrology and Soils (State and Local) Information 0 Obtain Other Relevant Permits • Prepare SWMP (e.g.,404, Floodplain, Dewatering) Representative Phases: Management Practices: ■ Clearing and Grubbing K Phase Construction Activities to Minimize ■ Rough Grading Disturbed Area at a Given Time ■ Road Construction Sequence Contruction within Phases to Avoid Idle Disturbed Areas • Utility and Infrastructure Installation ■ Install,Inspect and Proactively Maintain BMPs • Vertical Construction(Buildings) Appropriate for Each Phase of Construction ■ Final Grading Maintain and Update SWMP as Construction Progresses Final Stabilization ■ Revegetate Site ■ Activate Post Construction BMPs (e.g.,convert sediment basin to extended Closeout State and Local Stormwater Permits detention basin) • ■ Remove Temporary BMPs Figure 7-2. Construction Stormwater Management November 2010 Urban Drainage and Flood Control District 7-13 Urban Storm Drainage Criteria Manual Volume 3 Construction BMPs Construction BMPs Table 7-2. Overview of Construction BMPs Erosion Sediment Site/Material Functions Control Control Management Erosion Control BMPs Surface Roughening Yes No No Temporary/Permanent Seeding Yes No No Soil Binders Yes No Moderate Mulching Yes Moderate No Compost Blankets and Filter Berms Yes Moderate No Rolled Erosion Control Products Yes No No Temporary Slope Drains Yes No No Temporary Outlet Protection Yes Moderate No Rough Cut Street Control Yes Moderate No Earth Dikes/Drainage Swales Yes Moderate No Terracing Yes Moderate No Check Dams Yes Moderate No Streambank Stabilization Yes No No Wind Erosion/Dust Control Yes No Moderate Sediment Control BMPs Silt Fence No Yes No Sediment Control Log Moderate Yes No Straw Bale Barrier No Moderate No Brush Barrier Moderate Moderate No Rock Sock(perimeter control) No Yes No Inlet Protection(various forms) No Yes No Sediment Basins No Yes No Sediment Traps No Yes No Vegetative Buffers Moderate Yes Yes Chemical Treatment Moderate Yes No Materials Management Concrete Washout Area No No Yes Stockpile Management Yes Yes Yes Good Houskeeping(multiple practices) No No Yes Site Management and Other Specific Practices Construction Phasing Moderate Moderate Yes Protection of Existing Vegetation Yes Moderate Yes Construction Fence No No Yes Vehicle Tracking Control Moderate Yes Yes Stabilized Construction Roadway Yes Moderate Yes Stabilized Staging Area Yes Moderate Yes Street Sweeping/Vacuuming No Yes Yes Temporary Diversion Channel Yes No No Dewatering Operations Moderate Yes Yes Temporary Stream Crossing Yes Yes No Temporary Batch Plants No No Yes Paving and Grinding Operations No No Yes 7-14 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Surface Roughening (SR) EC-1 Description Surface roughening is an erosion control - practice that involves tracking, scarifying, imprinting,or tilling a - - disturbed area to provide temporary stabilization of disturbed areas. Surface roughening creates variations in the soil surface that help to minimize wind and = - - water erosion. Depending on the technique used, surface roughening may also help establish conditions favorable �. to establishment of vegetation. s - - Appropriate Uses = Surface roughening can be used to Photograph SR-1. Surface roughening via imprinting for temporary provide temporary stabilization of stabilization. disturbed areas, such as when revegetation cannot be immediately established due to seasonal planting limitations. Surface roughening is not a stand-alone BMP, and should be used in conjunction with other erosion and sediment controls. Surface roughening is often implemented in conjunction with grading and is typically performed using heavy construction equipment to track the surface. Be aware that tracking with heavy equipment will also compact soils,which is not desirable in areas that will be revegetated. Scarifying,tilling, or ripping are better surface roughening techniques in locations where revegetation is planned. Roughening is not effective in very sandy soils and cannot be effectively performed in rocky soil. Design and Installation Typical design details for surfacing roughening on steep and mild slopes are provided in Details SR-1 and SR-2,respectively. Surface roughening should be performed either after final grading or to temporarily stabilize an area during active construction that may be inactive for a short time period. Surface roughening should create depressions 2 to 6 inches deep and approximately 6 inches apart. The surface of exposed soil can be roughened by a number of techniques and equipment. Horizontal grooves (running parallel to the contours of the land) can be made using tracks from equipment treads, stair-step grading,ripping, or tilling. Fill slopes can be constructed with a roughened surface. Cut slopes that have been smooth graded can be roughened as a subsequent operation. Roughening should follow along the contours of the slope. The tracks left by truck mounted equipment working perpendicular to the contour can leave acceptable horizontal depressions; Surface Roughening however,the equipment will also compact the soil. Functions Erosion Control Yes Sediment Control No Site/Material Management No November 2010 Urban Drainage and Flood Control District SR-1 Urban Storm Drainage Criteria Manual Volume 3 EC-1 Surface Roughening (SR) Maintenance and Removal Care should be taken not to drive vehicles or equipment over areas that have been surface roughened. Tire tracks will smooth the roughened surface and may cause runoff to collect into rills and gullies. Because surface roughening is only a temporary control, additional treatments may be necessary to maintain the soil surface in a roughened condition. Areas should be inspected for signs of erosion. Surface roughening is a temporary measure, and will not provide long-term erosion control. SR-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Surface Roughening (SR) EC-1 x SR l - TRACKING OR IMPRINTING f!r r 6" MAX l FURROWS 2" TO 4" DEEP 2" TO WITH 6" MAXIMUM SPACING 4" DEEP f PARALLEL TO CONTOURS SR- 1 . SURFACE ROUGHENING FOR STEEP SLOPES (3:1 OR STEEPER) SCARIFYING OR TILLING i / ROUGHENED ROWS SHALL BE 4" TO 6'* 4" TO 6" DEEP WITH 6" MAXIMUM SPACING PARALLEL DEEP TO CONTOURS SR-2. SURFACE ROUGHENING FOR LOW SLOPES (LESS THAN 3:1) November 2010 Urban Drainage and Flood Control District SR-3 Urban Storm Drainage Criteria Manual Volume 3 EC-1 Surface Roughening (SR) SURFACE ROUGHENING INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION(S) OF SURFACE ROUGHENING. 2 SURFACE ROUGHENING SHALL BE PROVIDED PROMPTLY AFTER COMPLETION OF FINISHED GRADING (FOR AREAS NOT RECEIVING TOPSOIL) OR PRIOR TO TOPSOIL PLACEMENT OR ANY FORECASTED RAIN EVENT. 3 AREAS WHERE BUILDING FOUNDATIONS, PAVEMENT, OR SOD WILL BE PLACED WITHOUT DELAY IN THE CONSTRUCTION SEQUENCE, SURFACE ROUGHENING IS NOT REQUIRED. 4. DISTURBED SURFACES SHALL BE ROUGHENED USING RIPPING OR TILLING EQUIPMENT ON THE CONTOUR OR TRACKING UP AND DOWN A SLOPE USING EQUIPMENT TREADS. 5. A FARMING DISK SHALL NOT BE USED FOR SURFACE ROUGHENING. SURFACE ROUGHENING MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE. NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION, INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACE UPON DISCOVERY OF THE FAILURE. 4. VEHICLES AND EQUIPMENT SHALL NOT BE DRIVEN OVER AREAS THAT HAVE BEEN SURFACE ROUGHENED. 5. IN NON—TURF GRASS FINISHED AREAS, SEEDING AND MULCHING SHALL TAKE PLACE DIRECTLY OVER SURFACE ROUGHENED AREAS WITHOUT FIRST SMOOTHING OUT THE SURFACE 6. IN AREAS NOT SEEDED AND MULCHED AFTER SURFACE ROUGHENING, SURFACES SHALL BE RE—ROUGHENED AS NECESSARY TO MAINTAIN GROOVE DEPTH AND SMOOTH OVER RILL EROSION. (DETAILS ADAPTED FROM TOWN OF PARKER. COLORADO. NOT AVAILABLE IN ALITOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. SR-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary and Permanent Seeding (TS/PS) EC-2 Description Temporary seeding can be used to stabilize disturbed areas that will be inactive for an extended period. Permanent seeding should be used to stabilize areas at final grade that will not be otherwise stabilized. Effective seeding includes preparation of a seedbed, selection of an appropriate seed mixture, proper planting techniques,and protection of the seeded area with mulch,geotextiles, or other appropriate measures. " ^ Appropriate Uses - When the soil surface is disturbed and Photograph TS/PS-1. Equipment used to drill seed. Photo courtesy of will remain inactive for an extended Douglas County. period(typically 30 days or longer), proactive stabilization measures should be implemented. If the inactive period is short-lived(on the order of two weeks),techniques such as surface roughening may be appropriate. For longer periods of inactivity,temporary seeding and mulching can provide effective erosion control. Permanent seeding should be used on finished areas that have not been otherwise stabilized. Typically, local governments have their own seed mixes and timelines for seeding. Check jurisdictional requirements for seeding and temporary stabilization. Design and Installation Effective seeding requires proper seedbed preparation,selection of an appropriate seed mixture,use of appropriate seeding equipment to ensure proper coverage and density, and protection with mulch or fabric until plants are established. The USDCM Volume 2 Revegetation Chapter contains detailed seed mix, soil preparations, and seeding and mulching recommendations that may be referenced to supplement this Fact Sheet. Drill seeding is the preferred seeding method. Hydroseeding is not recommended except in areas where steep slopes prevent use of drill seeding equipment, and even in these instances it is preferable to hand seed and mulch. Some jurisdictions do not allow hydroseeding or hydromulching. Seedbed Preparation Prior to seeding, ensure that areas to be revegetated have soil conditions capable of supporting vegetation. Overlot Temporary and Permanent Seeding grading can result in loss of topsoil,resulting in poor quality subsoils at the ground surface that have low nutrient value, Functions little organic matter content, few soil microorganisms, Erosion Control Yes rooting restrictions, and conditions less conducive to Sediment Control No infiltration of precipitation. As a result,it is typically Site/Material Management No necessary to provide stockpiled topsoil, compost, or other November 2010 Urban Drainage and Flood Control District TS/PS-1 Urban Storm Drainage Criteria Manual Volume 3 EC-2 Temporary and Permanent Seeding (TS/PS) soil amendments and rototill them into the soil to a depth of 6 inches or more. Topsoil should be salvaged during grading operations for use and spread on areas to be revegetated later. Topsoil should be viewed as an important resource to be utilized for vegetation establishment, due to its water-holding capacity, structure,texture, organic matter content,biological activity, and nutrient content. The rooting depth of most native grasses in the semi-arid Denver metropolitan area is 6 to 18 inches. At a minimum,the upper 6 inches of topsoil should be stripped, stockpiled, and ultimately respread across areas that will be revegetated. Where topsoil is not available, subsoils should be amended to provide an appropriate plant-growth medium. Organic matter, such as well digested compost,can be added to improve soil characteristics conducive to plant growth. Other treatments can be used to adjust soil pH conditions when needed. Soil testing,which is typically inexpensive, should be completed to determine and optimize the types and amounts of amendments that are required. If the disturbed ground surface is compacted,rip or rototill the surface prior to placing topsoil. If adding compost to the existing soil surface,rototilling is necessary. Surface roughening will assist in placement of a stable topsoil layer on steeper slopes,and allow infiltration and root penetration to greater depth. Prior to seeding,the soil surface should be rough and the seedbed should be firm,but neither too loose nor compacted. The upper layer of soil should be in a condition suitable for seeding at the proper depth and conducive to plant growth. Seed-to-soil contact is the key to good germination. Seed Mix for Temporary Vegetation To provide temporary vegetative cover on disturbed areas which will not be paved,built upon, or fully landscaped or worked for an extended period(typically 30 days or more),plant an annual grass appropriate for the time of planting and mulch the planted areas. Annual grasses suitable for the Denver metropolitan area are listed in Table TS/PS-l. These are to be considered only as general recommendations when specific design guidance for a particular site is not available. Local governments typically specify seed mixes appropriate for their jurisdiction. Seed Mix for Permanent Revegetation To provide vegetative cover on disturbed areas that have reached final grade,a perennial grass mix should be established. Permanent seeding should be performed promptly(typically within 14 days)after reaching final grade. Each site will have different characteristics and a landscape professional or the local jurisdiction should be contacted to determine the most suitable seed mix for a specific site. In lieu of a specific recommendation, one of the perennial grass mixes appropriate for site conditions and growth season listed in Table TS/PS-2 can be used. The pure live seed(PLS)rates of application recommended in these tables are considered to be absolute minimum rates for seed applied using proper drill-seeding equipment. If desired for wildlife habitat or landscape diversity, shrubs such as rubber rabbitbrush(Chrysothamnus nauseosus), fourwing saltbush(Atriplex canescens)and skunkbrush sumac (Rhus trilobata) could be added to the upland seedmixes at 0.25, 0.5 and 1 pound PLS/acre,respectively. In riparian zones, planting root stock of such species as American plum(Prunus americans),woods rose(Rosa woodsii), plains cottonwood(Populus sargentii), and willow(Populus spp.)may be considered. On non-topsoiled upland sites, a legume such as Ladak alfalfa at 1 pound PLS/acre can be included as a source of nitrogen for perennial grasses. TS/PS-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary and Permanent Seeding (TS/PS) EC-2 Seeding dates for the highest success probability of perennial species along the Front Range are generally in the spring from April through early May and in the fall after the first of September until the ground freezes. If the area is irrigated, seeding may occur in summer months, as well. See Table TS/PS-3 for appropriate seeding dates. Table TS/PS-1. Minimum Drill Seeding Rates for Various Temporary Annual Grasses Pounds of Planting Species' Growth Pure Live Seed Depth (Common name) Season (PLS)/acre (inches) 1. Oats Cool 35 - 50 1 -2 2. Spring wheat Cool 25 - 35 1 -2 3. Spring barley Cool 25 -35 1 -2 4. Annual ryegrass Cool 10-15 '/z 5. Millet Warm 3 - 15 '/2-3/4 6. Sudangrass Warm 5-10 '/2-3/4 7. Sorghum Warm 5-10 'h-% 8. Winter wheat Cool 20-35 1 -2 9. Winter barley Cool 20-35 1 -2 10. Winter rye Cool 20-35 1 -2 11. Triticale Cool 25-40 1 -2 a Successful seeding of annual grass resulting in adequate plant growth will usually produce enough dead-plant residue to provide protection from wind and water erosion for an additional year. This assumes that the cover is not disturbed or mowed closer than 8 inches. Hydraulic seeding may be substituted for drilling only where slopes are steeper than 3:1 or where access limitations exist. When hydraulic seeding is used, hydraulic mulching should be applied as a separate operation,when practical,to prevent the seeds from being encapsulated in the mulch. See Table TS/PS-3 for seeding dates. Irrigation,if consistently applied, may extend the use of cool season species during the summer months. Seeding rates should be doubled if seed is broadcast,or increased by 50 percent if done using a Brillion Drill or by hydraulic seeding. November 2010 Urban Drainage and Flood Control District TS/PS-3 Urban Storm Drainage Criteria Manual Volume 3 EC-2 Temporary and Permanent Seeding (TS/PS) Table TS/PS-2. Minimum Drill Seeding Rates for Perennial Grasses Commona Botanical Growth Growth Seeds/ Pounds of Name Name Season Form Pound PLS/acre Alakali Soil Seed Mix Alkali sacaton Sporobolus airoides Cool Bunch 1,750,000 0.25 Basin wildrye Elymus cinereus Cool Bunch 165,000 2.5 Sodar streambank wheatgrass Agropyron riparium 'Sodar' Cool Sod 170,000 2.5 Jose tall wheatgrass Agropyron elongatum 'Jose' Cool Bunch 79,000 7.0 Arriba western wheatgrass Agropyron smithii'Arriba' Cool Sod 110,000 5.5 Total 17.75 Fertile Loamy Soil Seed Mix Ephriam crested wheatgrass Agropyron cristatum Cool Sod 175,000 2.0 Ephriam' Dural hard fescue Festuca ovina 'duriuscula' Cool Bunch 565,000 1.0 Lincoln smooth brome Bromus inermis leyss Cool Sod 130,000 3.0 'Lincoln' Sodar streambank wheatgrass Agropyron riparium 'Sodar' Cool Sod 170,000 2.5 Arriba western wheatgrass Agropyron smithii Arriba' Cool Sod 110,000 7.0 Total 15.5 High Water Table Soil Seed Mix Meadow foxtail Alopecurus pratensis Cool Sod 900,000 0.5 Redtop Agrostis alba Warm Open sod 5,000,000 0.25 Reed canarygrass Phalaris arundinacea Cool Sod 68,000 0.5 Lincoln smooth brome Bromus inermis leyss Cool Sod 130,000 3.0 Lincoln' Pathfinder switchgrass Panicum virgatum Warm Sod 389,000 1.0 'Pathfinder' Alkar tall wheatgrass Agropyron elongatum Cool Bunch 79,000 5.5 Alkar' Total 10.75 Transition Turf Seed Mix` Ruebens Canadian bluegrass Poa compressa 'Ruebens' Cool Sod 2,500,000 0.5 Dural hard fescue Festuca ovina 'duriuscula' Cool Bunch 565,000 1.0 Citation perennial ryegrass Lolium perenne'Citation' Cool Sod 247,000 3.0 Lincoln smooth brome Bromus inermis leyss Cool Sod 130,000 3.0 Lincoln' Total I I I 1 1 7.5 TS/PS-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary and Permanent Seeding (TS/PS) EC-2 Table TS/PS-2. Minimum Drill Seeding Rates for Perennial Grasses (cont.) Common Botanical Growth Growth Seeds/ Pounds of Name Name Season Form Pound PLS/acre Sandy Soil Seed Mix Blue grama Bouteloua gracilis Warm Sod-forming 825,000 0.5 bunchgrass Camper little bluestem Schizachyrium scoparium Warm Bunch 240,000 1.0 'Camper' Prairie sandreed Calamovilfa longifolia Warm Open sod 274,000 1.0 Sand dropseed Sporobolus cryptandrus Cool Bunch 5,298,000 0.25 Vaughn sideoats grama Bouteloua curtipendula Warm Sod 191,000 2.0 'Vaughn' Arriba western wheatgrass Agropyron smithii'Arriba' Cool Sod 110,000 5.5 Total 10.25 Heavy Clay,Rocky Foothill Seed Mix Agropyron cristatum Ephriam crested wheatgrass d 'Ephriam' Cool Sod 175,000 1.5 Oahe Intermediate wheatgrass Agropyron intermedium Cool Sod 115,000 5.5 'Oahe' Vaughn sideoats grama' 'Vaughn'oua curtipendula' Warm Sod 191,000 2.0 'Vaug Lincoln smooth brome Bromus inermis leyss Cool Sod 130,000 3.0 Lincoln' Arriba western wheatgrass Agropyron smithii'Arriba' Cool Sod 110,000 5.5 Total 17.5 a All of the above seeding mixes and rates are based on drill seeding followed by crimped hay or straw mulch. These rates should be doubled if seed is broadcast and should be increased by 50 percent if the seeding is done using a Brillion Drill or is applied through hydraulic seeding. Hydraulic seeding may be substituted for drilling only where slopes are steeper than 3:1. If hydraulic seeding is used,hydraulic mulching should be done as a separate operation. b See Table TS/PS-3 for seeding dates. If site is to be irrigated,the transition turf seed rates should be doubled. d Crested wheatgrass should not be used on slopes steeper than 6H to IV. Can substitute 0.5 lbs PLS of blue grama for the 2.0 lbs PLS of Vaughn sideoats grama. November 2010 Urban Drainage and Flood Control District TS/PS-5 Urban Storm Drainage Criteria Manual Volume 3 EC-2 Temporary and Permanent Seeding (TS/PS) Table TS/PS-3. Seeding Dates for Annual and Perennial Grasses Annual Grasses Perennial Grasses (Numbers in table reference species in Table TS/PS-1) Seeding Dates Warm Cool Warm Cool January 1—March 15 ✓ ✓ March 16—April30 4 1,2,3 ✓ ✓ May 1—May 15 4 ✓ May 16—June 30 4,5,6,7 July 1—July 15 5,6,7 July 16—August 31 September 1—September 30 8,9,10,11 October 1—December 31 1 ✓ ✓ Mulch Cover seeded areas with mulch or an appropriate rolled erosion control product to promote establishment of vegetation. Anchor mulch by crimping,netting or use of a non-toxic tackifier. See the Mulching BMP Fact Sheet for additional guidance. Maintenance and Removal Monitor and observe seeded areas to identify areas of poor growth or areas that fail to germinate. Reseed and mulch these areas,as needed. An area that has been permanently seeded should have a good stand of vegetation within one growing season if irrigated and within three growing seasons without irrigation in Colorado. Reseed portions of the site that fail to germinate or remain bare after the first growing season. Seeded areas may require irrigation,particularly during extended dry periods. Targeted weed control may also be necessary. Protect seeded areas from construction equipment and vehicle access. TS/PS-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Soil Binders (SB) EC-3 Description Soil binders include a broad range of treatments that can be applied to exposed soils for temporary stabilization to reduce wind and water erosion. Soil binders may be applied alone or as tackifiers in conjunction with mulching and seeding applications. Acknowledgement: This BMP Fact Sheet has been adapted from the 2003 California Stormwater Quality Association (CASQA)Stormwater BMP Handbook: Construction - (www.cabmphandbooks.com). Photograph SB-1. Tackifier being applied to provide temporary soil Appropriate Uses stabilization. Photo courtesy of Douglas County. Soil binders can be used for short-term,temporary stabilization of soils on both mild and steep slopes. Soil binders are often used in areas where work has temporarily stopped,but is expected to resume before revegetation can become established. Binders are also useful on stockpiled soils or where temporary or permanent seeding has occurred. Prior to selecting a soil binder, check with the state and local jurisdiction to ensure that the chemicals used in the soil binders are allowed. The water quality impacts of some types of soil binders are relatively unknown and may not be allowed due to concerns about potential environmental impacts. Soil binders must be environmentally benign(non-toxic to plant and animal life), easy to apply,easy to maintain, economical, and should not stain paved or painted surfaces. Soil binders should not be used in vehicle or pedestrian high traffic areas,due to loss in effectiveness under these conditions. Site soil type will dictate appropriate soil binders to be used. Be aware that soil binders may not function effectively on silt or clay soils or highly compacted areas. Check manufacturer's recommendations for appropriateness with regard to soil conditions. Some binders may not be suitable for areas with existing vegetation. Design and Installation Properties of common soil binders used for erosion control are provided in Table SB-1. Design and installation Soil Binders guidance below are provided for general reference. Follow the manufacturer's instructions for application rates and Functions procedures. Erosion Control Yes Sediment Control No Site/Material Management Moderate November 2010 Urban Drainage and Flood Control District SB-1 Urban Storm Drainage Criteria Manual Volume 3 EC-3 Soil Binders (SB) Table SB-1. Properties of Soil Binders for Erosion Control(Source: CASQA 2003) Binder Type Evaluation Criteria Plant Material Plant Material Polymeric Cementitious- Based Based Emulsion Blends Based Binders (short lived) (long lived) Resistance to Leaching High High Low to Moderate Moderate Resistance to Abrasion Moderate Low Moderate to High Moderate to High Longevity Short to Medium Medium Medium to Long Medium Minimum Curing Time 9 to 18 hours 19 to 24 hours 0 to 24 hours 4 to 8 hours before Rain Compatibility with Good Poor Poor Poor Existing Vegetation Photodegradable/ Photodegradable/ Mode of Degradation Biodegradable Biodegradable Chemically Chemically Degradable Degradable Water Truck or Water Truck or Specialized Application Water Truck or Water Truck or Hydraulic Hydraulic Equipment Hydraulic Mulcher Hydraulic Mulcher Mulcher Mulcher Liquid/Powder Powder Liquid Liquid/Powder Powder Yes,but Yes,but dissolves on Surface Crusting dissolves on Yes Yes rewetting rewetting Clean Up Water Water Water Water Erosion Control Varies Varies Varies 4,000 to 12,000 Application Rate lbs/acre Typ. S13-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Soil Binders (SB) EC-3 Factors to consider when selecting a soil binder generally include: ■ Suitability to situation: Consider where the soil binder will be applied,if it needs a high resistance to leaching or abrasion,and whether it needs to be compatible with existing vegetation. Determine the length of time soil stabilization will be needed, and if the soil binder will be placed in an area where it will degrade rapidly. In general, slope steepness is not a discriminating factor. ■ Soil types and surface materials: Fines and moisture content are key properties of surface materials. Consider a soil binder's ability to penetrate, likelihood of leaching, and ability to form a surface crust on the surface materials. ■ Frequency of application: The frequency of application can be affected by subgrade conditions, surface type,climate, and maintenance schedule. Frequent applications could lead to high costs. Application frequency may be minimized if the soil binder has good penetration, low evaporation, and good longevity. Consider also that frequent application will require frequent equipment clean up. An overview of major categories of soil binders, corresponding to the types included in Table SB-1 follows. Plant-Material Based (Short Lived) Binders ■ Guar: A non-toxic,biodegradable,natural galactomannan-based hydrocolloid treated with dispersant agents for easy field mixing. It should be mixed with water at the rate of 11 to 15 lbs per 1,000 gallons. Recommended minimum application rates are provided in Table S13-2. Table SB-2. Application Rates for Guar Soil Stabilizer Slo a(H:V) Flat 4:1 3:1 2:1 1:1 Application Rate(lb/acre) 40 45 50 60 70 ■ Psyllium: Composed of the finely ground muciloid coating of plantago seeds that is applied as a wet slurry to the surface of the soil. It dries to form a firm but rewettable membrane that binds soil particles together but permits germination and growth of seed. Psyllium requires 12 to 18 hours drying time. Application rates should be from 80 to 200 lbs/acre,with enough water in solution to allow for a uniform slurry flow. ■ Starch: Non-ionic,cold-water soluble(pre-gelatinized) granular cornstarch. The material is mixed with water and applied at the rate of 150 lb/acre. Approximate drying time is 9 to 12 hours. Plant-Material Based (Long Lived) Binders ■ Pitch and Rosin Emulsion: Generally, a non-ionic pitch and rosin emulsion has a minimum solids content of 48 percent. The rosin should be a minimum of 26 percent of the total solids content. The soil stabilizer should be a non-corrosive,water dilutable emulsion that upon application cures to a water insoluble binding and cementing agent. For soil erosion control applications,the emulsion is diluted and should be applied as follows: o For clayey soil: 5 parts water to 1 part emulsion November 2010 Urban Drainage and Flood Control District S13-3 Urban Storm Drainage Criteria Manual Volume 3 EC-3 Soil Binders (SB) o For sandy soil: 10 parts water to 1 part emulsion Application can be by water truck or hydraulic seeder with the emulsion and product mixture applied at the rate specified by the manufacturer. Polymeric Emulsion Blend Binders ■ Acrylic Copolymers and Polymers: Polymeric soil stabilizers should consist of a liquid or solid polymer or copolymer with an acrylic base that contains a minimum of 55 percent solids. The polymeric compound should be handled and mixed in a manner that will not cause foaming or should contain an anti-foaming agent. The polymeric emulsion should not exceed its shelf life or expiration date;manufacturers should provide the expiration date. Polymeric soil stabilizer should be readily miscible in water,non-injurious to seed or animal life,non-flammable, should provide surface soil stabilization for various soil types without inhibiting water infiltration, and should not re-emulsify when cured. The applied compound should air cure within a maximum of 36 to 48 hours. Liquid copolymer should be diluted at a rate of 10 parts water to 1 part polymer and the mixture applied to soil at a rate of 1,175 gallons/acre. ■ Liquid Polymers of Methacrylates and Acrylates: This material consists of a tackifier/sealer that is a liquid polymer of methacrylates and acrylates. It is an aqueous 100 percent acrylic emulsion blend of 40 percent solids by volume that is free from styrene, acetate,vinyl, ethoxylated surfactants or silicates. For soil stabilization applications,it is diluted with water in accordance with manufacturer's recommendations,and applied with a hydraulic seeder at the rate of 20 gallons/acre. Drying time is 12 to 18 hours after application. ■ Copolymers of Sodium Acrylates and Acrylamides: These materials are non-toxic, dry powders that are copolymers of sodium acrylate and acrylamide. They are mixed with water and applied to the soil surface for erosion control at rates that are determined by slope gradient, as summarized in Table SB-3. Table SB-3. Application Rates for Copolymers of Sodium Acrylates and Acrylamides Slope H: Flat to 5:1 5:1 to 3:1 2:2 to 1:1 Application Rate(lb/acre) 3.0-5.0 5.0-10.0 10.0-20.0 ■ Polyacrylamide and Copolymer of Acrylamide: Linear copolymer polyacrylamide is packaged as a dry flowable solid. When used as a stand-alone stabilizer, it is diluted at a rate of 11 lb/1,000 gal. of water and applied at the rate of 5.0 lb/acre. ■ Hydrocolloid Polymers: Hydrocolloid Polymers are various combinations of dry flowable polyacrylamides,copolymers, and hydrocolloid polymers that are mixed with water and applied to the soil surface at rates of 55 to 60 lb/acre. Drying times are 0 to 4 hours. Cementitious-Based Binders ■ Gypsum: This formulated gypsum based product readily mixes with water and mulch to form a thin protective crust on the soil surface. It is composed of high purity gypsum that is ground, calcined and processed into calcium sulfate hemihydrate with a minimum purity of 86 percent. It is mixed in a hydraulic seeder and applied at rates 4,000 to 12,000 lb/acre. Drying time is 4 to 8 hours. S13-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Soil Binders (SB) EC-3 Installation After selecting an appropriate soil binder,the untreated soil surface must be prepared before applying the soil binder. The untreated soil surface must contain sufficient moisture to assist the agent in achieving uniform distribution. In general,the following steps should be followed: ■ Follow manufacturer's written recommendations for application rates,pre-wetting of application area, and cleaning of equipment after use. ■ Prior to application,roughen embankment and fill areas. ■ Consider the drying time for the selected soil binder and apply with sufficient time before anticipated rainfall. Soil binders should not be applied during or immediately before rainfall. ■ Avoid over spray onto roads, sidewalks,drainage channels, sound walls, existing vegetation, etc. ■ Soil binders should not be applied to frozen soil,areas with standing water,under freezing or rainy conditions, or when the temperature is below 40°F during the curing period. ■ More than one treatment is often necessary, although the second treatment may be diluted or have a lower application rate. ■ Generally, soil binders require a minimum curing time of 24 hours before they are fully effective. Refer to manufacturer's instructions for specific cure time. ■ For liquid agents: o Crown or slope ground to avoid ponding. o Uniformly pre-wet ground at 0.03 to 0.3 gal/yd2 or according to manufacturer's recommendations. o Apply solution under pressure. Overlap solution 6 to 12 in. o Allow treated area to cure for the time recommended by the manufacturer,typically at least 24 hours. o Apply second treatment before first treatment becomes ineffective,using 50 percent application rate. o In low humidity,reactivate chemicals by re-wetting with water at 0.1 to 0.2 gal/yd2. Maintenance and Removal Soil binders tend to break down due to natural weathering. Weathering rates depend on a variety of site- specific and product characteristics. Consult the manufacturer for recommended reapplication rates and reapply the selected soil binder as needed to maintain effectiveness. Soil binders can fail after heavy rainfall events and may require reapplication. In particular, soil binders will generally experience spot failures during heavy rainfall events. If runoff penetrates the soil at the top of a slope treated with a soil binder,it is likely that the runoff will undercut the stabilized soil layer and discharge at a point further down slope. November 2010 Urban Drainage and Flood Control District S13-5 Urban Storm Drainage Criteria Manual Volume 3 EC-3 Soil Binders (SB) Areas where erosion is evident should be repaired and soil binder or other stabilization reapplied, as needed. Care should be exercised to minimize the damage to protected areas while making repairs. Most binders biodegrade after exposure to sun,oxidation,heat and biological organisms;therefore, removal of the soil binder is not typically required. SB-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Mulching (MU) EC-4 Description s Mulching consists of evenly applying L.6 straw,hay, shredded wood mulch,bark or compost to disturbed soils and securing the mulch by crimping,tackifiers,netting or other