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Home My WebLink AboutUPTOWN PLAZA - FDP - FDP140010 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE AND EROSION CONTROL STUDY 1501 WEST ELIZABETH STREET Prepared for: Jim Hillhouse Hillhouse Architects Windsor, CO 80550 Prepared by: North Star Design, Inc. 700 Automation Drive, Unit I Windsor, Colorado 80550 (970) 686-6939 April 4, 2014 Job Number 350-01 iii TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................... iii 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location ...................................................................................................................1 1.2 Description of Property ............................................................................................1 2. DRAINAGE BASINS AND SUB-BASINS 2.1 Major Basin Description ..........................................................................................2 2.2 Sub-Basin Description .............................................................................................2 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations ..............................................................................................................2 3.2 Development Criteria Reference and Constraints ...................................................2 3.3 Hydrologic Criteria ..................................................................................................3 3.4 Hydraulic Criteria ....................................................................................................3 4. DRAINAGE FACILITY DESIGN 4.1 General Concept ......................................................................................................3 4.2 Specific Flow Routing .............................................................................................4 4.3 Drainage Summary ..................................................................................................4 5. STORMWATER MANAGEMENT CONTROLS 5.1 Written Analysis .....................................................................................................5 5.2 SWMP Contact Information ...................................................................................6 5.3 Identification and location of all potential pollution sources ..................................6 5.4 Best Management Practices (BMP’s) for Stormwater Pollution Prevention ...........7 5.5 BMP Implementation ...............................................................................................9 6. CONCLUSIONS 6.1 Compliance with Standards ..................................................................................12 6.2 Drainage Concept ..................................................................................................12 7. REFERENCES ..................................................................................................................13 APPENDICES A Vicinity Map B Hydrologic Computations C Detention Pond Calculations D BMP Schedule and Cost Estimate E Floodplain Waiver F Excerpts from Other Reports 1 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location The site is located on the Lot 20, Block 11 Fairview 9th Filing in the Southeast ¼ of Section 15, Township 7 North, Range 68 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. The address of the existing site is 1501 West Elizabeth Street. See the location map in Appendix A. The project is located on the south side of West Elizabeth Street between South Bryan Avenue and City Park Avenue. The project is bounded on all sides by existing commercial development. 1.2 Description of Property The entire site consists of approximately 1.46 acres of land. The land was previously developed with a c-store and car wash which were destroyed in a fire. The buildings have been removed from the site but some pavement and utilities currently remain on the site. These and all surface improvements will be removed with the redevelopment of this site. The site currently drains to a detention pond on the south portion of the site. Slopes on site range from approximately 1% to 2%. This site was located in the City regulatory 100 year Canal Importation Basin floodplain but was removed prior to the approval of this proposed redevelopment via the City Floodplain Waiver process. This project will include the development of a single building that has commercial, restaurant and retail uses on the main floor located in the north half of the site. There will be private drives, parking and landscaping on the remainder of the site. The site will have the required pervious pavement in the parking areas (as shown on the plan in Appendix A) and will provide detention storage under the parking lot with a combination of infiltration and collection in a system of perforated pipes. 2 2. DRAINAGE BASINS AND SUB-BASINS 2.1 Major Basin Description The proposed development lies within the Canal Importation Drainage Basin. The site is was previously located in a 100 year floodplain. With this proposed development, an application for a City Floodplain Waiver was approved to remove this site from the 100 year floodplain (refer to Appendix E for a copy of this approved waiver). The waiver was justified based on the information contained in the “As-Built Design Summary & Floodplain Modeling report for Canal Importation Ponds and Outfall” by Ayres Associates dated February 2013. Since the property was removed from the floodplain by the waiver process, there will be no Chapter 10 compliance issues. 2.2 Sub-basin Description This site was included in the “Final Drainage Report for Diamond Shamrock Gas Station, Convenience Store and Car Wash, Lot 2 Fairview Shopping Center II” by Galloway, Romero & Associates dated February 6, 1989 and revised May 16, 1989. Portions of this report are included in the Appendix. 