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HomeMy WebLinkAboutNEC LAKE AND SHIELDS - FDP190008 - DOCUMENT MARKUPS - ROUND 2 - STORMWATER MANAGEMENT PLANSTORMWATER MANAGEMENT PLAN (SWMP) NEC LAKE AND SHIELDS Fort Collins, CO October 2, 2018 Prepared for: CSURF 2537 Research Boulevard, Suite 200 Fort Collins, CO 80526 Prepared by: 301 North Howes Street, Suite 100 Fort Collins, Colorado 80521 Phone: 970.221.4158 Fax: 970.221.4159 www.northernengineering.com Project Number: 232-047  This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is absolutely necessary, we recommend double-sided printing. October 2, 2018 CSURF 2537 Research Boulevard, Suite 200 Fort Collins, Co 80526 RE: Stormwater Management Plan NEC Lake and Shields To Whom It May Concern: Northern Engineering Services, Inc. is pleased to submit this Stormwater Management Plan for NEC Lake and Shields project. This report outlines Best Management Practices (BMPs) to be implemented with the proposed construction in order to minimize potential pollutants in stormwater discharges. We have prepared this report to accompany 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). A copy of the issuance cover letter can be found in the Appendix D of this document (to be provided 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 takes place. As such, this version was prepared to facilitate initial plan approvals and permitting, 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 make changes to what is contained herein so that the SWMP works as effectively and efficiently as possible. It shall be the responsibility of the SWMP Administrator and/or the permit holder (or applicant thereof) to ensure the plan is properly maintained and followed. If you should have any questions or comments as you review this report, please feel free to contact us at your convenience. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Blaine Mathisen, EI Project Engineer NEC Lake and Shields Stormwater Management Plan TABLE OF CONTENTS Vicinity Map 1.0 General Requirements ................................................................................................ 1 1.1 Objectives .................................................................................................................. 1 1.2 SMWP Availability ...................................................................................................... 1 1.3 Definitions.................................................................................................................. 1 1.4 Additional Permitting ................................................................................................... 1 2.0 Narrative Site Description ........................................................................................... 2 2.1 Existing Site Description .............................................................................................. 2 2.2 Nature of Construction Activity ..................................................................................... 2 2.3 Sequence of Major Activities ......................................................................................... 2 2.4 Site Disturbance ......................................................................................................... 2 2.5 Existing Data .............................................................................................................. 2 2.6 Existing Vegetation ...................................................................................................... 2 2.7 Potential Pollution Sources ........................................................................................... 3 2.8 Non-stormwater discharges .......................................................................................... 3 2.9 Receiving Waters ........................................................................................................ 4 3.0 Stormwater Management Controls ............................................................................... 4 3.1 SWMP Administrator ................................................................................................... 4 3.2 Best Management Practices (BMP’s) for Stormwater Pollution Prevention.......................... 4 3.3 Structural Practices for Erosion and Sediment Control ..................................................... 4 3.4 Non-Structural Practices for Erosion and Sediment Control .............................................. 6 3.5 Phased BMP Installation .............................................................................................. 9 3.6 Material Handling and Spill Prevention .......................................................................... 9 3.7 Dedicated Concrete or Asphalt Batch Plant .................................................................. 10 3.8 Vehicle Tracking Control ............................................................................................ 10 3.9 Waste Management and Disposal ............................................................................... 10 3.10 Groundwater and Stormwater Dewatering .................................................................... 11 4.0 Final Stabilization and Long-Term Stormwater Management ........................................ 11 4.1 Final Stabilization ..................................................................................................... 11 4.2 Long-Term Stormwater Management ........................................................................... 12 5.0 Inspection, Maintenance and Record Keeping ............................................................. 12 5.1 BMP Inspection ........................................................................................................ 12 5.2 BMP Maintenance .................................................................................................... 