measures. Mulching helps reduce erosion by protecting bare soil from rainfall impact, increasing infiltration,and reducing runoff. Although often applied in conjunction with temporary or s permanent seeding, it can also be used for temporary stabilization of areas that cannot be reseeded due to seasonal constraints. Mulch can be applied either using standard mechanical dry application methods or using hydromulching equipment Photograph MU-1. An area that was recently seeded,mulched, that hydraulically applies a slurry of water, and crimped. wood fiber mulch,and often a tackifier. Appropriate Uses Use mulch in conjunction with seeding to help protect the seedbed and stabilize the soil. Mulch can also be used as a temporary cover on low to mild slopes to help temporarily stabilize disturbed areas where growing season constraints prevent effective reseeding. Disturbed areas should be properly mulched and tacked,or seeded,mulched and tacked promptly after final grade is reached(typically within no longer than 14 days)on portions of the site not otherwise permanently stabilized. Standard dry mulching is encouraged in most jurisdictions; however,hydromulching may not be allowed in certain jurisdictions or may not be allowed near waterways. Do not apply mulch during windy conditions. Design and Installation Prior to mulching, surface-roughen areas by rolling with a crimping or punching type roller or by track walking. Track walking should only be used where other methods are impractical because track walking with heavy equipment typically compacts the soil. A variety of mulches can be used effectively at construction sites, including the following types: Mulch Functions Erosion Control Yes Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District MU-1 Urban Storm Drainage Criteria Manual Volume 3 EC-4 Mulching (MU) ■ Clean,weed-and seed-free,long-stemmed grass hay(preferred)or cereal grain straw. Hay is preferred because it is less susceptible to removal by wind. Mulch should be applied evenly at a rate of 2 tons per acre and must be tacked or fastened by an approved method suitable for the type of mulch used. At least 50 percent of the grass hay mulch,by weight, should be 10 inches or more in length. ■ Grass hay mulch must be anchored and not merely placed on the surface. This can be accomplished mechanically by crimping or with the aid of tackifiers or nets. Anchoring with a crimping implement is preferred,and is the recommended method for areas flatter than 3:1. Mechanical crimpers must be capable of tucking the long mulch fibers into the soil to a depth of 3 inches without cutting them. An agricultural disk, while not an ideal substitute,may work if the disk blades are dull or blunted and set vertically; however,the frame may have to be weighted to afford proper soil penetration. ■ On small areas sheltered from the wind and heavy runoff, spraying a tackifier on the mulch is satisfactory for holding it in place. For steep slopes and special situations where greater control is needed,erosion control blankets anchored with stakes should be used instead of mulch. ■ Hydraulic mulching consists of wood cellulose fibers mixed with water and a tackifying agent and should be applied at a rate of no less than 1,500 pounds per acre(1,425 lbs of fibers mixed with at least 75 lbs of tackifier)with a hydraulic mulcher. For steeper slopes,up to 2000 pounds per acre may be required for effective hydroseeding. Hydromulch typically requires up to 24 hours to dry;therefore,it should not be applied immediately prior to inclement weather. Application to roads,waterways and existing vegetation should be avoided. ■ Erosion control mats,blankets,or nets are recommended to help stabilize steep slopes(generally 3:1 and steeper) and waterways. Depending on the product,these may be used alone or in conjunction with grass or straw mulch. Normally,use of these products will be restricted to relatively small areas. Biodegradable mats made of straw and jute,straw-coconut, coconut fiber, or excelsior can be used instead of mulch. (See the ECM/TRM BMP for more information.) ■ Some tackifiers or binders may be used to anchor mulch. Check with the local jurisdiction for allowed tackifiers. Manufacturer's recommendations should be followed at all times. (See the Soil Binder BMP for more information on general types of tackifiers.) ■ Rock can also be used as mulch. It provides protection of exposed soils to wind and water erosion and allows infiltration of precipitation. An aggregate base course can be spread on disturbed areas for temporary or permanent stabilization. The rock mulch layer should be thick enough to provide full coverage of exposed soil on the area it is applied. Maintenance and Removal After mulching,the bare ground surface should not be more than 10 percent exposed. Reapply mulch, as needed,to cover bare areas. MU-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Compost Blanket and Filter Berm (CB) EC-5 Description CHI I a _ A compost blanket is a layer of compost uniformly applied -_ to the soil in disturbed areas to control erosion, facilitate : . revegetation, and retain sediment resulting from sheet-flow r - runoff. ` A compost filter berm is a dike of compost or a compost t e product that is laced perpendicular to runoff to control P p p tP erosion in disturbed areas and retain sediment. Compost berms can be placed at regular intervals to help reduce the formation of rill and gully erosion when a compost blanket is stabilizing a slope. fi Appropriate Uses Compost blankets can be used as an alternative to erosion control blankets and mulching to help stabilize disturbed areas where sheet flow conditions are present. Compost blankets should not be used in areas of concentrated flows. Compost provides an excellent source of nutrients for plant Photograph CB-1. Application of a compost growth, and should be considered for use in areas that will be blanket to a disturbed area. Photo courtesy of permanently vegetated. Caltrans. Design and Installation See Detail CB-1 for design details and notes. Do not place compost in areas where it can easily be transported into drainage pathways or waterways. When using a compost blanket on a slope,berms should be installed periodically to reduce the potential for concentrated flow and rilling. Seeding should be completed before an area is composted or incorporated into the compost. Compost quality is an important consideration when selecting compost blankets or berms. Representative compost quality factors include pH, salinity,moisture content, organic matter content, stability(maturity), and physical contaminants. The compost should meet all local, state,and federal quality requirements. Biosolids compost must meet the Standards for Class A biosolids outlined in 40 CFR Part 503. The U.S. Composting Council(USCC)certifies compost products under its Seal of Testing Assurance(STA) Program. Compost producers whose products have been certified through the STA Program provide customers with a standard product label that allows comparison between compost products. Only STA certified, Class I compost should be used. Compost Blankets and Berms Functions Erosion Control Yes Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District CB-1 Urban Storm Drainage Criteria Manual Volume 3 EC-5 Compost Blanket and Filter Berm (CB) Maintenance and Removal When rills or gullies develop in an area that has been composted, fill and cover the area with additional compost and install berms as necessary to help reduce erosion. Weed control can be a maintenance challenge in areas using compost blankets. A weed control strategy may be necessary,including measures such as mechanical removal and spot application of targeted herbicides by licensed applicators. For compost berms, accumulated sediments should be removed from behind the berm when the sediments reach approximately one third the height of the berm. Areas that have been washed away should be replaced. If the berm has experienced significant or repeated washouts,a compost berm may not be the appropriate BMP for this area. Compost blankets and berms biodegrade and do not typically require removal following site stabilization. C13-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Compost Blanket and Filter Berm (CB) EC-5 � OT2' MIN CBMIN 15' MAk 1' MIN CLASS 1 COMPOST FILTER BERM 1" TO 3" THICK (2" TYP.) STA CERTIFIED CLASS 1 COMPOST BLANKET PROPER SOIL PREPARATION AND SURFACE ROUGHENING WHEN APPROPRIATE 2 TABLE CB-1. CLASS 1 COMPOST PARAMETERS CHARACTERISTIC MINIMUM STABILITY INDICATOR STABLE TO VERY STABLE SOLUBLE SALTS MAXIMUM 5 mmhos/cm PH 6.0 — 8.0 AG INDEX > 10 MATURITY INDICATOR EXPRESSED AS 80+/80+ PERCENTAGE OF GERMINATION/VIGOR MATURITY INDICATOR EXPRESSED AS < 4 AMMONIA N/ NITRATE N RATIO MATURITY INDEX AS CARBON TO 20:1 NITROGEN RATIO TESTED FOR CLOPYRALID YES/NEGATIVE RESULT MOISTURE CONTENT 30-60% ORGANIC MATTER CONTENT 25-45% OF DRY WEIGHT PARTICLE SIZE DISTRIBUTION 3" (75mm) 100% PASSING PRIMARY, SECONDARY NUTRIENTS; TRACE MUST BE REPORTED ELEMENTS TESTING AND TEST REPORT SUBMITTAL STA + CLOPYRALID REQUIREMENTS ORGANIC MATTER PER CUBIC YARD MUST REPORT CHEMICAL CONTAMINANTS COMPLY WITH US EPA CLASS A STANDARD, 40 CFR 503.1 TABLES 1 & 3 LEVELS MINIMUM MANUFACTURING/PRODUCTION FULLY PERMITTED UNDER COLORADO DEPARTMENT OF REQUIREMENT PUBLIC HEALTH AND ENVIRONMENT, HAZARDOUS MATERIALS AND WASTE MANAGEMENT DIVISION RISK FACTOR RELATING TO PLANT LOW GERMINATION AND HEALTH CB- 1 . COMPOST BLANKET AND COMPOST FILTER BERM November 2010 Urban Drainage and Flood Control District C13-3 Urban Storm Drainage Criteria Manual Volume 3 EC-5 Compost Blanket and Filter Berm (CB) COMPOST FILTER BERM AND COMPOST BLANKET INSTALLATION NOTES 1. SEE PLAN VIEW FOR —LOCATION OF COMPOST FILTER BERM(S). —LENGTH OF COMPOST FILTER BERM(S). 2. COMPOST BERMS AND BLANKETS MAY BE USED IN PLACE OF STRAW MULCH OR GEOTEXTILE FABRIC IN AREAS WHERE ACCESS TO LANDSCAPING IS DIFFICULT DUE TO LANDSCAPING OR OTHER OBJECTS OR IN AREAS WHERE A SMOOTH TURF GRASS FINISH IS DESIRED. 3. FILTER BERMS SHALL RUN PARALLEL TO THE CONTOUR. 4. FILTER BERMS SHALL BE A MINIMUM OF 1 FEET HIGH AND 2 FEET WIDE. 5. FILTER BERMS SHALL BE APPLIED BY PNEUMATIC BLOWER OR BY HAND. 6. FILTER BERMS SHALL ONLY BE UTILIZED IN AREAS WHERE SHEET FLOW CONDITIONS PREVAIL AND NOT IN AREAS OF CONCENTRATED FLOW. 7. COMPOST BLANKETS SHALL BE APPLIED AT A DEPTH OF 1 —3 INCHES (TYPICALLY 2 INCHES). FOR AREAS WITH EXISTING VEGETATION THAT ARE TO BE SUPPLEMENTED BY COMPOST, A THIN 0.5—INCH LAYER MAY BE USED. 8. SEEDING SHALL BE PERFORMED PRIOR TO THE APPLICATION OF COMPOST. ALTERNATIVELY, SEED MAY BE COMBINED WITH COMPOST AND BLOWN WITH THE PNEUMATIC BLOWER. 9. WHEN TURF GRASS FINISH IS NOT DESIRED, SURFACE ROUGHENING ON SLOPES SHALL TAKE PLACE PRIOR TO COMPOST APPLICATION. 10. COMPOST SHALL BE A CLASS 1 COMPOST AS DEFINED BY TABLE CB-1. COMPOST FILTER BERM MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. COMPOST BERMS AND BLANKETS SHALL BE REAPPLIED OR REGRADED AS NECESSARY IF RILLING IN THE COMPOST SURFACE OCCURS. (DETAILS ADAPTED FROM ARAPAHOE COUNTY, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CB-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC-6 Description ' Y Rolled Erosion Control Products �_ •»- _.'- �:� (RECPs)include a variety of temporary or permanently installed i ir�i, manufactured products designed to � - _ - control erosion and enhance vegetation establishment and survivability, particularly on slopes and in channels. - For applications where natural vegetation alone will provide sufficient permanent erosion protection, temporary products such as netting, open weave textiles and a variety of erosion control blankets(ECBs)made of biodegradable natural materials Photograph RECP-1. Erosion control blanket protecting the slope from (e.g., straw, coconut fiber)can be used. erosion and providing favorable conditions for revegetation. For applications where natural vegetation alone will not be sustainable under expected flow conditions,permanent rolled erosion control products such as turf reinforcement mats (TRMs)can be used. In particular,turf reinforcement mats are designed for discharges that exert velocities and sheer stresses that exceed the typical limits of mature natural vegetation. Appropriate Uses RECPs can be used to control erosion in conjunction with revegetation efforts,providing seedbed protection from wind and water erosion. These products are often used on disturbed areas on steep slopes, in areas with highly erosive soils,or as part of drainageway stabilization. In order to select the appropriate RECP for site conditions, it is important to have a general understanding of the general types of these products,their expected longevity, and general characteristics. The Erosion Control Technology Council(ECTC 2005)characterizes rolled erosion control products according to these categories: ■ Mulch control netting: A planar woven natural fiber or extruded geosynthetic mesh used as a temporary degradable rolled erosion control product to anchor loose fiber mulches. ■ Open weave textile: A temporary degradable rolled erosion control product composed of processed natural or polymer yarns woven into a matrix,used to provide erosion control and facilitate vegetation establishment. ■ Erosion control blanket(ECB): A temporary degradable rolled erosion control product composed of processed natural or polymer fibers which are Rolled Erosion Control Products mechanically, structurally or chemically bound together to form a continuous matrix to provide erosion control Functions and facilitate vegetation establishment. ECBs can be Erosion Control Yes further differentiated into rapidly degrading single-net Sediment Control No and double-net types or slowly degrading types. Site/Material Management No November 2010 Urban Drainage and Flood Control District RECP-1 Urban Storm Drainage Criteria Manual Volume 3 EC-6 Rolled Erosion Control Products (RECP) ■ Turf Reinforcement Mat(TRM): A rolled erosion control product composed of non-degradable synthetic fibers,filaments,nets,wire mesh, and/or other elements,processed into a permanent,three- dimensional matrix of sufficient thickness. TRMs,which may be supplemented with degradable components,are designed to impart immediate erosion protection, enhance vegetation establishment and provide long-term functionality by permanently reinforcing vegetation during and after maturation. Note: TRMs are typically used in hydraulic applications, such as high flow ditches and channels,steep slopes, stream banks, and shorelines,where erosive forces may exceed the limits of natural,unreinforced vegetation or in areas where limited vegetation establishment is anticipated. Tables RECP-1 and RECP-2 provide guidelines for selecting rolled erosion control products appropriate to site conditions and desired longevity. Table RECP-1 is for conditions where natural vegetation alone will provide permanent erosion control,whereas Table RECP-2 is for conditions where vegetation alone will not be adequately stable to provide long-term erosion protection due to flow or other conditions. RECP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC-6 Table RECP-1. ECTC Standard Specification for Temporary Rolled Erosion Control Products (Adapted from Erosion Control Technology Council 2005) Slope Channel Minimum Expected Product Description Applications* Applications* Tensile Longevity Strength Maximum C Factor2'5 Max. Shear Gradient Stress ' ' @ Mulch Control Nets 5:1 (H:V) <0.10 0.25 lbs/ft2 5 lbs/ft5:1 (12 Pa) (0.073 kN/m) Netless Rolled <0.10 @ 0.5 lbs/ft2 5 lbs/ft Erosion Control 4:1 (H:V) 4:1 (24 Pa) (0.073 kN/m) Blankets Up to 12 Single-net Erosion <0.15 @ 1.51bs/ft2 50 lbs/ft months Control Blankets& 3:1 (H:V) 3:1 (72 Pa) (0.73 kN/m) Open Weave Textiles Double-net Erosion <0.20 @ 1.75 lbs/ft2 75 lbs/ft Control Blankets 2:1 (H:V) — 2:1 (84 Pa) (1.09 kN/m) Mulch Control Nets 5:1 (H:V) <0.10 @ 0.25 lbs/ft2 25 lbs/ft5:1 (12 Pa) (0.36 Min) 24 months Erosion Control Blankets &Open _<0.25 @ 2.00 lbs/ft2 1001bs/ft Weave Textiles L5:1 (H:V) 1.5:1 (96 Pa) (1.45 kN/m) 24 months (slowly degrading) Erosion Control <0.25 @ 2.25 lbs/ft2 125 lbs/ft Blankets &Open 1:1 (H:V) — 36 months Weave Textiles 1:1 (108 Pa) (1.82 kN/m) * C Factor and shear stress for mulch control nettings must be obtained with netting used in conjunction with pre-applied mulch material. (See Section 5.3 of Chapter 7 Construction BMPs for more information on the C Factor.) ' Minimum Average Roll Values,Machine direction using ECTC Mod. ASTM D 5035. 2 C Factor calculated as ratio of soil loss from RECP protected slope(tested at specified or greater gradient,H:V)to ratio of soil loss from unprotected(control)plot in large-scale testing. 3 Required minimum shear stress RECP(unvegetated)can sustain without physical damage or excess erosion(> 12.7 min(0.5 in) soil loss)during a 30-minute flow event in large-scale testing. 4 The permissible shear stress levels established for each performance category are based on historical experience with products characterized by Manning's roughness coefficients in the range of 0.01 -0.05. 5 Acceptable large-scale test methods may include ASTM D 6459,or other independent testing deemed acceptable by the engineer. 6 Per the engineer's discretion. Recommended acceptable large-scale testing protocol may include ASTM D 6460, or other independent testing deemed acceptable by the engineer. November 2010 Urban Drainage and Flood Control District RECP-3 Urban Storm Drainage Criteria Manual Volume 3 EC-6 Rolled Erosion Control Products (RECP) Table RECP-2. ECTC Standard Specification for Permanent' Rolled Erosion Control Products (Adapted from: Erosion Control Technology Council 2005) Product Type Slope Channel Applications Applications Maximum Maximum Minimum Gradient Shear Stress4'S Tensile Strength 2,1 TRMs with a minimum thickness of 2 125 lbs/ft(1.82 0.5:1 (H:V) 6.0 lbs/ft (288 Pa) 0.25 inches(6.35 mm)per ASTM D kN/m) 6525 and UV stability of 80%per ASTM D 4355 (500 hours 2 150 lbs/ft(2.19 exposure). 0.5:1 (H:V) 8.0 lbs/ft (384 Pa) kN/m) 0.5:1 (H:V) 10.0 lbs/ft2(480 Pa) 175 lbs/ft(2.55 kN/m) ' For TRMs containing degradable components, all property values must be obtained on the non- degradable portion of the matting alone. 2 Minimum Average Roll Values,machine direction only for tensile strength determination using ASTM D 6818 (Supersedes Mod. ASTM D 5035 for RECPs) 3 Field conditions with high loading and/or high survivability requirements may warrant the use of a TRM with a tensile strength of 44 kN/m(3,000 lb/ft)or greater. 4 Required minimum shear stress TRM(fully vegetated) can sustain without physical damage or excess erosion(> 12.7 mm(0.5 in.) soil loss) during a 30-minute flow event in large scale testing. 5 Acceptable large-scale testing protocols may include ASTM D 6460, or other independent testing deemed acceptable by the engineer. Design and Installation RECPs should be installed according to manufacturer's specifications and guidelines. Regardless of the type of product used, it is important to ensure no gaps or voids exist under the material and that all corners of the material are secured using stakes and trenching. Continuous contact between the product and the soil is necessary to avoid failure. Never use metal stakes to secure temporary erosion control products. Often wooden stakes are used to anchor RECPs;however,wood stakes may present installation and maintenance challenges and generally take a long time to biodegrade. Some local jurisdictions have had favorable experiences using biodegradable stakes. This BMP Fact Sheet provides design details for several commonly used ECB applications,including: ECB-1 Pipe Outlet to Drainageway ECB-2 Small Ditch or Drainageway ECB-3 Outside of Drainageway RECP-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC-6 Staking patterns are also provided in the design details according to these factors: ■ ECB type ■ Slope or channel type For other types of RECPs including TRMs,these design details are intended to serve as general guidelines for design and installation;however, engineers should adhere to manufacturer's installation recommendations. Maintenance and Removal Inspection of erosion control blankets and other RECPs includes: ■ Check for general signs of erosion,including voids beneath the mat. If voids are apparent, fill the void with suitable soil and replace the erosion control blanket, following the appropriate staking pattern. ■ Check for damaged or loose stakes and secure loose portions of the blanket. Erosion control blankets and other RECPs that are biodegradable typically do not need to be removed after construction. If they must be removed,then an alternate soil stabilization method should be installed promptly following removal. Turf reinforcement mats,although generally resistant to biodegradation, are typically left in place as a dense vegetated cover grows in through the mat matrix. The turf reinforcement mat provides long-term stability and helps the established vegetation resist erosive forces. November 2010 Urban Drainage and Flood Control District RECP-5 Urban Storm Drainage Criteria Manual Volume 3 EC-6 Rolled Erosion Control Products (RECP) ECB UNDISTURBED PERIMETER JOINT ANCHOR TOP OF SOIL ANCHOR TRENCH, TYP. CHANNEL BANK TRENCH, TYP. f ANCHOR DETAILS GEOTEXTILE FABRIC OR MAT, TYP. --I I-- 3" MIN, TYP. Y 'MIN, YP. NGLE EDGE AKE, TYP. [ TYPE OF ECG AS INDICATED/IN PLAN VIEW. INSTALL IN ALL BACKFILL, TYP. DISTURBED AREAS OF STREAMS AND DRAINAGE CHANNELS TO DEPTH PERIMETER ANCHOR TRENCH D A8OVE CHANNEL INVERT. ECB SHALL GENERALLY BE ORIENTED PARALLEL TO FLOW DIRECTION (I.E. LONG DIMENSIONS OF BLANKET PARALLEL TO FLOWLINES) STAKING PATTERN SHALL MATCH EC8 AND/OR CHANNEL TYPE. ECB- 1 . PIPE OUTLET TO DRAINAGEWAY F TWOocEs ADJACENT ROLLS TYPE OF ECB, JOINT ANCHOR TRENCH JOINT ANCHOR TRENCH, TYP, INDICATED IN PLAN VIEW LOOP FROM TOPSOIL �. ECB SHALL ~ MIDDLE OF M EXTEND TO THE ROLL TOP OF THE �• j CHANNEL INTERMEDIATE ANCHOR TRENCH r D PERIMETER ANCHOR FLOW ---�� TRENCH, TYP. COMPACTED SUBGRADE STAKING PATTERN PER MANUFACTURER SPEC. OR PATTERN BASED ON ECB AND/OR CHANNEL TYPE (SEE STAKING OVERLAPPING JOINT PATTERN DETAIL) �I I�ECB-2. SMALL DITCH OR DRAINAGEWAY - 3" MIN. 12" MIN. WOOD STAKE DETAIL RECP-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC-6 STAGGER OVERLAPS DIVERSION DITCH OVERLAPPING JOINT TYPICALLY AT TOP OF SLOPE STAKING PATTERN PER MANUFACTURER SPEC. OR PATTERN BASED ON ECB AND/OR SLOPE TYPE (SEE STAKING PATTERN DETAIL) ERIMETER ANCHOR TRENCH ECB-3. OUTSIDE OF DRAINAGEWAY ROLL PERIMETER WIDTH ANCHOR W TYP, TRENCH OR JOINT, TYP. l2 W 0 I Y2 W � 3' o o � W W o 0 6' 0 6' 0 ~0 h W I t�3 4' I T F 1 0 0 0 12' STRAW STRAW-COCONUT COCONUT OR EXCELSIOR STAKING PATTERNS BY ECB TYPE 3' 2' ---I �-- Y2 W 0 0 3' 4• 0—o Y4 W 6' }t� W 6 o W o —i h W F1-I Y. W o 0 0 0 4:1-3:1 3:1-2:1 2:1 AND STEEPER SLOPES 2 SLOPES SLOPES 4' o'bo h W 4' 000 h W 0 0 0 0000 2' 20" 20" I� 0 0 0 LOW FLOW CHANNEL HIGH FLOW CHANNEL STAKING PATTERNS BY SLOPE OR CHANNEL TYPE November 2010 Urban Drainage and Flood Control District RECP-7 Urban Storm Drainage Criteria Manual Volume 3 EC-6 Rolled Erosion Control Products (RECP) EROSION CONTROL BLANKET INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION OF ECB. —TYPE OF ECB (STRAW, STRAW—COCONUT, COCONUT, OR EXCELSIOR). —AREA, A, IN SQUARE YARDS OF EACH TYPE OF ECB. 2. 100% NATURAL AND BIODEGRADABLE MATERIALS ARE PREFERRED FOR RECPS, ALTHOUGH SOME JURISDICTIONS MAY ALLOW OTHER MATERIALS IN SOME APPLICATIONS. 3. IN AREAS WHERE ECBs ARE SHOWN ON THE PLANS, THE PERMITTEE SHALL PLACE TOPSOIL AND PERFORM FINAL GRADING, SURFACE PREPARATION, AND SEEDING AND MULCHING. SUBGRADE SHALL BE SMOOTH AND MOIST PRIOR TO ECB INSTALLATION AND THE ECB SHALL BE IN FULL CONTACT WITH SUBGRADE. NO GAPS OR VOIDS SHALL EXIST UNDER THE BLANKET. 4. PERIMETER ANCHOR TRENCH SHALL BE USED ALONG THE OUTSIDE PERIMETER OF ALL BLANKET AREAS. 5. JOINT ANCHOR TRENCH SHALL BE USED TO JOIN ROLLS OF ECBs TOGETHER (LONGITUDINALLY AND TRANSVERSELY) FOR ALL ECBs EXCEPT STRAW WHICH MAY USE AN OVERLAPPING JOINT. 6. INTERMEDIATE ANCHOR TRENCH SHALL BE USED AT SPACING OF ONE—HALF ROLL LENGTH FOR COCONUT AND EXCELSIOR ECBs. 7. OVERLAPPING JOINT DETAIL SHALL BE USED TO JOIN ROLLS OF ECBs TOGETHER FOR ECBs ON SLOPES. S. MATERIAL SPECIFICATIONS OF ECBs SHALL CONFORM TO TABLE ECB—I. 9. ANY AREAS OF SEEDING AND MULCHING DISTURBED IN THE PROCESS OF INSTALLING ECBS SHALL BE RESEEDED AND MULCHED. 10. DETAILS ON DESIGN PLANS FOR MAJOR DRAINAGEWAY STABILIZATION WILL GOVERN IF DIFFERENT FROM THOSE SHOWN HERE. TABLE ECB-1. ECB MATERIAL SPECIFICATIONS TYPE COCONUT STRAW EXCELSIOR RECOMMENDED CONTENT CONTENT CONTENT NETTING" STRAW' — 100% _ DOUBLE/ NATURAL STRAW— 30% MIN 70% MAX _ DOUBLE/ COCONUT NATURAL COCONUT 100% — — DOUBLE/ NATURAL EXCELSIOR 100% DOUBLE/ NATURAL •STRAW CBS MAY ONLY BE USED OUTSIDE OF STREAMS AND DRAINAGE CHANNEL. ••ALTERNATE NETTING MAY BE ACCEPTABLE IN SOME JURISDICTIONS RECP-8 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC-6 EROSION CONTROL BLANKET MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. ECBs SHALL BE LEFT IN PLACE TO EVENTUALLY BIODEGRADE, UNLESS REQUESTED TO BE REMOVED BY THE LOCAL JURISDICTION. 5. ANY ECB PULLED OUT, TORN, OR OTHERWISE DAMAGED SHALL BE REPAIRED OR REINSTALLED. ANY SUBGRADE AREAS BELOW THE GEOTEXTILE THAT HAVE ERODED TO CREATED A VOID UNDER THE BLANKET, OR THAT REMAIN DEVOID OF GRASS SHALL BE REPAIRED, RESEEDED AND MULCHED AND THE ECB REINSTALLED. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAILS ADAPTED FROM DOUGLAS COUNTY, COLORADO AND TOWN OF PARKER COLORADO, NOT AVAILABLE IN AUTOCAO) November 2010 Urban Drainage and Flood Control District RECP-9 Urban Storm Drainage Criteria Manual Volume 3 Temporary Slope Drains (TSD) EC-7 Description A temporary slope drain is a pipe or culvert used to convey water down a slope where there is a high potential for erosion. A drainage channel or swale at the top of the slope typically directs upgradient runoff to the pipe entrance for conveyance down the slope. The pipe outlet must be equipped with outlet protection. Photograph TSD-1. A temporary slope drain installed to convey runoff down a slope during construction. Photo courtesy of the City of Aurora. Appropriate Uses Use on long, steep slopes when there is a high potential of flow concentration or rill development. Design and Installation Effective use of temporary slope drains involves design of an effective collection system to direct flows to the pipe,proper sizing and anchoring of the pipe, and outlet protection. Upgradient of the temporary slope drain, a temporary drainage ditch or swale should be constructed to collect surface runoff from the drainage area and convey it to the drain entrance. The temporary slope drain must be sized to safely convey the desired flow volume. At a minimum,it should be sized to convey the 2-year,24-hour storm. Temporary slope drains may be constructed of flexible or rigid pipe,riprap, or heavy(30 mil)plastic lining. When piping is used,it must be properly anchored by burying it with adequate cover or by using an anchor system to secure it to the ground. The discharge from the slope drain must be directed to a stabilized outlet,temporary or permanent channel, and/or sedimentation basin. See Detail TSD-1 for additional sizing and design Temporary Slope Drains information. Functions Erosion Control Yes Sediment Control No Site/Material Management No November 2010 Urban Drainage and Flood Control District SD-1 Urban Storm Drainage Criteria Manual Volume 3 EC-7 Temporary Slope Drains (TSD) Maintenance and Removal Inspect the entrance for sediment accumulation and remove,as needed. Clogging as a result of sediment deposition at the entrance can lead to ponding upstream causing flooding or overtopping of the slope drain. Inspect the downstream outlet for signs of erosion and stabilize, as needed. It may also be necessary to remove accumulated sediment at the outfall. Inspect pipe anchors to ensure that they are secure. If the pipe is secured by ground cover, ensure erosion has not compromised the depth of cover. Slope drains should be removed when no longer needed or just prior to installation of permanent slope stabilization measures that cannot be installed with the slope drain in place. When slope drains are removed,the disturbed areas should be covered with topsoil, seeded,mulched or otherwise stabilized as required by the local jurisdiction. SD-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary Slope Drains (TSD) EC-7 COMPACTED O MIN (TOP OF PIPE TO TOP TSD EMBANKMENT A OF EMBANKMENT, PIPE MUST BE ANCHORED BERM CHECK HEADWATER WITH SOIL OR OTHER >3 _ DEPTH) SUITABLE ANCHOR RIPRAP 2xD50 MIN SCH 40 PIPE D= 12" (MIN) ` PLASTIC PIPE, HEAVY CANVAS RIPRAP t STOCK. RIPRAP LINED TRENCH, BEDDING 6xD50 MIN OR GEOMEMBRANE LINED TRENCH TEMPORARY SLOPE DRAIN PROFILE 12" MIN COVER (CHECK HEADWATER DEPTH COMPACTED AND PROVIDE FOR ARMORED OVERFLOW EMBANKMENT BERM FOR EVENTS EXCEEDING DESIGN STORM) UNDISTURBED OR COMPACTED SOIL SECTION A D (10" MIN) PERIMETER ANCHOR „Y TRENCH, SEE ECB 30 MIL (MIN) IMPERMEABLE GEOMEMBRANE �2xD50 � 4xD RIPRAP MIN COMPACTED EMBANKMENT BERM UNDISTURBED OR COMPACTED SOIL TERMINATION OF RIPRAP GEOMEMBRANE LINED SLOPE DRAIN LINED SLOPE DRAIN 30 MIL (MIN) IMPERMEABLE PERIMETER ANCHOR GEOMEMBRANE TRENCH, SEE ECB D (10" MIN) 1L >3 4xD MIN TERMINATION OF GEOMEMBRANE LINED SLOPE DRAIN TSD- 1 . TEMPORARY SLOPE DRAIN PROFILE November 2010 Urban Drainage and Flood Control District SD-3 Urban Storm Drainage Criteria Manual Volume 3 EC-7 Temporary Slope Drains (TSD) SLOPE DRAIN INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION AND LENGTH OF SLOPE DRAIN —PIPE DIAMETER, D, AND RIPRAP SIZE, D50. 2. SLOPE DRAIN SHALL BE DESIGNED TO CONVEY PEAK RUNOFF FOR 2—YEAR 24—HOUR STORM AT A MINIMUM. FOR LONGER DURATION PROJECTS, LARGER MAY BE APPROPRIATE. 3. SLOPE DRAIN DIMENSIONS SHALL BE CONSIDERED MINIMUM DIMENSIONS; CONTRACTOR MAY ELECT TO INSTALL LARGER FACILITIES. 4. SLOPE DRAINS INDICATED SHALL BE INSTALLED PRIOR TO UPGRADIENT LAND—DISTURBING ACTIVITIES. 5. CHECK HEADWATER DEPTHS FOR TEMPORARY AND PERMANENT SLOPE DRAINS. DETAILS SHOW MINIMUM COVER; INCREASE AS NECESSARY FOR DESIGN HEADWATER DEPTH. 6. RIPRAP PAD SHALL BE PLACED AT SLOPE DRAIN OUTFALL. 7. ANCHOR PIPE BY COVERING WITH SOIL OR AN ALTERNATE SUITABLE ANCHOR MATERIAL. SLOPE DRAIN MAINTENANCE NOTES 1. INSPECT 8MPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. INSPECT INLET AND OUTLET POINTS AFTER STORMS FOR CLOGGING OR EVIDENCE OF OVERTOPPING. BREACHES IN PIPE OR OTHER CONVEYANCE SHALL BE REPAIRED AS SOON AS PRACTICABLE IF OBSERVED. 5. INSPECT RIPRAP PAD AT OUTLET FOR SIGNS OF EROSION. IF SIGNS OF EROSION EXIST, ADDITIONAL ARMORING SHALL BE INSTALLED. 6. TEMPORARY SLOPE DRAINS ARE TO REMAIN IN PLACE UNTIL NO LONGER NEEDED, BUT SHALL BE REMOVED PRIOR TO THE END OF CONSTRUCTION. WHEN SLOPE DRAINS ARE REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOP SOIL, SEEDED, MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND THE CITY OF COLORADO SPRINGS, COLORADO. NOT AVAILABLE IN AurocAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. SD-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary Outlet Protection (TOP) EC-8 Description Outlet protection helps to reduce erosion immediately downstream of a pipe, culvert, slope drain,rundown or other conveyance with concentrated,high- r velocityflows. Typical outlet protection Yp P consists of riprap or rock aprons at the - .r - conveyance outlet. Appropriate Uses Outlet protection should be used when a conveyance discharges onto a disturbed area where there is potential for accelerated Photograph TOP-1. Riprap outlet protection. erosion due to concentrated flow. Outlet protection should be provided where the velocity at the culvert outlet exceeds the maximum permissible velocity of the material in the receiving channel. Note: This Fact Sheet and detail are for temporary outlet protection, outlets that are intended to be used for less than 2 years. For permanent,long-term outlet protection,see the Major Drainage chapter of Volume 1. Design and Installation Design outlet protection to handle runoff from the largest drainage area that may be contributing runoff during construction(the drainage area may change as a result of grading). Key in rock,around the entire perimeter of the apron,to a minimum depth of 6 inches for stability. Extend riprap to the height of the culvert or the normal flow depth of the downstream channel,whichever is less. Additional erosion control measures such as vegetative lining, turf reinforcement mat and/or other channel lining methods may be required downstream of the outlet protection if the channel is susceptible to erosion. See Design Detail OP-1 for additional information. Maintenance and Removal Inspect apron for damage and displaced rocks. If rocks are missing or significantly displaced,repair or replace as necessary. If rocks are continuously missing or displaced, consider increasing the size of the riprap or deeper keying of the perimeter. Remove sediment accumulated at the outlet before the outlet protection becomes buried and ineffective. When sediment accumulation is noted, check that upgradient BMPs, including inlet protection,are in effective operating condition. Outlet Protection Outlet protection may be removed once the pipe is no longer draining an upstream area,or once the downstream area has Functions been sufficiently stabilized. If the drainage pipe is Erosion Control Yes permanent, outlet protection can be left in place;however, Sediment Control Moderate permanent outlet protection should be designed and Site/Material Management No constructed in accordance with the requirements of the Major Drainage chapter of Volume 2. November 2010 Urban Drainage and Flood Control District TOP-1 Urban Storm Drainage Criteria Manual Volume 3 EC-8 Temporary Outlet Protection (TOP) EXTEND RIPRAP TO HEIGHT OF CULVERT OR NORMAL CHANNEL O DEPTH, WHICHEVER IS LESS 3(Do) Do 4(Do) .j TEMPORARY OUTLET PROTECTION PLAN Lo 0% r D - 2 x 050 1� NON-WOVEN GEOTEXTILE L KEY IN TO 2 x D50 AROUND PERIMETER SECTION A TABLE OP-1. TEMPORARY OUTLET PROTECTION SIZING TABLE PIPE APRON RIPRAP D50 DIAMETER, DISCHARGE, DIAMETER Do Q (CFS) LENGTH, La MIN (INCHES) (FT) MIN 8 2.5 5 4 5 10 6 12 5 10 4 10 13 6 10 10 6 18 20 16 9 30 23 12 40 26 16 30 16 9 40 26 9 `� 50 26 12 60 30 16 OP- 1 . TEMPORARY OUTLET PROTECTION TOP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary Outlet Protection (TOP) EC-8 TEMPORARY OUTLET PROTECTION INSTALLATION NOTES 1. SEE PLAN VIEW FOR —LOCATION OF OUTLET PROTECTION. —DIMENSIONS OF OUTLET PROTECTION. 