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the “City of Fort Collins Storm Drainage Design Criteria Manual” specifications. Where applicable, the criteria established in the “Urban Storm Drainage Criteria Manual” (UDFCD), developed by the Denver Regional Council of Governments, has been used. 3.2 Development Criteria Reference and Constraints The runoff from this site has been routed to maintain the same general patterns as previously established. The site is restricted to a 2 year historic release rate with this development. The historic condition for this site is an undeveloped condition without consideration of the previous development condition. The runoff from the entirety of the site, including the entire proposed building, will be directed to the parking lot where the water will enter the under parking lot detention area via the proposed porous pavements 3 or via an inlet proposed near the southeast corner of the site. The runoff from the roof will be connected to the underground detention pipes without discharging to the surface pavement. The release rate for the detention pond has been calculated to be 0.45 cfs which is equivalent to the 2 year historic runoff rate for this site in an undeveloped condition. An orifice plate will be installed in the manhole on site to restrict the release rate to the 2 year historic rate. An overflow will also be provided in the manhole to allow overtopping of the plate if the orifice becomes plugged. The detention pond will release to the north into an existing storm manhole as the site previously has done. 3.3 Hydrologic Criteria Runoff coefficients calculations were prepared for the 2 and 10-year minor and 100-year major storm frequency utilizing the rational method. Detention is proposed on site under the parking lot with a release rate equal to the 2 year historic runoff rate. The amount of detention provided under the parking lot was based on an assumed porosity of the chosen aggregate of 0.4. Based on the results of the geotechnical report for the site (excerpts included in Appendix F), some of the site runoff is expected to infiltrate into the existing site soils and enter the groundwater table. 3.4 Hydraulic Criteria The onsite collection system is 4” or 6” perforated pipe which is collect in a larger pipe and conveyed to the outlet point with a restriction to the historic runoff rate. An inlet is located in the parking lot which will act as a collection point if the porous pavements cannot intercept all of the site runoff. Sizes for the inlet and pipes have not been calculated as the amount of runoff expected in these conveyances are difficult to predict. Stormwater will also infiltrate into the groundwater as indicated by the geotechnical report, portion of which are included in the appendix. 4. DRAINAGE FACILITY DESIGN 4.1 General Concept The runoff from this site will flow into the parking lot which will be constructed using 75% conventional materials (asphalt or concrete) and 25% porous pavement (concrete or 4 pavers). The runoff from the site will enter the subsurface material (3/4” poorly graded angular rock) via the porous pavements or via pipe from the roof drains. In a situation where the porous pavements are clogged, the runoff will flow to the proposed inlet in the southeast corner of the site and enter the subsurface material. A small amount of flow from the patio on the north is anticipated to enter West Elizabeth Street without detention. No offsite flows will enter this site. 4.2 Specific Flow Routing A summary of the drainage patterns within each basin is provided in the following paragraphs. Basin 1 encompasses the majority of the proposed development including the entire building, parking lot, private drives and the landscaping on the west side of the site. A majority of the runoff flows to the parking lot in the south half of the site which will convey the flows beneath the parking lot to the proposed detention pond. This detention pond will have a small release rate (0.45 cfs) which equate to the 2 year undeveloped runoff. The water quality extended detention is incorporated into the subsurface detention system. The detention system will have an overflow to the east along the private drive that extends into the adjacent property. This site is being developed under the City criterion that requires that 25% of the site pavements be pervious. This site has approximately 21,950 square feet of proposed parking lot pavement on site which is entirely within Basin 1. Of the 28,700 square feet, 25% of this area would equate to 5490 square feet of required pervious pavement and with this proposed development, approximately 5650 square feet of pervious pavements are being proposed and will be located in the parking spaces as shown on the grading and drainage plan. 4.3 Drainage Summary All runoff from this site and the adjacent sites will be safely conveyed via surface flow to the detention pond. The site will generally conform to the Canal Importation Master Drainage plan which this site is included in. 5 The City of Fort Collins will be responsible for maintenance of the existing storm drainage facilities located within the right-of-way. The drainage facilities located outside of the right of way (including the detention pond) will be maintained by the property owner. 5. STORMWATER MANAGEMENT CONTROLS 5.1 Written Analysis The soils on this site are classified by the USGS Soil Survey as Altvan-Santana Loams and are classified in the hydrologic group B. The soils are described as being well drained and having a moderately high to high ability to transmit water (0.6 to 2.0 inches per hour). The geotechnical report indicates that the soils on site have a porosity as high as 108 feet per day. The rainfall and wind erodibility is deemed to be moderate. The site is surrounded by developed sites including streets and paved areas. The construction shall utilize silt fence around the perimeter to control sediment transport from rainfall and from wind. The silt fence that is located in the proposed pavement areas will be removed prior to placing new pavement. Rock socks will be utilized in the existing curb to capture sediments that are not fully contained by the silt fence placement. The locations of the rock socks will be in the areas of concentrated flow such as the existing curb and on the existing concrete sidewalks. The site may also utilize a vehicle tracking control pad to minimize sediment from being tracked onto adjacent pavements. Sediment that is tracked will be removed and placed within the site or permanently disposed of offsite. A concrete washout will be used on site during the concrete placement. All hardened concrete will be disposed of offsite. These BMP’s have not been located on the site map due to the fact that the site is very small and these BMP’s will need to be placed by the contractor in locations that are most beneficial and will minimize disruption of adjacent traffic. Permanent erosion control consists of covering the soils with a building, concrete walks, concrete drives and sod. No soil will be left exposed to erosion after the construction is complete. Refer to the landscape plan for areas of and instructions for placement of sod and soil amendments required prior to placement of sod. 6 Refer to Appendix D for the timing of the construction phases and the sequential installation of all BMP phasing for this site. Refer to the end of Appendix D for the Erosion Control Surety calculations. 