12 5.3 Record Keeping ........................................................................................................ 12 6.0 Additional SWMP and BMP Resources ....................................................................... 14 References 15 NEC Lake and Shields Stormwater Management Plan LIST OF TABLES: Table 1 – Preliminary Permit and Construction Schedule .......................................................... 9 APPENDICES: APPENDIX A – Site Maps APPENDIX B – Erosion Control Details APPENDIX C – Landscape Plan APPENDIX D – Copies of Permits/Applications APPENDIX E – Inspection Logs APPENDIX F – Contractor Inserts (as needed) APPENDIX G – Contractor Inserts (as needed) NEC Lake and Shields Stormwater Management Plan 1 1.0 General Requirements 1.1 Objectives The objective of a Stormwater Management Plan (SWMP) is to identify all potential sources of pollution likely to occur as a result of construction activity associated with the site construction, and to describe the practices that will be used to reduce the pollutants in stormwater discharges from the site. The SWMP must be completed and implemented at the time the project breaks ground, and revised as necessary as construction proceeds to accurately reflect the conditions and practices at the site. This report summarizes the Stormwater Management Plan for the construction activity that will occur with NEC Lake and Shields in Fort Collins, CO. This plan has been prepared according to regulations of the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division. 1.2 SMWP Availability This report is intended to remain on the aforementioned construction site to allow for maintenance and inspection updates, and for review during inspection. 1.3 Definitions BMP – Best Management Practice encompassing a wide range of erosion and sediment control practices, both structural and non-structural in nature, which are intended to reduce or eliminate any possible water quality impacts from stormwater leaving a construction site. Erosion Control BMPs – Practices that PREVENT the erosion of soil, such as minimizing the amount of disturbed area through phasing, temporary stabilization, and preserving existing vegetation. Sediment Control BMP’s – Practices to REMOVE sediment from runoff, such as sediment basins, silt fence, or inlet protection. Non-structural BMP’s – The implementation of methods, practices, and procedures to minimize water quality impacts, such as the preservation of natural vegetation, preventive maintenance and spill response procedures. Structural BMP’s – Physical devices that prevent or minimize water quality impacts, such as sediment basins, inlet protection, or silt fence. 1.4 Additional Permitting As mentioned above, this Stormwater Management Plan is associated with the Colorado Department of Public Health and Environment Stormwater Permit that is issued by the Water Quality Control Division of the CDPHE. Additional Environmental permitting not described in this report may be required as a part of this project. An example is the Construction Dewatering Permit for groundwater. Another example is the Air Pollution Emission Notice (APEN). The CDPHE website contains links to both of these permits, as well as many other potential permits. The Contractor is responsible for ensuring the proper permits are acquired. NEC Lake and Shields Stormwater Management Plan 2 2.0 Narrative Site Description 2.1 Existing Site Description The project is located in the Southwest Quarter of Section 14, Township 7 North, Range 69 West of the 6th P.M., City of Fort Collins, County of Larimer, State of Colorado. 2.2 Nature of Construction Activity The proposed NEC Lake and Shields project will include a daycare facility with associated parking and landscaping. All detention and water quality will be contained and treated through the use of rain gardens and extended detention within the landscaping. 2.3 Sequence of Major Activities To complete the project, many basic categories of construction activity will take place. The first part will be the removal of the existing infrastructure that is still on site. Most of the previously existing infrastructure has already been removed (four houses and associated driveways) but there is still some driveways and curb and gutter that needs replaced. Once the existing infrastructure has been removed the topsoil and native grasses that are currently on-site will be removed followed by overlot grading. Next, utility installation and foundation excavation will begin. Vertical construction of the building along with the parking lot will commence after foundation and underground work is complete. The final stages of site construction will be fine grading of the areas around the buildings, and the installation of landscaping throughout the project. The aforementioned sequencing is an initial best guess and is subject to change at the Contractor’s discretion. 2.4 Site Disturbance The site disturbance will occur across roughly 2.17 acres. It is recommended that existing site condition photos be taken prior to the demolition. 2.5 Existing Data In order to complete the associated construction plans, a topographical survey of the site was completed. This survey consisted of field measurements made by Northern Engineering on July 13, 2018. In addition to the field survey, that Natural Resources Conservation Service (NRCS) Soil Survey was used to determine existing soil types found on-site. According to the NRCS Soil Survey, the site consists of 100% Altvan-Satanta loams which is classified as a Hydrologic Soil Group B. Type B soil is cohesive and has often been cracked or disturbed, with pieces that don’t stick together as well as Type A soils. Because the soil is less cohesive than the desired Type A soils the potential for erosion due to soil structure is slightly higher. It is recommended that erosion control blankets be placed anywhere there is a proposed 4:1 slope. This will insure slope stability and reduce the potential for future erosion. 