2. DETAIL IS INTENDED FOR PIPES WITH SLOPE S 10%. ADDITIONAL EVALUATION OF RIPRAP SIZING AND OUTLET PROTECTION DIMENSIONS REQUIRED FOR STEEPER SLOPES. 3. TEMPORARY OUTLET PROTECTION INFORMATION IS FOR OUTLETS INTENDED TO BE UTILIZED LESS THAN 2 YEARS. TEMPORARY OUTLET PROTECTION INSPECTION AND MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAILS ADAPTED FROM AURORA, COLORADO AND PREVIOUS VERSION OF VOLUME 3, NOT AVAILABLE IN AUTOCAO) November 2010 Urban Drainage and Flood Control District TOP-3 Urban Storm Drainage Criteria Manual Volume 3 Rough Cut Street Control (RCS) EC-9 Description Rough cut street controls are rock or earthen berms placed along dirt roadways that are under construction or used for : construction access. These temporary berms intercept sheet flow and divert runoff from the roadway, and control erosion by minimizing concentration of flow and reducing runoff velocity. u Appropriate Uses Appropriate uses include: ■ Temporary dirt construction roadways that have not received roadbase. Photograph RCS-1.Rough cut street controls. ■ Roadways under construction that will not be paved within 14 days of final grading, and that have not yet received roadbase. Design and Installation Rough cut street controls are designed to redirect sheet flow off the dirt roadway to prevent water from concentrating and eroding the soil. These controls consist of runoff barriers that are constructed at intervals along the road. These barriers are installed perpendicular to the longitudinal slope from the outer edge of the roadside swale to the crown of the road. The barriers are positioned alternately from the right and left side of the road to allow construction traffic to pass in the lane not barred. If construction traffic is expected to be congested and a vehicle tracking control has been constructed,rough-cut street controls may be omitted for 400 feet from the entrance. Runoff from the controls should be directed to another stormwater BMP such as a roadside swale with check dams once removed from the roadway. See Detail RCS-1 for additional information. Maintenance and Removal Inspect street controls for erosion and stability. If rills are forming in the roadway or cutting through the control berms,place the street controls at shorter intervals. If earthen berms are used,periodic recompaction may be necessary. When rock berms are used, repair and/or replace as necessary when damaged. Street Rough Cut Street Control controls may be removed 14 days prior to road surfacing and Functions paving. Erosion Control Yes Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District RCS-1 Urban Storm Drainage Criteria Manual Volume 3 EC-9 Rough Cut Street Control (RCS) RCS A SPACING 200' MAXIMUM (SEE TABLE RCS-2) PL EXCAVATED STREET :j W = 1/2 ROADBED ROADBED SLOPE WIDTH CL - - - X SEE TABLE RCS-1 8' MINIMUM SPACING B FOR VEHICLE PASSAGE PL GEOTEXTILE SOCK(S) FILLED WITH CRUSHED ROCK OR COMPACTED EARTHEN BERM(S) ROUGH CUT STREET CONTROL PLAN PL CL W PL EFW y FLOW GEOTEXTILE SOCK(S) FILLED EXCAVATED ROADBED WITH CRUSH ROCK OR COMPACTED EARTHEN BERM(S) SECTION A l2" TO 18" ;_; 12" TO 18" SECTION B TABLE RCS-1 TABLE RCS-2 W (FT) X (FT) LONGITUDINAL SPACING (FT) STREET SLOPE (%) 20-30 5 <2 NOT TYPICALLY NEEDED 2 200 31-40 7 3 200 41-50 9 4 150 51-60 10.5 5 100 6 50 61-70 12 7 25 8 25 RCS- 1 . ROUGH CUT STREET CONTROL RCS-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rough Cut Street Control (RCS) EC-9 ROUGH CUT STREET CONTROL INSTALLATION NOTES 1, SEE PLAN VIEW FOR —LOCATION OF ROUGH CUT STREET CONTROL MEASURES. 2. ROUGH CUT STREET CONTROL SHALL BE INSTALLED AFTER A ROAD HAS BEEN CUT IN, AND WILL NOT BE PAVED FOR MORE THAN 14 DAYS OR FOR TEMPORARY CONSTRUCTION ROADS THAT HAVE NOT RECEIVED ROAD BASE. ROUGH CUT STREET CONTROL INSPECTION AND MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. (DETAILS ADAPTED FROM AURORA, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District RCS-3 Urban Storm Drainage Criteria Manual Volume 3 Earth Dikes and Drainage Swales (ED/DS) EC-10 Description Earth dikes and drainage swales are temporary storm conveyance channels constructed either to divert runoff around slopes or to convey runoff to additional sediment control BMPs prior to discharge of runoff from a site. Drainage swales may be lined or unlined,but if an unlined swale is used,it must be well compacted and capable of resisting erosive velocities. Appropriate Uses = *� Earth dikes and drainage swales are typically used to control the flow path of : . runoff at a construction site by diverting , runoff around areas prone to erosion,such 4_ as steep slopes. Earth dikes and drainageY swales may also be constructed as temporary conveyance features. This will direct runoff to additional sediment control Photograph ED/DS-1. Example of an earth dike used to divert flows at a construction site. Photo courtesy of CDOT. treatment BMPs, such as sediment traps or basins. Design and Installation When earth dikes are used to divert water for slope protection,the earth dike typically consists of a horizontal ridge of soil placed perpendicular to the slope and angled slightly to provide drainage along the contour. The dike is used in conjunction with a swale or a small channel upslope of the berm to convey the diverted water. Temporary diversion dikes can be constructed by excavation of a V-shaped trench or ditch and placement of the fill on the downslope side of the cut. There are two types of placement for temporary slope diversion dikes: ■ A dike located at the top of a slope to divert upland runoff away from the disturbed area and convey it in a temporary or permanent channel. ■ A diversion dike located at the base or mid-slope of a disturbed area to intercept runoff and reduce the effective slope length. Depending on the project, either an earth dike or drainage swale may be more appropriate. If there is a need for cut on the project,then an excavated drainage Swale may be better suited. When the project is primarily Earth Dikes and Drainage Swales fill,then a conveyance constructed using a berm may be the better option. Functions All dikes or swales receiving runoff from a disturbed Erosion Control Yes area should direct stormwater to a sediment control Sediment Control Moderate BMP such as a sediment trap or basin. Site/Material Management No November 2010 Urban Drainage and Flood Control District ED/DS-1 Urban Storm Drainage Criteria Manual Volume 3 EC-10 Earth Dikes and Drainage Swales (ED/DS) Unlined dikes or swales should only be used for intercepting sheet flow runoff and are not intended for diversion of concentrated flows. Details with notes are provided for several design variations, including: ED-1. Unlined Earth Dike formed by Berm DS-1. Unlined Excavated Swale DS-2. Unlined Swale Formed by Cut and Fill DS-3. ECB-lined Swale DS-4. Synthetic-lined Swale DS-5. Riprap-lined Swale The details also include guidance on permissible velocities for cohesive channels if unlined approaches will be used. Maintenance and Removal Inspect earth dikes for stability, compaction,and signs of erosion and repair. Inspect side slopes for erosion and damage to erosion control fabric. Stabilize slopes and repair fabric as necessary. If there is reoccurring extensive damage, consider installing rock check dams or lining the channel with riprap. If drainage swales are not permanent,remove dikes and fill channels when the upstream area is stabilized. Stabilize the fill or disturbed area immediately following removal by revegetation or other permanent stabilization method approved by the local jurisdiction. ED/DS-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Earth Dikes and Drainage Swales (ED/DS) EC-10 ED/ DS 5" NJ TRANSV SE FLOW TO SWALE EXISTING GRADE ED- 1 . COMPACTED UNLINED EARTH DIKE FORMED BY BERM TRANSVERSE FLOW f TO WALE 1- r_ � � EXISTING GRADE 15" MIN.rZ- >3 >3 DS- 1 . COMPACTED UNLINED EXCAVATED SWALE r LOW >3 F _L 1 EXISTING GRADE >_3 15" MIN DS-2. COMPACTED UNLINED SWALE FORMED BY CUT AND FILL W 5' MIN. STAKES (SEE ECB) GEOTEXTILE OR MAT (SEE ECB) D (10" MIN.) ANCHOR TRENCH AT PERIMETER OF I BLANKET AND AT OVERLAPPING JOINTS WITH ANY ADJACENT ROLLS OF BLANKET INTERMEDIATE ANCHOR TRENCH AT (SEE ECB) ONE-HALF ROLL LENGTH (SEE ECB) TRANSVERSE ANCHOR TRENCHES AT PERIMETER OF BLANKET AND AT OVERLAPPING JOINTS WITH ANY ADJACENT ROLLS OF BLANKET (SEE ECB) DS-3. ECB LINED SWALE (CUT AND FILL OR BERM November 2010 Urban Drainage and Flood Control District ED/DS-3 Urban Storm Drainage Criteria Manual Volume 3 EC-10 Earth Dikes and Drainage Swales (ED/DS) NO 30 MIL MIN. W (5. MIN.) STAKING THICKNESS rD (10" MIN.) ANCHOR TRENCH AT PERIMETER OF BLANKET AND AT OVERLAPPING JOINTS WITH ANY ADJACENT ROLLS OF BLANKET, INTERMEDIATE ANCHOR / SIMILAR TO ECB, BUT NO TRENCH AT ONE-HALF ROLL STAKING LENGTH SIMILAR TO ECB, TRANSVERSE ANCHOR TRENCHES AT PERIMETER OF BUT NO STAKING BLANKET AND AT OVERLAPPING JOINTS WITH ANY ADJACENT ROLLS OF BLANKET, SIMILAR TO ECB, BUT NO STAKING DS-4. SYNTHETIC LINED SWALE THICKNESS=2 X D50 W (5' MIN.) D (10" MIN.) I LINE WITH AASHTO #3 ROCK (COOT SECT. 703. #3) OR RIPRAP CALLED FOR IN THE PLANS DS-5. RIPRAP LINED SWALE EARTH DIKE AND DRAINAGE SWALE INSTALLATION NOTES 1. SEE SITE PLAN FOR- - LOCATION OF DIVERSION SWALE - TYPE OF SWALE (UNLINED, COMPACTED AND/OR LINED). - LENGTH OF EACH SWALE. - DEPTH, D, AND WIDTH, W DIMENSIONS. - FOR ECB/TRM LINED DITCH, SEE ECB DETAIL. - FOR RIPRAP LINED DITCH, SIZE OF RIPRAP, D50. 2 SEE DRAINAGE PLANS FOR DETAILS OF PERMANENT CONVEYANCE FACILITIES AND/OR DIVERSION SWALES EXCEEDING 2-YEAR FLOW RATE OR 10 CFS. 3. EARTH DIKES AND SWALES INDICATED ON SWMP PLAN SHALL BE INSTALLED PRIOR TO LAND-DISTURBING ACTIVITIES IN PROXIMITY. 4. EMBANKMENT IS TO BE COMPACTED TO 90% OF MAXIMUM DENSITY AND WITHIN 2% OF OPTIMUM MOISTURE CONTENT ACCORDING TO ASTM D698. 5. SWALES ARE TO DRAIN TO A SEDIMENT CONTROL BMP. 6 FOR LINED DITCHES, INSTALLATION OF ECB/TRM SHALL CONFORM TO THE REQUIREMENTS OF THE ECB DETAIL. 7. WHEN CONSTRUCTION TRAFFIC MUST CROSS A DIVERSION SWALE, INSTALL A TEMPORARY CULVERT WITH A MINIMUM DIAMETER OF 12 INCHES. ED/DS-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Earth Dikes and Drainage Swales (ED/DS) EC-10 EARTH DIKE AND DRAINAGE SWALE MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SWALES SHALL REMAIN IN PLACE UNTIL THE END OF CONSTRUCTION; IF APPROVED BY LOCAL JURISDICTION, SWALES MAY BE LEFT IN PLACE. 5, WHEN A SWALE IS REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY LOCAL JURISDICTION. (DETAIL ADAPTED FROM OOUCLAS COUNTY, COLORADO AND THE CITY OF COLORADO SPRINGS, COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED, November 2010 Urban Drainage and Flood Control District ED/DS-5 Urban Storm Drainage Criteria Manual Volume 3 Terracing (TER) EC-11 Description Terracing involves grading steep slopes into a series of relatively flat sections, or terraces,separated at intervals by steep slope segments. Terraces shorten the uninterrupted flow lengths on steep slopes,helping to reduce the „• ••4L .� development of rills and gullies. + ~ Retaining walls,gabions,cribbing, deadman anchors,rock-filled slope .« mattresses,and other types of soil ` retention systems can be used in terracing. Photograph TER-1. Use of a terrace to reduce erosion by controlling slope length on a long,steep slope. Photo courtesy of Douglas Appropriate Uses county. Terracing techniques are most typically used to control erosion on slopes that are steeper than 4:1. Design and Installation Design details with notes are provided in Detail TER-1. The type,number, and spacing of terraces will depend on the slope, slope length, and other factors. The Revised Universal Soil Loss Equation(RUSLE)may be helpful in determining spacing of terraces on slopes. Terracing should be used in combination with other stabilization measures that provide cover for exposed soils such as mulching, seeding, surface roughening, or other measures. Maintenance and Removal Repair rill erosion on slopes and remove accumulated sediment, as needed. Terracing may be temporary or permanent. If terracing is temporary,the slope should be topsoiled,seeded, and mulched when the slope is graded to its final configuration and terraces are removed. Due to the steepness of the slope, once terraces are graded, erosion control blankets or other stabilization measures are typically required. If terraces are permanent,vegetation should be established on slopes and terraces as soon as practical. Terracing Functions Erosion Control Yes Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District TER-1 Urban Storm Drainage Criteria Manual Volume 3 EC-11 Terracing (TER) TER W — (--� ) EXISTING GRADE "H" VARIES (1 5' MAX.) ~ _ SEE GRADING PLAN FINISHED _�^ 3% MIN., TYP. GRADE TER- 1 . TERRACING TERRACING INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION OF TERRACING —WIDTH (W), AND SLOPE (Z). 2. TERRACING IS TYPICALLY NOT REQUIRED FOR SLOPES OF 4:1 OR FLATTER. 3. GRADE TERRACES TO DRAIN BACK TO SLOPE AT A MINIMUM OF 3% GRADE. TERRACING MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPS IN EFFECTIVE OPERATING CONDITION, INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. RILL EROSION OCCURRING ON TERRACED SLOPES SHALL BE REPAIRED, RESEEDED, MULCHED OR STABILIZED IN A MANNER APPROVED BY LOCAL JURISDICTION. 5. TERRACING MAY NEED TO BE RE—GRADED TO RETURN THE SLOPE TO THE FINAL DESIGN GRADE. THE SLOPE SHALL THEN BE COVERED WITH TOPSOIL, SEEDED AND MULCHED, OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND TOWN OF PARKER, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. TER-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Check Dams (CD) EC-12 Description - Check dams are temporary grade control structures placed in drainage channels to limit the erosivity of stormwater by reducing flow velocity. Check dams are typically constructed from rock, gravel bags, sand bags, or sometimes, proprietary devices. Reinforced check dams are typically constructed from rock and wire gabion. Although the primary function of check dams is to reduce the velocity of concentrated flows, a secondary benefit is sediment trapping Photograph CD-1. Rock check dams in a roadside ditch. Photo upstream of the structure. courtesy of W WE. Appropriate Uses Use as a grade control for temporary drainage ditches or swales until final soil stabilization measures are established upstream and downstream. Check dams can be used on mild or moderately steep slopes. Check dams may be used under the following conditions: ■ As temporary grade control facilities along waterways until final stabilization is established. ■ Along permanent swales that need protection prior to installation of a non-erodible lining. ■ Along temporary channels,ditches or swales that need protection where construction of a non- erodible lining is not practicable. ■ Reinforced check dams should be used in areas subject to high flow velocities. Design and Installation Place check dams at regularly spaced intervals along the drainage swale or ditch. Check dams heights should allow for pools to develop upstream of each check dam, extending to the downstream toe of the check dam immediately upstream. When rock is used for the check dam,place rock mechanically or by hand. Do not dump rocks into the drainage channel. Where multiple check dams are used,the top of the lower dam should be at the same elevation as the toe of the upper dam. When reinforced check dams are used,install erosion control fabric under and around the check dam to prevent erosion on the upstream and downstream sides. Each section of the dam should be keyed in to reduce the potential Check Dams for washout or undermining. A rock apron upstream and Functions downstream of the dam may be necessary to further control Erosion Control Yes erosion. Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District CD-1 Urban Storm Drainage Criteria Manual Volume 3 EC-12 Check Dams (CD) Design details with notes are provided for the following types of check dams: ■ Rock Check Dams (CD-1) ■ Reinforced Check Dams (CD-2) Sediment control logs may also be used as check dams; however, silt fence is not appropriate for use as a check dam. Many jurisdictions also prohibit or discourage use of straw bales for this purpose. Maintenance and Removal Replace missing rocks causing voids in the check dam. If gravel bags or sandbags are used,replace or repair torn or displaced bags. Remove accumulated sediment, as needed to maintain BMP effectiveness,typically before the sediment depth upstream of the check dam is within'/2 of the crest height. Remove accumulated sediment prior to mulching, seeding, or chemical soil stabilization. Removed sediment can be incorporated into the earthwork with approval from the Project Engineer,or disposed of at an alternate location in accordance with the standard specifications. Check dams constructed in permanent swales should be removed when perennial grasses have become established,or immediately prior to installation of a non-erodible lining. All of the rock and accumulated sediment should be removed, and the area seeded and mulched, or otherwise stabilized. CD-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Check Dams (CD) EC-12 CD LENGTH, L CREST LENGTH, CL B SECTION B TYP_ D SECTION A (1. 6" MIN") - 1' 6" 2 (MIN) 1f COMPACTED (TYP.) CHANNEL GRADE UPSTREAM AND TOP OF CHECK DAM DOWNSTREAM A CHECK DAM ELEVATION VIEW 2' 6' CHANNEL GRADE 1 6 FLOW - MIN. r 1' MIN. ~ EXCAVATION TO NEAT ," „_, •� LINE, AVOID OVER-EXCAVATION, (TYP.) D50 = 12" RIPRAP, TYPE M OR TYPE L 050= 9" (SEE TABLE MD-7, MAJOR DRAINAGE, VOL. 1 FOR GRADATION) SECTION A FLOW -- CHANNEL GRADE `1 EXCAVATION TO NEAT 1' MIN. i w�pi LINE, AVOID OVER-EXCAVATION D50 = 12" RIPRAP, TYPE M OR TYPE L D50=9" (SEE TABLE MD-7, MAJOR DRAINAGE, VOL. 1 FOR GRADATION) SECTION B SPACING BETWEEN CHECK DAMS SUCH THAT q A AND B ARE EQUAL ELEVATION CHANNEL GRADE PROFILE CD- 1 . CHECK DAM November 2010 Urban Drainage and Flood Control District CD-3 Urban Storm Drainage Criteria Manual Volume 3 EC-12 Check Dams (CD) CHECK DAM INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION OF CHECK DAMS. —CHECK DAM TYPE (CHECK DAM OR REINFORCED CHECK DAM). —LENGTH (L), CREST LENGTH (CL), AND DEPTH (D). 2. CHECK DAMS INDICATED ON INITIAL SWMP SHALL BE INSTALLED AFTER CONSTRUCTION FENCE, BUT PRIOR TO ANY UPSTREAM LAND DISTURBING ACTIVITIES. 3. RIPRAP UTILIZED FOR CHECK DAMS SHOULD BE OF APPROPRIATE SIZE FOR THE APPLICATION. TYPICAL TYPES OF RIPRAP USED FOR CHECK DAMS ARE TYPE M (D50 12") OR TYPE L (D50 9"). 4. RIPRAP PAD SHALL BE TRENCHED INTO THE GROUND A MINIMUM OF 1'. 5. THE ENDS OF THE CHECK DAM SHALL BE A MINIMUM OF 1' 6" HIGHER THAN THE CENTER OF THE CHECK DAM. CHECK DAM MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF THE CHECK DAMS SHALL BE REMOVED WHEN THE SEDIMENT DEPTH IS WITHIN YZ OF THE HEIGHT OF THE CREST. 5. CHECK DAMS ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 6 WHEN CHECK DAMS ARE REMOVED, EXCAVATIONS SHALL BE FILLED WITH SUITABLE COMPACTED BACKFILL. DISTURBED AREA SHALL BE SEEDED AND MULCHED AND COVERED WITH GEOTEXTILE OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM DOUGLAS COUNTY. COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CD-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Check Dams (CD) EC-12 RCD ALTERNATIVE TO STEPS ON BANKS ABOVE CREST DEFORM GABIONS AS NECESSARY TO ALIGN TOP OF GABIONS WITH GROUND SURFACE: AVOID GAPS BETWEEN GABIONS A LENGTH L MAX. STEP CREST LENGTH CL HEIGHT 1'6" D I S4 6 TYP (1'6" MIN) COMPACTED } ROCK FILLED GABION BACKFILL HOG RINGS MIN. BURY J SECURED TO (TYP) DEPTH 1'6" ADJACENT GABION REINFORCED CHECK DAM ELEVATION VIEW 3' D50=6" RIPRAP ENCLOSED IN GABION 6" MIN. FLOW - 1'6" MIN } _ - -- !_ 1,6„ 172XTILE CHANNEL GRADE COMPACTED BACKFILL r' BLANKET SECTION A REINFORCED CHECK DAM INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATIONS OF CHECK DAMS. -CHECK DAM TYPE (CHECK DAM OR REINFORCED CHECK DAM). -LENGTH (L), CREST LENGTH (CL), AND DEPTH (0). 2. CHECK DAMS INDICATED ON THE SWMP SHALL BE INSTALLED PRIOR TO AN UPSTREAM LAND-DISTURBING ACTIVITIES. 3. REINFORCED CHECK DAMS, GABIONS SHALL HAVE GALVANIZED TWISTED WIRE NETTING WITH A MAXIMUM OPENING DIMENSION OF 02" AND A MINIMUM WIRE THICKNESS OF 0.10". WIRE "HOG RINGS" AT 4" SPACING OR OTHER APPROVED MEANS SHALL BE USED AT ALL GABION SEAMS AND TO SECURE THE GABION TO THE ADJACENT SECTION. 4. THE CHECK DAM SHALL BE TRENCHED INTO THE GROUND A MINIMUM OF 1' 6". 5. GEOTEXTILE BLANKET SHALL BE PLACED IN THE REINFORCED CHECK DAM TRENCH EXTENDING A MINIMUM OF 1' 6" ON BOTH THE UPSTREAM AND DOWNSTREAM SIDES OF THE REINFORCED CHECK DAM. CD-2. REINFORCED CHECK DAM November 2010 Urban Drainage and Flood Control District CD-5 Urban Storm Drainage Criteria Manual Volume 3 EC-12 Check Dams (CD) REINFORCED CHECK DAM MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF REINFORCED CHECK DAMS SHALL BE REMOVED AS NEEDED TO MAINTAIN THE EFFECTIVENESS OF BMP, TYPICALLY WHEN THE UPSTREAM SEDIMENT DEPTH IS WITHIN Y2 THE HEIGHT OF THE CREST. 5. REPAIR OR REPLACE REINFORCED CHECK DAMS WHEN THERE ARE SIGNS OF DAMAGE SUCH AS HOLES IN THE GABION OR UNDERCUTTING. 6. REINFORCED CHECK DAMS ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 7. WHEN REINFORCED CHECK DAMS ARE REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED, AND COVERED WITH A GEOTEXTILE BLANKET, OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND CITY OF AURORA, COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CD-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Streambank Stabilization (SS) EC-13 Description Streambank stabilization involves a combination of erosion and sediment control practices to protect streams, banks, and in-stream habitat from '""�N -` accelerated erosion. BMPs associated with streambank stabilization may include protection of existing vegetation,check dams/grade control, temporary and permanent seeding, outlet protection,rolled erosion control products,temporary diversions, `p. dewatering operations and = bioengineering practices such as brush layering, live staking and fascines. Photograph SS-1. Streambank stabilization using geotextiles Appropriate Uses following installation of a permanent in-stream grade control structure. Streambank stabilization may be a construction activity in and of itself, or it may be in conjunction with a broader construction project that discharges to a waterway that is susceptible to accelerated erosion due to increases in the rate and volume of stormwater runoff. Depending on the health of the stream,water quality sampling and testing may be advisable prior to and/or during construction to evaluate health and stability of the stream and potential effects from adjacent construction activities. Design and Installation Streambank stabilization consists of protecting the stream in a variety of ways to minimize negative effects to the stream environment. The following lists the minimum requirements necessary for construction streambank stabilization: ■ Protect existing vegetation along the stream bank in accordance with the Vegetated Buffers and Protection of Existing Vegetation Fact Sheets. Preserving a riparian buffer along the streambank will help to remove sediment and decrease runoff rates from the disturbed area. ■ Outside the riparian buffer,provide sediment control in the form of a silt fence or equivalent sediment control practice along the entire length of the stream that will receive runoff from the area of disturbance. In some cases,a double-layered perimeter control may be justified adjacent to sensitive receiving waters and wetlands to provide additional protection. ■ Stabilize all areas that will be draining to the stream. Use rolled erosion control products,temporary or permanent seeding, or other appropriate measures. ■ Ensure all point discharges entering the stream are Streambank Stabilization adequately armored with a velocity dissipation device and appropriate outlet protection. Functions Erosion Control Yes See individual design details and notes for the various BMPs Sediment Control No referenced in this practice. Additional information on bioengineering techniques for stream stabilization can be Site/Material Management No November 2010 Urban Drainage and Flood Control District SS-1 Urban Storm Drainage Criteria Manual Volume 3 EC-13 Streambank Stabilization (SS) found in the Major Drainage chapter of Volume 1 and additional guidance on BMPs for working in waterways can be found in UDFCD's Best Management Practices for Construction in Waterways Training Manual. Maintenance and Removal Inspect BMPs protecting the stream for damage on a daily basis. Maintain,repair, or replace damaged BMPs following the guidance provided in individual BMP Fact Sheets for practices that are implemented. Some streambank stabilization BMPs are intended to remain in place as vegetation matures(e.g. erosion control blankets protecting seeded stream banks and turf reinforcement mats). For BMPs that are not to remain in place as a part of final stabilization such as silt fence and other temporary measures, BMPs should be removed when all land disturbing activities have ceased and areas have been permanently stabilized. SS-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Wind Erosion/Dust Control (DC) EC-14 Description Wind erosion and dust control BMPs help to keep soil particles from entering ' the air as a result of land disturbing construction activities. These BMPs include a variety of practices generally focused on either graded disturbed areas or construction roadways. For graded areas,practices such as seeding and mulching,use of soil binders, site watering, or other practices that provide prompt surface cover should be used. For construction roadways,road watering and stabilized surfaces should be considered. Photograph DC-1. Water truck used for dust suppression. Photo courtesy of Douglas County. Appropriate Uses Dust control measures should be used on any site where dust poses a problem to air quality. Dust control is important to control for the health of construction workers and surrounding waterbodies. Design and Installation The following construction BMPs can be used for dust control: ■ An irrigation/sprinkler system can be used to wet the top layer of disturbed soil to help keep dry soil particles from becoming airborne. ■ Seeding and mulching can be used to stabilize disturbed surfaces and reduce dust emissions. ■ Protecting existing vegetation can help to slow wind velocities across the ground surface,thereby limiting the likelihood of soil particles to become airborne. ■ Spray-on soil binders form a bond between soil particles keeping them grounded. Chemical treatments may require additional permitting requirements. Potential impacts to surrounding waterways and habitat must be considered prior to use. ■ Placing rock on construction roadways and entrances will help keep dust to a minimum across the construction site. ■ Wind fences can be installed on site to reduce wind speeds. Install fences perpendicular to the prevailing Wind Erosion Control/ wind direction for maximum effectiveness. Dust Control Functions Maintenance and Removal Erosion Control Yes When using an irrigation/sprinkler control system to aid in Sediment Control No dust control,be careful not to overwater. Overwatering will Site/Material Management Moderate cause construction vehicles to track mud off-site. November 2010 Urban Drainage and Flood Control District DC-1 Urban Storm Drainage Criteria Manual Volume 3 Concrete Washout Area (CWA) MM-1 Description Concrete waste management involves designating and properly managing a specific area of the construction site as a concrete washout area. A concrete niannun,,mllnm III'4nI Xl[I m,Iminml. IW,,,,IplADlllp,,lli 1,11111:mnmT Inn AIfOA FI IVI,IAIII,I Ii1NElA washout area can be created using one of - - several approaches designed to receive wash water from washing of tools and concrete mixer chutes, liquid concrete waste from dump trucks,mobile batch mixers, or pump trucks. Three basic approaches are available: excavation of a pit in the ground,use of an above ground storage area, or use of prefabricated haul- away concrete washout containers. Surface discharges of concrete washout water from construction sites are prohibited. Photograph CWA-1. Example of concrete washout area. Note gravel tracking pad for access and sign. Appropriate Uses Concrete washout areas must be designated On all sites that will generate concrete wash water or liquid concrete waste from onsite concrete mixing or concrete delivery. Because pH is a pollutant of concern for washout activities,when unlined pits are used for concrete washout,the soil must have adequate buffering capacity to result in protection of state groundwater standards; otherwise, a liner/containment must be used. The following management practices are recommended to prevent an impact from unlined pits to groundwater: ■ The use of the washout site should be temporary(less than 1 year), and ■ The washout site should be not be located in an area where shallow groundwater may be present, such as near natural drainages, springs,Or wetlands. Design and Installation Concrete washout activities must be conducted in a manner that does not contribute pollutants to surface waters or stormwater runoff. Concrete washout areas may be lined or unlined excavated pits in the ground, commercially manufactured prefabricated washout containers,or aboveground holding areas constructed of berms, sandbags or straw bales with a plastic liner. Although unlined washout areas may be used, lined pits may be required to protect groundwater under certain conditions. Concrete Washout Area Do not locate an unlined washout area within 400 feet Functions of any natural drainage pathway or waterbody or within 1,000 feet of any wells or drinking water Erosion Control No sources. Even for lined concrete washouts,it is Sediment Control No advisable to locate the facility away from waterbodies Site/Material Management Yes and drainage paths. If site constraints make these November 2010 Urban Drainage and Flood Control District CWA-1 Urban Storm Drainage Criteria Manual Volume 3 MM-1 Concrete Washout Area (CWA) setbacks infeasible or if highly permeable soils exist in the area,then the pit must be installed with an impermeable liner(16 mil minimum thickness) or surface storage alternatives using prefabricated concrete washout devices or a lined aboveground storage area should be used. Design details with notes are provided in Detail CWA-1 for pits and CWA-2 for aboveground storage areas. Pre-fabricated concrete washout container information can be obtained from vendors. Maintenance and Removal A key consideration for concrete washout areas is to ensure that adequate signage is in place identifying the location of the washout area. Part of inspecting and maintaining washout areas is ensuring that adequate signage is provided and in good repair and that the washout area is being used,as opposed to washout in non-designated areas of the site. Remove concrete waste in the washout area, as needed to maintain BMP function(typically when filled to about two-thirds of its capacity). Collect concrete waste and deliver offsite to a designated disposal location. Upon termination of use of the washout site,accumulated solid waste, including concrete waste and any contaminated soils,must be removed from the site to prevent on-site disposal of solid waste. If the wash water is allowed to evaporate and the concrete hardens,it may be recycled. '�• HCRErE Photograph CWA-2. Prefabricated concrete washout. Photo Photograph CWA-3. Earthen concrete washout. Photo courtesy of CDOT. courtesy of CDOT. CWA-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Concrete Washout Area (CWA) MM-1 CONCRETE WASHOUT A SIGN CWA 3:1 4' MIN. 3:1 8 X 8 MIN. 3:1 VEHICLE TRACKING CONTROL (SEE ' VTC DETAIL) OR �- OTHER STABLE . ltlr", - - - SURFACE 3:1 � 25 MIN. I i CONCRETE WASHOUT AREA PLAN 12" TYP. COMPACTED BERM AROUND >4 THE PERIMETER 1F- 2% SLOPE 1L S3' MIN. <- UNDISTURBED OR >3 >3 COMPACTED SOIL S X 8 MIN. VEHICLE TRACKING CONTROL (SEE VTC SECTION A DETAIL CWA- 1 . CONCRETE WASHOUT AREA CWA INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -CWA INSTALLATION LOCATION, 2. DO NOT LOCATE AN UNLINED CWA WITHIN 400' OF ANY NATURAL DRAINAGE PATHWAY OR WATERBODY. DO NOT LOCATE WITHIN 1,000' OF ANY WELLS OR DRINKING WATER SOURCES. IF SITE CONSTRAINTS MAKE THIS INFEASIBLE, OR IF HIGHLY PERMEABLE SOILS EXIST ON SITE, THE CWA MUST BE INSTALLED WITH AN IMPERMEABLE LINER (16 MIL MIN. THICKNESS) OR SURFACE STORAGE ALTERNATIVES USING PREFABRICATED CONCRETE WASHOUT DEVICES OR A LINED ABOVE GROUND STORAGE ARE SHOULD BE USED. 3. THE CWA SHALL BE INSTALLED PRIOR TO CONCRETE PLACEMENT ON SITE. 4. CWA SHALL INCLUDE A FLAT SUBSURFACE PIT THAT IS AT LEAST 8' BY 8' SLOPES LEADING OUT OF THE SUBSURFACE PIT SHALL BE 3:1 OR FLATTER. THE PIT SHALL BE AT LEAST 3' DEEP. 5. BERM SURROUNDING SIDES AND BACK OF THE CWA SHALL HAVE MINIMUM HEIGHT OF 1'- 6. VEHICLE TRACKING PAD SHALL BE SLOPED 2% TOWARDS THE CWA. 7. SIGNS SHALL BE PLACED AT THE CONSTRUCTION ENTRANCE, AT THE CWA, AND ELSEWHERE AS NECESSARY TO CLEARLY INDICATE THE LOCATION OF THE CWA TO OPERATORS OF CONCRETE TRUCKS AND PUMP RIGS. 8. USE EXCAVATED MATERIAL FOR PERIMETER BERM CONSTRUCTION. November 2010 Urban Drainage and Flood Control District CWA-3 Urban Storm Drainage Criteria Manual Volume 3 MM-1 Concrete Washout Area (CWA) CWA MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. I WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. THE CWA SHALL BE REPAIRED, CLEANED, OR ENLARGED AS NECESSARY TO MAINTAIN CAPACITY FOR CONCRETE WASTE. CONCRETE MATERIALS, ACCUMULATED IN PIT, SHALL BE REMOVED ONCE THE MATERIALS HAVE REACHED A DEPTH OF 2'. 