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Home My WebLink AboutDrainage Reports - 05/11/2017City of Ft: Cdlins` pro ed t?Ians Approved By Date S - J 14 FINAL DRAINAGE AND EROSION. CONTROL REPORT FOR VILLAGE ON HORSETOOTH AT 1506 W. HORSETOOTH ROAD FORT COLLINS, CO 80526 PREPARED FOR HOUSING CATALYST ■❑111111110■ ;r HOUSING Slum CATALYST Building Community. Inspiring Change. Fort Collins, CO 80521 MAY 8, 2017 ENGINEERS STATEMENT: "I hereby certify that this report (plan) for the Preliminary Drainage Design for the Housing Catalyst Village on Horsetooth was prepared by me (or under my direct supervision) in accordance with the provisions of the City of Fort Collins Standards for the Responsible Parties thereof. I understand that the City of Fort Collins does not and shall not assume liability for drainage facilities designed by others." Qp REqq ��Uiiq�� \� OQPX,....,,, es 37146 Charles R. Hager, IV, P.E. Registered Professional Engineer State of Colorado No. 37146 Housing Catalyst - Village on Horsetooth FINAL DRAINAGE AND EROSION CONTROL REPORT 1110IN HOUSING CATALYST VILLAGE ON HORSETOOTH JVA, Inc. 213 Linden Street, Suite 200 Fort Collins, CO 80524 phone: 970-225-9099 JVA Project No. 2595c MAY 8, 2017 Housing Catalyst - Village on Horsetooth TABLE Of CONTENTS SITE LOCATION AND DESCRIPTION.........................................................................................5 ' DRAINAGE BASINS AND HISTORIC RUNOFF.............................................................................6 HISTORICDRAINAGE......................................................................................................... 6 DRAINAGE DESIGN CRITERIA................................................................................................6 ' HYDROLOGIC METHOD AND DESIGN STORM FREQUENCIES................................................... 6 HYDRAULIC CRITERIA........................................................................................................ 6 VARIANCES FROM THE CRITERIA............................................................................................ 7 DRAINAGE FACILITY DESIGN.................................................................................................7 GENERALCONCEPT......................................................................................................... 7 ' PROPOSED DEVELOPED SUBBASINS....................................................................................8 PROPOSED DETENTION POND AND LID............................................................................ 1 1 HISTORIC/DEVELOPED BASIN COMPARISON..................................................................... 13 ' STORMWATER POLLUTION PREVENTION/EROSION CONTROL .................................................. 13 TEMPORARY EROSION CONTROL..................................................................................... 13 PERMANENT EROSION CONTROL..................................................................................... 13 ' STORMWATER MANAGEMENT CONTROLS............................................................................ 14 SEQUENCE OF CONSTRUCTION ACTIVITIES............................................................................ 17 CONCLUSIONS.................................................................................................................. 18 REFERENCES........................................................................................................................ 3 ' LIST OF TABLES TABLE 1. HISTORIC BASIN PROPERTIES AND FLOWS..................................................................... 6 TABLE 2. DEVELOPED BASIN PROPERTIES AND FLOWS COEFFICIENTS ........................................... 1 1 Housing Catalyst - Village on Horsetooth Page 3 of 19 APPENDICES ' Appendix A - Figures Appendix B - Hydraulic/Hydrologic Computations Appendix C - Referenced Documents Appendix D - Erosion Control Escrow Housing Catalyst - Village on Horsetooth Page 4 of 19 SITE LOCATION AND DESCRIPTION The Village on Horsetooth (site) is being developed by the Housing Catalyst and is located in Southeast Quarter of Section 27, Township 7 North, Range 69 West of the 6" Principal Meridian, ' in Larimer County, Fort Collins, Colorado. Refer to Appendix A, Figure 1, for the site vicinity map. Horsetooth Road (Horsetooth) to the south, Pleasant Valley and Lake Canal (Canal) to the east, and residential subdivisions to the north and west border the property. There is open space ' and residential housing to the west. The site is located in the Foothills Stormwater