5.2 SWMP contact information Permit holder: Name: Address: Phone Number: Email Address: Appointed agent: Name: Address: Phone Number: Email Address: 5.3 Identification and location of all potential pollution sources Potential Pollutant Source Activity Potential Pollutant Generated Applicable to this project Disturbed Areas Sediment X Soil stockpiles Sediment X Travel to adjacent public streets Tracked sediment X Contaminated soils Sediment, chemicals Possible Loading and unloading chemicals Chemicals Unloading of building materials Trash, debris X Outdoor storage of chemicals Chemicals On site equipment maintenance Oil, grease On site equipment fueling Diesel, gasoline X Dust generating activities Particulates, sediment X Use of fertilizer, pesticides, herbicides Fertilizer, pesticides Use of detergents, solvents, oils Detergents, solvents, oil X Waste dumpsters, waste piles Chemicals, trash, debris X 7 Concrete washout Concrete, sediment, wash water X On site equipment washing Detergents, oil On site asphalt batch plant Asphaltic cement, sediment On site concrete batch plant Cement, sediment Portable toilets Domestic sewage X 5.4 Best Management Practices (BMP’s) for Stormwater Pollution Prevention Structural Practices for Erosion and Sediment Control Structural practices for the site will consist mainly of silt fence and rock sock filters and are described in detail in the following paragraphs. These BMP's are expected to change as the construction progresses and it is the responsibility of the contractor to ensure appropriate BMP's are in place and/or removed at the appropriate time in the construction sequence. All temporary and permanent erosion and sediment control practices must be maintained and repaired as needed to assure continued performance of their intended function. Silt fence and rock sock filters shall be in place prior to commencement of construction activities. During clearing and grubbing necessary for silt fence installation, all cleared material shall be placed on the uphill side so that if erosion occurs from the cleared material, the sediment will be trapped and not transported downstream. Rock socks shall be implemented in the existing curb line as shown on the Drainage & Erosion Control Plan. All BMP's shall be installed per the details shown on the construction plan set. Temporary & Permanent Structural BMP’s: Structural BMP Approximate location on site Applicable to this Project Silt Fence Site perimeter, refer to site map X Straw bale dams Rock Socks At proposed sidewalk culverts, refer to site map X Earthen diversion dams Vegetated swales Sediment trap/pond Pipe slope drains Geogrid Inlet/outlet protection Culverts Riprap 8 Erosion control mats Inlet protection At inlet on site. X Vehicle Tracking Control Pad At site entrances, refer to site map X Concrete Washout To be located by Contractor X Non-Structural Practices for Erosion and Sediment Control: Soils exposed during the earthwork phase and landscape prep phase shall be kept in a roughened condition by ripping or disking along land contours until mulch, vegetation, or other permanent erosion control is installed. No large amount of soils (in excess of 15 yards) will be allowed to be stock piled on site. Overburden from the utility pipe trenching will be piled adjacent to trenches upstream of sediment controls and will be replaced in the trenches within 72 hours. Excess excavated materials from the demolition and grading phases of the project that cannot be reused on site will be exported as it is excavated. This includes any asphalt pavement from the existing site that is to be removed. A vehicle tracking pad will be installed at a location most beneficial to the site construction as determined by the contractor. Vehicles will not be permitted in the excavated area if soil is muddy. Gravel sub base will be placed and compacted in the areas indicated for pavement following excavation. In the current pre construction state the site enables tracking of silt onto the adjacent streets during wet conditions. During construction activities the street will be monitored for foreign debris tracked out of the site and mechanical sweeping and clean up will be performed as needed. No area shall remain exposed by land disturbing activity for more than thirty (30) days before required temporary or permanent erosion control (e.g. seed/mulch, landscaping, etc.) is installed. Temporary & Permanent non-structural BMP’s: Non-Structural BMP Approximate location on site Applicable to this Project Surface roughening Entire site X Soil stockpile height limit (less than 10’) Perimeter vegetative buffer West boundary of site X Minimization of site disturbance Mulch Seed & mulch stockpiles after 30 days Stockpile toe protection (silt fence, wattles or ditch) Preservation & protection of existing vegetation & trees West boundary of site X 9 Good site housekeeping (routine cleanup of trash & constr debris) Entire Site X Sweeping & scraping of hardscape areas On and off site pavements X Heavy equip staged on site, properly maintained & inspected daily (no onsite maintenance) Staging area X 5.5 BMP Implementation 1) Phased BMP Implementation BMP’s are expected to change as the construction progresses and it is the responsibility of the contractor to ensure appropriate BMP’s are in place and/or removed at the appropriate time in the construction sequence. A construction sequence schedule has been included on the Drainage & Erosion Control Plan and included in the construction plans for this site. All BMP’s shall be inspected and repaired or replaced as required to satisfy the conditions of the Stormwater Discharge Permit. All BMP’s must be maintained and repaired as needed to assure continued performance