5. CONCRETE WASHOUT WATER, WASTED PIECES OF CONCRETE AND ALL OTHER DEBRIS IN THE SUBSURFACE PIT SHALL BE TRANSPORTED FROM THE JOB SITE IN A WATER—TIGHT CONTAINER AND DISPOSED OF PROPERLY. 6. THE CWA SHALL REMAIN IN PLACE UNTIL ALL CONCRETE FOR THE PROJECT IS PLACED. 7. WHEN THE CWA IS REMOVED, COVER THE DISTURBED AREA WITH TOP SOIL, SEED AND MULCH OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND THE CITY OF PARKER, COLORADO, NOT AVAILABLE IN AUTOCAD). NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CWA-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Stockpile Management (SP) MM-2 Description Stockpile management includes _ measures to minimize erosion and _ sediment transport from soil stockpiles. Appropriate Uses Stockpile management should be used when soils or other erodible materials ~; are stored at the construction site. ,s,. _ - �� ' � A.. �= ►- Special attention should be given to stockpiles in close proximity to natural or manmade storm systems. Photograph SP-1. A topsoil stockpile that has been partially Design and Installation revegetated and is protected by silt fence perimeter control. Locate stockpiles away from all drainage system components including storm sewer inlets. Where practical,choose stockpile locations that that will remain undisturbed for the longest period of time as the phases of construction progress. Place sediment control BMPs around the perimeter of the stockpile, such as sediment control logs,rock socks, silt fence, straw bales and sand bags. See Detail SP-1 for guidance on proper establishment of perimeter controls around a stockpile. For stockpiles in active use,provide a stabilized designated access point on the upgradient side of the stockpile. Stabilize the stockpile surface with surface roughening,temporary seeding and mulching, erosion control blankets, or soil binders. Soils stockpiled for an extended period(typically for more than 60 days) should be seeded and mulched with a temporary grass cover once the stockpile is placed(typically within 14 days). Use of mulch only or a soil binder is acceptable if the stockpile will be in place for a more limited time period(typically 30-60 days). Timeframes for stabilization of stockpiles noted in this fact sheet are "typical" guidelines. Check permit requirements for specific federal,state, and/or local requirements that may be more prescriptive. Stockpiles should not be placed in streets or paved areas unless no other practical alternative exists. See the Stabilized Staging Area Fact Sheet for guidance when staging in roadways is unavoidable due to space or right-of-way constraints. For paved areas,rock socks must be used for perimeter control and all inlets with the potential to receive sediment from the stockpile(even from vehicle tracking)must be protected. Maintenance and Removal Inspect perimeter controls and inlet protection in accordance with their respective BMP Fact Sheets. Where seeding,mulch and/or soil binders are used,reseeding or reapplication of soil binder may be necessary. When temporary removal of a perimeter BMP is necessary Stockpile Management to access a stockpile,ensure BMPs are reinstalled in Functions accordance with their respective design detail section. Erosion Control Yes Sediment Control Yes Site/Material Management Yes November 2010 Urban Drainage and Flood Control District SP-1 Urban Storm Drainage Criteria Manual Volume 3 MM-2 Stockpile Management (SM) When the stockpile is no longer needed,properly dispose of excess materials and revegetate or otherwise stabilize the ground surface where the stockpile was located. SP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Stockpile Management (SP) MM-2 3.0' MIN STOCKPILE / A SILT FENCE (SEE SF DETAIL FOR INSTALLATION REQUIREMENTS) STOCKPILE PROTECTION PLAN MAXIMUM 2 SILT FENCE (SEE SF DETAIL FOR 1 INSTALLATION REQUIREMENTS) i SECTION A SP- 1 . STOCKPILE PROTECTION STOCKPILE PROTECTION INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATION OF STOCKPILES. -TYPE OF STOCKPILE PROTECTION. 2. INSTALL PERIMETER CONTROLS IN ACCORDANCE WITH THEIR RESPECTIVE DESIGN DETAILS. SILT FENCE IS SHOWN IN THE STOCKPILE PROTECTION DETAILS; HOWEVER, OTHER TYPES OF PERIMETER CONTROLS INCLUDING SEDIMENT CONTROL LOGS OR ROCK SOCKS MAY BE SUITABLE IN SOME CIRCUMSTANCES. CONSIDERATIONS FOR DETERMINING THE APPROPRIATE TYPE OF PERIMETER CONTROL FOR A STOCKPILE INCLUDE WHETHER THE STOCKPILE IS LOCATED ON A PERVIOUS OR IMPERVIOUS SURFACE, THE RELATIVE HEIGHTS OF THE PERIMETER CONTROL AND STOCKPILE, THE ABILITY OF THE PERIMETER CONTROL TO CONTAIN THE STOCKPILE WITHOUT FAILING IN THE EVENT THAT MATERIAL FROM THE STOCKPILE SHIFTS OR SLUMPS AGAINST THE PERIMETER, AND OTHER FACTORS. 3 STABILIZE THE STOCKPILE SURFACE WITH SURFACE ROUGHENING, TEMPORARY SEEDING AND MULCHING, EROSION CONTROL BLANKETS, OR SOIL BINDERS. SOILS STOCKPILED FOR AN EXTENDED PERIOD (TYPICALLY FOR MORE THAN 60 DAYS) SHOULD BE SEEDED AND MULCHED WITH A TEMPORARY GRASS COVER ONCE THE STOCKPILE IS PLACED (TYPICALLY WITHIN 14 DAYS). USE OF MULCH ONLY OR A SOIL BINDER IS ACCEPTABLE IF THE STOCKPILE WILL BE IN PLACE FOR A MORE LIMITED TIME PERIOD (TYPICALLY 30-60 DAYS). 4. FOR TEMPORARY STOCKPILES ON THE INTERIOR PORTION OF A CONSTRUCTION SITE, WHERE OTHER DOWNGRADIENT CONTROLS, INCLUDING PERIMETER CONTROL, ARE IN PLACE, STOCKPILE PERIMETER CONTROLS MAY NOT BE REQUIRED. November 2010 Urban Drainage and Flood Control District SP-3 Urban Storm Drainage Criteria Manual Volume 3 MM-2 Stockpile Management (SM) STOCKPILE PROTECTION MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPS SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. I WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. STOCKPILE PROTECTION MAINTENANCE NOTES 4. IF PERIMETER PROTECTION MUST BE MOVED TO ACCESS SOIL STOCKPILE, REPLACE PERIMETER CONTROLS BY THE END OF THE WORKDAY. 5. STOCKPILE PERIMETER CONTROLS CAN BE REMOVED ONCE ALL THE MATERIAL FROM THE STOCKPILE HAS BEEN USED. (DETAILS ADAPTED FROM PARKER, COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. SP-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Stockpile Management (SP) MM-2 © A POLY LINER SA ® ® R BERM ORANGE SAFETY CONE SOIL/LANDSCAPE MATERIAL � m m POLY TARP TARP ANCHOR 6" PVC PIPE FOR DRAINAGE IN FLOWLINE ® CURB LINE ROAD CL TARP ANCHOR (CINDER POLY TARP BLOCK, OR 5 GALLON BUCKET OF WATER) ROADWAY �; 6' MAX. POLY LINER BERM MATERIAL (TRIANGULAR SILT DIKE, 6"MIN. SEDIMENT CONTROL LOG, 1 6' MAX., MUST NOT 6" PVC PIPE ROCK SOCK, OR OTHER I BE LOCATED WITHIN WRAPPED MATERIAL) A DRIVE LANE SP-2. MATERIALS STAGING IN ROADWAY MATERIALS STAGING IN ROADWAYS INSTALLATION NOTES 1. SEE PLAN VIEW FOR -LOCATION OF MATERIAL STAGING AREA(S). -CONTRACTOR MAY ADJUST LOCATION AND SIZE OF STAGING AREA WITH APPROVAL FROM THE LOCAL JURISDICTION. 2. FEATURE MUST BE INSTALLED PRIOR TO EXCAVATION, EARTHWORK OR DELIVERY OF MATERIALS. 3. MATERIALS MUST BE STATIONED ON THE POLY LINER. ANY INCIDENTAL MATERIALS DEPOSITED ON PAVED SECTION OR ALONG CURB LINE MUST BE CLEANED UP PROMPTLY. 4. POLY LINER AND TARP COVER SHOULD BE OF SIGNIFICANT THICKNESS TO PREVENT DAMAGE OR LOSS OF INTEGRITY. 5. SAND BAGS MAY BE SUBSTITUTED TO ANCHOR THE COVER TARP OR PROVIDE BERMING UNDER THE BASE LINER. 6. FEATURE IS NOT INTENDED FOR USE WITH WET MATERIAL THAT WILL BE DRAINING AND/OR SPREADING OUT ON THE POLY LINER OR FOR DEMOLITION MATERIALS. 7. THIS FEATURE CAN BE USED FOR: -UTILITY REPAIRS. -WHEN OTHER STAGING LOCATIONS AND OPTIONS ARE LIMITED. -OTHER LIMITED APPLICATION AND SHORT DURATION STAGING. November 2010 Urban Drainage and Flood Control District SP-5 Urban Storm Drainage Criteria Manual Volume 3 MM-2 Stockpile Management (SM) MATERIALS STAGING IN ROADWAY MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. I WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. INSPECT PVC PIPE ALONG CURB LINE FOR CLOGGING AND DEBRIS. REMOVE OBSTRUCTIONS PROMPTLY. 5. CLEAN MATERIAL FROM PAVED SURFACES BY SWEEPING OR VACUUMING. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAJLS ADAPTED FROM AURORA, COLORADO) SP-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Good Housekeeping Practices (GH) MM-3 Description - Implement construction site good housekeeping practices to _ prevent pollution associated with solid, liquid and hazardous construction-related materials and wastes. Stormwater Management Plans (SWMPs) should clearly specify BMPs jzuoGO including these good housekeeping practices: - ■ Provide for waste management. ■ Establish proper building material staging areas. ■ Designate paint and concrete washout areas. ■ Establish proper equipment/vehicle fueling and maintenance practices. ■ Control equipment/vehicle washing and allowable non- stormwater discharges. ■ Develop a spill prevention and response plan. _ Acknowledgement: This Fact Sheet is based directly on EPA guidance provided in Developing Your Stormwater Photographs GH-1 and GH-2. Proper materials Pollution Prevent Plan(EPA 2007). storage and secondary containment for fuel tanks are important good housekeeping practices. Photos Appropriate Uses courtesy of CDOT and City of Aurora. Good housekeeping practices are necessary at all construction sites. Design and Installation The following principles and actions should be addressed in SWMPs: ■ Provide for Waste Management. Implement management procedures and practices to prevent or reduce the exposure and transport of pollutants in stormwater from solid,liquid and sanitary wastes that will be generated at the site. Practices such as trash disposal,recycling,proper material handling, and cleanup measures can reduce the potential for stormwater runoff to pick up construction site wastes and discharge them to surface waters. Implement a comprehensive set of waste-management practices for hazardous or toxic materials, such as paints, solvents,petroleum products,pesticides, wood preservatives, acids,roofing tar, and other materials. Practices should include storage, handling, inventory,and cleanup procedures, in case of spills. Specific practices that should be considered include: Solid or Construction Waste Good Housekeeping o Designate trash and bulk waste-collection areas on- Functions site. Erosion Control No Sediment Control No Site/Material Management Yes November 2010 Urban Drainage and Flood Control District GH-1 Urban Storm Drainage Criteria Manual Volume 3 MM-3 Good Housekeeping Practices (GH) o Recycle materials whenever possible(e.g.,paper,wood, concrete, oil). o Segregate and provide proper disposal options for hazardous material wastes. o Clean up litter and debris from the construction site daily. o Locate waste-collection areas away from streets,gutters,watercourses, and storm drains. Waste- collection areas(dumpsters, and such) are often best located near construction site entrances to minimize traffic on disturbed soils. Consider secondary containment around waste collection areas to minimize the likelihood of contaminated discharges. o Empty waste containers before they are full and overflowing. Sanitary and Septic Waste o Provide convenient,well-maintained, and properly located toilet facilities on-site. o Locate toilet facilities away from storm drain inlets and waterways to prevent accidental spills and contamination of stormwater. o Maintain clean restroorn facilities and empty portable toilets regularly. o Where possible,provide secondary containment pans under portable toilets. o Provide tie-downs or stake-downs for portable toilets. o Educate employees, subcontractors,and suppliers on locations of facilities. o Treat or dispose of sanitary and septic waste in accordance with state or local regulations. Do not discharge or bury wastewater at the construction site. o Inspect facilities for leaks. If found,repair or replace immediately. o Special care is necessary during maintenance(pump out)to ensure that waste and/or biocide are not spilled on the ground. Hazardous Materials and Wastes o Develop and implement employee and subcontractor education, as needed, on hazardous and toxic waste handling, storage, disposal, and cleanup. ., o Designate hazardous waste-collection areas on-site. o Place all hazardous and toxic material wastes in secondary containment. Photograph GH-3. Locate portable toilet facilities on level surfaces away from waterways and storm drains. Photo courtesy of W WE. GH-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Good Housekeeping Practices (GH) MM-3 o Hazardous waste containers should be inspected to ensure that all containers are labeled properly and that no leaks are present. ■ Establish Proper Building Material Handling and Staging Areas. The SWAP should include comprehensive handling and management procedures for building materials,especially those that are hazardous or toxic. Paints, solvents,pesticides,fuels and oils, other hazardous materials or building materials that have the potential to contaminate stormwater should be stored indoors or under cover whenever possible or in areas with secondary containment. Secondary containment measures prevent a spill from spreading across the site and may include dikes,berms, curbing, or other containment methods. Secondary containment techniques should also ensure the protection of groundwater. Designate staging areas for activities such as fueling vehicles,mixing paints,plaster,mortar,and other potential pollutants. Designated staging areas enable easier monitoring of the use of materials and clean up of spills. Training employees and subcontractors is essential to the success of this pollution prevention principle. Consider the following specific materials handling and staging practices: o Train employees and subcontractors in proper handling and storage practices. o Clearly designate site areas for staging and storage with signs and on construction drawings. Staging areas should be located in areas central to the construction site. Segment the staging area into sub-areas designated for vehicles, equipment, or stockpiles. Construction entrances and exits should be clearly marked so that delivery vehicles enter/exit through stabilized areas with vehicle tracking controls(See Vehicle Tracking Control Fact Sheet). o Provide storage in accordance with Spill Protection, Control and Countermeasures(SPCA requirements and plans and provide cover and impermeable perimeter control, as necessary, for hazardous materials and contaminated soils that must be stored on site. o Ensure that storage containers are regularly inspected for leaks, corrosion, support or foundation failure,or other signs of deterioration and tested for soundness. o Reuse and recycle construction materials when possible. ■ Designate Concrete Washout Areas. Concrete contractors should be encouraged to use the washout facilities at their own plants or dispatch facilities when feasible;however, concrete washout commonly occurs on construction sites. If it is necessary to provide for concrete washout areas on- site, designate specific washout areas and design facilities to handle anticipated washout water. Washout areas should also be provided for paint and stucco operations. Because washout areas can be a source of pollutants from leaks or spills, care must be taken with regard to their placement and proper use. See the Concrete Washout Area Fact Sheet for detailed guidance. Both self-constructed and prefabricated washout containers can fill up quickly when concrete,paint, and stucco work are occurring on large portions of the site. Be sure to check for evidence that contractors are using the washout areas and not dumping materials onto the ground or into drainage facilities. If the washout areas are not being used regularly,consider posting additional signage, relocating the facilities to more convenient locations,or providing training to workers and contractors. When concrete,paint, or stucco is part of the construction process, consider these practices which will help prevent contamination of stormwater. Include the locations of these areas and the maintenance and inspection procedures in the SWMP. November 2010 Urban Drainage and Flood Control District GH-3 Urban Storm Drainage Criteria Manual Volume 3 MM-3 Good Housekeeping Practices (GH) o Do not washout concrete trucks or equipment into storm drains, streets, gutters,uncontained areas, or streams. Only use designated washout areas. o Establish washout areas and advertise their locations with signs. Ensure that signage remains in good repair. o Provide adequate containment for the amount of wash water that will be used. o Inspect washout structures daily to detect leaks or tears and to identify when materials need to be removed. o Dispose of materials properly. The preferred method is to allow the water to evaporate and to recycle the hardened concrete. Full service companies may provide dewatering services and should dispose of wastewater properly. Concrete wash water can be highly polluted. It should not be discharged to any surface water, storm sewer system, or allowed to infiltrate into the ground in the vicinity of waterbodies. Washwater should not be discharged to a sanitary sewer system without first receiving written permission from the system operator. ■ Establish Proper Equipment/Vehicle Fueling and Maintenance Practices. Create a clearly designated on-site fueling and maintenance area that is clean and dry. The on-site fueling area should have a spill kit,and staff should know how to use it. If possible, conduct vehicle fueling and maintenance activities in a covered area. Consider the following practices to help prevent the discharge of pollutants to stormwater from equipment/vehicle fueling and maintenance. Include the locations of designated fueling and maintenance areas and inspection and maintenance procedures in the SWMP. o Train employees and subcontractors in proper fueling procedures(stay with vehicles during fueling,proper use of pumps, emergency shutoff valves, etc.). o Inspect on-site vehicles and equipment regularly for leaks, equipment damage, and other service problems. o Clearly designate vehicle/equipment service areas away from drainage facilities and watercourses to prevent stormwater run-on and runoff. o Use drip pans,drip cloths,or absorbent pads when replacing spent fluids. o Collect all spent fluids, store in appropriate labeled containers in the proper storage areas, and recycle fluids whenever possible. ■ Control Equipment/Vehicle Washing and Allowable Non-Stormwater Discharges. Implement practices to prevent contamination of surface and groundwater from equipment and vehicle wash water. Representative practices include: o Educate employees and subcontractors on proper washing procedures. o Use off-site washing facilities,when available. o Clearly mark the washing areas and inform workers that all washing must occur in this area. o Contain wash water and treat it using BMPs. Infiltrate washwater when possible,but maintain separation from drainage paths and waterbodies. GH-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Good Housekeeping Practices (GH) MM-3 o Use high-pressure water spray at vehicle washing facilities without detergents. Water alone can remove most dirt adequately. o Do not conduct other activities, such as vehicle repairs,in the wash area. o Include the location of the washing facilities and the inspection and maintenance procedures in the SWMP. ■ Develop a Spill Prevention and Response Plan. Spill prevention and response procedures must be identified in the SWMP. Representative procedures include identifying ways to reduce the chance of spills, stop the source of spills,contain and clean up spills, dispose of materials contaminated by spills, and train personnel responsible for spill prevention and response. The plan should also specify material handling procedures and storage requirements and ensure that clear and concise spill cleanup procedures are provided and posted for areas in which spills may potentially occur. When developing a spill prevention plan, include the following: o Note the locations of chemical storage areas, storm drains,tributary drainage areas, surface waterbodies on or near the site, and measures to stop spills from leaving the site. o Provide proper handling and safety procedures for each type of waste. Keep Material Safety Data Sheets(MSDSs)for chemical used on site with the SWMP. o Establish an education program for employees and subcontractors on the potential hazards to humans and the environment from spills and leaks. o Specify how to notify appropriate authorities, such as police and fire departments,hospitals, or municipal sewage treatment facilities to request assistance. Emergency procedures and contact numbers should be provided in the SWMP and posted at storage locations. o Describe the procedures, equipment and materials for immediate cleanup of spills and proper disposal. o Identify personnel responsible for implementing the plan in the event of a spill. Update the spill prevention plan and clean up materials as changes occur to the types of chemicals stored and used at the facility. November 2010 Urban Drainage and Flood Control District GH-5 Urban Storm Drainage Criteria Manual Volume 3 MM-3 Good Housekeeping Practices (GH) Spill Prevention, Control,and Countermeasure(SPCC)Plan Construction sites may be subject to 40 CFR Part 112 regulations that require the preparation and implementation of a SPCC Plan to prevent oil spills from aboveground and underground storage tanks. The facility is subject to this rule if it is a non-transportation-related facility that: ■ Has a total storage capacity greater than 1,320 gallons or a completely buried storage capacity greater than 42,000 gallons. ■ Could reasonably be expected to discharge oil in quantities that may be harmful to navigable waters of the United States and adjoining shorelines. Furthermore, if the facility is subject to 40 CFR Part 112,the SWMP should reference the SPCC Plan. To find out more about SPCC Plans, see EPA's website on SPPC at www.epa. og v/oilspill/spcc.htm. Reporting Oil Spills In the event of an oil spill,contact the National Response Center toll free at 1-800-424- 8802 for assistance, or for more details,visit their website: www.nrc.uscg.mil. Maintenance and Removal Effective implementation of good housekeeping practices is dependent on clear designation of personnel responsible for supervising and implementing good housekeeping programs, such as site cleanup and disposal of trash and debris,hazardous material management and disposal,vehicle and equipment maintenance, and other practices. Emergency response "drills" may aid in emergency preparedness. Checklists may be helpful in good housekeeping efforts. Staging and storage areas require permanent stabilization when the areas are no longer being used for construction-related activities. Construction-related materials,debris and waste must be removed from the construction site once construction is complete. Design Details See the following Fact Sheets for related Design Details: MM-1 Concrete Washout Area MM-2 Stockpile Management SM-4 Vehicle Tracking Control Design details are not necessary for other good housekeeping practices;however,be sure to designate where specific practices will occur on the appropriate construction drawings. GH-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Silt Fence (SF) SC-1 Description A silt fence is a woven geotextile fabric 4 attached to wooden posts and trenched into the ground. It is designed as a sediment barrier to intercept sheet flow runoff from disturbed areas. Appropriate Uses -- A silt fence can be used where runoff is conveyed from a disturbed area as sheet flow. Silt fence is not designed to receive concentrated flow or to be used as a filter fabric. Typical uses include: ■ Down slope of a disturbed area to accept sheet flow. Photograph SF-1. Silt fence creates a sediment barrier,forcing sheet flow runoff to evaporate or infiltrate. ■ Along the perimeter of a receiving water such as a stream,pond or wetland. ■ At the perimeter of a construction site. Design and Installation Silt fence should be installed along the contour of slopes so that it intercepts sheet flow. The maximum recommended tributary drainage area per 100 lineal feet of silt fence,installed along the contour, is approximately 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no steeper than 3:1. Longer and steeper slopes require additional measures. This recommendation only applies to silt fence installed along the contour. Silt fence installed for other uses, such as perimeter control, should be installed in a way that will not produce concentrated flows. For example,a"J-hook" installation may be appropriate to force runoff to pond and evaporate or infiltrate in multiple areas rather than concentrate and cause erosive conditions parallel to the silt fence. See Detail SF-1 for proper silt fence installation,which involves proper trenching, staking, securing the fabric to the stakes,and backfilling the silt fence. Properly installed silt fence should not be easily pulled out by hand and there should be no gaps between the ground and the fabric. Silt fence must meet the minimum allowable strength requirements, depth of installation requirement,and other specifications in the design details. Improper installation of silt fence is a common reason for silt fence failure; however, Silt Fence when properly installed and used for the appropriate purposes, it can be highly effective. Functions Erosion Control No Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District SF-1 Urban Storm Drainage Criteria Manual Volume 3 SC-1 Silt Fence (SF) Maintenance and Removal „ Inspection of silt fence includes observing the material for tears or holes and checking for slumping fence and undercut areas bypassing flows. Repair of silt fence typically involves replacing the damaged section with a new section. Sediment accumulated behind silt fence should be removed, as needed to maintain BMP effectiveness,typically before it reaches a depth of 6 inches. = Silt fence may be removed when the upstream area { has reached final stabilization. Photograph SF-2. When silt fence is not installed along the contour,a"J-hook"installation may be appropriate to ensure that the BMP does not create concentrated flow parallel to the silt fence. Photo courtesy of Tom Gore. SF-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Silt Fence (SF) SC-1 SF SF - SF S F 1 YZ" x 1 Y1„ (RECOMMENDED) WOODEN FENCE POST WITH 10' MAX SPACING SILT FENCE GEOTEXTILE A COMPACTED BAC KFI LL FJ OW --- 36"-48„ "- -> TYP. EXISTING GROUND 6" MIN 1 8' AT LEAST 10" MIN OF SILT FENCE "TAIL" SHALL BE 4" MIN BURIED SILT FENCE POSTS SHALL OVERLAP AT JOINTS SO THAT NO GAPS JOIN EXIST IN SILT FENCE FIRST ROTATE SECOND POSTS SHALL BE JOINED AS SHOWN, THEN ROTATED 180 DEC. THICKNESS OF GEOTEXTILE HAS , IN DIRECTION SHOWN AND DRIVEN BEEN EXAGGERATED, TYP INTO THE GROUND SECTION A SF- 1 . SILT FENCE November 2010 Urban Drainage and Flood Control District SF-3 Urban Storm Drainage Criteria Manual Volume 3 SC-1 Silt Fence (SF) SILT FENCE INSTALLATION NOTES 1. SILT FENCE MUST BE PLACED AWAY FROM THE TOE OF THE SLOPE TO ALLOW FOR WATER PONDING. SILT FENCE AT THE TOE OF A SLOPE SHOULD BE INSTALLED IN A FLAT LOCATION AT LEAST SEVERAL FEET (2-5 FT) FROM THE TOE OF THE SLOPE TO ALLOW ROOM FOR PONDING AND DEPOSITION_ 2. A UNIFORM 6" X 4" ANCHOR TRENCH SHALL BE EXCAVATED USING TRENCHER OR SILT FENCE INSTALLATION DEVICE. NO ROAD GRADERS, BACKHOES, OR SIMILAR EQUIPMENT SHALL BE USED. 3. COMPACT ANCHOR TRENCH BY HAND WITH A "JUMPING JACK" OR BY WHEEL ROLLING. COMPACTION SHALL BE SUCH THAT SILT FENCE RESISTS BEING PULLED OUT OF ANCHOR TRENCH BY HAND. 4. SILT FENCE SHALL BE PULLED TIGHT AS IT IS ANCHORED TO THE STAKES. THERE SHOULD BE NO NOTICEABLE SAG BETWEEN STAKES AFTER IT HAS BEEN ANCHORED TO THE STAKES. 5. SILT FENCE FABRIC SHALL BE ANCHORED TO THE STAKES USING 1" HEAVY DUTY STAPLES OR NAILS WITH 1" HEADS. STAPLES AND NAILS SHOULD BE PLACED 3" ALONG THE FABRIC DOWN THE STAKE. 6. AT THE END OF A RUN OF SILT FENCE ALONG A CONTOUR, THE SILT FENCE SHOULD BE TURNED PERPENDICULAR TO THE CONTOUR TO CREATE A "J—HOOK." THE "J—HOOK" EXTENDING PERPENDICULAR TO THE CONTOUR SHOULD BE OF SUFFICIENT LENGTH TO KEEP RUNOFF FROM FLOWING AROUND THE END OF THE SILT FENCE (TYPICALLY 10' — 20'). 7. SILT FENCE SHALL BE INSTALLED PRIOR TO ANY LAND DISTURBING ACTIVITIES. SILT FENCE MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY, 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF THE SILT FENCE SHALL BE REMOVED AS NEEDED TO MAINTAIN THE FUNCTIONALITY OF THE BMP, TYPICALLY WHEN DEPTH OF ACCUMULATED SEDIMENTS IS APPROXIMATELY 6". 5. REPAIR OR REPLACE SILT FENCE WHEN THERE ARE SIGNS OF WEAR, SUCH AS SAGGING, TEARING, OR COLLAPSE. 6. SILT FENCE IS TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION, OR IS REPLACED BY AN EQUIVALENT PERIMETER SEDIMENT CONTROL BMP. 7. WHEN SILT FENCE IS REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAIL ADAPTED FROM TOWN OF PARKER, COLORADO AND CITY OF AURORA, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. SF-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Control Log (SCL) SC-2 Description A sediment control log is a linear roll made of natural materials such as straw, coconut fiber, or other fibrous material trenched into the ground and held with a wooden stake. Sediment control logs are also often referred to as "straw wattles." They are used as a - sediment barrier to intercept sheet flow - runoff from disturbed areas. - Appropriate Uses Sediment control logs can be used in the following applications to trap sediment: ■ As perimeter control for stockpiles and the site. ■ As part of inlet protection designs. ■ As check dams in small drainage ditches. (Sediment control logs r are not intended for use in channels with high flow velocities.) Photographs SCL-1 and SCL-2. Sediment control logs used as 1)a perimeter control around a soil stockpile;and,2)as a'J-hook" ■ On disturbed slopes to shorten flow perimeter control at the corner of a construction site. lengths(as an erosion control). ■ As part of multi-layered perimeter control along a receiving water such as a stream,pond or wetland. Sediment control logs work well in combination with other layers of erosion and sediment controls. Design and Installation Sediment control logs should be installed along the contour to avoid concentrating flows. The maximum allowable tributary drainage area per 100 lineal feet of sediment control log, installed along the contour,is approximately 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no steeper than 3:1.Longer and steeper slopes require additional measures. This recommendation only applies to sediment control logs installed along the contour. When installed for other uses, such as perimeter control, it should be installed in a way that will not produce concentrated flows. For example, a"J-hook" Sediment Control Lo installation may be appropriate to force runoff to pond and Functions evaporate or infiltrate in multiple areas rather than concentrate Erosion Control Moderate and cause erosive conditions parallel to the BMP. Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District SCL-1 Urban Storm Drainage Criteria Manual Volume 3 SC-2 Sediment Control Log (SCL) Although sediment control logs initially allow runoff to flow through the BMP,they can quickly become a barrier and should be installed is if they are impermeable. Design details and notes for sediment control logs are provided in Detail SCL-1. Sediment logs must be properly trenched and staked into the ground to prevent undercutting,bypassing and displacement. When installed on slopes, sediment control logs should be installed along the contours(i.e.,perpendicular to flow). Improper installation can lead to poor performance. Be sure that sediment control logs are properly trenched, anchored and tightly jointed. Maintenance and Removal Be aware that sediment control logs will eventually degrade. Remove accumulated sediment before the depth is one-half the height of the sediment log and repair damage to the sediment log,typically by replacing the damaged section. Once the upstream area is stabilized,remove and properly dispose of the logs. Areas disturbed beneath the logs may need to be seeded and mulched. Sediment control logs that are biodegradable may occasionally be left in place(e.g.,when logs are used in conjunction with erosion control blankets as permanent slope breaks). However,removal of sediment control logs after final stabilization is typically recommended when used in perimeter control, inlet protection and check dam applications. SCL-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Control Log (SCL) SC-2 SCL A 111'. x 1112" x 18" (MIN) WOODEN STAKE 9" DIAMETER (MIN) } SEDIMENT CONTROL LOG l 3" 4' MAX. CENTER (TYP.) 6" �. Y3 FLOW �� OF SCL DIAM. ` Y!` NOTE: LARGER (TYP.) / SC � DIAMETER SEDIMENT CONTROL LOGS MAY v ��\��,,,"""�� \yam' \� • / NEED TO BE EMBEDDED DEEPER. SEDIMENT CONTROL LOG CENTER STAKE IN CONTROL LOG COMPACTED EXCAVATED 3 9" DIAMETER (MIN) TRENCH SOIL SEDIMENT CONTROL LOG FLOW Y3 DIAM. SCL (TYP.) SECTION A 12" OVERLAP 1Y2" x 1Y1" x 18" (MIN) WOODEN STAKE 9" DIAMETER (MIN) SEDIMENT CONTROL LOG SEDIMENT CONTROL LOG JOINTS SCL- 1 . SEDIMENT CONTROL LOG November 2010 Urban Drainage and Flood Control District SCL-3 Urban Storm Drainage Criteria Manual Volume 3 SC-2 Sediment Control Log (SCL) COMPACTED EXCAVATED 3 CENTER STAKE IN CONTROL LOG TRENCH SOIL 9" DIAMETER (MIN) SEDIMENT CONTROL LOG FLOW —� PLACE LOG AGAINST BACK OF CURB Y3 DIAM. SCL (TYP.) 6" MIN. SCL-2. SEDIMENT CONTROL LOG AT BACK OF CURB CENTER STAKE IN CONTROL LOG 3 9" DIAMETER (MIN) SEDIMENT CONTROL LOG TREE LAWN (TYPICAL) Y3 DIAM. SCL (TYP.) CURB FLOW MIN:: '� •z//� �; ., ,/ ''ijs i% '''/,•a•i.. ;i;; .'