Basin. The Foothill basin drains west to east through open channels and storm sewer that discharges into the Fossil Creek Reservoir Inlet Ditch. The Foothills Basin Master Plan Water Quality Conceptual Alternatives Map, provided by the City of Fort Collins, shows that the site is required to provide flood control and water quality; the map is attached in Appendix C. ' The current site is approximately 7.96 acres of partially developed land with an existing house and horse stable, arena and grazing open space area with a total percent impervious of 16.0%. The site historically generally drains to the east towards and into the Canal via overland flow with slopes ' ranging from 0.2% to 8.0%. The north half of Horsetooth bordering the site drains to the north onto the site and into the Canal. From the geotechnical report dated July 19, 2016, the soil is mainly sandy clay and clayey sand with no bedrock encountered in the borings. Ground water was t located 19 to 22 feet below ground surface and did not drastically change several days after drilling. A soil map created using the USDA Natural Resources Conservation Service Web Soil Survey identifies the site's soil as Altvan-Satanta Loams, which is in the hydrologic soil group B ' with infiltration rates ranging from 0.6 to 2 inches/hour. Further investigation of the soils infiltration rate in the locations of the detention pond and low impact development (LID) ponds will be completed. A summary of the conclusions of the geotechnical report and the web soil ' survey results are provided in Appendix C. According to the FEMA Flood Insurance Rate Map Panel Number 08069C0986G dated ' 05/02/2012, the site is located outside of the ] 00-year floodplain area. The map panel is attached in Appendix C. ' The proposed site construction includes the demolition of the existing home, horse stables and arena, gravel roadway and the construction of 9 new multi -unit residential buildings and a clubhouse building with surrounding asphalt parking areas, playground and grass fields, sidewalks, ' LID water quality controls and a detention pond. The site development will increase the overall percent impervious to 48.3%. The proposed development cannot drain or discharge into the Canal and must tie into the City of Fort Collins (City) storm sewer system located in Horsetooth or now ' onto Horsetooth, which eventually drains to Fossil Creek Reservoir Inlet Ditch. Storm valley gutters, catch basins, area inlets, under drains, curb cuts, chases, channels and culverts are located throughout the site to capture and convey runoff to the LIDS and detention pond. The main purpose of this study is to analyze the existing and developed drainage patterns in order to convey stormwater into the Horsetooth storm sewer system without causing adverse effects to ' the site and the surrounding and downstream properties. The proposed scope of work will include new storm piping, valley gutters, area drains, catch basins, curb cuts, and site grading to accommodate three bioretention ponds, a detention pond, and piping to the existing Horsetooth Housing Catalyst - Village on Horsetooth ' Page 5 of 19 storm system. An outlet structure and pipe with a restrictor plate will be installed in the pond to control the 100-year storm outflow rate to the calculated 2-year historical runoff rate. WQCV will be attained in the three bioretention ponds. An emergency spillway is located along the southeast edge of the pond to direct flow onto Horsetooth if the outlet structure is ever clogged or not performing correctly. DRAINAGE BASINS AND HISTORIC RUNOFF HISTORIC DRAINAGE The site historically drains to the east towards and into the Pleasant Valley and Lake Canal via overland flow with slopes ranging from 0.2% to 8.0%. Runoff from the north half of Horsetooth bordering the site drains north onto the site and into the Canal. The site consists of a gravel roadway, house, horse stables, arena, and grazing area which have an overall percent impervious of 16.0%. The peak 2-year and 100-year runoff rates are 2.21 cfs and 28.78 cfs, respectively. The historic drainage is outlined below. Design flow calculations and the historical drainage map are provided in Appendix A. Table 1. Historic Basin Properties and Flows Drainage Basin Design Point Area (acre) % Impervious Q-2 (cfs) Q-10 (cfs) Q-100 (cfs) Runoff Coefficient H1 1 7.96 16.0% 2.21 6.75 28.78 0.53 Total 7.96 16.0% 2.21 6.75 28.78 0.53 DRAINAGE DESIGN CRITERIA , HYDROLOGIC METHOD AND DESIGN STORM FREQUENCIES ' The drainage for the site was designed to meet or exceed the City of Fort