2.6 Existing Vegetation The existing site vegetation consists of native grasses as well as some deciduous and conifer trees. It is highly recommended that pre-construction photos be taken to clearly document vegetative conditions prior any disturbance activities. NEC Lake and Shields Stormwater Management Plan 3 2.7 Potential Pollution Sources As is typical with most construction sites, there are a number of potential pollution sources which could affect water quality. It is not possible for this report to identify all materials that will be used or stored on the construction site. It is the sole responsibility of the Contractor to identify and properly handle all materials that are potential pollution sources. The following are some common examples of potential pollution sources: • Exposed and stored soils • Management of contaminated soils • Off-site tracking of soils and sediment • Loading and unloading operations • Outdoor storage of building materials, fertilizers, chemicals, etc. • Vehicle and equipment maintenance and fueling • Significant dust or particulate generating processes • Routine maintenance activities involving fertilizers, pesticides, detergents, fuels, solvents, oils, etc. • On-site waste disposal practices (waste piles, dumpsters, etc.) • Concrete truck/equipment washing • Non-industrial waste sources that may be significant, such as worker trash and portable toilets • Uncovered trash bins • Other areas or procedures where potential spills can occur • Stockpiling of materials that can be transported to receiving waterway(s) Management of Contaminated Soils: We are not aware of on-site contaminated soils. However, the contractor should conduct a thorough, pre-construction environmental site assessment. If contaminated soils are discovered, the contractor will identify appropriate practices and procedures for the specific contaminants discovered on-site. Loading and Unloading Operations: As site development and building construction progresses, space constraints will limit the number of on-site locations for loading and unloading activities to the building from Perennial Lane. The contractor will be responsible for the proper handling and management of pollution sources during loading and unloading operations. Dedicated Asphalt and Concrete Batch Plants: Neither a dedicated asphalt or concrete batch plant will be constructed on-site. 2.8 Non-stormwater discharges The Stormwater Construction Permit only covers discharges composed entirely of stormwater. Emergency firefighting water is the only authorized exception. Concrete Washout water can NOT be discharged to surface waters or to storm sewer systems without separate permit coverage. The discharge of Concrete Washout water to the ground, under specific conditions, may be allowed by the Stormwater Construction Permit when appropriate BMPs are implemented. The discharge of pumped stormwater, ONLY, from excavations, ponds, depressions, etc. to surface waters, or to a municipal storm sewer system is allowed by the Stormwater Construction Permit, as long as the dewatering activity and associated BMPs are identified in the Stormwater Management Plan (SWMP) and are implemented in accordance with the SWMP. Aside from the exceptions noted above, non-stormwater discharges must be addressed in a separate permit issued for that discharge. If groundwater is encountered, and dewatering is required, a Construction Dewatering Permit must be acquired from the Colorado Department of Public Health and Environment. NEC Lake and Shields Stormwater Management Plan 4 2.9 Receiving Waters The property historically drains from the west to the east where the runoff has been getting collected in existing detention ponds that are situated at the north and south sides of the existing parking lot to the east of the project site. NEC Lake and Shields is located in the Old Town Basin. Therefore, all the runoff generated and treated at NEC Lake and Shields will eventually discharge into the Poudre River. 3.0 Stormwater Management Controls 3.1 SWMP Administrator A SWMP Administrator must be designated in conjunction with the Stormwater Permit. This person shall be responsible for developing, implementing, maintaining, and revising the SWMP. The SWMP Administrator will also be the contact for all SWMP-related issues and will be the person responsible for the accuracy, completeness, and implementation of the SWMP. The Administrator should be a person with authority to adequately manage and direct day-to-day stormwater quality management activities at the site. The SWMP Administrator for this site is: Name: (to be filled-in by permittee) Company: (to be filled-in by permittee) Phone: (to be filled-in by permittee) E-mail: (to be filled-in by permittee) 3.2 Best Management Practices (BMP’s) for Stormwater Pollution Prevention Beginning from mobilization, and throughout the entire construction of the project, erosion control devices shall be installed to ensure minimal pollutant migration. These erosion control devices 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 practices 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. 