�%:<!:;v,z(i; `��,�•'`., ii ,'!j'''.�;:i: I NO SCL-3. SEDIMENT CONTROL LOG AT SIDEWALK WITH TREE LAWN STAKING AT 4' MAX. ON CENTER (TYP. VERTICAL SPACING VARIES DEPENDING ON SLOPE \\ice:' CONTINUOUS SCL z x/ AT PERIMETER OF "' '' •% '' ! CONSTRUCTION SITE SCL-4. SEDIMENT CONTROL LOGS TO CONTROL SLOPE LENGTH SCL-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Control Log (SCL) SC-2 SEDIMENT CONTROL LOG INSTALLATION NOTES 1. SEE PLAN VIEW FOR LOCATION AND LENGTH OF SEDIMENT CONTROL LOGS. 2. SEDIMENT CONTROL LOGS THAT ACT AS A PERIMETER CONTROL SHALL BE INSTALLED PRIOR TO ANY UPGRADIENT LAND—DISTURBING ACTIVITIES. 3 SEDIMENT CONTROL LOGS SHALL CONSIST OF STRAW, COMPOST, EXCELSIOR OR COCONUT FIBER, AND SHALL BE FREE OF ANY NOXIOUS WEED SEEDS OR DEFECTS INCLUDING RIPS, HOLES AND OBVIOUS WEAR. 4. SEDIMENT CONTROL LOGS MAY BE USED AS SMALL CHECK DAMS IN DITCHES AND SWALES. HOWEVER, THEY SHOULD NOT BE USED IN PERENNIAL STREAMS OR HIGH VELOCITY DRAINAGE WAYS. 5. IT IS RECOMMENDED THAT SEDIMENT CONTROL LOGS BE TRENCHED INTO THE GROUND TO A DEPTH OF APPROXIMATELY Y3 OF THE DIAMETER OF THE LOG IF TRENCHING TO THIS DEPTH IS NOT FEASIBLE AND/OR DESIRABLE (SHORT TERM INSTALLATION WITH DESIRE NOT TO DAMAGE LANDSCAPE) A LESSER TRENCHING DEPTH MAY BE ACCEPTABLE WITH MORE ROBUST STAKING 6. THE UPHILL SIDE OF THE SEDIMENT CONTROL LOG SHALL BE BACKFILLED WITH SOIL THAT IS FREE OF ROCKS AND DEBRIS. THE SOIL SHALL BE TIGHTLY COMPACTED INTO THE SHAPE OF A RIGHT TRIANGLE USING A SHOVEL OR WEIGHTED LAWN ROLLER. 7. FOLLOW MANUFACTURERS' GUIDANCE FOR STAKING. IF MANUFACTURERS' INSTRUCTIONS 00 NOT SPECIFY SPACING, STAKES SHALL BE PLACED ON 4' CENTERS AND EMBEDDED A MINIMUM OF 6" INTO THE GROUND. 3" OF THE STAKE SHALL PROTRUDE FROM THE TOP OF THE LOG. STAKES THAT ARE BROKEN PRIOR TO INSTALLATION SHALL BE REPLACED. SEDIMENT CONTROL LOG MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4, SEDIMENT ACCUMULATED UPSTREAM OF SEDIMENT CONTROL LOG SHALL BE REMOVED AS NEEDED TO MAINTAIN FUNCTIONALITY OF THE BMP, TYPICALLY WHEN DEPTH OF ACCUMULATED SEDIMENTS IS APPROXIMATELY Y6 OF THE HEIGHT OF THE SEDIMENT CONTROL LOG. 5. SEDIMENT CONTROL LOG SHALL BE REMOVED AT THE END OF CONSTRUCTION. IF DISTURBED AREAS EXIST AFTER REMOVAL, THEY SHALL BE COVERED WITH TOP SOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM TOwN OF PARKER. COLORADO. jEFFERSON COUNTY, COLORADO, DOUGLAS COUNTY, COLORADO, AND CITY OF AURORA, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District SCL-5 Urban Storm Drainage Criteria Manual Volume 3 Brush Barrier (BB) SC-4 Description A brush barrier is a perimeter sediment control constructed with stacked shrubs, tree limbs, and bushy vegetation that has been cleared from a construction area. Brush barriers reduce sediment loads by intercepting and slowing sheet flow from disturbed areas. Appropriate Uses A brush barrier is an appropriate BMP at sites where there is adequate brush from .•'' the clearing and grubbing of the construction site to construct an effective brush barrier. Brush barriers are typically used at the toe of slopes and Photograph BB-1. Brush barrier constructed with chipped wood. should be implemented in combination Photo courtesy of EPA. with other BMPs such as surface roughening and reseeding. Brush barriers should be considered short-term, supplemental BMPs because they are constructed of materials that naturally decompose. Brush barriers are not acceptable as a sole means of perimeter control,but they may be used internally within a site to reduce slope length or at the site perimeter in combination with other perimeter control BMPs for multi-layered protection. Brush barriers are not appropriate for high-velocity flow areas. A large amount of material is needed to construct a useful brush barrier; therefore, alternative perimeter controls such as a fabric silt fence may be more appropriate for sites with little material from clearing. Design and Installation The drainage area for brush barriers should be no greater than 0.25 acre per 100 feet of barrier length. Additionally,the drainage slope leading down to a brush barrier must be no greater than 3:1 and no longer than 150 feet. To construct an effective brush barrier,use only small shrubs and limbs with diameters of 6 inches or less. Larger materials(such as a tree stump)can create void spaces in the barrier,making it ineffective. The brush barrier mound should be at least 3 feet high and 5 feet wide at its base. In order to avoid significant movement of the brush and improve effectiveness,a filter fabric can be placed over the top of the brush pile,keyed in on the upstream side,and anchored on the downstream side. On the upgradient side,the filter fabric cover should be buried in a trench 4 inches deep and 6 inches wide. Brush Barrier Functions Erosion Control Moderate Sediment Control Moderate Site/Material No November 2010 Urban Drainage and Flood Control District BB-1 Urban Storm Drainage Criteria Manual Volume 3 SC-4 Brush Barrier (BB) Maintenance and Removal Inspect the brush barrier for voids where concentrated flow or erosion is occurring. Voids in the brush barrier should be filled with additional brush. Accumulated sediment should be removed from the uphill side of the barrier when sediment height reaches one-third of the height of the barrier. If filter fabric is used,inspect the filter fabric for damage;replace and properly secure it, as needed. Once the upstream area has been vegetated or stabilized,the brush barrier should be removed and the underlying area revegetated. 1313-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rock Sock (RS) SC-5 Description A rock sock is constructed of gravel 00 that has been wrapped by wire mesh or � a geotextile to form an elongated cylindrical filter. Rock socks are A typically used either as a perimeter - - control or as part of inlet protection. - _ When placed at angles in the curb line, rock socks are typically referred to as curb socks. Rock socks are intended to _ trap sediment from stormwater runoff that flows onto roadways as a result of construction activities. Appropriate Uses = Photograph RS-1. Rock socks placed at regular intervals in a curb Rock socks can be used at the perimeter line can help reduce sediment loading to storm sewer inlets. Rock of a disturbed area to control localized socks can also be used as perimeter controls. sediment loading. A benefit of rock socks as opposed to other perimeter controls is that they do not have to be trenched or staked into the ground; therefore,they are often used on roadway construction projects where paved surfaces are present. Use rock socks in inlet protection applications when the construction of a roadway is substantially complete and the roadway has been directly connected to a receiving storm system. Design and Installation When rock socks are used as perimeter controls,the maximum recommended tributary drainage area per 100 lineal feet of rock socks is approximately 0.25 acres with disturbed slope length of up to 150 feet and a tributary slope gradient no steeper than 3:1. A rock sock design detail and notes are provided in Detail RS-1. Also see the Inlet Protection Fact Sheet for design and installation guidance when rock socks are used for inlet protection and in the curb line. When placed in the gutter adjacent to a curb,rock socks should protrude no more than two feet from the curb in order for traffic to pass safely. If located in a high traffic area,place construction markers to alert drivers and street maintenance workers of their presence. Maintenance and Removal Rock socks are susceptible to displacement and breaking due to vehicle traffic. Inspect rock socks for damage and repair or replace as necessary. Remove sediment by sweeping or vacuuming as needed to maintain the functionality of the BMP,typically when sediment has accumulated behind the rock sock to one-half of the sock's Rock Sock height. Functions Once upstream stabilization is complete,rock socks and Erosion Control No accumulated sediment should be removed and properly disposed. Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District RS-1 Urban Storm Drainage Criteria Manual Volume 3 SC-5 Rock Sock (RS) o RS IY2" (MINUS) CRUSHED ROCK ENCLOSED IN WIRE MESH 1Y2" (MINUS) CRUSHED ROCK ENCLOSED IN WIRE MESH WIRE TIE ENDS f 4" TO 6" MAX AT 10" ON BEDROCK OR GROUND SURFACE CURBS, OTHERWISE ll HARD SURFACE, 2" C-10" DEPENDING IN SOIL ON EXPECTED SEDIMENT LOADS ROCK SOCK SECTION ROCK SOCK PLAN ANY GAP AT JOINT SHALL BE FILLED WITH AN ADEQUATE AMOUNT OF 0N" (MINUS) CRUSHED ROCK AND WRAPPED WITH ADDITIONAL WIRE MESH SECURED TO ENDS OF ROCK ROCK SOCK, REINFORCED SOCK. AS AN ALTERNATIVE TO FILLING JOINTS TYP BETWEEN ADJOINING ROCK SOCKS WITH CRUSHED ROCK AND 12" 12" ADDITIONAL WIRE WRAPPING, ROCK SOCKS CAN BE OVERLAPPED (TYPICALLY 12-INCH OVERLAP) TO AVOID GAPS. .Y GRADATION TABLE SIEVE SIZE MASS PERCENT PASSING SQUARE MESH SIEVES ROCK SOCK JOINTING NO. 4 2 100 1 90 - 100 j1' 20 - 55 -34" 0 - 15 3,j" 0 - 5 ROCK SOCK INSTALLATION NOTES MATCHES SPECIFICATIONS FOR NO. 4 COARSE AGGREGATE FOR CONCRETE 1. SEE PLAN VIEW FOR: PER AASHTO M43. ALL ROCK SHALL BE -LOCATION(S) OF ROCK SOCKS. FRACTURED FACE, ALL SIDES. 2. CRUSHED ROCK SHALL BE 1Y2" (MINUS) IN SIZE WITH A FRACTURED FACE (ALL SIDES) AND SHALL COMPLY WITH GRADATION SHOWN ON THIS SHEET (1,¢" MINUS). 3. WIRE MESH SHALL BE FABRICATED OF 10 GAGE POULTRY MESH, OR EQUIVALENT, WITH A MAXIMUM OPENING OF Y2", RECOMMENDED MINIMUM ROLL WIDTH OF 48" 4, WIRE MESH SHALL BE SECURED USING "HOG RINGS" OR WIRE TIES AT 6" CENTERS ALONG ALL JOINTS AND AT 2" CENTERS ON ENDS OF SOCKS. 5. SOME MUNICIPALITIES MAY ALLOW THE USE OF FILTER FABRIC AS AN ALTERNATIVE TO WIRE MESH FOR THE ROCK ENCLOSURE. RS- 1 . ROCK SOCK PERIMETER CONTROL RS-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rock Sock (RS) SC-5 ROCK SOCK MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. ROCK SOCKS SHALL BE REPLACED IF THEY BECOME HEAVILY SOILED, OR DAMAGED BEYOND REPAIR. 5. SEDIMENT ACCUMULATED UPSTREAM OF ROCK SOCKS SHALL BE REMOVED AS NEEDED TO MAINTAIN FUNCTIONALITY OF THE BMP, TYPICALLY WHEN DEPTH OF ACCUMULATED SEDIMENTS IS APPROXIMATELY J� OF THE HEIGHT OF THE ROCK SOCK. 6. ROCK SOCKS ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 7. WHEN ROCK SOCKS ARE REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAIL ADAPTED FROM TOWN OF PARKER, COLORADO AND CITY OF AURORA, COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. NOTE: THE DETAILS INCLUDED WITH THIS FACT SHEET SHOW COMMONLY USED, CONVENTIONAL METHODS OF ROCK SOCK INSTALLATION IN THE DENVER METROPOLITAN AREA THERE ARE MANY OTHER SIMILAR PROPRIETARY PRODUCTS ON THE MARKET. UDFCD NEITHER NDORSES NOR DISCOURAGES USE OF PROPRIETARY PROTECTION PRODUCTS; HOWEVER, IN THE EVENT PROPRIETARY METHODS ARE USED, THE APPROPRIATE DETAIL FROM THE MANUFACTURER MUST BE INCLUDED IN THE SWMP AND THE BMP MUST BE INSTALLED AND MAINTAINED AS SHOWN IN THE MANUFACTURER'S DETAILS. November 2010 Urban Drainage and Flood Control District RS-3 Urban Storm Drainage Criteria Manual Volume 3 Inlet Protection (IP) SC-6 Description Inlet protection consists of permeable barriers installed installed around an inlet to - - filter runoff and remove sediment prior to entering a storm drain inlet. Inlet protection can be constructed from rock -� socks,sediment control logs, silt fence, block and rock socks, or other materials approved by the local jurisdiction. Area inlets can also be protected by over-excavating around the inlet to form a sediment trap. Appropriate Uses Install protection at storm sewer inlets that are operable during construction. Photograph IP-1. Inlet protection for a curb opening inlet. Consider the potential for tracked-out sediment or temporary stockpile areas to contribute sediment to inlets when determining which inlets must be protected. This may include inlets in the general proximity of the construction area,not limited to downgradient inlets. Inlet protection is not a stand-alone BMP and should be used in conjunction with other upgradient BMPs. Design and Installation To function effectively,inlet protection measures must be installed to ensure that flows do not bypass the inlet protection and enter the storm drain without treatment. However, designs must also enable the inlet to function without completely blocking flows into the inlet in a manner that causes localized flooding. When selecting the type of inlet protection,consider factors such as type of inlet(e.g., curb or area, sump or on-grade conditions),traffic, anticipated flows,ability to secure the BMP properly, safety and other site-specific conditions. For example,block and rock socks will be better suited to a curb and gutter along a roadway, as opposed to silt fence or sediment control logs,which cannot be properly secured in a curb and gutter setting,but are effective area inlet protection measures. Several inlet protection designs are provided in the Design Details. Additionally, a variety of proprietary products are available for inlet protection that may be approved for use by local governments. If proprietary products are used, design details and installation procedures from the manufacturer must be followed. Regardless of the type of inlet protection selected,inlet protection is most effective when combined with other BMPs such as curb socks and check dams. Inlet protection is often the last barrier before runoff enters the storm sewer or receiving water. Design details with notes are provided for these forms of inlet Inlet Protection protection: (various forms) Functions IP-1. Block and Rock Sock Inlet Protection for Sump or On-grade Erosion Control No Inlets Sediment Control Yes IP-2. Curb(Rock) Socks Upstream of Inlet Protection, On-grade Site/Material Management No Inlets November 2010 Urban Drainage and Flood Control District IP-1 Urban Storm Drainage Criteria Manual Volume 3 SC-6 Inlet Protection (IP) IP-3. Rock Sock Inlet Protection for Sump/Area Inlet IP-4. Silt Fence Inlet Protection for Sump/Area Inlet IP-5. Over-excavation Inlet Protection IP-6. Straw Bale Inlet Protection for Sump/Area Inlet CIP-1. Culvert Inlet Protection Propriety inlet protection devices should be installed in accordance with manufacturer specifications. More information is provided below on selecting inlet protection for sump and on-grade locations. Inlets Located in a Sump When applying inlet protection in sump conditions, it is important that the inlet continue to function during larger runoff events. For curb inlets,the maximum height of the protective barrier should be lower than the top of the curb opening to allow overflow into the inlet during larger storms without excessive localized flooding. If the inlet protection height is greater than the curb elevation,particularly if the filter becomes clogged with sediment,runoff will not enter the inlet and may bypass it,possibly causing localized flooding,public safety issues, and downstream erosion and damage from bypassed flows. Area inlets located in a sump setting can be protected through the use of silt fence,concrete block and rock socks(on paved surfaces), sediment control logs/straw wattles embedded in the adjacent soil and stacked around the area inlet(on pervious surfaces), over-excavation around the inlet, and proprietary products providing equivalent functions. Inlets Located on a Slope For curb and gutter inlets on paved sloping streets,block and rock sock inlet protection is recommended in conjunction with curb socks in the gutter leading to the inlet. For inlets located along unpaved roads, also see the Check Dam Fact Sheet. Maintenance and Removal Inspect inlet protection frequently. Inspection and maintenance guidance includes: ■ Inspect for tears that can result in sediment directly entering the inlet, as well as result in the contents of the BMP(e.g.,gravel)washing into the inlet. ■ Check for improper installation resulting in untreated flows bypassing the BMP and directly entering the inlet or bypassing to an unprotected downstream inlet. For example, silt fence that has not been properly trenched around the inlet can result in flows under the silt fence and directly into the inlet. ■ Look for displaced BMPs that are no longer protecting the inlet. Displacement may occur following larger storm events that wash away or reposition the inlet protection. Traffic or equipment may also crush or displace the BMP. ■ Monitor sediment accumulation upgradient of the inlet protection. IP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Inlet Protection (IP) SC-6 ■ Remove sediment accumulation from the area upstream of the inlet protection,as needed to maintain BMP effectiveness,typically when it reaches no more than half the storage capacity of the inlet protection. For silt fence,remove sediment when it accumulates to a depth of no more than 6 inches. Remove sediment accumulation from the area upstream of the inlet protection as needed to maintain the functionality of the BMP. ■ Propriety inlet protection devices should be inspected and maintained in accordance with manufacturer specifications. If proprietary inlet insert devices are used, sediment should be removed in a timely manner to prevent devices from breaking and spilling sediment into the storm drain. Inlet protection must be removed and properly disposed of when the drainage area for the inlet has reached final stabilization. November 2010 Urban Drainage and Flood Control District IP-3 Urban Storm Drainage Criteria Manual Volume 3 SC-6 Inlet Protection (IP) I A SEE ROCK SOCK DESIGN ROCK DETAIL FOR JOINTING ROCK SOCKS ifi" CINDER SOCKS 16" CINDER _ BLOCKS BLOCKS FLOW Y U-1 2"x4" WOOD STUD MIN CURB INLET 2"x4" WOOD - SECTION A - STUD IP- 1 . BLOCK AND ROCK SOCK SUMP OR ON GRADE INLET PROTECTION BLOCK AND CURB SOCK INLET PROTECTION INSTALLATION NOTES 1. SEE ROCK SOCK DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. CONCRETE "CINDER" BLOCKS SHALL BE LAID ON THEIR SIDES AROUND THE INLET IN A SINGLE ROW, ABUTTING ONE ANOTHER WITH THE OPEN END FACING AWAY FROM THE CURB. 3. GRAVEL BAGS SHALL BE PLACED AROUND CONCRETE BLOCKS, CLOSELY ABUTTING ONE ANOTHER AND JOINTED TOGETHER IN ACCORDANCE WITH ROCK SOCK DESIGN DETAIL. MINIMUM OF TWO CURB SOCKS APPROX 30 DEG, BLOCK AND ROCK SOCK INLET PROTECTION(SEE DETAIL IP-1) CURB SOCK FLOW 5' MIN 3'-5' TYP. IP-2. CURB ROCK SOCKS UPSTREAM OF INLET PROTECTION CURB ROCK SOCK INLET PROTECTION INSTALLATION NOTES 1. SEE ROCK SOCK DESIGN DETAIL INSTALLATION REQUIREMENTS. 2. PLACEMENT OF THE SOCK SHALL BE APPROXIMATELY 30 DEGREES FROM PERPENDICULAR IN THE OPPOSITE DIRECTION OF FLOW. 3. SOCKS ARE TO BE FLUSH WITH THE CURB AND SPACED A MINIMUM OF 5 FEET APART. 4. AT LEAST TWO CURB SOCKS IN SERIES ARE REQUIRED UPSTREAM OF ON-GRADE INLETS. IP-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Inlet Protection (IP) SC-6 INLET GRATE I P SEE ROCK SOCK DETAIL FOR JOINTING ROCK SOCK IP-3. ROCK SOCK SUMPZAREA INLET PROTECTION ROCK SOCK SUMP/AREA INLET PROTECTION INSTALLATION NOTES 1. SEE ROCK SOCK DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. STRAW WATTLES/SEDIMENT CONTROL LOGS MAY BE USED IN PLACE OF ROCK SOCKS FOR INLETS IN PERVIOUS AREAS. INSTALL PER SEDIMENT CONTROL LOG DETAIL. INLET GRATE SF N � SILT FENCE (SEE SILT --SF� FENCE DESIGN DETAIL ) IP-4. SILT FENCE FOR SUMP INLET PROTECTION SILT FENCE INLET PROTECTION INSTALLATION NOTES 1. SEE SILT FENCE DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. POSTS SHALL BE PLACED AT EACH CORNER OF THE INLET AND AROUND THE EDGES AT A MAXIMUM SPACING OF 3 FEET. 3. STRAW WATTLES/SEDIMENT CONTROL LOGS MAY BE USED IN PLACE OF SILT FENCE FOR INLETS IN PERVIOUS AREAS. INSTALL PER SEDIMENT CONTROL LOG DETAIL. November 2010 Urban Drainage and Flood Control District IP-5 Urban Storm Drainage Criteria Manual Volume 3 SC-6 Inlet Protection (IP) SILT FENCE (LF AREA INLET SILT FENCE ECB 2:1 MAX 1 1� 1' MIN >3 AREA 2' MAX INLET } ECB 4' ROCK FILTER L CONCENTRATED FLOW OR ROCK SOCK (USE IF FLOW IS CONCENTRATED) IP-5. OVEREXCAVATION INLET PROTECTION OVEREXCAVATION INLET PROTECTION INSTALLATION NOTES 1. THIS FORM OF INLET PROTECTION IS PRIMARILY APPLICABLE FOR SITES THAT HAVE NOT YET REACHED FINAL GRADE AND SHOULD BE USED ONLY FOR INLETS WITH A RELATIVELY SMALL CONTRIBUTING DRAINAGE AREA 2. WHEN USING FOR CONCENTRATED FLOWS, SHAPE BASIN IN 2:1 RATIO WITH LENGTH ORIENTED TOWARDS DIRECTION OF FLOW. 3. SEDIMENT MUST BE PERIODICALLY REMOVED FROM THE OVEREXCAVATED AREA. 0 o a INLET GRATE 0 0 0 0 STRAW BALE (SEE STRAW o a BALE DESIGN DETAIL) e e e o 0 IP-6. STRAW BALE FOR SUMP INLET PROTECTION STRAW BALE BARRIER INLET PROTECTION INSTALLATION NOTES 1. SEE STRAW BALE DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. BALES SHALL BE PLACED IN A SINGLE ROW AROUND THE INLET WITH ENDS OF BALES TIGHTLY ABUTTING ONE ANOTHER. IP-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Inlet Protection (IP) SC-6 GENERAL INLET PROTECTION INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION OF INLET PROTECTION. —TYPE OF INLET PROTECTION (IP.1, IP.2, IP.3, IP.4, IP.5, IP.6) 2. INLET PROTECTION SHALL BE INSTALLED PROMPTLY AFTER INLET CONSTRUCTION OR PAVING IS COMPLETE (TYPICALLY WITHIN 48 HOURS). IF A RAINFALL/RUNOFF EVENT IS FORECAST, INSTALL INLET PROTECTION PRIOR TO ONSET OF EVENT. 3. MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED INLET PROTECTION MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF INLET PROTECTION SHALL BE REMOVED AS NECESSARY TO MAINTAIN BMP EFFECTIVENESS, TYPICALLY WHEN STORAGE VOLUME REACHES 50% OF CAPACITY, A DEPTH OF 6" WHEN SILT FENCE IS USED, OR Y4 OF THE HEIGHT FOR STRAW BALES. 5. INLET PROTECTION IS TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS PERMANENTLY STABILIZED, UNLESS THE LOCAL JURISDICTION APPROVES EARLIER REMOVAL OF INLET PROTECTION IN STREETS. 6. WHEN INLET PROTECTION AT AREA INLETS IS REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOP SOIL, SEEDED AND MULCHED, OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAIL ADAPTED FROM TOWN OF PARKER, COLORADO AND CITY OF AURORA, COLORADO, NOT AVAILABLE IN ALITOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. NOTE- THE DETAILS INCLUDED WITH THIS FACT SHEET SHOW COMMONLY USED, CONVENTIONAL METHODS OF INLET PROTECTION IN THE DENVER METROPOLITAN AREA, THERE ARE MANY PROPRIETARY INLET PROTECTION METHODS ON THE MARKET. UDFCD NEITHER ENDORSES NOR DISCOURAGES USE OF PROPRIETARY INLET PROTECTION; HOWEVER, IN THE EVENT PROPRIETARY METHODS ARE USED, THE APPROPRIATE DETAIL FROM THE MANUFACTURER MUST BE INCLUDED IN THE SWMP AND THE BMP MUST BE INSTALLED AND MAINTAINED AS SHOWN IN THE MANUFACTURER'S DETAILS. NOTE: SOME MUNICIPALITIES DISCOURAGE OR PROHIBIT THE USE OF STRAW BALES FOR INLET PROTECTION. CHECK WITH LOCAL JURISDICTION TO DETERMINE IF STRAW BALE INLET PROTECTION IS ACCEPTABLE. November 2010 Urban Drainage and Flood Control District IP-7 Urban Storm Drainage Criteria Manual Volume 3 Sediment Basin (SB) SC-7 Description A sediment basin is a temporary pond built on a construction site to capture eroded or disturbed soil transported in storm runoff prior to discharge from the site. Sediment basins are designed to capture site runoff and slowly release it to allow time for settling of sediment prior to discharge. Sediment basins are often constructed in locations that will later be + modified to serve as post-construction stormwater basins. Appropriate Uses Most large construction sites(typically Photograph S13-1. Sediment basin at the toe of a slope. Photo greater than 2 acres)will require one or courtesy of WWE. more sediment basins for effective management of construction site runoff. On linear construction projects, sediment basins may be impractical; instead, sediment traps or other combinations of BMPs may be more appropriate. Sediment basins should not be used as stand-alone sediment controls. Erosion and other sediment controls should also be implemented upstream. When feasible,the sediment basin should be installed in the same location where a permanent post- construction detention pond will be located. Design and Installation The design procedure for a sediment basin includes these steps: ■ Basin Storage Volume: Provide a storage volume of at least 3,600 cubic feet per acre of drainage area. To the extent practical,undisturbed and/or off-site areas should be diverted around sediment basins to prevent"clean"runoff from mixing with runoff from disturbed areas. For undisturbed areas (both on-site and off-site)that cannot be diverted around the sediment basin,provide a minimum of 500 ft3/acre of storage for undeveloped(but stable) off-site areas in addition to the 3,600 ft3/acre for disturbed areas. For stable,developed areas that cannot be diverted around the sediment basin, storage volume requirements are summarized in Table S13-1. ■ Basin Geometry: Design basin with a minimum length-to-width ratio of 2:1 (L:W). If this cannot be achieved because of site space constraints,baffling may be required to extend the effective distance between the inflow point(s) and the outlet to minimize short-circuiting. Sediment Basins ■ Dam Embankment: It is recommended that Functions embankment slopes be 4:1 (H:V) or flatter and no steeper Erosion Control No than 3:1 (H:V)in any location. Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District S13-1 Urban Storm Drainage Criteria Manual Volume 3 SC-7 Sediment Basin (SB) ■ Inflow Structure: For concentrated flow entering the basin,provide energy dissipation at the point of inflow. Table SB-1. Additional Volume Requirements for Undisturbed and Developed TributaryAreas Draining through Sediment Basins Additional Storage Volume(ft) Imperviousness % Per Acre of Tributary Area Undeveloped 500 10 800 20 1230 30 1600 40 2030 50 2470 60 2980 70 3560 80 4360 90 5300 100 6460 ■ Outlet Works: The outlet pipe shall extend through the embankment at a minimum slope of 0.5 percent. Outlet works can be designed using one of the following approaches: o Perforated Riser/Plate: Follow the design criteria for Full Spectrum Detention outlets in the EDB BMP Fact Sheet provided in Chapter 4 of this manual for sizing of outlet perforations with an emptying time of approximately 72 hours. In lieu of the well-screen trash rack,pack uniformly sized 1'/2-to 2-inch gravel in front of the plate. This gravel will need to be cleaned out frequently during the construction period as sediment accumulates within it. The gravel pack will need to be removed and disposed of following construction to reclaim the basin for use as a permanent detention facility. If the basin will be used as a permanent extended detention basin for the site, a well-screen trash rack will need to be installed once contributing drainage areas have been stabilized and the gravel pack and accumulated sediment have been removed. o Floating Skimmer: If a floating skimmer is used,install it using manufacturer's recommendations. Illustration S13-1 provides an illustration of a Faircloth Skimmer Floating OutletTM, one of the more commonly used floating skimmer outlets. A skimmer should be designed to release the design volume in no less than 48 hours. The use of a floating skimmer outlet can increase the sediment capture efficiency of a basin significantly. A floating outlet continually decants cleanest water off the surface of the pond and releases cleaner water than would discharge from a perforated riser pipe or plate. S13-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Basin (SB) SC-7 Illustration S13-1. Outlet structure for a temporary sediment basin-Faircloth Skimmer Floating Outlet. Illustration courtesy of J.W.Faircloth&Sons,Inc.,FairclothSkimmer.com. o Outlet Protection: Outlet protection should be provided where the velocity of now will exceed the maximum permissible velocity of the material of the waterway into which discharge occurs. This may require the use of a riprap apron at the outlet location and/or other measures to keep the waterway from eroding. o Emergency Spillway: Provide a stabilized emergency overflow spillway for rainstorms that exceed the capacity of the sediment basin volume and its outlet. Protect basin embankments from erosion and overtopping. If the sediment basin will be converted to a permanent detention basin, design and construct the emergency spillway(s) as required for the permanent facility. If the sediment basin will not become a permanent detention basin, it may be possible to substitute a heavy polyvinyl membrane or properly bedded rock cover to line the spillway and downstream embankment, depending on the height, slope, and width of the embankments. Maintenance and Removal Maintenance activities include the following: • Dredge sediment from the basin, as needed to maintain BMP effectiveness,typically when the design storage volume is no more than one-third filled with sediment. • Inspect the sediment basin embankments for stability and seepage. • Inspect the inlet and outlet of the basin,repair damage,and remove debris. Remove, clean and replace the gravel around the outlet on a regular basis to remove the accumulated sediment within it and keep the outlet functioning. • Be aware that removal of a sediment basin may require dewatering and associated permit requirements. • Do not remove a sediment basin until the upstream area has been stabilized with vegetation. November 2010 Urban Drainage and Flood Control District SB-3 Urban Storm Drainage Criteria Manual Volume 3 SC-7 Sediment Basin (SB) Final disposition of the sediment basin depends on whether the basin will be converted to a permanent post-construction stormwater basin or whether the basin area will be returned to grade. For basins being converted to permanent detention basins,remove accumulated sediment and reconfigure the basin and outlet to meet the requirements of the final design for the detention facility. If the sediment basin is not to be used as a permanent detention facility, fill the excavated area with soil and stabilize with vegetation. SB-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Basin (SB) SC-7 INLETS TO SEDIMENT BASIN SHALL ENTER AT FURTHEST DISTANCE TO OUTLET AND SHALL 1 TO 2 S B CONSIST OF A TEMPORARY SLOPE CRUSHED ROCK DRAIN RISER PIPE 6" PVC RIPRAP PAD = - o 3 g " L=2 x W MIN. HOLE BOTTOM LENGTH o `+ DIAMETER, 00 m HD 01 1 02 EL. 03.00 03 SPILLWAY 04 f SINGLE B 4" COLUMN TYp —1 OF FIVE 1 HOLES' SEDIMENT BASIN PLAN "EXCEPT WHERE THE HOLES EXCEED 1" EL. 01. DIAMETER, THEN UP TO TWO COLUMNS OF SAME SIZED HOLES MAY BE USED SCHEDULE 40 2' 4' PVC OR GREATER 4i � t2„ EL. 00.00 r v r ry r w 'ry 1 6" EXCAVATION 050=9" RIPRAP TYPE L. (SEE TABLE RIPRAP BEDDING MD-7, MAJOR } DRAINAGE, VOL. 1) 1 2" SECTION A CL 3. CREST LENGTH 3, EMBANKMENT MATERIAL II EL. 03.00 EL. 04.00 i AT CREST 3 D50=9" RIPRAP TYPE L (SEE TABLE MD-7, MAJOR DRAINAGE, VOLA) SECTION B SB- 1 . SEDIMENT BASIN November 2010 Urban Drainage and Flood Control District SB-5 Urban Storm Drainage Criteria Manual Volume 3 SC-7 Sediment Basin (SB) TABLE SB—1. SIZING INFORMATION FOR STANDARD SEDIMENT BASIN Upstream Drainage Basin Bottom Width Spillway Crest Hole Area (rounded to (yy) (ft) Length (CL), (ft) Diameter nearest acre), (ac) (HD), (in) 1 12 Y2 2 b2 2 21 3 '-i6 3 28 5 Y2 4 33 Y2 6 5 38 )/2 8 2Y32 6 43 9 2,32 " 7 47 Y4 1 1 2%2 8 51 12 23�2 9 55 13 % 10 58 Y4 15 17y16 11 61 16 3Yj2 12 64 18 1 13 67 Y2 19 1 K6 14 70 Yz 21 1 )6 15 73 Y4 22 1 '/16 SEDIMENT BASIN INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION OF SEDIMENT BASIN. —TYPE OF BASIN (STANDARD BASIN OR NONSTANDARD BASIN). —FOR STANDARD BASIN, BOTTOM WIDTH W, CREST LENGTH CL, AND HOLE DIAMETER, HD. —FOR NONSTANDARD BASIN, SEE CONSTRUCTION DRAWINGS FOR DESIGN OF BASIN INCLUDING RISER HEIGHT H, NUMBER OF COLUMNS N, HOLE DIAMETER HD AND PIPE DIAMETER D. 2. FOR STANDARD BASIN, BOTTOM DIMENSION MAY BE MODIFIED AS LONG AS BOTTOM AREA IS NOT REDUCED. 3. SEDIMENT BASINS SHALL BE INSTALLED PRIOR TO ANY OTHER LAND—DISTURBING ACTIVITY THAT RELIES ON ON BASINS AS AS A STORMWATER CONTROL, 4. EMBANKMENT MATERIAL SHALL CONSIST OF SOIL FREE OF DEBRIS, ORGANIC MATERIAL, AND ROCKS OR CONCRETE GREATER THAN 3 INCHES AND SHALL HAVE A MINIMUM OF 15 PERCENT BY WEIGHT PASSING THE NO. 200 SIEVE. 5. EMBANKMENT MATERIAL SHALL BE COMPACTED TO AT LEAST 95 PERCENT OF MAXIMUM DENSITY IN ACCORDANCE WITH ASTM D698. 6. PIPE SCH 40 OR GREATER SHALL BE USED. 7. THE DETAILS SHOWN ON THESE SHEETS PERTAIN TO STANDARD SEDIMENT BASIN(S) FOR DRAINAGE AREAS LESS THAN 15 ACRES. SEE CONSTRUCTION DRAWINGS FOR EMBANKMENT, STORAGE VOLUME, SPILLWAY, OUTLET, AND OUTLET PROTECTION DETAILS FOR ANY SEDIMENT BASIN(S) THAT HAVE BEEN INDIVIDUALLY DESIGNED FOR DRAINAGE AREAS LARGER THAN 15 ACRES. SB-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Basin (SB) SC-7 SEDIMENT BASIN MAINTENANCE NOTES t. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED IN BASIN SHALL BE REMOVED AS NEEDED TO MAINTAIN BMP EFFECTIVENESS, TYPICALLY WHEN SEDIMENT DEPTH REACHES ONE FOOT (I.E., TWO FEET BELOW THE SPILLWAY CREST). 5. SEDIMENT BASINS ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND GRASS COVER IS ACCEPTED BY THE LOCAL JURISDICTION. 