Collin's Standards and Specifications, including the Stormwater Criterial Manual which incorporates most of the Urban Drainage and Flood Control District Criteria Manual (USDCM). The site's basin percent ' impervious values were calculated using impervious values from Table 6-3 in the USDCM. For the Modified FAA calculations, the values for the 10-year and 100-year event rainfall intensity duration for 0 to 60 minutes were taken from Table RA-7 in the City of Fort Collins' Stormwater ' Criteria Manual. Equation 5.30 from the USDCM was used to calculate intensities for the 60 to 180 minute time steps. The runoff coefficients were calculated using USDCM's Table 6-4 equations. HYDRAULIC CRITERIA The proposed drainage facility has been designed to comply with the City of Fort Collins , Stormwater Criteria Manual, the Foothills Basin Master Plan design, and UDFCD's Drainage Criteria Manual. The Foothills Basin Master Plan requires best management practices to have ' Housing Catalyst - Village on Horsetooth Page 6 of 19 ' both flood control and water quality. UD-Inlet Version 3.14, Manning's Equation, Hydraflow, and/or Flowmaster will be utilized as needed for the inlet and pipe sizing calculations. Final drainage and pipe network plans are included in the construction documents. As required by the City's stormwater criteria manual, the pond volume was calculated using the modified FAA method and includes the required 100-year runoff volume. The required LID area and WQCV are being captured and treated separately in the site's three bioretention ponds. Pond volume, WQCV,- bioretention sizing, and runoff calculations are attached in Appendix B. VARIANCES FROM THE CRITERIA ' As per the City's comments dated May 9, 2016, the site is required to discharge the 100-year event at the historical 2-year rate. There is a micropool in the detention basin outlet structure to allow the bioretention underdrains to tie into the structure without causing standing water in the underdrain system. There are no forebays in the pond since all concentrated flows entering the detention pond pass through one of the three bioretention ponds. Riprap aprons will act as velocity dissipaters for the concentrated runoff entering the bioretention ponds. DRAINAGE FACILITY DESIGN GENERAL CONCEPT As per the Foothills Basin Master Plan design, the site was graded in an attempt to capture all site ' runoff to be treated and detained in the three bioretention ponds and the extended detention basin located along the east side of the site. The detention pond has an outlet structure that ties into the City's existing storm sewer system on the south side of Horsetooth. The shallow elevation of this ' connection restricts the bottom elevation of the detention pond. A very small portion of the site, 10.2%, was not able to be captured and treated onsite. This offsite flow will either drain onto Horsetooth Road and follow existing drainage pathways to the east, drain to the east into the Canal, or drain west into the neighboring detention pond. The open space area in the center of the site will capture the runoff from the playground, sidewalk, and open space through the uses of area t inlets which tie into the proposed storm system and discharges into LID Pond 3. Area drains around buildings 1, 3, 5, 6, and 7, and the southwest parking lot area will tie into the same storm system. The area between Building 1 and Building 2 will be piped into LID Pond 3. Furthermore, ' the east portion of the parking lot and portions of runoff from buildings 2, 6 and 7 will sheet flow into LID Pond 3. The west side of the site, a portion of the north parking lot, buildings 9 and 10 and areas around those buildings will drain to the north into LID Pond 1 by sheet flow and curb ' and gutter. LID Pond 1 is hydraulically connected to LID Pond 2 by a culvert set I foot above the bottom of the pond. A portion of the parking lot to the north and east, building 8 and the area around the building will drain into LID Pond 2. Therefore, all onsite runoff, besides the detention ' pond, will be directed to one of the three LID ponds. The ponds will capture the sites entire required water quality volume with the assumption that the detention pond is a mostly grass area which will act as a filter for the basins water quality needs. There are overflows in LID Ponds 2 ' and 3 to allow for larger storm events to discharge into the detention pond at peak flow rates. The filter areas correspond with the required LID area for each pond. The filter area includes 12 inches of growing media, 6 inches of pee gravel, and at