of their intended function. Refer to Appendix D for BMP Implementation Schedule Refer to Appendix D for BMP Estimated Costs 10 2) Materials Handling and Spill Prevention: Materials Handling & Spill Prevention BMP Approximate location on site Applicable to this Project Portable toilets, anchored & located away from drainages Contractor to determine X Fuel storage located in bulk tanks with secondary containment & spill kit Mobile fueling performed at least 200 feet away from drainages & fully attended Contractor to determine X Fertilizers, form oil, solvents, cleaners, detergent stored in 55 gal or smaller containers, kept in storage units Contractor to determine X Dumpsters containing used chemicals containers & liquid wastes kept covered Contractor to determine X Equipment cleaning (on site) uses no detergents & flows to onsite retention basin In case of a release of fuel or other chemicals, absorbent booms or earthen berms will be immediately constructed to contain the spill & prevent runoff to adjacent surface waters Location of spill X MSDS sheets for onsite chemicals will be kept at the construction trailer to facilitate spill response & cleanup Contractor to determine X 3) Dedicated Asphalt or Concrete Batch Plant: Not proposed with this development 4) Vehicle Tracking Pad: Vehicle tracking control pad shall be installed wherever construction vehicle access routes intersect paved public roads. Vehicle tracking control pads shall be installed to minimize the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface. Any mud tracked to public roads shall be removed on a daily basis and after any significant storm that causes sediment to be transported. It is unlawful to track sediment/mud onto public streets and may be enforced by the City of Fort Collins, by the State of Colorado or by the EPA. 11 5) Waste Management and Disposal: Portable toilets will be anchored & periodically maintained by waste management company. Dumpsters on site will be covered & periodically emptied by waste management company. Concrete waste will be allowed to harden and then will be removed from site. No washing activities will occur on site. Location of the concrete washout is shown on the site map. The washout will be sufficiently deep to accommodate all anticipated concrete truck wash water. Waste concrete will be allowed to harden and be removed from site periodically as the washout reaches 50% of its capacity. Truck wash water will not be allowed to reach the curb & gutter or any other water course. 6) Groundwater and Stormwater Dewatering: No groundwater was encountered during soils exploration therefore ground water is not anticipated to be an issue. If groundwater is encountered a groundwater discharge permit shall be obtained and a detailed report shall be completed describing the location and the route of where pumped groundwater will be conveyed and the measures taken to prevent the transport of any pollutants to downstream waters. 7) Inspection & Maintenance: It is required that routine site inspections are performed to effectively address maintenance and repair of Best Management Practices (BMP's). The site inspections are to performed by the contractor or an inspector designated by the administrator at a minimum of once every fourteen (14) calendar days on active construction sites and after any significant storm event (an event causing runoff). As part of the site inspections the inspector is required to keep documentation of all inspections and BMP maintenance, including an updated Site Map indicating new BMP's or the removal of BMP's since the previous inspection. Any maintenance, repair, or necessary installation of BMP's that are noted during the inspection must be completed within seven (7) calendar days from the date of the inspection. 12 6. CONCLUSIONS 6.1 Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria Manual and the Canal Importation Master Drainage Plan. The site was removed from the City regulatory 100 year Canal Importation Basin floodplain by the waiver process which was justified based on the information contained in the “As-Built Design Summary & Floodplain Modeling report for Canal Importation Ponds and Outfall” by Ayres Associates dated February 2013. Since the property was removed from the floodplain, there will be no Chapter 10 compliance issues. 6.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for conveyance of runoff to the detention areas. Conveyance elements have been designed to pass required flows and to minimize future maintenance. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit would be required. 13 7. REFERENCES 1. City of Fort Collins, “Storm Drainage Criteria Manual”, (SDCM), dated March, 1986. 2. Urban Drainage and Flood Control District, “Urban Storm Drainage Criteria Manual”, Volumes 1 and 2, dated March, 1969, and Volume 3 dated September, 1992. 13 7. REFERENCES 1. City of Fort Collins, “Storm Drainage Criteria Manual”, (SDCM), dated March, 1986. 2. Urban Drainage and Flood Control District, “Urban Storm Drainage Criteria Manual”, Volumes 1 and 2, dated March, 1969, and Volume 3 dated September, 1992. A APPENDIX A VICINITY MAP B APPENDIX B HYDROLOGIC COMPUTATIONS North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria Recommended % Impervious from Urban Storm Drainage Criteria Manual Runoff % coefficient Impervious C Streets, parking lots (asphalt): 0.95 100 Sidewalks (concrete): 0.95 96 Roofs: 0.95 90 Lawns (flat <2%, heavy soil): 0.20 0 SUBBASIN TOTAL TOTAL ROOF PAVED SIDEWALK LANDSCAPE RUNOFF % ID AREA AREA AREA AREA AREA AREA COEFF. Impervious REMARKS (ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C) 1 Historic 1.28 55,864 0 1,565 0 54,299 0.22 3 Pre Development 1 1.28 55,864 17,000 21,950 7,520 9,394 0.82 80 Post Development Equations - Calculated C coefficients & % Impervious are area weighted C =  (Ci Ai) / At Ci = runoff coefficient for specific area, Ai Ai = areas of surface with runoff coefficient of Ci n = number of different surfaces to consider At = total area over which C is applicable; the sum of all Ai's Flow.xls Cval North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 TIME OF CONCENTRATION - 2 YR LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 2-yr storm Cf = 1.00 SUB-BASIN DATA INITIAL / OVERLAND TIME TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS (ti) (tt) (URBANIZED