6. WHEN SEDIMENT BASINS ARE REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAILS ADAPTED FROM DOUGLAS COUNTY, COLORADO) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District S13-7 Urban Storm Drainage Criteria Manual Volume 3 Sediment Trap (ST) SC-8 Description - Y Sediment traps are formed by excavating " r - an area or by placing an earthen embankment across a low area or drainage swale. Sediment traps are designed to capture drainage from disturbed areas less than one acre and allow settling of sediment. Appropriate Uses Sediment traps can be used in combination with other layers of erosion Photograph ST-l. Sediment traps are used to collect sediment-laden and sediment controls to trap sediment runoff from disturbed area.Photo courtesy of EPA Menu of BMPs. from small drainage areas(less than one acre) or areas with localized high sediment loading. For example, sediment traps are often provided in conjunction with vehicle tracking controls and wheel wash facilities. Design and Installation A sediment trap consists of a small excavated basin with an earthen berm and a riprap outlet. The berm of the sediment trap may be constructed from the excavated material and must be compacted to 95 percent of the maximum density in accordance with ASTM D698. An overflow outlet must be provided at an elevation at least 6 inches below the top of the berm. See Detail ST-1 for additional design and installation information. Maintenance and Removal Inspect the sediment trap embankments for stability and seepage. Remove accumulated sediment as needed to maintain the effectiveness of the sediment trap,typically when the sediment depth is approximately one-half the height of the outflow embankment. Inspect the outlet for debris and damage. Repair damage to the outlet, and remove all obstructions. A sediment trap should not be removed until the upstream area is sufficiently stabilized. Upon removal of the trap,the disturbed area should be covered with topsoil and stabilized. Sediment Trap Functions Erosion Control No Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District ST-1 Urban Storm Drainage Criteria Manual Volume 3 SC-8 Sediment Trap (ST) ST RIPRAP, TYPE M (D50=12") TYP.SMALLER ROCK SIZE MAY BE ALLOWABLE FOR SMALLER TRAPS IF APPROVED BY LOCAL JURISDICTION TOP OF EARTHEN BERM 2 1 MAX. i 2 1 MAX FLOW - TRANSITION EXISTING B FLOW - CHANNEL INTO W SEDIMENT TRAP 2 1 MAX 2 1 MAX. L SEDIMENT TRAP PLAN 6" (CENTER OF RIPRAP 6" LOWER THAN ENDS 6" MINIMUM 12' MIN. 30" FREEBOARD SECTION A CHANNEL GRADE 1 6" 2' 6' MIN. FLOW - /RIPRAP, TYPE m (D50=12") TYP. MIN. SMALLER ROCK SIZE MAY BE ALLOWABLE FOR SMALLER TRAPS IF APPROVED BY LOCAL JURISDICTION SECTION Q ST- 1 . SEDIMENT TRAP ST-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Trap (ST) SC-8 SEDIMENT TRAP INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATION, LENGTH AND WIDTH OF SEDIMENT TRAP. 2. ONLY USE FOR DRAINAGE AREAS LESS THAN 1 ACRE. 3 SEDIMENT TRAPS SHALL BE INSTALLED PRIOR TO ANY UPGRADIENT LAND—DISTURBING ACTIVITIES. 4. SEDIMENT TRAP BERM SHALL BE CONSTRUCTED FROM MATERIAL FROM EXCAVATION. THE BERM SHALL BE COMPACTED TO 95% OF THE MAXIMUM DENSITY IN ACCORDANCE WITH ASTM D698. 5. SEDIMENT TRAP OUTLET TO BE CONSTRUCTED OF RIPRAP, TYPE M (050=12") TYP.SMALLER ROCK SIZE MAY BE ALLOWABLE FOR SMALLER TRAPS IF APPROVED BY LOCAL JURISDICTION. 6 THE TOP OF THE EARTHEN BERM SHALL BE A MINIMUM OF 6" HIGHER THAN THE TOP OF THE RIPRAP OUTLET STRUCTURE. 7. THE ENDS OF THE RIPRAP OUTLET STRUCTURE SHALL BE A MINIMUM OF 6" HIGHER THAN THE CENTER OF THE OUTLET STRUCTURE. SEDIMENT TRAP MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. REMOVE SEDIMENT ACCUMULATED IN TRAP AS NEEDED TO MAINTAIN THE FUNCTIONALITY OF THE BMP, TYPICALLY WHEN THE SEDIMENT DEPTH REACHES Y2 THE HEIGHT OF THE RIPRAP OUTLET. 5. SEDIMENT TRAPS SHALL REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 6. WHEN SEDIMENT TRAPS ARE REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM DOUGL S COUNTY, COLORADO, NOT AVAILABLE IN AUTOCAO) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District ST-3 Urban Storm Drainage Criteria Manual Volume 3 Vegetated Buffers (VB) SC-9 Description = _ A. Buffer strips of preserved natural vegetation or grass help protect 49- waterways and wetlands from land disturbing activities. Vegetated buffers - improve stormwater runoff quality by - straining sediment,promoting infiltration, and slowing runoff velocities. Appropriate Uses Vegetated buffers can be used to Photograph VB-1. A vegetated buffer is maintained between the separate land disturbing activities and area of active construction and the drainage swale. Photo courtesy natural surface waters or conveyances. of wwE. In many jurisdictions, local governments require some type of setback from natural waterways. Concentrated flow should not be directed through a buffer; instead,runoff should be in the form of sheet flow. Vegetated buffers are typically used in combination with other perimeter control BMPs such as sediment control logs or silt fence for multi- layered protection. Design and Installation Minimum buffer widths may vary based on local regulations. Clearly delineate the boundary of the natural buffer area using construction fencing, silt fence,or a comparable technique. In areas that have been cleared and graded,vegetated buffers such as sod can also be installed to create or restore a vegetated buffer around the perimeter of the site. Maintenance and Removal Inspect buffer areas for signs of erosion such as gullies or rills. Stabilize eroding areas, as needed. If erosion is due to concentrated flow conditions, it may be necessary to install a level spreader or other technique to restore sheet flow conditions. Inspect perimeter controls delineating the vegetative buffer and repair or replace as needed. Vegetated Buffers Functions Erosion Control Moderate Sediment Control Yes Site/Material Management Yes November 2010 Urban Drainage and Flood Control District VB-1 Urban Storm Drainage Criteria Manual Volume 3 Chemical Treatment (CT) SC-10 Description Chemical treatment for erosion and ! sediment control can take several forms: °[,�� ="'='""=N- ms ��:eun: ,7teT [w..o •.�.. �lir 11 i 1. Applying chemicals to disturbed �, ��+• �� ""��' U�I surfaces to reduce erosion(these uses , are discussed in the Soil Binders Fact Sheet). 2. Adding flocculants to sedimentation Y� ponds or tanks to enhance sediment removal prior. 3. Using proprietary barriers Or flow- Photograph CT-1. Proprietary chemical treatment system being through devices containing flocculants used on a construction site with sensitive receiving waters. Photo (e.g., "floc logs"). courtesy of WWE. The use of flocculants as described in No.2 and No.3 above will likely require special permitting. Check with the state permitting agency. See the Soil Binder BMP Fact Sheet for information on surface application of chemical treatments,as described in No. 1. Appropriate Uses At sites with fine-grained materials such as clays, chemical addition to sedimentation ponds or tanks can enhance settling of suspended materials through flocculation. Prior to selecting and using chemical treatments,it is important to check state and local permit requirements related to their use. Design and Installation Due to variations among proprietary chemical treatment methods, design details are not provided for this BMP. Chemical feed systems for sedimentation ponds, settling tanks and dewatering bags should be installed and operated in accordance with manufacturer's recommendations and applicable regulations. Alum and chitosan are two common chemicals used as flocculants. Because the potential long-term impact of these chemicals to natural drainageways is not yet fully understood,the state does not currently allow chemical addition under the CDPS General Stormwater Construction Discharge Permit. Additional permitting may be necessary,which may include sampling requirements and numeric discharge limits. Any devices or barriers containing chemicals should be installed following manufacturer's guidelines. Check for state and local jurisdiction usage restrictions and requirements before including these practices in the SWMP and implementing them onsite. Chemical Treatment Functions Erosion Control Moderate Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District CT-1 Urban Storm Drainage Criteria Manual Volume 3 SC-10 Chemical Treatment (CT) Maintenance and Removal Chemical feed systems for sedimentation ponds or tanks should be maintained in accordance with manufacturer's recommendations and removed when the systems are no longer being used. Accumulated sediment should be dried and disposed of either at a landfill or in accordance with applicable regulations. Barriers and devices containing chemicals should be removed and replaced when tears or other damage to the devices are observed. These barriers should be removed and properly disposed of when the site has been stabilized. CT-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Construction Phasing/Sequencing (CP) SM-1 Description Effective construction site management to minimize erosion and sediment transport includes attention to construction phasing, scheduling, and sequencing of land disturbing activities. On most construction projects, erosion and sediment controls will need to be adjusted as the project progresses and should be documented in the SWMP. Construction phasing refers to disturbing only part of a site at a time to limit the potential for erosion from dormant parts of a site. Grading activities and construction are completed Photograph CP-1. Construction phasing to avoid disturbing the and soils are effectively stabilized on one entire area at one time. Photo courtesy of WWE. part of a site before grading and construction begins on another portion of the site. Construction sequencing or scheduling refers to a specified work schedule that coordinates the timing of land disturbing activities and the installation of erosion and sediment control practices. Appropriate Uses All construction projects can benefit from upfront planning to phase and sequence construction activities to minimize the extent and duration of disturbance. Larger projects and linear construction projects may benefit most from construction sequencing or phasing,but even small projects can benefit from construction sequencing that minimizes the duration of disturbance. Typically, erosion and sediment controls needed at a site will change as a site progresses through the major phases of construction. Erosion and sediment control practices corresponding to each phase of construction must be documented in the SWMP. Design and Installation BMPs appropriate to the major phases of development should be identified on construction drawings. In some cases,it will be necessary to provide several drawings showing construction-phase BMPs placed according to stages of development(e.g., clearing and grading,utility installation, active construction, final stabilization). Some municipalities in the Denver area set maximum sizes for disturbed area associated with phases of a construction project. Additionally,requirements for phased construction drawings vary among local governments within the UDFCD boundary. Some local governments require separate erosion and sediment control drawings for initial Construction Scheduling BMPs, interim conditions(in active construction), and final stabilization. Functions Erosion Control Moderate Sediment Control Moderate Site/Material Management Yes November 2010 Urban Drainage and Flood Control District CP-1 Urban Storm Drainage Criteria Manual Volume 3 SM-1 Construction Phasing/Sequencing (CP) Typical construction phasing BMPs include: ■ Limit the amount of disturbed area at any given time on a site to the extent practical. For example,a 100-acre subdivision might be constructed in five phases of 20 acres each. ■ If there is carryover of stockpiled material from one phase to the next,position carryover material in a location easily accessible for the pending phase that will not require disturbance of stabilized areas to access the stockpile. Particularly with regard to efforts to balance cut and fill at a site, careful planning for location of stockpiles is important. Typical construction sequencing BMPs include: ■ Sequence construction activities to minimize duration of soil disturbance and exposure. For example, when multiple utilities will occupy the same trench, schedule installation so that the trench does not have to be closed and opened multiple times. ■ Schedule site stabilization activities (e.g., landscaping, seeding and mulching, installation of erosion control blankets) as soon as feasible following grading. ■ Install initial erosion and sediment control practices before construction begins. Promptly install additional BMPs for inlet protection,stabilization,etc., as construction activities are completed. Table CP-I provides typical sequencing of construction activities and associated BMPs. Maintenance and Removal When the construction schedule is altered, erosion and sediment control measures in the SWMP and construction drawings should be appropriately adjusted to reflect actual"on the ground" conditions at the construction site. Be aware that changes in construction schedules can have significant implications for site stabilization,particularly with regard to establishment of vegetative cover. CP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Construction Phasing/Sequencing (CP) SM-1 Table CP-1. Typical Phased BMP Installation for Construction Projects Project BMPs Phase ■ Install sediment controls downgradient of access point(on paved streets this may consist of inlet protection). ■ Establish vehicle tracking control at entrances to paved streets. Fence as needed. Pre- disturbance, 0 Use construction fencing to define the boundaries of the project and limit access to areas of Site Access the site that are not to be disturbed. Note: it may be necessary to protect inlets in the general vicinity of the site,even if not downgradient,if there is a possibility that sediment tracked from the site could contribute to the inlets. ■ Install perimeter controls as needed on downgradient perimeter of site(silt fence,wattles, etc). ■ Limit disturbance to those areas planned for disturbance and protect undisturbed areas within the site(construction fence,flagging,etc). ■ Preserve vegetative buffer at site perimeter. ■ Create stabilized staging area. ■ Locate portable toilets on flat surfaces away from drainage paths. Stake in areas susceptible to high winds. ■ Construct concrete washout area and provide signage. ■ Establish waste disposal areas. Site Clearing and Grubbing Install sediment basins. ■ Create dirt perimeter berms and/or brush barriers during grubbing and clearing. ■ Separate and stockpile topsoil,leave roughened and/or cover. ■ Protect stockpiles with perimeter control BMPs. Stockpiles should be located away from drainage paths and should be accessed from the upgradient side so that perimeter controls can remain in place on the downgradient side. Use erosion control blankets,temporary seeding,and/or mulch for stockpiles that will be inactive for an extended period. ■ Leave disturbed area of site in a roughened condition to limit erosion. Consider temporary revegetation for areas of the site that have been disturbed but that will be inactive for an extended period. ■ Water to minimize dust but not to the point that watering creates runoff. November 2010 Urban Drainage and Flood Control District CP-3 Urban Storm Drainage Criteria Manual Volume 3 SM-1 Construction Phasing/Sequencing (CP) Project BMPs Phase In Addition to the Above BMPs: • Close trench as soon as possible(generally at the end of the day). Utility And Use rough-cut street control or apply road base for streets that will not be promptly paved. Infrastructure Installation EProvide inlet protection as streets are paved and inlets are constructed. ■ Protect and repair BMPs,as necessary. • Perform street sweeping as needed. In Addition to the Above BMPs: ■ Implement materials management and good housekeeping practices for home building activities. Building Construction 0 Use perimeter controls for temporary stockpiles from foundation excavations. ■ For lots adjacent to streets, lot-line perimeter controls may be necessary at the back of curb. In Addition to the Above BMPs; Final Grading ' Remove excess or waste materials. ■ Remove stored materials. In Addition to the Above BMPs: Final ■ Seed and mulch/tackify. Stabilization Seed and install blankets on steep slopes. ■ Remove all temporary BMPs when site has reached final stabilization. CP-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Protection of Existing Vegetation (PV) SM-2 Description Protection of existing vegetation on a construction site can be accomplished - - through installation of a construction fence around the area requiring protection. In cases where upgradient areas are disturbed, it may also be necessary to • s install perimeter controls to minimize sediment loading to sensitive areas such as wetlands. Existing vegetation may be designated for protection to maintain a stable surface cover as part of construction phasing, or vegetation may be protected in areas designated to remain in natural condition under post-development conditions(e.g.,wetlands,mature trees, Photograph PV-1. Protection of existing vegetation and a sensitive riparian areas, open space). area. Photo courtesy of CDOT. Appropriate Uses Existing vegetation should be preserved for the maximum practical duration on a construction site through the use of effective construction phasing. Preserving vegetation helps to minimize erosion and can reduce revegetation costs following construction. Protection of wetland areas is required under the Clean Water Act,unless a permit has been obtained from the U.S. Army Corps of Engineers(USACE)allowing impacts in limited areas. If trees are to be protected as part of post-development landscaping, care must be taken to avoid several types of damage, some of which may not be apparent at the time of injury. Potential sources of injury include soil compaction during grading or due to construction traffic, direct equipment-related injury such as bark removal,branch breakage, surface grading and trenching, and soil cut and fill. In order to minimize injuries that may lead to immediate or later death of the tree,tree protection zones should be developed during site design, implemented at the beginning of a construction project, as well as continued during active construction. Design and Installation General Once an area has been designated as a preservation area,there should be no construction activity allowed within a set distance of the area. Clearly mark the area with construction fencing. Do not allow stockpiles,equipment,trailers or parking within the protected area. Guidelines to protect various types of Protection of Existing Vegetation existing vegetation follow. Functions Erosion Control Yes Sediment Control Moderate Site/Material Management Yes November 2010 Urban Drainage and Flood Control District PV-1 Urban Storm Drainage Criteria Manual Volume 3 SM-2 Protection of Existing Vegetation (PV) Surface Cover During Phased Construction Install construction fencing or other perimeter controls around areas to be protected from clearing and grading as part of construction phasing. Maintaining surface cover on steep slopes for the maximum practical duration during construction is recommended. Open Space Preservation Where natural open space areas will be preserved as part of a development, it is important to install construction fencing around these areas to protect them from compaction. This is particularly important when areas with soils with high infiltration rates are preserved as part of LID designs. Preserved open space areas should not be used for staging and equipment storage. Wetlands and Riparian Areas Install a construction fence around the perimeter of the wetland or riparian(streamside vegetation) area to prevent access by equipment. In areas downgradient of disturbed areas, install a perimeter control such as silt fence, sediment control logs, or similar measure to minimize sediment loading to the wetland. Tree Protection' ■ Before beginning construction operations, establish a tree protection zone around trees to be preserved by installing construction fences. Allow enough space from the trunk to protect the root zone from soil compaction and mechanical damage, and the branches from mechanical damage(see Table PV-1). If low branches will be kept,place the fence outside of the drip line. Where this is not possible,place fencing as far away from the trunk as possible. In order to maintain a healthy tree,be aware that about 60 percent of the tree's root zone extends beyond the drip line. Table PV-1 Guidelines for Determining the Tree Protection Zone (Source: Matheny and Clark, 1998; as cited in GreenCO and WWE 2008) Distance from Trunk(ft)per inch of DBH Species Tolerance to Damage Young Mature Over mature Good 0.5' 0.75' 1.0' Moderate 0.75' 1.0' 1.25' Poor 1.0' 1.25' 1.5' Notes: DBH= diameter at breast height(4.5 ft above grade); Young=<20% of life expectancy; Mature = 20%-80% of life expectancy; Over mature =>80% of life expectancy ■ Most tree roots grow within the top 12 to 18 inches of soil. Grade changes within the tree protection zone should be avoided where possible because seemingly minor grade changes can either smother 1 Tree Protection guidelines adapted from GreenCO and W WE(2008). Green Industry Best Management Practices(BMPs)for the Conservation and Protection of Water Resources in Colorado: Moving Toward Sustainability, Third Release. See www.greenco.org for more detailed guidance on tree preservation. PV-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Protection of Existing Vegetation (PV) SM-2 roots (in fill situations) or damage roots (in cut situations). Consider small walls where needed to avoid grade changes in the tree protection zone. ■ Place and maintain a layer of mulch 4 to 6-inch thick from the tree trunk to the fencing,keeping a 6-inch space between the mulch and the trunk. Mulch helps to preserve moisture and decrease soil compaction if construction traffic is unavoidable. When planting operations are completed,the mulch may be reused throughout planting areas. ■ Limit access,if needed at all, and appoint one route as the main entrance and exit to the tree protection zone. Within the tree protection zone, do not allow any equipment to be stored, chemicals to be dumped, or construction activities to take place except fine grading,irrigation system installation, and planting operations. These activities should be conducted in consultation with a landscaping professional, following Green Industry BMPs. ■ Be aware that soil compaction can cause extreme damage to tree health that may appear gradually over a period of years. Soil compaction is easier to prevent than repair. Maintenance and Removal Repair or replace damaged or displaced fencing or other protective barriers around the vegetated area. If damage occurs to a tree,consult an arborist for guidance on how to care for the tree. If a tree in a designated preservation area is damaged beyond repair,remove and replace with a 2-inch diameter tree of the same or similar species. Construction equipment must not enter a wetland area, except as permitted by the U.S.Army Corps of Engineers(USACE). Inadvertent placement of fill in a wetland is a 404 permit violation and will require notification of the USACE. If damage to vegetation occurs in a protected area,reseed the area with the same or similar species, following the recommendations in the USDCM Revegetation chapter. November 2010 Urban Drainage and Flood Control District PV-3 Urban Storm Drainage Criteria Manual Volume 3 Construction Fence (CF) SM-3 Description A construction fence restricts site access _ _ to designated entrances and exits, delineates construction site boundaries, ` and keeps construction out of sensitive areas such as natural areas to be a preserved as open space,wetlands and riparian areas. Appropriate Uses A construction fence can be used to delineate the site perimeter and locations within the site where access is restricted to protect natural resources such as Photograph CF-1. A construction fence helps delineate areas where existing vegetation is being protected. Photo courtesy of Douglas wetlands,waterbodies,trees, and other County. natural areas of the site that should not be disturbed. If natural resource protection is an objective,then the construction fencing should be used in combination with other perimeter control BMPs such as silt fence,sediment control logs or similar measures. Design and Installation Construction fencing may be chain link or plastic mesh and should be installed following manufacturer's recommendations. See Detail CF-I for typical installations. Do not place construction fencing in areas within work limits of machinery. Maintenance and Removal ■ Inspect fences for damage; repair or replace as necessary. ■ Fencing should be tight and any areas with slumping or fallen posts should be reinstalled. ■ Fencing should be removed once construction is complete. Construction Fence Functions Erosion Control No Sediment Control No Site/Material Management Yes November 2010 Urban Drainage and Flood Control District CF-I Urban Storm Drainage Criteria Manual Volume 3 SM-3 Construction Fence (CF) cF-cF cF PLASTIC CAP, TYP. OCF STUDDED STEEL TEE POST ORANGE RESINET 5' MIN CONSTRUCTION FENCE EXISTING OR APPROVED EQUAL F GRADE r 1' MIN. 10' MAX SPACING STUDDED STEEL TEE POST 4 MIN. CF- 1 . PLASTIC MESH CONSTRUCTION FENCE CONSTRUCTION FENCE INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATION OF CONSTRUCTION FENCE. 2. CONSTRUCTION FENCE SHOWN SHALL BE INSTALLED PRIOR TO ANY LAND DISTURBING ACTIVITIES. 3. CONSTRUCTION FENCE SHALL BE COMPOSED OF ORANGE, CONTRACTOR-GRADE MATERIAL THAT IS AT LEAST 4' HIGH. METAL POSTS SHOULD HAVE A PLASTIC CAP FOR SAFETY. 4. STUDDED STEEL TEE POSTS SHALL BE UTILIZED TO SUPPORT THE CONSTRUCTION FENCE. MAXIMUM SPACING FOR STEEL TEE POSTS SHALL BE 10'. 5. CONSTRUCTION FENCE SHALL BE SECURELY FASTENED TO THE TOP, MIDDLE, AND BOTTOM OF EACH POST. CF-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Construction Fence (CF) SM-3 CONSTRUCTION FENCE MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. CONSTRUCTION FENCE SHALL BE REPAIRED OR REPLACED WHEN THERE ARE SIGNS OF DAMAGE SUCH AS RIPS OR SAGS. CONSTRUCTION FENCE IS TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 5. WHEN CONSTRUCTION FENCES ARE REMOVED, ALL DISTURBED AREAS ASSOCIATED WITH THE INSTALLATION, MAINTENANCE, AND/OR REMOVAL OF THE FENCE SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED, OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAIL ADAPTED FROM TOWN OF PARKER, COLORADO. NOT AVAILABLE IN AUTOCAD) November 2010 Urban Drainage and Flood Control District CF-3 Urban Storm Drainage Criteria Manual Volume 3 Vehicle Tracking Control (VTC) SM-4 Description - _ - Vehicle tracking controls provide _ stabilized construction site access where �l _ vehicles exit the site onto paved public - - roads. An effective vehicle tracking control helps remove sediment(mud or dirt)from vehicles,reducing tracking onto _ - _ the paved surface. Appropriate Uses - Implement a stabilized construction entrance or vehicle tracking control where Photograph VTC-1. A vehicle tracking control pad constructed with frequent heavy vehicle traffic exits the properly sized rock reduces off-site sediment tracking. construction site onto a paved roadway. An effective vehicle tracking control is particularly important during the following conditions: ■ Wet weather periods when mud is easily tracked off site. ■ During dry weather periods where dust is a concern. ■ When poorly drained,clayey soils are present on site. Although wheel washes are not required in designs of vehicle tracking controls,they may be needed at particularly muddy sites. Design and Installation Construct the vehicle tracking control on a level surface. Where feasible, grade the tracking control towards the construction site to reduce off-site runoff. Place signage,as needed,to direct construction vehicles to the designated exit through the vehicle tracking control. There are several different types of stabilized construction entrances including: VTC-1. Aggregate Vehicle Tracking Control. This is a coarse-aggregate surfaced pad underlain by a geotextile. This is the most common vehicle tracking control, and when properly maintained can be effective at removing sediment from vehicle tires. VTC-2. Vehicle Tracking Control with Construction Mat or Turf Reinforcement Mat. This type of control may be appropriate for site access at very small construction sites with low traffic volume over vegetated areas. Although this application does not typically remove sediment from vehicles,it helps protect existing vegetation and provides a stabilized entrance. Vehicle Tracking Control Functions Erosion Control Moderate Sediment Control Yes Site/Material Management Yes November 2010 Urban Drainage and Flood Control District VTC-1 Urban Storm Drainage Criteria Manual Volume 3 SM-4 Vehicle Tracking Control (VTC) VTC-3. Stabilized Construction Entrance/Exit with Wheel Wash. This is an aggregate pad, similar to VTC-1,but includes equipment for tire washing. The wheel wash equipment may be as simple as hand-held power washing equipment to more advance proprietary systems. When a wheel wash is provided, it is important to direct wash water to a sediment trap prior to discharge from the site. Vehicle tracking controls are sometimes installed in combination with a sediment trap to treat runoff. Maintenance and Removal Inspect the area for degradation and replace aggregate or material used for a ` a ; stabilized entrance/exit as needed. If the - - area becomes clogged and ponds water, .� remove and dispose of excess sediment or replace material with a fresh layer of aggregate as necessary. With aggregate vehicle tracking controls, - ensure rock and debris from this area do not enter the public right-of-way. r Remove sediment that is tracked onto the i public right of way daily or more , = f +# frequently as needed. Excess sediment "fit in the roadway indicates that the stabilized construction entrance needs maintenance. Photograph VTC-2. A vehicle tracking control pad with wheel wash facility. Photo courtesy of Tom Gore. Ensure that drainage ditches at the entrance/exit area remain clear. A stabilized entrance should be removed only when there is no longer the potential for vehicle tracking to occur. This is typically after the site has been stabilized. When wheel wash equipment is used,be sure that the wash water is discharged to a sediment trap prior to discharge. Also inspect channels conveying the water from the wash area to the sediment trap and stabilize areas that may be eroding. When a construction entrance/exit is removed, excess sediment from the aggregate should be removed and disposed of appropriately. The entrance should be promptly stabilized with a permanent surface following removal,typically by paving. VTC-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Vehicle Tracking Control (VTC) SM-4 VTC 20 FOOT (WIDTH CAN BE LESS IF CONST. VEHICLES ARE PHYSICALLY CONFINED ON BOTH SIDES) SIDEWALK OR OTHER 50 FOOT (MIN.) PAVED SURFACE .46 - _ _ - _ .. -� 9" (MIN ) PUBLIC UNLESS OTHERWISE SPECIFIED ROADWAY BY LOCAL JURISDICTION, USE • CDOT SECT. #703. AASHTO #3 COARSE AGGREGATE OR 6" MINUS ROCK NON-WOVEN GEOTEXTILE FABRIC BETWEEN SOIL AND ROCK UNLESS OTHERWISE SPECIFIED BY LOCAL INSTALL ROCK FLUSH WITH JURISDICTION, USE CDOT SECT. #703, AASHTO OR BELOW TOP OF PAVEMENT #3 COARSE AGGREGATE OR 6" MINUS ROCK g„ (MIN.) -� 77 f NON-WOVEN GEOTEXTILE FABRIC COMPACTED SUBGRADE SECTION A VTC- 1 . AGGREGATE VEHICLE TRACKING CONTROL November 2010 Urban Drainage and Flood Control District VTC-3 Urban Storm Drainage Criteria Manual Volume 3 SM-4 Vehicle Tracking Control (VTC) TC WW DITCH TO CARRY WASH WATER TO SEDIMENT TRAP OR BASIN i PUBLIC ROADWAY / NOTE: WASH WATER MAY NOT CONTAIN CHEMICALS OR SOAPS WITHOUT OBTAINING A SEPARATE PERMIT WASH RACK 6'7" MIN. MA REINFORCED CONCRETE RACK j :v (MAY SUBSTITUTE STEEL CATTLE DRAIN SPACE GUARD FOR CONCRETE RACK) SECTION A VTC-2. AGGREGATE VEHICLE TRACKING CONTROL WITH WASH RACK VTC-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Vehicle Tracking Control (VTC) SM-4 VTC/ VTC/ CM TR DISTURBED AREA, CONSTRUCTION SITE, STABILIZED STORAGE AREA 107- MAX, OR STAGING AREA O O O EXISTING 12' MIN PAVED CONSTRUCTION MATS, WOVEN OR TRM ROADWAY 50' MIN 18" MIN pQ Q SPIKES OR STAKES TRM END OVERLAP WITH } �& SPIKES OR STAKES a CONSTRUCTION MATS, WOVEN o Q�p��Q �� OR TURF REINFORCEMENT STRAP oa G��o,�� MAT (TRM) CONNECTORS CONSTRUCTION MAT ENO d RESTRICT CONST. VEHICLE OVERLAP INTERLOCK WITH ACCESS TO SIDES OF MAT STRAP CONNECTORS z V 11 x T 20' OR AS REQUIRED TO ACCOMMODATE ANTICIPATED TRAFFIC (WIDTH CAN BE LESS IF CONST. VEHICLES ARE PHYSICALLY CONFINED ON BOTH SIDES) VTC-3. VEHICLE TRACKING CONTROL W/ CONSTRUCTION MAT OR TURF REINFORCEMENT MAT (TRM) November 2010 Urban Drainage and Flood Control District VTC-5 Urban Storm Drainage Criteria Manual Volume 3 SM-4 Vehicle Tracking Control (VTC) STABILIZED CONSTRUCTION ENTRANCE/EXIT INSTALLATION NOTES 1, SEE PLAN VIEW FOR —LOCATION OF CONSTRUCTION ENTRANCE(S)/EXIT(S). —TYPE OF CONSTRUCTION ENTRANCE(S)/EXITS(S) (WITH/WITHOUT WHEEL WASH, CONSTRUCTION MAT OR TRM). 2. CONSTRUCTION MAT OR TRM STABILIZED CONSTRUCTION ENTRANCES ARE ONLY TO BE USED ON SHORT DURATION PROJECTS (TYPICALLY RANGING FROM A WEEK TO A MONTH) WHERE THERE WILL BE LIMITED VEHICULAR ACCESS. 3. A STABILIZED CONSTRUCTION ENTRANCE/EXIT SHALL BE LOCATED AT ALL ACCESS POINTS WHERE VEHICLES ACCESS THE CONSTRUCTION SITE FROM PAVED RIGHT—OF—WAYS. 4. STABILIZED CONSTRUCTION ENTRANCE/EXIT SHALL BE INSTALLED PRIOR TO ANY LAND DISTUR8ING ACTIVITIES. 5 A NON—WOVEN GEOTEXTILE FABRIC SHALL BE PLACED UNDER THE STABILIZED CONSTRUCTION ENTRANCE/EXIT PRIOR TO THE PLACEMENT OF ROCK. 6. UNLESS OTHERWISE SPECIFIED BY LOCAL JURISDICTION, ROCK SHALL CONSIST OF DOT SECT. #703, AASHTO #3 COARSE AGGREGATE OR 6" (MINUS) ROCK. STABILIZED CONSTRUCTION ENTRANCE/EXIT MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE 4. ROCK SHALL BE REAPPLIED OR REGRADED AS NECESSARY TO THE STABILIZED ENTRANCE/EXIT TO MAINTAIN A CONSISTENT DEPTH. 