3.3 Structural Practices for Erosion and Sediment Control Structural BMPs are physical devices that are implemented to prevent erosion from happening or to limit erosion once it occurs. These devices can be temporary or permanent, and installation of individual components will vary depending on the stage of construction. A table depicting construction sequence and BMP application/removal has been placed on the “Dynamic Site Plan” to help document the implementation of these BMPs. Refer to the Stormwater NEC Lake and Shields Stormwater Management Plan 5 Management Plan Static Site Plan in the Appendix for the assumed location of all BMPs. Construction Details for Temporary BMPs are located in the Appendix for reference. Again, the final determination for which BMP’s will be installed, where they will be located, and when they will be installed shall be made by the Contractor, along with all documentation throughout the construction process. Silt Fencing (Phase I) Silt fencing shall be provided to prevent migration of sediment off-site or into adjacent properties. All silt fencing shall be installed prior to any land disturbing activity (demolition, stockpiling, stripping, grading, etc.). Silt fencing is to be installed prior to site excavation or earthwork activities. Inspections of the silt fence should identify tears or holes in the material, and should check for slumping fence or undercut areas that allow flows to bypass the fencing. Damaged sections of the silt fence should be removed to maintain BMP effectiveness, typically before it reaches a depth of 6 inches. It is suggested that silt fencing be located along north, south, east, and west portions of the limits of disturbance. It is recommended that the silt fence be placed along the east side of the existing sidewalk that is adjacent to Shields St. Please see sheet C5.00 within the Utility Plans or in Appendix A for additional clarification. Sediment Control Log – aka “Straw Wattles” (Phase I) 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 can be used in many instances. Examples include perimeter control for stockpiles, as part of inlet protection designs, as check dams in small drainage ways, on disturbed slopes to shorten flow lengths, or in lieu of silt fencing (where appropriate). Sediment Control Logs should be inspected for excess sediment accumulation. Sediment should be removed prior to reaching half the height of the log. At a minimum, Sediment Control Logs should be used around soil stockpiles (including landscape material) and at all stormwater discharge locations other than inlets. There are several flared end sections associated with this project that will require straw wattles. All five proposed flared end sections will require straw wattles as well as the existing FES at the northeast corner of the project site. Please see sheet C5.00 within the Utility Plans or in Appendix A for additional clarification. Vehicle Tracking Control Pads (Phase I) Vehicle tracking control pads shall be provided to minimize tracking of mud and sediment onto paved surfaces and neighboring roadways. All vehicle tracking control pads shall be installed prior to any land disturbing activity (demolition – as necessary, stockpiling, stripping, grading, etc.). Location of vehicle tracking control pads will be located at any and all existing and future vehicle accesses being used during any of the construction phases. These locations will primarily be dictated by gates or openings in the temporary construction fencing that is expected to be installed. Vehicle tracking control pads are to be installed prior to demolition (as appropriate), site excavation or earthwork activities. Vehicle tracking pads should be inspected for degradation and aggregate material should be replaced as needed. If the area becomes clogged with water, excess sediment should be removed. Aggregate material should remain rough, and at no point should aggregate be allowed to compact in a manner that causes the tracking pad to stop working as intended. NEC Lake and Shields Stormwater Management Plan 6 Suggested locations for the vehicle tracking pad is at the proposed access off Lake Street. Concrete Washout Area (Phase II) A concrete washout should be provided on the site. The washout can be lined or unlined excavated pits in the ground, commercially manufactured prefabricated containers, or aboveground holding areas. The concrete washout must be located a minimum of 400 feet from any natural drainage way or body of water, and at least 1000 feet from any wells or drinking water sources. Washout areas should not be located in an area where shallow groundwater may be present. Contractor shall clearly show the desired location and access to the Concrete Washout Area on the Stormwater Management Plan - Dynamic Site Plan. Contractor shall place a Vehicle Tracking Pad if the selected location for the Concrete Washout Area is detached from pavement. Clear signage identifying the concrete washout should also be provided. The Concrete Washout Area should be inspected regularly. Particular attention should be paid to signage to ensure that the area is clearly marked. Confirmation that the washout is being used should also be noted to ensure that other undesignated areas of the site are not being used incorrectly as a concrete washout. It is suggested the Contractor build a concrete wash out pit for this project. It is recommended that the concrete wash out pit be placed next to the vehicle tracking pad along Lake Street. This location is only a suggestion, and can be relocated at the discretion of the Contractor. Permanent/Established Vegetation (Phase IV) Permanent or established vegetation and landscaping is considered a permanent form of sediment and erosion control for common open spaces, steep slopes and areas not exposed to prolonged scour velocities, or acute incipient motion bed shear stresses that will create soil erosion, rill formation and subsequent sediment transport. Areas where the previous conditions apply will contain sufficient permanent BMPs, such as riprap or cobble mulch. Permanent vegetation shall conform to the approved Landscape Plan prepared by The TB Group. Permanent/Established vegetation and hardscape defines Phase IV of development. 