BASIN) tc DESIGN SUBBASIN Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 POINT ID (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) 1 Historic 1 Historic 1.28 0.22 0.22 187 0.7 24.4 190 0.50 0.030 0.8 4.2 28.5 377 12.1 12.1 Pre Development 1 1 1.28 0.82 0.82 118 1.1 5.2 186 1.20 0.013 2.7 1.1 6.4 304 11.7 6.4 Post Development EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L 0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check minimum tc = 5 minutes Flow.xls TOC-2 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 TIME OF CONCENTRATION - 10 YR LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 10-yr storm Cf = 1.00 SUB-BASIN DATA INITIAL / OVERLAND TIME TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS (ti) (tt) (URBANIZED BASIN) tc DESIGN SUBBASIN Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 POINT ID (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) 1 Historic 1 Historic 1.28 0.22 0.22 20 2.0 5.6 300 1.00 0.016 2.0 2.5 8.1 320 11.8 8.1 Pre Development 1 1 1.28 0.82 0.82 50 15.0 1.4 0 1.00 0.016 2.0 0.0 1.4 50 10.3 5.0 Post Development EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L 0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check minimum tc = 5 minutes Flow.xls TOC-10 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 TIME OF CONCENTRATION - 100 YR LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 100-yr storm Cf = 1.25 SUB-BASIN DATA INITIAL / OVERLAND TIME TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS (ti) (tt) tc DESIGN SUBBASIN Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 POINT ID (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) 1 Historic 1 Historic 1.28 0.22 0.28 20 2.0 5.3 300 1.00 0.016 2.0 2.49 7.8 320 11.8 7.8 Pre Development 1 1 1.28 0.82 1.00 50 15.0 0.5 0 1.00 0.016 2.0 0.00 0.5 50 10.3 5.0 Post Development EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L 0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check minimum tc = 5 minutes (URBANIZED BASIN) Flow.xls TOC-100 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (2-YEAR) LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 2-yr storm, Cf = 1.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Subbasin A C*Cf tc i Q (2) Design Q (2) Q(2)tot Point ID (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) 1 Historic 1 Historic 1.28 0.22 12.1 1.57 0.45 0.45 Release Rate 1 1 1.28 0.82 6.4 2.60 2.7 2.7 Post Development Q = C iA Q = peak discharge (cfs) C = runoff coefficient I = rainfall intensity (in/hr) from IDF curve A = drainage area (acres) Flow.xls Q2 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (10-YEAR) LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 10-yr storm, Cf = 1.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Subbasin A C*Cf tc i Q (10) Design Q (10) Q(10)tot Point ID (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) 1 Historic 1 Historic 1.28 0.22 8.1 3.91 1.1 1.1 Pre Development 1 1 1.28 0.82 5.0 4.87 5.1 5.1 Post Development Q = C iA Q = peak discharge (cfs) C = runoff coefficient I = rainfall intensity (in/hr) from IDF curve A = drainage area (acres) Flow.xls Q10 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (100-YEAR) LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: ppk DATE: 1/28/2014 100-yr storm, Cf = 1.25 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Subbasin A C*Cf tc i Q (100) Design Q (100) Q(100)tot Point ID (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) 1 Historic 1 Historic 1.28 0.28 7.8 8.19 2.9 2.9 Pre Development 1 1 1.28 1.00 5.0 9.95 12.8 12.8 Post Development Q = C iA Q = peak discharge (cfs) C = runoff coefficient I = rainfall intensity (in/hr) from IDF curve A = drainage area (acres) Flow.xls Q100 C APPENDIX C DETENTION POND CALCULATIONS 100-YEAR DETENTION VOLUME REQUIRED UNDER PARKING LOT DETENTION POND FAA METHOD LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: PPK DATE: 1/28/2014 Equations: A trib. To pond = 1.28 acre QD = CIA C100 = 1.00 Vi = T C I A = T QD Developed C A = 1.3 acre Vo =K QPO TQPO = 0.45 cfs S = Vi - Vo K = 0.9 Rainfall intensity from City of Fort Collins IDF Curve Storm Rainfall QD Vol. In Vol. Out Storage Storage Duration, T Intensity, i (cfs) Vi Vo S S (min) (in/hr) (ft3) (ft3) (ft3) (ac-ft) 5 9.95 12.7 3821 0 3821 0.088 10 7.72 9.9 5929 0 5929 0.136 20 5.60 7.2 8602 243 8359 0.192 30 4.52 5.8 10414 486 9928 0.228 40 3.74 4.8 11489 729 10760 0.247 50 3.23 4.1 12403 972 11431 0.262 60 2.86 3.7 13179 1215 11964 0.275 70 2.62 3.4 14085 1458 12627 0.290 80 2.38 3.0 14623 1701 12922 0.297 90 2.22 2.8 15345 1944 13401 0.308 100 2.05 2.6 15744 2187 13557 0.311 110 1.93 2.5 16305 2430 13875 0.319 120 1.80 2.3 16589 2673 13916 0.319 130 1.60 2.0 15974 2916 13058 0.300 140 1.40 1.8 15053 3159 11894 0.273 150 1.20 1.5 13824 3402 10422 0.239 160 1.15 1.5 14131 3645 10486 0.241 170 1.10 1.4 14362 3888 10474 0.240 180 1.05 1.3 14515 4131 10384 0.238 Required Storage Volume: 13916 ft3 0.319 acre-ft WATER QUALITY CALCULATIONS LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: PPK DATE: 1/28/2014 Use 24-hour brim-full volume drain time for extended detention basin Required Storage = a * ( 0.91 * I3 - 1.19 * I2 + 0.78 * I ) Water Quality Capture Volume = WQCV = (required storage/12)*(tributary drainage area) SUB BASIN Trib. % Imperv. Req. Storage WQCV req. vol DWQ req. area/row area (in. of runoff) WQCV *1.2 from Fig. EDB-3 (ac) from Fig. SQ-2 (ac-ft) (ac-ft) (ft) (in2/row) POND 3 1.28 80 0.33 0.035 0.042 1.00 0.381 WQ outlet sizing for pond 1 From Figure 5, for 3/4 in. hole diameter Area of hole = 0.442 in2 # of columns = 1 Area provided/row = 0.442 in2 Area Required/row = 0.381 in2 Use 1 columns of 3/4" diam holes STAGE - STORAGE TABLE 100-YEAR LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: PPK DATE: 1/28/2014 With 0.40 porosity POND 1 Extended Water Quality Volume Required = 0.042 0.105 ac ft 100 yr Detention Volume Required = 0.319 0.799 ac ft Total 100 yr Volume Required = 0.361 0.904 ac ft Surface Incremental Total Stage Area Storage Storage (ft) (ft2) (ac-ft) (ac-ft) 5033.47 0 WQCV 5034.50 13,888 0.109 0.109 5035 20,630 0.242 0.242 5036 20,630 0.474 0.715 100 year WSEL 5036.40 20,630 0.189 0.905 Spillway Elevation 5037 20,630 0.284 1.189 Detention Pond Outlet Sizing 100-YEAR LOCATION: 1501 West Elizabeth PROJECT NO: 350-01 COMPUTATIONS BY: PPK DATE: 1/28/2014 Submerged