5. SEDIMENT TRACKED ONTO PAVED ROADS IS TO BE REMOVED THROUGHOUT THE DAY AND AT THE END OF THE DAY BY SHOVELING OR SWEEPING. SEDIMENT MAY NOT BE WASHED DOWN STORM SEWER DRAINS. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAILS ADAPTED FROM CITY OF BROOMFIELD. COLORADO. NOT AVAILABLE IN ALITOCAO) VTC-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Stabilized Construction Roadway (SCR) SM-5 Description � A stabilized construction roadway is a temporary method to control sediment runoff,vehicle tracking, and dust from roads during construction activities. -'' Appropriate Uses Use on high traffic construction roads to minimize dust and erosion. Stabilized construction roadways are used instead of rough-cut street controls on roadways with frequent construction traffic. Photograph SCR-1. Stabilized construction roadway. Design and Installation Stabilized construction roadways typically involve two key components: 1) stabilizing the road surface with an aggregate base course of 3-inch-diameter granular material and 2) stabilizing roadside ditches, if applicable. Early application of road base is generally suitable where a layer of coarse aggregate is specified for final road construction. Maintenance and Removal Apply additional gravel as necessary to ensure roadway integrity. Inspect drainage ditches along the roadway for erosion and stabilize, as needed,through the use of check dams or rolled erosion control products. Gravel may be removed once the road is ready to be paved. Prior to paving,the road should be inspected for grade changes and damage. Regrade and repair as necessary. Stabilized Construction Roadway Functions Erosion Control Yes Sediment Control Moderate Site/Material Management Yes November 2010 Urban Drainage and Flood Control District SCR-1 Urban Storm Drainage Criteria Manual Volume 3 Stabilized Staging Area (SSA) SM-6 Description A stabilized staging area is a clearly designated area where construction equipment and vehicles, stockpiles,waste - bins, and other construction-related materials are stored. The contractor office trailer may also be located in this - - area. Depending on the size of the r construction site,more than one staging area may be necessary. Appropriate Uses Most construction sites will require a staging area,which should be clearly Photograph SSA-1. Example of a staging area with a gravel surface to designated in SWMP drawings. The layout Prevent mud tracking and reduce runoff. Photo courtesy of Douglas of the staging area may vary depending on County. the type of construction activity. Staging areas located in roadways due to space constraints require special measures to avoid materials being washed into storm inlets. Design and Installation Stabilized staging areas should be completed prior to other construction activities beginning on the site. Major components of a stabilized staging area include: ■ Appropriate space to contain storage and provide for loading/unloading operations, as well as parking if necessary. ■ A stabilized surface, either paved or covered,with 3-inch diameter aggregate or larger. ■ Perimeter controls such as silt fence, sediment control logs,or other measures. ■ Construction fencing to prevent unauthorized access to construction materials. ■ Provisions for Good Housekeeping practices related to materials storage and disposal,as described in the Good Housekeeping BMP Fact Sheet. ■ A stabilized construction entrance/exit,as described in the Vehicle Tracking Control BMP Fact Sheet, to accommodate traffic associated with material delivery and waste disposal vehicles. Over-sizing the stabilized staging area may result in disturbance of existing vegetation in excess of that required for the project. This increases costs, as well as requirements for long-term stabilization following the Stabilized Staging Area construction period. When designing the stabilized staging area, minimize the area of disturbance to the extent practical. Functions Erosion Control Yes Sediment Control Moderate Site/Material Yes November 2010 Urban Drainage and Flood Control District SSA-1 Urban Storm Drainage Criteria Manual Volume 3 SM-6 Stabilized Staging Area (SSA) Minimizing Long-Term Stabilization Requirements ■ Utilize off-site parking and restrict vehicle access to the site. ■ Use construction mats in lieu of rock when staging is provided in an area that will not be disturbed otherwise. ■ Consider use of a bermed contained area for materials and equipment that do not require a stabilized surface. ■ Consider phasing of staging areas to avoid disturbance in an area that will not be otherwise disturbed. See Detail SSA-1 for a typical stabilized staging area and SSA-2 for a stabilized staging area when materials staging in roadways is required. Maintenance and Removal Maintenance of stabilized staging areas includes maintaining a stable surface cover of gravel,repairing perimeter controls, and following good housekeeping practices. When construction is complete, debris,unused stockpiles and materials should be recycled or properly disposed. In some cases,this will require disposal of contaminated soil from equipment leaks in an appropriate landfill. Staging areas should then be permanently stabilized with vegetation or other surface cover planned for the development. SSA-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Stabilized Staging Area (SSA) SM-6 SF/CF SF/CF fl FF SSA � ONSITE U n CONSTRUCTION CONSTRUCTION VEHICLE TRAILERS PrARKING (IF NEEDED), CONSTRUCTION SITE ACCESS n N 1� 3° MIN. THICKNESS I I MATERIAL GRANULAR MATERIAL STABILIZED STORAGE CONSTRUCTION ' ENTRANCE (SEE cn DETAILS VTC-1 TO VTC-3) SF/CF SF/CF _--�__ SILT FENCE OR CONSTRUCTION FENCING AS NEEDED EXISTING ROADWAY SSA- 1 . STABILIZED STAGING AREA STABILIZED STAGING AREA INSTALLATION NOTES 1. SEE PLAN VIEW FOR —LOCATION OF STAGING AREA(S). —CONTRACTOR MAY ADJUST LOCATION AND SIZE OF STAGING AREA WITH APPROVAL FROM THE LOCAL JURISDICTION. 2. STABILIZED STAGING AREA SHOULD BE APPROPRIATE FOR THE NEEDS OF THE SITE. OVERSIZING RESULTS IN A LARGER AREA TO STABILIZE FOLLOWING CONSTRUCTION. 3. STAGING AREA SHALL BE STABILIZED PRIOR TO OTHER OPERATIONS ON THE SITE. 4, THE STABILIZED STAGING AREA SHALL CONSIST OF A MINIMUM 3" THICK GRANULAR MATERIAL. 5. UNLESS OTHERWISE SPECIFIED BY LOCAL JURISDICTION, ROCK SHALL CONSIST OF DOT SECT. #703, AASHTO #3 COARSE AGGREGATE OR 6" (MINUS) ROCK. 6. ADDITIONAL PERIMETER BMPs MAY BE REQUIRED INCLUDING BUT NOT LIMITED TO SILT FENCE AND CONSTRUCTION FENCING. STABILIZED STAGING AREA MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. ROCK SHALL BE REAPPLIED OR REGRADED AS NECESSARY IF RUTTING OCCURS OR UNDERLYING SUBGRADE BECOMES EXPOSED. November 2010 Urban Drainage and Flood Control District SSA-3 Urban Storm Drainage Criteria Manual Volume 3 SM-6 Stabilized Staging Area (SSA) STABILIZED STAGING AREA MAINTENANCE NOTES 5. STABILIZED STAGING AREA SHALL BE ENLARGED IF NECESSARY TO CONTAIN PARKING, STORAGE, AND UNLOADING/LOADING OPERATIONS. 6 THE STABILIZED STAGING AREA SHALL BE REMOVED AT THE END OF CONSTRUCTION THE GRANULAR MATERIAL SHALL BE REMOVED OR, IF APPROVED BY THE LOCAL JURISDICTION, USED ON SITE, AND THE AREA COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY LOCAL JURISDICTION. NOTE: MANY MUNICIPALITIES PROHIBIT THE USE OF RECYCLED CONCRETE AS GRANULAR MATERIAL FOR STABILIZED STAGING AREAS DUE TO DIFFICULTIES WITH RE-ESTABLISHMENT OF VEGETATION IN AREAS WHERE RECYCLED CONCRETE WAS PLACED. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAILS ADAPTED FROM DOUGLAS COUNTY, COLORADO. NOT AVAILABLE IN AUTOCAD) SSA-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Street Sweeping and Vacuuming (SS) SM-7 Description Street sweeping and vacuuming remove sediment that has been tracked onto - roadways to reduce sediment transport - into storm drain systems or a surface waterway. , Appropriate Uses s Use this practice at construction sites where vehicles may track sediment offsite onto paved roadways. Design and Installation Photograph SS-1. A street sweeper removes sediment and potential Street sweeping or vacuuming should be pollutants along the curb line at a construction site. Photo courtesy of conducted when there is noticeable Tom Gore. sediment accumulation on roadways adjacent to the construction site. Typically,this will be concentrated at the entrance/exit to the construction site. Well-maintained stabilized construction entrances,vehicle tracking controls and tire wash facilities can help reduce the necessary frequency of street sweeping and vacuuming. On smaller construction sites, street sweeping can be conducted manually using a shovel and broom. Never wash accumulated sediment on roadways into storm drains. Maintenance and Removal ■ Inspect paved roads around the perimeter of the construction site on a daily basis and more frequently, as needed. Remove accumulated sediment,as needed. ■ Following street sweeping,check inlet protection that may have been displaced during street sweeping. ■ Inspect area to be swept for materials that may be hazardous prior to beginning sweeping operations. Street Sweeping/Vacuuming Functions Erosion Control No Sediment Control Yes Site/Material Management Yes November 2010 Urban Drainage and Flood Control District SS-1 Urban Storm Drainage Criteria Manual Volume 3 Temporary Diversion Channel (TDC) SM-8 Description ` A temporary diversion channel divertsSv 1' water from a stream to allow for construction activities to take place k i underneath or in the stream. Diversion channels are often required during the +6 construction of detention ponds, dams, _ q in-stream grade control structures, 1 utility installation and other activities that require working in waterways. Appropriate Uses Temporary diversion channels vary with the size of the waterway that is Photograph TDC-1. Use of a temporary diversion channel(right side) being diverted. For large streams, a to enable installation of a grade control structure(left side). Photo temporary diversion may consist of courtesy of wwE. berms or coffer dams constructed in the stream to confine flow to one side of the stream while work progresses on the dry side of the berm. For smaller streams and often for construction of dams and detention basins, a temporary diversion channel may divert the entire waterway,as illustrated in Figure TDC-1. For very short duration projects(typically less than 4 weeks)during dry periods with low base flows, a pump and bypass pipe may serve as a temporary diversion. Whenever a temporary diversion is used,construction should be scheduled during drier times of the year if possible(October 1 through April 1),and construction in the waterway should progress as quickly as possible to reduce the risk of exceeding the temporary diversion channel capacity. Some construction activities within a waterway are very short lived,namely a few hours or days in duration,and are minor in nature. These are typically associated with maintenance of utilities and stream crossings and minor repairs to outfalls and eroded banks. In these cases, construction of temporary diversion channels can often cause more soil disturbance and sediment movement than the maintenance activity itself. If it can be reasonably determined based on area and duration of disturbance that channel work will result in less disturbance and movement of sediment than would be done through installation of a temporary diversion channel, it is reasonable to exempt these activities from the requirement to construct a temporary diversion. Design and Installation Temporary Diversion Channel sizing procedures typically include the following steps: ■ Using the tributary area,A(in acres), determine the design peak flow rate according to Figure TDC-2. Note: For long duration projects, or where the consequences of diversion failure warrant, a larger design flow may be necessary. Temporary Diversion Channel ■ Determine depth of flow, 1-foot maximum for flows Functions less than 20 cfs and 3 feet maximum for flows less Erosion Control Yes than 100 cfs. (Flows in excess of 100 cfs should be designed in accordance with the Major Drainage Sediment Control No chapter in Volume 1). 1 Site/Material Management No August 2011 Urban Drainage and Flood Control District TDC-1 Urban Storm Drainage Criteria Manual Volume 3 SM-8 Temporary Diversion Channel (TDC) ■ Determine channel slope based on existing and proposed site conditions. ■ Perform initial channel sizing calculations using Manning's Equation. Determine maximum permissible velocities based on lining material. ■ Determine the channel geometry and check the capacity using Manning's Equation and the"n"value given in Table TDC-1. The steepest side slope allowable for a temporary channel is two horizontal to one vertical (2:1),unless vertical walls are installed using sheet piling, concrete or stacked stone. Temporary diversion channels should have a minimum freeboard of 0.5 feet above the design water surface elevation. Figure TDC-2 may be used to estimate the design discharge for the sizing of temporary diversion channels and pipes. The curves in this figure were developed using annual peak flow data collected from 17 watersheds within the UDFCD boundary. These data were collected over extended periods of time (up to eleven years)and, as a result,provide a sound statistical basis for the figure. The data supporting Figure TDC-2 were taken during the high flood potential period of April through September. The values from Figure TDC-2 represent approximately the 95`h percentile event that can occur, on the average, any given year,which means that it is likely that about 95 percent of runoff peaks during an average year will be less than values from this chart. This may not be the case in wetter-than-average seasons. Figure TDC-2 provides estimated 2-year peak flow rates based on watershed imperviousness for small waterways (< 12 square miles). Because Figure TDC-2 was developed using data from small watersheds, it is not appropriate to extrapolate from this figure for larger,more complex watersheds.For larger waterways (e.g., South Platte River, Sand Creek,Bear Creek, etc.),including ones controlled by flood control reservoirs(e.g. Chatfield Dam, Cherry Creek Dam, etc.), site specific risk assessment may be necessary to evaluate the appropriate level of protection to be provided by the temporary diversion. It is also important to recognize that larger floods can and do occur. It is the responsibility of the designer and the contractor to assess their risk of having the temporary diversion being exceeded and to evaluate the damages such an event may cause to the project, adjacent properties and others. Consider larger capacity diversions to protect a project if it will require a temporary diversion for more than one year. Because temporary diversion channels typically are not in service long enough to establish adequate vegetative lining, they must be designed to be stable for the design flow with the channel shear stress less than the critical tractive shear stress for the channel lining material. This stability criterion applies not only to diversion channels,but also to the stream-side of berms when berms are used to isolate a work area within a stream. Unlined channels should not be used. Table TDC-1 gives Manning's "n" values for lining materials. Design procedures for temporary channels are described in detail in the Hydraulic Engineering Circular No. 15 published by the Federal Highway Administration. The methods presented in this Fact Sheet are greatly simplified and are based on information developed using the most commonly used erosion control materials. TDC-2 Urban Drainage and Flood Control District August 2011 Urban Storm Drainage Criteria Manual Volume 3 Temporary Diversion Channel (TDC) SM-8 Former Location of FLOW Stream Bank 1 1 VEHICULAR/EQUIPMENT STREAM CROSSING; ACCESS TO ORIGINAL STREAMBED ` l" PLACE FLOW RIPRAP AT TRANSITION _ / J •� FLOW BARRIER'DIVERSION (RIPRAP, SANDBAGS, JERSEY BARRIERS / J OR SHEET PILING) LOW ORIGINAL STREAM BED FLOW BARRIER FLOW `1 �� i IE1i`h _ Former Location of PLACE RIPRAP Al•� TRANSITION Stream Bank ��o Figure TDC-1. Typical Temporary Diversion Channel August 2011 Urban Drainage and Flood Control District TDC-3 Urban Storm Drainage Criteria Manual Volume 3 SM-8 Temporary Diversion Channel (TDC) 1000 - 900 Imp. = 60% 800 • 700 Imp. = 40% N 600 LL V 43.3% y 46.5%500 Imp. = 30% ... JJ L 400 ♦5 5.4/o �� 33.3% Imp. = 20% 300 200 o ' 10.1%� 15. 100 100 o � � +26.8% 0 4.3% 0 2 4 6 8 10 12 TRIBUTARY AREA (SQUARE MILES) Figure TDC-2. Temporary Diversion Facility Sizing Nomograph Based on 2-year Peak Flows- Denver Metropolitan and Adjacent Areas TDC-4 Urban Drainage and Flood Control District August 2011 Urban Storm Drainage Criteria Manual Volume 3 Temporary Diversion Channel (TDC) SM-8 Table TDC-1. Temporary Diversion Channel Design Criteria Manning's n for Manning's n for Manning's n for Lining Material Flow Depth Flow Depth Flow Depth 0ftto1.0ft 1.0ftto3.0ft 3.0ftto5.0ft Plastic Membrane 0.011 0.010 0.009 Straw or Curled Wood 0.035 0.025 0.020 Mats Riprap, Type VL 0.070 0.045 0.035 Riprap, Type L 0.100 0.070 0.040 Riprap, Type M 0.125 0.075 0.045 Notes: Use manufacturer's Manning's n when available. See the Major Drainage chapter of Volume 1 for riprap gradation. Erosion protection should extend a minimum of 0.5 feet above the design water depth. Maintenance and Removal Because temporary diversion channels are one of the most critical BMPs for work in waterways,they must be inspected and maintained frequently to remain in effective operating condition. Flow barriers should be inspected at the start and end of each workday and at any time that excess water is noted in dry work areas. The diversion channel itself should be inspected for signs of erosion,and the lining should be repaired or replaced if there are signs of failure. Check armoring at the diversion return point to the waterway,and add additional armoring if erosion is noted. Water should not be allowed to flow back through the natural stream until all construction is completed. After redirecting the flow through the natural channel,lining materials should be removed from the temporary diversion channel. The diversion channel should then be backfilled and stabilized. Points of tie-in to the natural channel should be protected with riprap sized in accordance with the Major Drainage chapter in Volume 1. August 2011 Urban Drainage and Flood Control District TDC-5 Urban Storm Drainage Criteria Manual Volume 3 SM-8 Temporary Diversion Channel (TDC) SILT FENCE, TYP (SEE SF DETAIL D FOR INSTALL4REREMENTS) ANCHOR TRENCH AT PERIMETER OF BLANKET 30 MIL MIN. W (VARIESAND AT OVERLAPPING PLASTIC OINTS WITH ADJACENT VD (VARIEROLLS OF BLANKET, BWSIMILAR TO ECB/TRM, BUT VARIES) NO STAKING INTERMEDIATE ANCHOR TRENCH AT / ONE-HALF ROLL-LENGTH SIMILAR TRANSVERSE ANCHOR TRENCHES ECB/TRM DETAIL, BUT NO AT PERIMETER OF BLANKET AND STAKING AT OVERLAPPING JOINTS WITH ADJACENT ROLLS OF BLANKET, SIMILAR TO ECB, BUT NO STAKING DC- 1 . PLASTIC LINED DIVERSION CHANNEL SILT FENCE, TYP (SEE SF DETAIL FOR STAKES (SEE DESIGN DETAIL EC-10) INSTALLATION REQUIREMENTS) EROSION CO4TRW (5'-0" MIN.) ANCHOR TRENCH AT BLANKET (ECB) OR PERIMETER OF BLANKET REINFORCED MAT AND AT OVERLAPPING (SEE EC (10" MIN.) JOINTS WITH ANY BW ADJACENT ROLLS OF (VARIES) BLANKET. (SEE DETAIL _ ECB/TRM) INTERMEDIATE ANCHOR TRENCH :AT �� TRANSVERSE ANCHOR TRENCHES AT ONE-HALF ROLL-LENGTH PERIMETER OF BLANKET AND AT (SEE ECB/TRM) OVERLAPPING JOINTS WITH ANY ADJACENT ROLLS OF BLANKET. (SEE ECB/TRM) DC-2. GEOTEXTILE OR MAT LINED DIVERSION CHANNEL SILT FENCE, TYP (SEE THICKNESS=2 x D50 W (5'-0" MIN.) SF FOR INSTALLATION REQUIREMENTS) D (10" MIN) 1j BW (VARIES) LINE WITH VL RIPRAP (D50 = 6") OR AS OTHERWISE CALLED FOR IN THE PLANS DC-3. RIPRAP LINED DIVERSION CHANNEL TDC-6 Urban Drainage and Flood Control District August 2011 Urban Storm Drainage Criteria Manual Volume 3 Temporary Diversion Channel (TDC) SM-8 CHANNEL DIVERSION INSTALLATION NOTES 1, SEE PLAN VIEW FOR: —LOCATION OF DIVERSION CHANNEL —TYPE OF CHANNEL (UNLINED. GEOTEXTILE OR MAT LINED, PLASTIC LINE, OR RIPRAP LINED). —LENGTH OF EACH TYPE OF CHANNEL. —DEPTH, D. WIDTH, W, AND BOTTOM WIDTH, BW —FOR RIPRAP LINED CHANNEL, SIZE OF RIPRAP, 050, SHALL BE SHOWN ON PLANS. 2. SEE DRAINAGE PLANS FOR DETAILS OF PERMANENT CONVEYANCE FACILITIES. 3. DIVERSION CHANNELS INDICATED ON THE SWMP PLAN SHALL BE INSTALLED PRIOR TO WORK IN DOWNGRADIENT AREAS OR NATURAL CHANNELS. 4. FOR GEOTEXTILE OR MAT LINED CHANNELS, INSTALLATION OF GEOTEXTILE OR MAT SHALL CONFORM TO THE REQUIREMENTS OF DETAIL EC8, FOR PLASTIC LINED CHANNELS, INSTALLATION OF ANCHOR TRENCHES SHALL CONFORM TO THE REQUIREMENTS OF DETAIL ECB. 5. WHERE CONSTRUCTION TRAFFIC MUST CROSS A DIVERSION CHANNEL, THE PERMITTEE SHALL INSTALL A TEMPORARY STREAM CROSSING CONFORMING TO THE REQUIREMENTS OF DETAIL TSC. DIVERSION CHANNEL MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION, MAINTENANCE OF BMPS SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. DIVERSION CHANNELS ARE TO REMAIN IN PLACE UNTIL WORK IN THE DOWNGRADIENT AREA OR NATURAL CHANNEL IS NO LONGER REQUIRED. IF APPROVED BY LOCAL JURISDICTION DIVERSION CHANNEL MAY BE LEFT IN PLACE. 5 IF DIVERSION CHANNELS ARE REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY LOCAL JURISDICTION. (DETAILS ADAPTED FROM DOUGLAS COUNTY, COLORADO) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. August 2011 Urban Drainage and Flood Control District TDC-7 Urban Storm Drainage Criteria Manual Volume 3 Dewatering Operations (DW) SM-9 Description „ The BMPs selected for construction dewatering vary depending on site- _ u,. specific features such as soils, topography, anticipated discharge quantities, and discharge location. Dewatering typically involves pumping water from an inundated area to a BMP, = .+ and then downstream to a receiving waterway, sediment basin,or well- vegetated area. Dewatering typically involves use of several BMPs in - - +4 - sequence. Photograph DW-1. A relatively small dewatering operation using straw Appropriate Uses bales and a dewatering bag. Dewatering operations are used when an area of the construction site needs to be J dewatered as the result of a large storm event,groundwater,or existing ponding conditions. This can occur during deep excavation,utility trenching, and wetland or pond excavation. Design and Installation --- Dewatering techniques will vary , depending on site conditions. However, all dewatering discharges must be treated to remove sediment before discharging from the construction site. Discharging water into a sediment trap or basin is an acceptable treatment option. Water may Photograph DW-2. Dewatering bags used for a relatively large also be treated using a dewatering filter bag, dewatering operation. and a series of straw bales or sediment logs. If these previous options are not feasible due to space or the ability to passively treat the discharge to remove sediment,then a settling tank or an active treatment system may need to be utilized. Settling tanks are manufactured tanks with a series of baffles to promote settling. Flocculants can also be added to the tank to induce more rapid settling. This is an approach sometimes used on highly urbanized construction sites. Contact the state agency for special requirements prior to using flocculents and land application techniques. Some commonly used methods to handle the pumped water without surface discharge include land application Dewatering Operations to vegetated areas through a perforated discharge hose Functions (i.e.,the "sprinkler method")or dispersal from a water Erosion Control Moderate truck for dust control. Sediment Control Yes Site/Material Management Yes November 2010 Urban Drainage and Flood Control District DW-1 Urban Storm Drainage Criteria Manual Volume 3 SM-9 Dewatering Operations (DW) Dewatering discharges to non-paved areas must minimize the potential for scour at the discharge point either using a velocity dissipation device or dewatering filter bag. Design Details are provided for these types of dewatering situations: DW-1. Dewatering for Pond Already Filled with Water DW-2 Dewatering Sump for Submersed Pump DW-3 Sump Discharge Settling Basin DW-4 Dewatering Filter Bag Maintenance and Removal When a sediment basin or trap is used to enable settling of sediment from construction dewatering discharges, inspect the basin for sediment accumulation. Remove sediment prior to the basin or trap reaching half full. Inspect treatment facilities prior to any dewatering activity. If using a sediment control practice such as a sediment trap or basin, complete all maintenance requirements as described in the fact sheets prior to dewatering. Properly dispose of used dewatering bags, as well as sediment removed from the dewatering BMPs. Depending on the size of the dewatering operation, it may also be necessary to revegetate or otherwise stabilize the area where the dewatering operation was occurring. DW-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Dewatering Operations (DW) SM-9 LID WITH HOLE CUT DW FOR SUCTION LINE PUMP SUCTION LINE = PLASTIC 5—GALLON BUCKET WITH OR SUBMERSIBLE PUMP MANY 3/8" HOLES DRILLED CENTERED IN BUCKET IN SIDES BUCKET FILLED WITH AASHTO #3 GRAVEL (COOT SECT. 703, #3) DW- 1 . DEWATERING POND ALREADY FILLED WITH WATER LOWEST SUBGRADE ELEVATION TO BE DEWATERED PUMP SUCTION LINE OR LID WITH HOLE CUT 2 ' MIN. SUBMERSIBLE PUMP FOR SUCTION LINE - =- PLASTIC 5—GALLON BUCKET WITH 12" MIN, AROUND ON >" •; rs MANY 3/8" HOLES DRILLED IN SIDES ALL SIDES OF BUCKET AND BOTTOM 12" MIN. ' AASHTO #3 GRAVEL BELOW BUCKET (COOT SECT. 703, #3) DW-2. DEWATERING SUMP FOR SUBMERSED PUMP DEWATERING PUMP 4' MIN. DISCHARGE LINE SETTLING POND 12 SURFACE AREA, "A" MIN. 2' MIN. 1 SF PER 1 GPM A IN 12" STAKES TO Z RIPRAP 12,' MIN. SECURE END OF D50=6" DISCHARGE LINE L 12" MIN j 2' MIN. 2 X D50 a .� . ,� . 3 4' (MIN.) SQUARE MIN (12" MIN) - �.•, : f RIPRAP PAD TO STABILIZE FLOW PATH f Y RIPRAP DISSIPATE THE TO OUTFALL OR 050=6" ENERGY OF THE RECEIVING WATERS FLOW EXITING THE DISCHARGE LINE DW-3. SUMP DISCHARGE SETTLING BASIN SETTLING BASIN SECTION A November 2010 Urban Drainage and Flood Control District DW-3 Urban Storm Drainage Criteria Manual Volume 3 SM-9 Dewatering Operations (DW) VEGETATION SEDIMENT CONTROL LOG (SEE SCL-1 DETAIL) ROCK WILL BE INSTALLED, �} D AS NECESSARY, TO '•d r: PREVENT EROSION 0 y�K DISCHARGE PIPE FILTER BAG ON STRAW BALES OR ROCK PAD DW-4. DEWATERING FILTER BAG DEWATERING INSTALLATION NOTES 1. SEE PLAN VIEW FOR; —LOCATION OF DEWATERING EQUIPMENT. —TYPE OF DEWATERING OPERATION (DW-1 TO DW-4). 2. THE OWNER OR CONTRACTOR SHALL OBTAIN A CONSTRUCTION DISCHARGE (DEWATERING) PERMIT FROM THE STATE PRIOR TO ANY DEWATERING OPERATIONS DISCHARGING FROM THE SITE ALL DEWATERING SHALL BE IN ACCORDANCE WITH THE REQUIREMENTS OF THE PERMIT. 3 THE OWNER OR OPERATOR SHALL PROVIDE, OPERATE, AND MAINTAIN DEWATERING SYSTEMS OF SUFFICIENT SIZE AND CAPACITY TO PERMIT EXCAVATION AND SUBSEQUENT CONSTRUCTION IN DRY CONDITIONS AND TO LOWER AND MAINTAIN THE GROUNDWATER LEVEL A MINIMUM OF 2—FEET BELOW THE LOWEST POINT OF EXCAVATION AND CONTINUOUSLY MAINTAIN EXCAVATIONS FREE OF WATER UNTIL BACK—FILLED TO FINAL GRADE. DW-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Dewatering Operations (DW) SM-9 DEWATERING INSTALLATION NOTES 4, DEWATERING OPERATIONS SHALL USE ONE OR MORE OF THE DEWATERING SUMPS SHOWN ABOVE, WELL POINTS, OR OTHER MEANS APPROVED BY THE LOCAL JURISDICTION TO REDUCE THE PUMPING OF SEDIMENT, AND SHALL PROVIDE A TEMPORARY SEDIMENT BASIN OR FILTRATION BMP TO REDUCE SEDIMENT TO ALLOWABLE LEVELS PRIOR TO RELEASE OFF SITE OR TO A RECEIVING WATER. A SEDIMENT BASIN MAY BE USED IN LIEU OF SUMP DISCHARGE SETTLING BASIN SHOWN ABOVE IF A 4—FOOT—SQUARE RIPRAP PAD IS PLACED AT THE DISCHARGE POINT AND THE DISCHARGE END OF THE LINE IS STAKED IN PLACE TO PREVENT MOVEMENT OF THE LINE. DEWATERING MAINTENANCE NOTES 1. INSPECT BMPS EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPS AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPS IN EFFECTIVE OPERATING CONDITION INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPS HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE- 4 DEWATERING BMPS ARE REQUIRED IN ADDITION TO ALL OTHER PERMIT REQUIREMENTS. 5. TEMPORARY SETTLING BASINS SHALL BE REMOVED WHEN NO LONGER NEEDED FOR DEWATERING OPERATIONS. ANY DISTURBED AREA SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. NOTE MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAILS ADAPTED FROM DOUGLAS COUNTY, COLORADO, NOT AVAILABLE IN AUTOCAD) November 2010 Urban Drainage and Flood Control District DW-5 Urban Storm Drainage Criteria Manual Volume 3 Temporary Stream Crossing (TSC) SM-10 Description ` U T'y Where an actively flowing watercourse must be crossed regularly by construction vehicles, a temporary crossing should be provided. Three primary methods are available: ■ Culvert crossing ■ Stream ford ■ Temporary bridge Culvert crossings and fords are the most commonly used methods. Due to the expense associated with a temporary bridge,these are used primarily on long- Photograph TSC-1. A temporary stream crossing using culverts. term projects. Photo courtesy of Tom Gore. Appropriate Uses Construction vehicles shall be kept out of waterways to the maximum extent practicable. Use a temporary stream crossing when it is absolutely necessary to cross a stream on a construction site. Construct a temporary crossing even if the stream or drainageway is typically dry. Multiple stream crossings should be avoided to minimize environmental impacts. A permit is required for placement of fill in a waterway under Section 404 of the Clean Water Act. The local office of the U.S.Army Corps of Engineers(USAGE) should be contacted concerning the requirements for obtaining a 404 permit. In addition, a permit from the U.S. Fish and Wildlife Service (USFWS)may be needed if endangered species are of concern in the work area. Typically,the USFWS issues are addressed by a 404 permit,if one is required. The municipality of jurisdiction should also be consulted,and can provide assistance. Other permits to be obtained may include a floodplain development permit from the local jurisdiction. Design and Installation Design details are provided for these types of stream crossings: TSC-1. Culvert Crossing TSC-2. Ford Crossing TSC-3. Flume Crossing Temporary Stream Crossin Functions Erosion Control Yes Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District TSC-1 Urban Storm Drainage Criteria Manual Volume 3 SM-10 Temporary Stream Crossing (TSC) A culvert crossing should be designed to pass at least the 2-year design flow. Use Figure DC-2 from the Temporary Channel Diversion Fact Sheet to determine the 2-year peak flow rate. Culvert sizing must account for the headwater and tailwater controls to properly size the culvert. For additional discussion on design of box culverts and pipes, see the Major Drainage chapter in Volume 1. The designer also needs to confirm that the riprap selected is appropriate for the conditions in the channel being crossed. When a ford must be used,namely when a culvert is not practical or the best solution,the ford should be lined with at least a 12-inch thick layer of Type VL(1350=6 inches) or Type L(D50=9 inches)riprap with void spaces filed with 1-1/2 inch diameter rock. Ford crossings are recommended primarily for crossings of ephemeral(i.e. intermittently,briefly flowing) streams. For a temporary bridge crossing,consult with a structural and/or geotechnical engineer for temporary bridge design or consider pre-fabricated alternatives. Maintenance and Removal Inspect stream for bank erosion and in-stream degradation. If bank erosion is occurring, stabilize banks using erosion control practices such as erosion control blankets. If in-stream degradation is occurring, armor the culvert outlet(s)with riprap to dissipate energy(see Outlet Protection Fact Sheet). If sediment is accumulating upstream of the crossing,remove excess sediment as needed to maintain the functionality of the crossing. Remove the temporary crossing when it is no longer needed for construction. Take care to minimize the amount of sediment lost into the stream upon removal. Once the crossing has been removed, stabilize the stream banks with seed and erosion control blankets. TSC-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary Stream Crossing (TSC) SM-10 TSC LENGTH L CREST LENGTH CL A >5 � AVOID BANK EXCAVATION EXISTING _ '% ; IF POSSIBLE GRADE DEPTH D —} CULVERT (AS SPECIFIED) HEIGHT H J ^CULVERT DIAMETER CD CULVERT CROSSING SECTION 8' MIN 1J2" (MINUS) CRUSHED ROCK D50-12" TYP. RIPRAP 12" MIN. COVER 6" CULVERTS AS SPECIFIED FLOW f s��._ — -— — — >2 GEOTEXTILE FABRIC FOR MATERIAL SEPARATION GEOTEXTILE OR MAT SECTION A TSC- 1 . CULVERT CROSSING November 2010 Urban Drainage and Flood Control District TSC-3 Urban Storm Drainage Criteria Manual Volume 3 SM-10 Temporary Stream Crossing (TSC) LENGTH L CREST LENGTH CL >5 A >5 EXISTING CHANNEL GRADE AVOID BANK EXCAVATION IF POSSIBLE FORD CROSSING SECTION 8' MIN EXISTING CHANNEL GRADE >2 FLOW 1 -, 050-6" RIPRAP VOIDS FILLED 12" MIN WITH 1Y2" (MINUS) CRUSHED ROCK GEOTEXTILE OR MAT SECTION A TSC-2. FORD CROSSING TSC-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary Stream Crossing (TSC) SM-10 TSC EXCAVATED UTILITY PROPOSED UTILITY TRENCH FLUME PIPE FLOW FLOW EMBANKMENT, TYP. EXISTING STREAM BANK FLUME CROSSING PLAN STABILIZED STREAM BANK EMBANKMENT, TYP. FLUME PIPE STREAM FLOW STREAM BOTTOM PROPOSED UTILITY EXCAVATED UTILITY TRENCH SECTION A TSC-3. FLUME CROSSING November 2010 Urban Drainage and Flood Control District TSC-5 Urban Storm Drainage Criteria Manual Volume 3 SM-10 Temporary Stream Crossing (TSC) TEMPORARY STREAM CROSSING INSTALLATION NOTES 1. SEE PLAN VIEW FOR: —LOCATIONS OF TEMPORARY STREAM CROSSINGS. —STREAM CROSSING TYPE (FORD, CULVERT, OR FLUME). —FOR FORD CROSSING LENGTH (L), CREST LENGTH (CL), AND DEPTH (D). —FOR CULVERT CROSSING: LENGTH (L), CREST LENGTH (CL), CROSSING HEIGHT (H), DEPTH (D), CULVERT DIAMETER (CD), AND NUMBER, TYPE AND CLASS OR GAUGE OF CULVERTS. 