3.4 Non-Structural Practices for Erosion and Sediment Control Non-Structural BMPs are practices or activities that are implemented to prevent erosion from happening or to limit erosion once it occurs. These BMPs can be a practice resulting in physical change to the site, such as mulching or slope stabilization. They can also result in behavioral changes on the site, such as changes to construction phasing to minimize exposure to weather elements, or increased employee awareness gained through training. Protection of Existing Vegetation (Phases I-IV) 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 up-gradient areas are disturbed, it may also be necessary to install perimeter controls to minimize sediment loading to sensitive areas such as wetlands. Trees that are to remain after construction is complete must be protected. Most tree roots grow within the top 12”-18” of soil, and soil compaction is a significant threat to tree health. As such, particular care should be taken to avoid activities within the drip-line of the tree. Direct equipment damage should also be prevented. The most effective way to ensure the health of trees is to establish a protection zone at the drip-line of the tree to prevent unintended activity in the area directly surrounding the tree. NEC Lake and Shields Stormwater Management Plan 7 Fencing should be inspected and repaired when needed. If damage occurs to a tree, an arborist should be consulted on how to care for the tree. If a tree is damage beyond repair, the City Forester should be consulted on remediation measures. At a minimum, protection to all trees identified for retention on the landscape plans by The TB Group. Stockpile Management (Phases I-III) Stockpile management should be utilized to minimize erosion and sediment transport from soil stockpiles. In general, soil stockpiles should be located a minimum of 100 feet from any drainage way and 50 feet from any storm sewer inlets. Where practical, choose a stockpile location that will remain undisturbed for the longest period of time as the phases of construction progress. Sediment control BMPs should be placed around the perimeter of the stockpile, and a designated access point on the upstream side of the stockpile should be identified. BMPs such as surface roughening, temporary seeding, mulching, erosion control blankets, or soil binders should be used to stabilize the stockpile surface. As a part of stockpile management, regular inspections of the perimeter controls should be completed. If BMPs have been utilized to stabilize the surface of the stockpile, they should be inspected and repaired as needed. While soil stockpiles are not expected with this project, it is possible that foundation excavation or the delivery landscaping material may generate temporary stockpiles. The location of any such stockpiles shall be the responsibility of the SWMP Administrator. Mulching (Phase I-III) Mulching helps reduce erosion by protecting bare soil from rainfall impact, increasing infiltration, and reducing runoff. Although often applied in conjunction with temporary or permanent seeding, it can also be used for temporary stabilization of areas that cannot be reseeded due to seasonal constraints. The most common type of mulch used is hay or grass that is crimped into the soil to keep it secure. However, crimping may not be practical on slopes steeper than three to one (3H:1V). The Contractor shall mulch all planted areas within twenty-four (24) hours after planting. Only weed-free and seed-free straw mulch may be used. Straw mulch should be applied at two (2) tons per acre, and shall be adequately secured by crimping, tackifier, netting or blankets. Hydraulic mulching may also be used on steep slopes or where access is limited. In the case that hydraulic mulching is utilized, the Contractor shall use wood cellulose fibers mixed with water at two thousands to two thousand five hundred (2,000-2,500) pounds per acre and organic tackifier at one hundred to four hundred (100-400) pounds per acre. The Contractor is responsible in applying wood chip mulch to all planted trees and shrubs as shown on the Landscape Plan prepared by The TB Group. Wind Erosion/Dust Control (Phase I-IV) Wind Erosion and Dust Control BMP’s help to keep soil particles from entering the air as a result of land disturbing construction activities. Attached at the end of the Appendix B is the Fort Collins Dust Prevention and Control Manual. The purpose of this manual is to establish minimum requirements consistent with nationally recognize BMP’s for controlling fugitive dust emissions and to describe applicable best management practices to prevent, minimize, and mitigate off-property transport or off-vehicle transport of fugitive dust emissions pursuant to Chapter 12, Article X of the Fort Collins City Code (§12-150 et. seq) for specific dust generating activities and sources. NEC Lake and Shields Stormwater Management Plan 8 Examples include use of a water truck or irrigation/sprinkler system to wet the top layer of disturbed soil, seeding and mulching, soil binders, or wind fences. Please refer to the last three pages of Appendix B for the Dust Control Plan. A Dust Control Plan is required for all development projects or construction sites with greater than five (5) acres in size. Street Sweeping (Phases I -IV) Street sweeping should be used to remove sediment that has been tracked onto adjacent roadways. Roadways should be inspected at least once a day, and sediment should be removed as needed. A check of the area inlet protection should be completed after sweeping to ensure nothing was displaced during sweeping operations. Street sweeping can reduce the sediment washed into the existing storm drain system. Street sweeping may be necessary on the existing hardscape areas which receive runoff from the disturbed areas. Saw Cutting Pollution Prevention (Phase I) The following protocol is recommended to prevent dust and slurry from asphalt and concrete saw cutting activities from migrating into the existing storm drain system. • Slurry and cuttings shall be vacuumed during cutting and