Orifice Outlet: release rate is described by the orifice equation, Qo = CoAo sqrt( 2g(h-Eo)) where Qo = orifice outflow (cfs) Co = orifice discharge coefficient g = gravitational acceleration = 32.2 ft/s Ao = effective area of the orifice (ft2) Eo = greater of geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) Qmax = 0.45 cfs outlet pipe dia = D = 12.0 in Invert elev. = 5033.47 ft Eo = 5033.61 ft h = 5036.00 ft - 100 yr WSEL Co = 0.6 solve for effective area of orifice using the orifice equation Ao = 0.060 ft2 = 8.7 in2 orifice dia. = d = 3.33 in Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering ) d / D = 0.28 kinematic viscosity, v = 1.22E-05 ft2/s Reynolds no. = Red = 4Q/(pdv ) = 1.69E+05 Co = (K in figure) = 0.6 check Use d = 3.300 in A o = 0.059 ft 2 = 8.55 in 2 Q o = 0.44 cfs Detention.xls D APPENDIX D BMP SCHEDULE & COST ESTIMATE Quantity Cost 1 CDR LF $0.00 2 CDR LF $0.00 3 CWA EA 1 $1,200.00 4 CF LF $0.00 5 CM LF $0.00 6 CIF LF $0.00 7 DW EA $0.00 8 DD LF $0.00 9 DD LF $0.00 10 ECM SY $0.00 11 IP LF 16 $160.00 12 RRB LF $0.00 13 SB LF $0.00 14 SCL LF $0.00 15 SM AC $0.00 16 SF LF 885 $2,655.00 17 RS LF 35 $350.00 18 SSA SY $0.00 19 SR AC $0.00 20 TSC EA $0.00 21 TSL AC $0.00 22 VTC EA 1 $1,500.00 $5,865.00 $2,932.50 #1 Erosion control amount $8,797.50 #2 Reseeding AC $1,200 1.28 $1,536.00 Erosion control escrow (greater of #1 & #2) $8,797.50 $1,500.00 Maintenance & replacements (50%) $3.00 $10.00 Construction Fence Vehicle Tracking Control (2) Topsoil (6-inch Lift) Temporary Stream Crossing Surface Roughening Stabilized Staging Area Reinforced Rock Berm Sediment Basin (1) Rock Sock Silt Fence Construction Markers Culvert Inlet Filter Dewatering Diversion Ditch (Unlined) Diversion Ditch (ECM or plastic) Sediment/Erosion Control Matting Inlet Protection Unit 1501 West Elizabeth (Uptown Plaza) g __________________________________________________________________________________________ Seeding and Mulching Sediment Control Log (Wattle) Item No. Check Dam (Reinforced) Concrete Washout Area E APPENDIX E FLOODPLAIN WAIVER F APPENDIX F EXCERPTS FROM OTHER REPORTS Geotechnical Engineering Report Uptown Plaza 1501 West Elizabeth Street Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Prepared for: D.K. Investments, Inc. Windsor, Colorado Prepared by: Terracon Consultants, Inc. Fort Collins, Colorado Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 4 Boring Number Depth to groundwater while drilling, ft. Depth to groundwater 1 day after drilling, ft. Elevation of groundwater 8 days after drilling, ft. 1 6 2.5 5,035.8 2 6 6.1 5,032.6 3 13.5 4.9 5,034.9 4 6 3.2 5,035.7 5 Not encountered 3.8 5,034.5 6 Not encountered 3.5 5,035.9 DP-1 Not encountered -- -- DP-2 2.7 -- -- These observations represent groundwater conditions at the time of the field exploration, and may not be indicative of other times or at other locations. Groundwater levels can be expected to fluctuate with varying seasonal and weather conditions, and other factors. Groundwater level fluctuations occur due to seasonal variations in amount of rainfall, runoff and other factors not evident at the time the borings were performed. Therefore, groundwater levels during construction or at other times in the life of the structure may be higher or lower than the levels indicated on the boring logs. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project. Fluctuations in groundwater levels can best be determined by implementation of a groundwater monitoring plan. Such a plan would include installation of groundwater piezometers, and periodic measurement of groundwater levels over a sufficient period of time. 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION 4.1 Geotechnical Considerations Based on subsurface conditions encountered in the borings, the site appears suitable for the proposed construction from a geotechnical point of view provided certain precautions and design and construction recommendations described in this report are followed. We have identified geotechnical conditions that could impact design and construction of the proposed structure, pavements, and other site improvements. 4.1.1 Existing, Undocumented Fill As previously noted, existing undocumented fill was encountered to depths up to about 4 feet in the borings drilled at the site. Deeper fills may be present on the site where buried tanks were removed during demolition of the gas station previously occupying the site. We do not recommend supporting shallow spread footing foundations or floor slabs on the existing fill Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 17 should refer to ACI 302 for procedures and cautions regarding the use and placement of a vapor retarder. Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1R are recommended. 4.5.2 Floor Systems - Construction Considerations Movements of slabs-on-grade using the recommendations discussed in previous sections of this report will likely be reduced and tend to be more uniform. The estimates discussed above assume that the other recommendations in this report are followed. Additional movement could occur should the subsurface soils become wetted to significant depths, which could result in potential excessive movement causing uneven floor slabs and severe cracking. This could be due to over watering of landscaping, poor drainage, improperly functioning drain systems, and/or broken utility lines. Therefore, it is imperative that the recommendations presented in this report be followed. 