2. TEMPORARY STREAM CROSSING DIMENSIONS, D50, AND NUMBER OF CULVERTS INDICATED (FOR CULVERT CROSSING) SHALL BE CONSIDERED MINIMUM DIMENSIONS; ENGINEER MAY ELECT TO INSTALL LARGER FACILITIES. ANY DAMAGE TO STREAM CROSSING OR EXISTING STREAM CHANNEL DURING BASEFLOW OR FLOOD EVENTS SHALL BE PROMPTLY REPAIRED. 3. SEE MAJOR DRAINAGE CHAPTER FOR RIPRAP GRADATIONS. 4. WHERE FAILURE OF A STREAM CROSSING CAN RESULT IN SIGNIFICANT DAMAGE OR HARM IT MUST BE DESIGNED BY A STRUCTURAL ENGINEER. TEMPORARY STREAM CROSSING MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. REMOVE SEDIMENT ACCUMULATED UPSTREAM OF CROSSING AS NEEDED TO MAINTAIN THE FUNCTIONALITY OF THE CROSSING. 5. STREAM CROSSINGS ARE TO REMAIN IN PLACE UNTIL NO LONGER NEEDED AND SHALL BE REMOVED PRIOR TO THE END OF CONSTRUCTION. 6 WHEN STREAM CROSSINGS ARE REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED AND COVERED WITH GEOTEXTILE OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND CITY OF AURORA, COLORADO (Va. DSWC), NOT AVAILABLE IN AUTOCAD) TSC-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Temporary Batch Plant (TBP) SM-11 Description Temporary batch plant management includes implementing multiple BMPs such as perimeter controls, concrete washout area, stabilized construction 71 access, good housekeeping, and other dti. practices designed to reduce polluted' " runoff from the batch plant area. Appropriate Uses - - -- Implement this BMP at temporary batch plants and identify the location of the batch plant in the SWMP. Photograph TBP-1. Effective stormwater management at temporary batch plants requires implementation of multiple BMPs. Photo Additional permitting may be required for courtesy of California Stormwater BMP Handbook. the operation of batch plants depending on their duration and location. Design and Installation The following lists temporary management strategies to mitigate runoff from batch plant operations: ■ When stockpiling materials, follow the Stockpile Management BMP. ■ Locate batch plants away from storm drains and natural surface waters. ■ A perimeter control should be installed around the temporary batch plant. ■ Install run-on controls where feasible. ■ A designated concrete washout should be located within the perimeter of the site following the procedures in the Concrete Washout Area BMP. ■ Follow the Good Housekeeping BMP, including proper spill containment measures,materials storage, and waste storage practices. ■ A stabilized construction entrance or vehicle tracking control pad should be installed at the plant entrance, in accordance with the Vehicle Tracking Control BMP. Maintenance and Removal Inspect the batch plant for proper functioning of the BMPs,with Temporary Batch Plants attention to material and waste storage areas, integrity of perimeter BMPs, and an effective stabilized construction Functions entrance. Erosion Control No Sediment Control No Site/Material Management Yes November 2010 Urban Drainage and Flood Control District TBP-1 Urban Storm Drainage Criteria Manual Volume 3 SM-11 Temporary Batch Plant (TBP) After the temporary batch plant is no longer needed,remove stockpiled materials and equipment,regrade the site as needed, and revegetate or otherwise stabilize the area. TBP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Paving and Grinding Operations (PGO) SM-12 Description Manage runoff from paving and grinding operations to reduce pollutants enteringr� storm drainage systems and natural - r drainageways. Appropriate Uses Use runoff management practices during all paving and grinding operations such - — as surfacing,resurfacing, and saw cutting. Design and Installation Photograph PGO-1. Paving operations on a Colorado highway. Photo courtesy of CDOT. There are a variety of management strategies that can be used to manage runoff from paving and grinding operations: ■ Establish inlet protection for all inlets that could potentially receive runoff. ■ Schedule paving operations when dry weather is forecasted. ■ Keep spill kits onsite for equipment spills and keep drip pans onsite for stored equipment. ■ Install perimeter controls when asphalt material is used on embankments or shoulders near waterways, drainages,or inlets. ■ Do not wash any paved surface into receiving storm drain inlets or natural drainageways. Instead, loose material should be swept or vacuumed following paving and grinding operations. ■ Store materials away from drainages or waterways. ■ Recycle asphalt and pavement material when feasible. Material that cannot be recycled must be disposed of in accordance with applicable regulations. See BMP Fact Sheets for Inlet Protection, Silt Fence and other perimeter controls selected for use during paving and grinding operations. Maintenance and Removal Perform maintenance and removal of inlet protection and perimeter controls in accordance with their respective fact sheets. Promptly respond to spills in accordance with the spill Paving and Grinding Operations prevention and control plan. Functions Erosion Control No Sediment Control No Site/Material Management Yes November 2010 Urban Drainage and Flood Control District PGO-1 Urban Storm Drainage Criteria Manual Volume 3 Grass Buffer T-1 Description Ix �- Grass buffers are densely vegetated strips of grass designed to accept sheet ' flow from upgradient development. , Properly designed grass buffers playa key role in LID, enabling infiltration and - slowing runoff. Grass buffers provide filtration(straining)of sediment. =:s Buffers differ from swales in that they s- - are designed to accommodate overland - - sheet flow rather than concentrated or channelized flow. Site Selection Grass buffers can be incorporated into a wide range of development settings. Photograph GB-1. A flush curb allows roadway runoff to sheet flow Runoff can be directly accepted from a through the grass buffer. Flows are then further treated by the grass parking lot,roadway, or the roof of a swale. Photo courtesy of Muller Engineering. structure,provided the flow is distributed in a uniform manner over the width of the buffer. This can be achieved through the use of flush curbs, slotted curbs,or level spreaders where needed. Grass buffers are often used in conjunction with grass swales. They are well suited for use in riparian zones to assist in stabilizing channel banks adjacent to major drainageways and receiving waters. These areas can also sometimes serve multiple functions such as recreation. Hydrologic Soil Groups A and B provide the best infiltration Grass Buffer capacity for grass buffers. For Type C and D soils,buffers still serve to provide filtration(straining)although infiltration rates are Functions lower. LID/Volume Red. Yes WQCV Capture No Designing for Maintenance WQCV+Flood Control No Fact Sheet Includes Recommended ongoing maintenance practices for all BMPs are EURV Guidance No provided in Chapter 6 of this manual. During design the Typical Effectiveness for Targeted following should be considered to ensure ease of maintenance Pollutants3 over the long-term: Sediment/Solids Good ■ Where appropriate(where vehicle safety would not be Nutrients Moderate impacted), install the top of the buffer 1 to 3 inches below the Total Metals Good adjacent pavement so that growth of vegetation and Bacteria Poor accumulation of sediment at the edge of the strip does not Other Considerations prevent runoff from entering the buffer. Alternatively, a Life-cycle Costs Low sloped edge can be used adjacent to vehicular traffic areas. • Amend soils to encourage deep roots and reduce irrigation 3 Based primarily on data from the requirements, as well as promote infiltration. International Stormwater BMP Database (www.bmpdatabase.orgy. November 2010 Urban Drainage and Flood Control District G13-1 Urban Storm Drainage Criteria Manual Volume 3 T-1 Grass Buffer ■ Design and adjust the irrigation system(temporary or Benefits permanent)to provide water in amounts appropriate for the selected vegetation. Irrigation needs will change from ■ Filters (strains) sediment and month to month and year to year. trash. ■ Protect the grass buffer from vehicular traffic when using ■ Reduces directly connected this BMP adjacent to roadways. This can be done with a impervious area. (See Chapter 3 slotted curb (or other type of barrier) or by constructing a for quantifying benefits.) reinforced grass shoulder(see Fact Sheet T-10.5). ■ Can easily be incorporated into a Design Procedure and Criteria treatment train approach. The following steps outline the grass buffer design procedure ' Provides green space available and criteria. Figure GB-1 is a schematic of the facility and its for multiple uses including components: recreation and snow storage. 1. Design Discharge: Use the hydrologic procedures ' Straightforward maintenance described in the Runoff chapter of Volume 1 to determine requirements when the buffer is the 2-year peak flow rate (Q2) of the area draining to the protected from vehicular traffic. grass buffer. Limitations 2. Minimum Width: The width(W),normal to flow of the buffer,is typically the same as the contributing basin(see ■ Frequently damaged by vehicles Figure GB-1). An exception to this is where flows become when adjacent to roadways and concentrated. Concentrated flows require a level spreader unprotected. to distribute flows evenly across the width of the buffer. The minimum width should be: ■ A thick vegetative cover is needed for grass buffers to be W _ Q2 Equation GB-1 effective. 0.05 ■ Nutrient removal in grass buffers Where: is typically low. W = width of buffer(ft) ■ High loadings of coarse solids, Q2 =2-year peak runoff(cfs) trash, and debris require pretreatment. 3. Length: The recommended length(L),the distance along . Space for grass buffers may not the sheet flow direction, should be a minimum of 14 feet. be available in ultra urban areas This value is based on the findings of Barrett et al. 2004 in (lot-line-to-lot-line). Stormwater Pollutant Removal in Roadside Vegetated Strips and is appropriate for buffers with greater than 80% _ vegetative cover and slopes up to 10%. The study found that pollutant removal continues throughout a length of 14 feet. Beyond this length,a point of diminishing returns in pollutant reduction was found. It is important to note that shorter lengths or slightly steeper slopes will also provide some level of removal where site constraints dictate the geometry of the buffer. GB-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Grass Buffer T-1 4. Buffer Slope: The design slope of a grass buffer in the Use of Grass Buffers direction of flow should not exceed 10%. Generally, a minimum slope of 2% or more in turf is adequate to Sheet flow of stormwater through a facilitate positive drainage. For slopes less than 2%, grassed area provides some benefit in consider including an underdrain system to mitigate pollutant removal and volume nuisance drainage. reduction even when the geometry of the BMP does not meet the criteria 5. Flow Characteristics (sheet or concentrated): provided in this Fact Sheet. These Concentrated flows can occur when the width of the criteria provide a design procedure watershed differs from that of the grass buffer. that should be used when possible; Additionally,when the product of the watershed flow however,when site constraints are length and the interface slope(the slope of the watershed limiting,this treatment concept is normal to flow at the grass buffer) exceeds approximately still encouraged. one, flows may become concentrated. Use the following equations to determine flow characteristics: Sheet Flow: FL(SI) < 1 Equation G13-2 Concentrated Flow: FL(SI) > 1 Equation G13-3 Where: FL =watershed flow length(ft) SI =interface slope(normal to flow) (ft/ft) 6. Flow Distribution: Flows delivered to a grass buffer must be sheet flows. Slotted or flush curbing, permeable pavements, or other devices can be used to spread flows. The grass buffer should have relatively consistent slopes to avoid concentrating flows within the buffer. A level spreader should be used when flows are concentrated. A level spreader can be a slotted drain designed to discharge flow through the slot as shown in Photo G13-2. It could be an exfiltration trench filled with gravel,which allows water to infiltrate prior to discharging over a level concrete or rock curb. There are many ways to design and construct a level spreader. They can also be used in series when the length of the buffer allows flows to re- concentrate. See Figure G13-2 for various level spreader sections. Photograph GB-2. This level spreader carries concentrated flows into a slotted pipe encased in concrete to distribute flows evenly to the grass buffer shown left in the photo. Photo courtesy of Bill Wenk. November 2010 Urban Drainage and Flood Control District G13-3 Urban Storm Drainage Criteria Manual Volume 3 T-1 Grass Buffer Photos GB-3 and GB-4 show a level spreader that includes a basin for sedimentation. Concentrated flows enter the basin via stormsewer. The basin is designed to drain slowly — while overflow is spread evenly to the downstream vegetation. A small notch,orifice, or pipe can be used to ' drain the level spreader completely. r.. The opening should be small to encourage frequent flows to overtop the level spreader but not so small that it is frequently clogged. 7. Soil Preparation: In order to encourage establishment and long- term health of the selected vegetation, Photograph GB-3. This level spreader includes the added benefit of a it is essential that soil conditions be sedimentation basin prior to even distribution of concentrated flows properly prepared prior to from the roadway into the grass buffer. Photo courtesy of Bill Wenk. installation. Following site grading, poor soil conditions often exist. When possible,remove, strip, stockpile, and reuse on-site topsoil. ' If the site does not contain topsoil, the soils should be amended prior to vegetation. Typically 3 to 5 cubic yards of soil amendment(compost) per 1,000 square feet,tilled 6 inches into the soil is required in order for vegetation to thrive, as well as to enable infiltration of runoff. Additionally, inexpensive soil tests _ can be conducted to determine - -- required soil amendments. (Some local governments may also require proof of soil amendment in landscaped areas for water conservation reasons.) Photograph GB-4. Maintenance access is provided via the ramp located at the end of the basin. Photo courtesy of Bill Wenk. 8. Vegetation: This is the most critical component for treatment within a grass buffer. Select durable, dense, and drought tolerant grasses to vegetate the buffer. Also consider the size of the watershed as larger watersheds will experience more frequent flows. The goal is to provide a dense mat of vegetative cover. Grass buffer performance falls off rapidly as the vegetation coverage declines below 80%(Barrett et a1.2004). GB-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Grass Buffer T-1 Turf grasses such as Kentucky bluegrass are often selected due to these qualities'. Dense native turf grasses may also be selected where a more natural look is desirable. Once established,these provide the benefit of lower irrigation requirements. See the Revegetation chapter in Volume 2 of this manual with regard to seed mix selection,planting and ground preparation. Depending on soils and anticipated flows,consider erosion control measures until vegetation has been established. 9. Irrigation: Grass buffers should be equipped with irrigation systems to promote establishment and survival in Colorado's semi-arid environment. Systems may be temporary or permanent, depending on the type of vegetation selected. Irrigation application rates and schedules should be developed and adjusted throughout the establishment and growing season to meet the needs of the selected plant species. Initially,native grasses require the same irrigation requirements as bluegrass. After the grass is established, irrigation requirements for native grasses can be reduced. Irrigation practices have a significant effect on the function of the grass buffer. Overwatering decreases the permeability of the soil,reducing the infiltration capacity and contributing to nuisance baseflows. Conversely, under watering may result in delays in establishment of the vegetation in the short term and unhealthy vegetation that provides less filtering and increased susceptibility to erosion and rilling over the long term. 10. Outflow Collection: Provide a means for downstream conveyance. A grass swale can be used for this purpose,providing additional LID benefits. Construction Considerations Success of grass buffers depends not only on a good design and long-term maintenance,but also on installing the facility in a manner that enables the BMP to function as designed. Construction considerations include: ■ The final grade of the buffer is critical. Oftentimes, following soil amendment and placement of sod, the final grade is too high to accept sheet flow. The buffer should be inspected prior to placement of seed or sod to ensure appropriate grading. ■ Perform soil amending, fine grading, and seeding only after tributary areas have been stabilized and utility work crossing the buffer has been completed. ■ When using sod tiles stagger the ends of the tiles to prevent the formation of channels along the joints. Use a roller on the sod to ensure there are no air pockets between the sod and soil. ■ Avoid over compaction of soils in the buffer area during construction to preserve infiltration capacities. ■ Erosion and sediment control measures on upgradient disturbed areas must be maintained to prevent excessive sediment loading to grass buffer. 'Although Kentucky bluegrass has relatively high irrigation requirements to maintain a lush,green aesthetic,it also withstands drought conditions by going dormant. Over-irrigation of Kentucky bluegrass is a common problem along the Colorado Front Range,and it can be healthy,although less lush,with much less irrigation than is typically applied. November 2010 Urban Drainage and Flood Control District GB-5 Urban Storm Drainage Criteria Manual Volume 3 T-1 Grass Buffer W, Uj r�t•c C �'WA 71tR5,RED rLOW L1;Nc,TN 0\1\ PLAN RNhlt i I"T03' LIP WNERE,.. � u SUITABLEOA 1 v 7 LEVEL SPR€ADER IE— AMENDED S0I1-5� PROFILE Figure GB-1. Typical Grass Buffer Graphic by Adia Davis. G13-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Grass Buffer T-1 CORRUGATED SLOTTED DRAIN PIPE GRASS BUFFER AGGREGATE BASE COURSE SECTION n LEVEL SPREADER FOR PIPE FLOWS �- PIPE AND HEADWALL BEYOND GRASS BUFFER =" /- SLOTTED CURB DRAIN PAN WITH CURBS SECTION 0 LEVEL SPREADER FOR PIPE FLOWS GRASS BUFFER UNDERDRAIN, SEE SECTION 5 (OR PROVIDE SMALL OPENING IN WALL) SECTION � LEVEL SPREADER FOR SURFACE FLOWS �' GRASS BUFFER UNDERDRAIN, SEE SECTION 5 (OPTIONAL) SECTION LEVEL SPREADER FOR SMALL SURFACE FLOWS CDOT CLASS C FILTER MATERIAL OR OTHER COMPATIBLE MATERIAL SUCH AS AASHTO #57 OR #67 CDOT VARIES, MIN 8" CLASS C ILTER 4" MATERIAL 1 PER TABLE SLOTTED PIPE PER TABLE GS-3' GS-2 1. SEE BMP FACT SHEET T-2, GRASS SWALE SECTION 'UNDERDRAIN ` Figure G13-2. Typical Level Spreader Details November 2010 Urban Drainage and Flood Control District GB-7 Urban Storm Drainage Criteria Manual Volume 3 Grass Swale T-2 Description ` Grass swales are densely vegetated trapezoidal or triangular channels with - ` low-pitched side slopes designed to convey runoff slowly. Grass swales have low longitudinal slopes and broad cross-sections that convey flow in a slow and shallow manner,thereby facilitating sedimentation and filtering(straining) while limiting erosion. Berms or check dams may be incorporated into grass swales to reduce velocities and encourage settling and infiltration. When using berms, an underdrain system should be provided. Grass swales are an integral part of the Low Photograph GS-1. This grass swale provides treatment of roadway Impact Development(LID) concept and runoff in a residential area. Photo courtesy of Bill Ruzzo. may be used as an alternative to a curb and gutter system. Site Selection Grass swales are well suited for sites with low to moderate slopes. Grass Swale Drop structures or other features designed to provide the same function as a drop structures (e.g., a driveway with a stabilized Functions grade differential at the downstream end)can be integrated into LIDNolume Red. Yes the design to enable use of this BMP at a broader range of site WQCV Capture No conditions. Grass swales provide conveyance so they can also be used to replace curb and gutter systems making them well suited WQCV+Flood Control No for roadway projects. Fact Sheet Includes EURV Guidance No DeSI nlri for Maintenance Typical Effectiveness for Targeted g g Pollutants Recommended ongoing maintenance practices for all BMPs are Sediment/Solids Good provided in Chapter 6 of this manual. During design,the Nutrients Moderate following should be considered to ensure ease of maintenance Total Metals Good over the long-term: Bacteria Poor Other Considerations ■ Consider the use and function of other site features so that the swale fits into the landscape in a natural way. This can Life-cycle Costs Low encourage upkeep of the area,which is particularly important 3 Based primarily on data from the in residential areas where a loss of aesthetics and/or function International Stormwater BMP Database can lead to homeowners filling in and/or piping reaches of (www.bmpdatabase.orQ). this BMP. November 2010 Urban Drainage and Flood Control District GS-1 Urban Storm Drainage Criteria Manual Volume 3 T-2 Grass Swale ■ Provide access to the swale for mowing equipment and Benefits design sideslopes flat enough for the safe operation of equipment. Removal of sediment and associated constituents through ■ Design and adjust the irrigation system(temporary or filtering(straining) permanent)to provide appropriate water for the selected vegetation. Reduces length of storm sewer systems in the upper portions of a ■ An underdrain system will reduce excessively wet areas, watershed which can cause rutting and damage to the vegetation during mowing operations. Provides a less expensive and more attractive conveyance ■ When using an underdrain,do not put a filter sock on the element pipe. This is unnecessary and can cause the slots or perforations in the pipe to clog. Reduces directly connected impervious area and can help Design Procedure and Criteria reduce runoff volumes. The following steps outline the design procedure and criteria Limitations for stormwater treatment in a grass swale. Figure GS-1 shows trapezoidal and triangular swale configurations. Requires more area than traditional storm sewers. I. Design Discharge: Determine the 2-year flow rate to be conveyed in the grass swale under fully developed Underdrains are recommended for conditions. Use the hydrologic procedures described in slopes under 2%. the Runoff Chapter in Volume 1. ■ Erosion problems may occur if not 2. Hydraulic Residence Time: Increased hydraulic designed and constructed residence time in a grass swale improves water quality properly. treatment. Maximize the length of the swale when possible. If the length of the Swale is limited due to site constraints,the slope can also be decreased or the cross-sectional area increased to increase hydraulic residence time. 3. Longitudinal Slope: Establish a longitudinal slope that will meet Froude number,velocity, and depth criteria while ensuring that the grass swale maintains positive drainage. Positive drainage can be achieved with a minimum 2% longitudinal slope or by including an underdrain system(see step 8). Use drop structures as needed to accommodate site constraints. Provide for energy dissipation downstream of each drop when using drop structures. 4. Swale Geometry: Select geometry for the grass swale. The cross section should be either trapezoidal or triangular with side slopes not exceeding 4:1 (horizontal:vertical),preferably flatter. Increase the wetted area of the swale to reduce velocity. Lower velocities result in improved pollutant removal efficiency and greater volume reduction. If one or both sides of the grass swale are also to be used as a grass buffer, follow grass buffer criteria. GS-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Grass Swale T-2 5. Vegetation: Select durable, dense, and drought tolerant grasses. Turf grasses, such as Kentucky bluegrass, are often selected due to these qualities'. Native turf grasses may also be selected where a more natural look is desirable. This will also provide the benefit of lower irrigation requirements, once established. Turf grass is a general term for any grasses that will form a turf or mat as opposed to bunch grass,which will grow in clumplike fashion. Grass selection should consider both short-term(for establishment) and long-term maintenance requirements, given that some varieties have higher maintenance Native grasses provide requirements than others. Follow criteria in the a more natural aesthetic Revegetation Chapter of Volume 2,with regard to seed and require less water mix selection,planting, and ground preparation. once established. 6. Design Velocity: Maximum flow velocity in the swale should not exceed one foot per second. Use the Soil Conservation Service(now the NRCS)vegetal retardance curves for the Manning coefficient(Chow 1959). Determining the retardance coefficient is an iterative process that the UD-BMP workbook automates. When starting the swale vegetation from sod, curve "D" (low retardance) should be used. When starting vegetation from seed,use the "E" curve(very low vegetal retardance). 7. Design Flow Depth: Maximum flow depth should not exceed one foot at the 2-year peak flow rate. Check the conditions for the 100-year flow to ensure that drainage is being handled without flooding critical areas, structures, or adjacent streets. Table GS-1. Grass Swale Design Summary for Water Quality Design Flow Maximum Maximum Maximum Froude Number Velocity Flow Depth 2-year event 0.5 1 ft/s 1 ft Use of Grass Swales Vegetated conveyance elements provide some benefit in pollutant removal and volume reduction even when the geometry of the BMP does not meet the criteria provided in this Fact Sheet. These criteria provide a design procedure that should be used when possible; however,when site constraints are limiting,vegetated conveyance elements designed for stability are still encouraged. Although Kentucky bluegrass has relatively high irrigation requirements to maintain a lush,green aesthetic,it also withstands drought conditions by going dormant. Over-irrigation of Kentucky bluegrass is a common problem along the Colorado Front Range. It can be healthy,although less lush,with much less irrigation than is typically applied. November 2010 Urban Drainage and Flood Control District GS-3 Urban Storm Drainage Criteria Manual Volume 3 T-2 Grass Swale 8. Underdrain: An underdrain is necessary for swales with longitudinal slopes less than 2.0%. The underdrain can drain directly into an inlet box at the downstream end of the swale,daylight through the face of a grade control structure or continue below grade through several grade control structures as shown in Figure GS-1. The underdrain system should be placed within an aggregate layer. If no underdrain is required,this layer is not required. The aggregate layer should consist of an 8-inch thick layer of CDOT Class C filter material meeting the gradation in Table GS-2. Use of CDOT Class C Filter material with a slotted pipe that meets the slot dimensions provided in Table GS-3 will eliminate the need for geotextile fabrics. Previous versions of this manual detailed an underdrain system that consisted of a 3-to 4-inch perforated HDPE pipe in a one-foot trench section of AASHTO#67 coarse aggregate surrounded by geotextile fabric. If desired,this system continues to provide an acceptable alternative for use in grass swales. Selection of the pipe size may be a function of capacity or of maintenance equipment. Provide cleanouts at approximately 150 feet on center. Table GS-2. Gradation Specifications for Class C Filter Material (Source: CDOT Table 703-7) Sieve Size Mass Percent Passing Square Mesh Sieves 19.0 mm(3/4") 100 4.75 mm(No. 4) 60— 100 300 µm(No. 50) 10—30 150 µm(No. 100) 0— 10 75 µm(No. 200) 0-3 Table GS-3. Dimensions for Slotted Pipe ' Pipe Diameter Slot Maximum Slot Slot 1 Open Area Length Width Centers' (per foot) 4" 1-1/16" 0.032" 0.413" 1.90 in 6" 1-3/8" 0.032" 0.516" 1.98 in' 'Some variation in these values is acceptable and is expected from various pipe manufacturers. Be aware that both increased slot length and decreased slot centers will be beneficial to hydraulics but detrimental to the structure of the pipe. GS-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Grass Swale T-2 9. Soil preparation: Poor soil conditions often exist following site grading. When the section includes an underdrain,provide 4 inches of sandy loam at the invert of the Swale extending up to the 2-year water surface elevation. This will improve infiltration and reduce ponding. For all sections, encourage establishment and long-term health of the bottom and side slope vegetation by properly preparing the soil. If the existing site provides a good layer of topsoil,this should be striped, stockpiled, and then replaced just prior to seeding or placing sod. If not available at the site,topsoil can be imported or the existing soil may be amended. Inexpensive soil tests can be performed following rough grading,to determine required soil amendments. Typically, 3 to 5 cubic yards of soil amendment per 1,000 square feet,tilled 4 to 6 inches into the soil is required in order for vegetation to thrive, as well as to enable infiltration of runoff. 10. Irrigation: Grass swales should be equipped with irrigation systems to promote establishment and survival in Colorado's semi-arid environment. Systems may be temporary or permanent, depending on the type of grass selected. Irrigation practices have a significant effect on the function of the grass swale. Overwatering decreases the permeability of the soil,reducing the infiltration capacity of the soil and contributing to nuisance baseflows. Conversely,under watering may result in delays in establishment of the vegetation in the short term and unhealthy vegetation that provides less filtering (straining) and increased susceptibility to erosion and riling over the long term. Construction Considerations Success of grass swales depends not only on a good design and maintenance,but also on construction NO practices that enable the BMP to function as designed. Construction considerations include: PA R K I N G ■ Perform fine grading, soil amendment, and seeding only after upgradient surfaces have been stabilized ON and utility work crossing the swale has been completed. SWALE ■ Avoid compaction of soils to preserve infiltration capacities. ■ Provide irrigation appropriate to the grass type. ■ Weed the area during the establishment of vegetation Photograph GS-2. This community used by hand or mowing. Mechanical weed control is signage to mitigate compaction of soils post- preferred over chemical weed killer. construction. Photo courtesy of Nancy styles. ■ Protect the swale from other construction activities. ■ When using an underdrain, ensure no filter sock is placed on the pipe. This is unnecessary and can cause the slots or perforations in the pipe to clog. November 2010 Urban Drainage and Flood Control District GS-5 Urban Storm Drainage Criteria Manual Volume 3 T-2 Grass Swale RESIDUAL CAPACITY FOR �--, LARGER FLOODS 1 P. 2—YR WSE 6" MI 4 MIN. V (2—YR)<1.0 FPS x c, W. y 4" (MIN) SANDY LOAM O 1" MIN 12" MIN BOTTOM WIDTH (W) GRADE CONTROL STRUCTURE BEYOND TRAPEZOIDAL SWALE SECTION N- RESIDUAL CAPACITY FOR 4 LARGER FLOODS r/. 12" MIN. 1 2—YR WSE 6� MIN 4 MIN. GRADE CONTROL STRUCTURE BEYOND O UNDERDRAIN AND SANDY LOAM RECOMMENDED FOR LONGITUDINAL SLOPES < 2.0%. 4" SLOTTED PIPE MEETING TABLE GS-3 WITH CDOT CLASS C FILTER 4" MIN. SANDY LOAM MATERIAL ALL AROUND OR PERFORATED HOPE Q 1" MIN. PIPE WITH AASHTO #67 ALL AROUND CONTAINED D (20YR) 1.0 FPS 12' IN. WITHIN GEOTEXTILE FABRIC. ASTM D4751—AOS US STD. SIEVE #50 TO #70, ASTM D4533 MIN. TRAPEZOIDAL TEAR STRENGTH 100 X 60 LBS, MINIMUM COE SPECIFIED OPEN AREA OF 4%. TRIANGULAR SWALE SECTION NTS CONCRETE COLLAR ENERGY GRADE CONTROL EXTEND GRADE CONTROL DISSIPATION__ STRUCTURE STRUCTURES INTO THE BANK A MIN. 0.5' ABOVE THE 2—YR WSE PROVIDE DOUBLE CLEANOUTS WITH WATER TIGHT CAPS ®150' O.C. USE 90' SWEEP OR (2) UNDERDRAIN 45- BENDS (OFFSET FROM SWALE CENTERLINE TO AVOID IMPEDING FLOW WHEN USING A TRIANGULAR ENSURE ACCESS TO OUTLET SECTION BY CLEAN OUT OR OTHER ACCESSIBLE STRUCTURE SWALE PROFILE NTS Figure GS-1. Grass Swale Profile and Sections Design Example The UD-BMP workbook, designed as a tool for both designer and reviewing agency is available at www.udfed.org. This section provides a completed design form from this workbook as an example. GS-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix D— Landscape Plans Kimley>>) Horn Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix E— Permits/Applications Kimley>>) Horn Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix F- Inspection Logs Kimley>>) Horn STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective I Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) STORM WATER MANAGEMENT PLAN INSPECTION TABLE BMP Name/Desc. Date Erosion Control Measures Effective Brief Revision Description Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Yes No Yes (w/Rev) Erosion Control Report Pederson Toyota — Fort Collins, Colorado Appendix G- Contractor Inserts Kimley>>) Horn