surfacing operations • Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight • Slurry and cuttings shall not drain to any natural or constructed drainage conveyance • Collected slurry and cuttings shall be disposed of in a manner that does not violate groundwater or surface water standards Good Housekeeping Practices (All phases) Good housekeeping practices that will prevent pollution associated with solid, liquid, and hazardous construction-related materials and wastes should be implemented throughout the project. Examples of good housekeeping include providing an appropriate location for waste management containers, establishing proper building material staging areas, designating paint and concrete washout areas, establishing proper equipment/vehicle fueling and maintenance practices. Development of a spill prevention and response plan is another example of Good Housekeeping practices that should be used on the project. The following items are detailed examples of some of the good housekeeping practices that should be utilized throughout the project. It should be noted that a complete list of practices and detailed discussion regarding good housekeeping has been included with Appendix B. Street Sweeping and Vacuuming – Street sweeping and vacuuming should be used to remove sediment that has been tracked onto adjacent roadways. Roadways should be inspected at least once a day, and sediment should be removed as needed. A check of inlet protection should be completed after sweeping to ensure nothing was displaced during sweeping operations. Waste Management – Designate trash and bulk waste collection areas on-site. When possible, materials should be recycled. Hazardous material waste should be segregated from other solid waste. Waste collection areas should be located away from streets, gutters, watercourses, and storm drains. Dumpsters should be located near site entrances to minimize traffic on disturbed soils, and they should be placed on a level soil surface. Establish Proper Building Material Handling and Staging areas – Clearly designate site areas for NEC Lake and Shields Stormwater Management Plan 9 staging and storage of building materials. Provide appropriate BMPs to ensure that spills or leaks are contained. Establish Proper Equipment/Vehicle Fueling and Maintenance Practices – If needed, create a clearly designated on-site fueling and maintenance area that is clean and dry. Provide appropriate BMPs to ensure that spills or leaks are contained. 3.5 Phased BMP Installation It is important to recognize the four (4) major Development Phases as defined by the State of Colorado’s Stormwater Discharge Permit (SDP). These four development phases (referred to as Sequencing by the City of Fort Collins) have been distinguished to aid in the appropriate timing of installation/implementation of BMPs at different stages of the construction process. These phases are described as follows: Phase I – Grading Stage; BMPs for initial installation of perimeter controls Phase II – Infrastructure Stage; BMPs for utility, paving and curb installation Phase III – Vertical Construction Stage; BMPs for individual building construction. Phase IV – Permanent BMPs and final site stabilization. The following is a rough estimate of the anticipated construction sequence for site improvements. The schedule outlined below is subject to change as the project progresses and as determined by the General Contractor. Table 1 – Preliminary Permit and Construction Schedule Included in the back map pockets are Site Plans: a “Static” Site Plan and a “Dynamic” Site Plan. The “Static” plan serves to display the overall management plan all at once. However, proper implementation of BMPs does not occur at once, and certain BMPs may move location in the construction process; therefore, the “Dynamic” Site Plans are intended for the Contractor to write in the BMP symbols to document the location and time the BMPs are installed and maintained throughout the entire construction process. 3.6 Material Handling and Spill Prevention Potential pollution sources, as discussed in earlier sections, are to be to be identified by the Contractor. Spill prevention procedures are to be determined and put in place prior to construction by the Contractor. A spill and flooding response procedure must also be determined and put in place prior to construction by the Contractor. Additionally, steps should be taken to reduce the TASK BEGINNING DATE ENDING DATE "BMP-PHASE OF DEVELOPMENT" Development Construction Permit Issued by City of Fort Collins December 2018 December 2018 I Overlot Grading (Demolition) December 2018 December 2018 I Utility Installation December 2018 January 2019 II Building Construction January 2019 September 2019 III Final Stabilization August 2019 September 2019 IV NEC Lake and Shields Stormwater Management Plan 10 potential for leaks and spills to come in contact with stormwater runoff, such as storing and handling toxic materials in covered areas or by storing chemicals within berms or other secondary containment devices. A notification procedure must be put in place by the Contractor, by which workers would first notify the site construction superintendent, who would then notify the SWMP Administrator. Depending on the severity of the spill, the site construction superintendent and SWMP Administrator would possibly notify the Colorado Department of Public Health and Environment - Water Quality Control Division, downstream water users, or other appropriate agencies. The release of any chemical, oil, petroleum product, sewage, etc., which enter waters of the State of Colorado (which include surface water, ground water, and dry gullies or storm sewers leading to surface water) must be reported immediately to the Division’s emergency spill reporting line at (877) 518-5608. All spills that will require cleanup, even if the spill is minor and