4.6 Hydraulic Conductivity Testing Two (2) hydraulic conductivity borings, presented as Exhibits A-10 and A-11, and designated as Boring DP-1 and DP-2, were performed to depths of approximately 3 feet below existing site grades. Logs of the borings along with a Boring Location Plan (Exhibit A-2) are included in Appendix A. 4.6.1 Hydraulic Conductivity – Field Investigation We understand a carwash building previously occupying the site was demolished and removed prior to our field investigation. During our field investigation, two (2) field hydraulic conductivity test borings were completed to a depth of approximately 3 feet below existing site grades. The field hydraulic conductivity test borings were completed in areas of the site planned for permeable pavements. One of the field hydraulic conductivity test borings (DP-1) was completed in the area where the car wash building previously occupied the site. The second field hydraulic conductivity test boring (DP-2) was completed in the area of the site where we believe an existing detention area is present. Field hydraulic conductivity test boring DP-1 was drilled with a CME-45 truck mounted drill rig with 4-inch outer diameter solid-stem augers. Field hydraulic conductivity test boring DP-2 was completed with a 3¾-inch hand auger. During the drilling operations, lithologic logs of the borings were recorded by the field engineer. Slotted PVC pipe was placed in each of the field hydraulic conductivity test holes full-depth and the annulus surrounding the slotted PVC pipe was filled with clean filter sand. The borings were then saturated with water and left to stabilize overnight. The soils encountered in DP-1 were visually classified in the field and consisted of existing fill materials comprised of lean clay with sand and gravel. The existing fill was slightly moist to Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 18 moist. The soils encountered in DP-2 were also visually classified in the field and consisted of native sandy lean clay. The soils encountered in DP-2 were very moist to wet. Groundwater was not encountered in field hydraulic conductivity test boring DP-1. Groundwater was encountered in field hydraulic conductivity test boring DP-2 at a depth of approximately 2.7 feet below existing site grade while drilling. During delayed groundwater measurements taken in other borings completed on the site, groundwater was measured in Boring No. 5 (located near hydraulic conductivity test boring DP-2) at a depth of approximately 3.8 feet below the existing ground surface. The groundwater levels measured in our borings at the time of our field study were used when calculating the field hydraulic conductivity at this site. 4.6.2 Hydraulic Conductivity - Discussion The field hydraulic conductivity testing performed as part of our study was developed by the U.S. Bureau of Reclamation and was referred to as the well permeameter method. The field hydraulic conductivity tests were performed by adding water to the test holes to maintain a constant water level (constant head test). The calculated hydraulic conductivity value for field hydraulic conductivity test holes DP-1 and DP-2 were 3 feet per day (ft/day) and 108 ft/day, respectively. The calculated value for DP-1 is within the expected ranges for the soil types encountered in our borings and is considered to be a representative value. The calculated value for DP-2 is much higher than the expected ranges for the soil types (upper clays) encountered in our borings. However, a layer of clean to silty gravel with sand was encountered in some of the other borings completed at this site at a depth of approximately 6 feet below existing site grades. It is likely the gravel layer extends below most of the site and would be expected near the bottom of DP-2. We believe the comparatively higher field hydraulic conductivity value measured in DP-2 is due to the higher flow rates that occur as water flows into the gravel layer below the site. The test results and schematics of the field hydraulic conductivity test hole details, Exhibit B-7 and B-8, are included in Appendix B. The field hydraulic conductivity test results and soils encountered in our borings completed at the site indicate infiltration of storm water retained in a reservoir below permeable pavements into the soils underlying this site will be favorable for the design of permeable pavements. However, shallow groundwater conditions may limit the allowable depth of the retention area below permeable pavements. The slotted PVC pipe was left in place for future groundwater readings. 4.7 Pavements 4.7.1 Pavements – Conventional Subgrade Preparation On most project sites, the site grading is accomplished relatively early in the construction phase. Fills are typically placed and compacted in a uniform manner. However as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, or rainfall/snow melt. As a result, the pavement subgrade may not be suitable for pavement construction and corrective action will be required. The subgrade should be carefully Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 19 evaluated at the time of pavement construction for signs of disturbance or instability. We recommend the pavement subgrade be thoroughly proofrolled with a loaded tandem-axle dump truck prior to final grading and paving. All pavement areas should be moisture conditioned and properly compacted to the recommendations in this report immediately prior to paving. 4.7.2 Pavements – Permeable Pavement Subgrade Preparation Unlike conventional pavements, permeable pavement subgrades are not compacted. When preparing the subgrade for permeable pavements, care should be taken to excavate the required reservoir storage volume without disturbing the underlying soils. Groundwater was encountered at depths of about 3.5 and 3.7 feet below existing site grades in the portion of the site planned for permeable pavements. Shallow groundwater conditions will limit the thickness of the rock reservoir layer used to store the storm water runoff. Shallow groundwater will also reduce infiltration rates as the water stored within the rock reservoir layer infiltrates into the groundwater. 4.7.2 Pavements – Design Recommendations Design of pavements for the project have been based on the procedures outlined in the 1993 Guideline for Design of Pavement Structures prepared by the American Association of State Highway and Transportation Officials (AASHTO) and the Larimer County Urban Area Street Standards (LCUASS). A sample of the fill materials selected for swell-consolidation testing exhibited no movement when wetted under an applied pressure of 200 psf which is less than the maximum 2 percent criteria established for determining if swell-mitigation procedures in the pavement sections are required per LCUASS standards. Therefore, we do not believe swell-mitigation of the subgrade materials prior to pavement operations is necessary. Traffic patterns and anticipated loading conditions were not available at the time that this report was prepared. However, we anticipate that the new parking areas (i.e., light-duty) will be primarily used by personal vehicles (cars and pick-up trucks). Delivery trucks and refuse disposal vehicles will be expected in the drive lanes and loading areas (i.e., medium-duty). A maximum of 10 trucks per week were considered developing our recommendations. If heavier traffic loading is expected, Terracon should be provided with the information and allowed to review these pavement sections. Rigid pavement design is based on an evaluation of the Modulus of Subgrade Reaction of the soils (k-value), the Modulus of Rupture of the concrete, and other factors previously described. A Modulus of Subgrade Reaction of 200 pci, and a Modulus of Rupture of 600 psi, were used for pavement concrete. The rigid pavement thickness was determined on the basis of the AASHTO design equation. Recommended minimum pavement sections are provided in the table below. Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 20 Conventional Pavements Traffic Area Alternative Recommended Pavement Thickness (inches) Asphaltic Concrete (AC) Aggregate Base Course (ABC) Portland Cement Concrete (PCC) Total Automobile Parking (light duty) A 3 4 - 7 B - - 5 5 Drive Lanes and Loading Areas (heavy duty) A 4 6 - 10 B - 4 5 9 Permeable Pavements Traffic Area Alternative Recommended Pavement Thickness (inches) Porous Asphalt Permeable Concrete Permeable Interlocking Concrete Pavement (PICP) Aggregate Base Course Total Automobile Parking A 3 - - 6 9 B - 6 - 3 9 C - - Typically 3 3 6 Terracon recommends the design and construction of permeable pavements should be completed by a specialty contractor who has demonstrated experience with placing, compacting, finishing, edging, jointing, curing, and protecting permeable pavements. There are several choices for base course depending upon which type of permeable pavement is chosen. Terracon recommends constructing perimeter curbing around permeable pavements and between conventional and permeable pavements to reduce infiltration of water below moisture sensitive subgrades. Where rigid pavements are used, portland cement concrete should be produced from an approved mix design with the following minimum properties: Properties Value Compressive strength 4,000 psi (mimum) Cement type Type I or II cement Entrained air content (%) 5 to 8 Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 21 Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes from the time the water is added to the mix. Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation per ACI 325. The location and extent of joints should be based upon the final pavement geometry. Joints should be sealed to prevent entry of foreign material and doweled where necessary for load transfer. Although not required for structural support, a minimum 4-inch thick aggregate base course layer is recommended for the PCC pavements in heavy-duty areas to help reduce the potential for slab curl, shrinkage cracking, and subgrade “pumping” through joints. Proper joint spacing will also be required for PCC pavements to prevent excessive slab curling and shrinkage cracking. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. For areas subject to concentrated and repetitive loading conditions such as dumpster pads, truck delivery docks and ingress/egress aprons, we recommend using a portland cement concrete pavement with a thickness of at least 6 inches underlain by at least 4 inches of granular base. Prior to placement of the granular base the areas should be thoroughly proofrolled. For dumpster pads, the concrete pavement area should be large enough to support the container and tipping axle of the refuse truck. Pavement performance is affected by its surroundings. In addition to providing preventive maintenance, the civil engineer should consider the following recommendations in the design and layout of pavements: Site grades should slope a minimum of 2 percent away from the pavements; The subgrade and the pavement surface have a minimum 2 percent slope to promote proper surface drainage; Consider appropriate edge drainage and pavement under drain systems; Install pavement drainage surrounding areas anticipated for frequent wetting; Install joint sealant and seal cracks immediately; Seal all landscaped areas in, or adjacent to pavements to reduce moisture migration to subgrade soils; and Placing compacted, low permeability backfill against the exterior side of curb and gutter. 4.7.3 Pavements – Maintenance Preventative maintenance should be planned and provided for an ongoing pavement management program in order to enhance future pavement performance. Preventive maintenance consists of both localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Geotechnical Engineering Report Uptown Plaza Fort Collins, Colorado July 24, 2013 Terracon Project No. 20135023 Responsive Resourceful Reliable 22 Permeable pavements require periodic inspection and cleaning. Consideration should be given to installing signage to restrict heavily loaded vehicles (i.e. trash trucks, delivery trucks, etc.) from driving on permeable pavement areas. Also, maintenance of permeable pavements should be completed by properly trained workers. 5.0 GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as described in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. APPENDIX A FIELD EXPLORATION DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES 1901 Sharp Point Drive, Suite C Fort Collins, Colorado 80521 PH. (970) 484-0359 FAX. (970) 484-0454 A-2 BORING LOCATION PLAN EXHIBIT Uptown Plaza 1501 West Elizabeth Street Fort Collins, Colorado Project Manager: Drawn By: Check By: Approved By: EDB BCJ EDB EDB Project No. Scale: File Name: Date: 20135023 1”=40’ 6/20/2013 0’ 20’ 40’ APPROXIMATE SCALE LEGEND Approximate Boring Location 1 1 2 3 4 5 6 Approximate Location of Temporary Benchmark (Top Man Hole Lid–Elevation 5,041.2’) DP-1 DP-2 DP-1 Approximate Field Hydraulic Conductivity Location This unofficial copy was downloaded on Aug-19-2013 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Aug-19-2013 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Aug-19-2013 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Aug-19-2013 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA Concrete aggregate ASTM C33 and CDOT Section 703 Check Dam $10.00 $1,200.00 SEDIMENT/EROSION CONTROL BEST MANAGEMENT PRACTICES (BMPs) COST OPINION SPREADSHEET BMP ID Installation Unit Cost _________________________________________________________________________________________ Subtotal