does not need to be reported to the state, should still be reported to the City of Fort Collins Utilities office at 970-221-6700. While not expected with this project, it will be the responsibility of the Contractor to designate a fueling area and take the necessary precautions to ensure that no stormwater pollution occurs in the event that a fueling area is needed. Fueling areas shall be located a minimum 100 feet from all drainage courses. A 12-inch high compacted earthen ridge capable of retaining potential spills shall enclose fueling areas. Other secondary containment devices can be used instead of the earthen ridge. The area shall be covered with a non-porous lining to prevent soil contamination. Printed instructions for cleanup procedures shall be posted in the fueling area and appropriate fuel absorbents shall be available along with containers for used absorbents within the fueling area. 3.7 Dedicated Concrete or Asphalt Batch Plant There are not any dedicated concrete or asphalt batch plants anticipated with this project. In the event that a plant is needed, the Contractor should be aware that additional permitting will be required. In particular, an Air Pollutant Emission Notice (APEN) will need to be obtained from the CDPHE. 3.8 Vehicle Tracking Control In addition to the vehicle tracking pads discussed previously, additional measures can be taken to minimize and control sediment discharges from the site due to vehicle tracking. These measures can include fencing around the site to control access points. Regular street sweeping can also be used to minimize the transmission of sediment from the site due to vehicles leaving the site. The use of gravel parking areas and wash racks can also be implemented to ensure minimal vehicle tracking from the site. 3.9 Waste Management and Disposal It will be the responsibility of the Contractor to designate a concrete truck chute washout area and to clearly identify that area. Detailed information about the design and maintenance of the Concrete Washout can be found under the Structural Practices section of this report. At no time should untreated wash water be allowed to discharge from the site or to enter a storm drain system or stream. Upon completion of construction activities the concrete washout material shall be removed and properly disposed of prior to the area being restored. Any waste material that currently exists on the site or that is generated by construction will be disposed of in such a manner as to not cause pollutants in stormwater discharges. If waste is to be stored on-site, it shall be in an area located a minimum of 100 feet from all drainage courses. Whenever waste is not stored in a non-porous container, it shall be in an area enclosed by a 12- NEC Lake and Shields Stormwater Management Plan 11 inch high compacted earthen ridge or some other approved secondary containment device. The area shall be covered with a non-porous lining to prevent soil contamination. Whenever precipitation is predicted, the waste shall be covered with a non-porous cover, anchored on all sides to prevent its removal by wind, in order to prevent precipitation from leaching out potential pollutants from the waste. On-site waste disposal practices, such as dumpsters, should be covered or otherwise contained as to prevent dispersion of waste materials from wind. It shall also be the responsibility of the Contractor to maintain a clean jobsite as to prevent dispersion of waste material and potential pollutants into adjacent properties or waterways. The location of, and protective measures for, temporary restroom facilities shall be the responsibility of the SWMP Administrator. 3.10 Groundwater and Stormwater Dewatering The BMPs selected for construction dewatering vary depending on the site-specific features, such as soils, topography, discharge quantities, and discharge location. Typically, dewatering involves pumping water from an inundated area to a BMP, prior to the water being released downstream into a receiving waterway, sediment basin, or well-vegetated area. Acceptable BMPs included discharging water into a sediment trap or basin, using a dewatering filter bag, or using a series of sediment logs. A settlement tank or an active treatment system can also be utilized. Another commonly used method to handle the pumped water is the “sprinkler method,” which involves applying the water to vegetated areas through a perforated discharge hose. Dispersal from a water truck for dust control can also be used to disperse the pumped water. 4.0 Final Stabilization and Long-Term Stormwater Management 4.1 Final Stabilization All disturbed areas will be seeded, crimped and mulched. Soil amendments such as compost, peat, aged manure, or other similar materials, shall also be utilized. Soil amendments shall be tilled into the soil to a minimum depth of 6”, and should comply with the requirements found in City Code Section 12-132 (refer also to Land Use Code 3.8.21). 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.” Table 2 - Native Grass Seed Mix Preferred Varieties Seeded Rate (lbs. per acre, drilled) PLS Seeded/acre Leymus Cinereus Great Basin Wilrye Mangar 3 285,000 Nassella Viridula Green Needlegrass Lodorm 2 362,000 Chnatherum Hymenoides Indian Ricegrass Paloma, Nezpar 1 188,000 Elymus Trachycaulus Slender Wheatgrass Primar, Revenue 2 320,000 Elymus Lanceolatus Thickspike Wheatgrass Critana 3 580,500 Pascopyrum Smithii Western Wheatgrass Arriba, Barton 4 504,000 Totals 15 2,239,500 Species NEC Lake and Shields Stormwater Management Plan 12 4.2 Long-Term Stormwater Management The method of long-term stormwater management will take place at Fossil Creek Reservoir. All disturbed areas will receive permanent paving or will be vegetated per the Landscape Plan. 5.0 Inspection, Maintenance and Record Keeping 5.1 BMP Inspection 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 in order to ensure the continued performance of their intended function. It is the responsibility of the SWMP Administrator to conduct bi-weekly inspections, maintain BMPs if needed, to keep records of site conditions and inspections, and to update the SWMP as necessary. The construction site perimeter, disturbed areas, all applicable/installed erosion and sediment control measures, and areas used for material storage that are exposed to precipitation shall be inspected for evidence of, or the potential for, pollutants entering the drainage system. Erosion and sediment control measures identified in the SWMP shall be observed to ensure that they are operating correctly. Attention should be paid to areas that have 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. 5.2 BMP Maintenance Any BMP’s not operating in accordance with the SWMP 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 so that the SWMP accurately reflects on-site conditions. The SWMP needs to accurately represent field conditions at all times. Uncontrolled releases of mud, muddy water, or measurable amounts of sediment found off-site 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 in order 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. Inspection and maintenance procedures specific to each BMP identified with this SWMP are discussed in Section 3. Details have also been included with Appendix B. 5.3 Record Keeping Documentation of site inspections must be maintained. The following items are to be recorded and kept with the SWMP: • Date of Inspection • Name(s) and title(s) of personnel making the inspection • Location(s) of sediment discharges or other pollutants from the site NEC Lake and Shields Stormwater Management Plan 13 • Location(s) of BMP’s that need to be maintained • Location(s) of BMP’s that failed to operate as designed or proved inadequate • Locations(s) where additional BMP’s are needed that were not in place at the time of inspection • Deviations from the minimum inspection schedule • Descriptions of corrective action taken to remedy deficiencies that have been identified • The report shall contain a signed statement indicating the site is in compliance with the permit to the best of the signer’s knowledge and belief after corrective actions have been taken. Provided within Appendix E of this SWMP is an Example Inspection Log to aid in the record keeping of BMP inspections and maintenance. Photographs, field notebooks, drawings and maps should be included by the SWMP Administrator when appropriate. In addition to the Inspection Log, records should be kept documenting: • BMP maintenance and operation • Stormwater contamination • Contacts with suppliers • Notes on the need for and performance of preventive maintenance and other repairs • Implementation of specific items in the SWMP • Training events (given or attended) • Events involving materials handling and storage • Contacts with regulatory agencies and personnel • Notes of employee activities, contact, notifications, etc. Records of spills, leaks, or overflows that result in the discharge of pollutants must be documented and maintained. A record of other spills that are responded to, even if they do not result in a discharge of pollutants, should be made. Information that should be recorded for all occurrences includes the time and date, weather conditions, reasons for the spill, etc. Some spills may need to be reported to authorities immediately. Specifically, a release of any chemical, oil, petroleum product, sewage, etc., which may enter waters of the State of Colorado (which include surface water, ground water and dry gullies or storm sewers leading to surface water) must be reported to the CDPHE. Additionally, the “Dynamic Site Plan” is intended to be a “living” document where the SWMP Administrator can hand write the location of BMPs as they are installed to appropriately reflect the current site conditions. Also on the “Dynamic Site Plan” is a “Table of Construction Sequence and BMP Application/Removal” that the SWMP Administrator can use to document when BMPs were installed or removed in conjunction with construction activities. These items have been included as an aid to the SWMP Administrator, and other methods of record keeping are at his or her discretion. This Stormwater Management Plan (both the text and map) is not a static document. It is a dynamic device intended to be kept current and logged as construction takes place. It shall be the responsibility of the SWMP Administrator and/or the permit holder (or applicant thereof) to ensure the plan is properly maintained and followed. Diligent administration is critical, including processing the Notice to Proceed and noting on the Stormwater Management Plan the dates that various construction activities occur and respective BMPs are installed and/or removed. NEC Lake and Shields Stormwater Management Plan 14 6.0 Additional SWMP and BMP Resources Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual - Volume 3 “Best Management Practices” Colorado Department of Transportation Erosion Control and Stormwater Quality Guide BMP Field Academy EPA Menu of BMP’s Construction Site Storm Water Runoff Control International Stormwater Best Management (BMP) Database Rocky Mountain Education Center Rocky Mountain Education Center Red Rocks Community College, Lakewood Keep It Clean Partnership Boulder NEC Lake and Shields Stormwater Management Plan 15 References 1. Final Drainage Report for NEC Lake and Shields, Northern Engineering Services, October 2, 2018 (NE Project No. 232-047) 2. Soil Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 3. Subsurface Exploration Report Sunshine House No. 213, Earth Engineering Consultants, LLC, June 18, 2018 (Project No. 1182044) 4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Water Resources Publications, LLC., Denver, Colorado, Updated November 2010.