least 10 inches of CDOT Class C filler material ' with a 6" slotted underdrain pipe along the bottom. This will ensure that no standing water will Housing Catalyst - Village on Horsetooth ' Page 7 of 19 occurring in the media material. The underdrain system is connected with storm drains and ties into the outlet structure's micropool. The parking lot will act as part of the detention pond for larger storm events, but will have no greater than one foot of ponding at the deepest point during the 100-year storm event. Vertical curb and gutter will be installed along Horsetooth road to convey flows east along the road, similar to what is occurring to the west and east of the site along Horsetooth. The on -site storm system was designed to convey the 10-year storm event with the 100-year storm event overflowing into the parking lots and sheet flowing into a LID Pond or ponding until flow can by conveyed to an LID Pond. PROPOSED DEVELOPED SUBBASINS The site was delineated into thirty subbasins, A 1-A 16, B 1-B4, and R 1-R10. Basins A 1-A 16 and Rl-R10 will be captured and treated in the bioretention ponds and detention pond. Basin Bl-B4 are the offsite basins and will not be have treatment before leaving the site either to Horsetooth Road, the Canal, or to the western property. Basin A], A2 and A 14 all contain a bioretention pond for water quality LID treatment. Basin A 16 contains the detention pond. All roofs will discharge to the surface. The developed drainage map is provided in Appendix A. SUBBASIN DESCRIPTIONS: • Subbasin A I contains the most of the northwest portion of the site. This includes parking lot, sidewalk and landscaped areas and LID Pond 1. Flow is directed into the parking lot and flows north into the curb and gutter that directs flow to a curb cut to direct flow into LID Pond 1. A culvert connects Basin A 1 to Basin A2. • Subbasin A2 contains the northeast portion of the site. This includes landscaped, parking lot, sidewalk areas, and LID Pond 2. Runoff is directed across the parking lot to the curb and gutter and a curb cut into the LID pond. Once the pond is at capacity, flow discharges into the detention pond through an overflow weir. • Subbasin A3 contains a portion of the southeast corner of the site. This includes parking lot, sidewalk, and landscaped areas. Runoff is directed to the parking lots north curb and gutter where it is collected in a double Type 16C inlet and piped to LID Pond 3. Flow greater than the 10-year event will pond around the inlet and at depths greater than a foot the water will flow south into the entrance road and onto Horsetooth Road. If the inlet is ever clogged flow will pond around the inlet and eventually discharge south along the entrance road into Horsetooth road. • Subbasin A4 includes a small landscaped area to the west of Building 3. Flow is collected in a 12-inch sumped area drain and piped into the storm system that discharges to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the south offsite onto Horsetooth Road. • Subbasin A5 includes a very small landscaped area to the west of Building 3 and north of basin A4. Flow is collected in an 8-inch sumped area drain and piped into the storm system that discharges to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the north into basin A3. • Subbasin A6 contains a small portion of the south parking lot, landscaped area and sidewalk. Flow is directed into the parking lots valley gutter, captured in a double Valley Gutter and piped into LID Pond 3. If the inlets are clogged or for larger storm events flow will pond around the inlet before flowing into basin A3. Housing Catalyst - Village on Horsetooth Page 8 of 19 • Subbasin A7 includes a very small landscaped area to the west of Building 1. Flow is collected in a 12-inch sumped area drain and piped into the storm system that discharges to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the north into basin A6. • Subbasin A8 includes the landscaped area around of Building 9 and a small portion of sidewalk. Flow is collected in an 8-inch area drain and piped into the storm system that discharges to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the east into basin A9. • Subbasin A9 contains the open space area in the middle of the site. The area also includes a playground, gravel picnic areas and a sidewalk system. Flow is directed to the center of the open space area, collected in two 24-inch sumped area drains and piped to LID Pond 3. For storm events greater than the 10-year event runoff will pond in the grass area. There is an overflow located between buildings 4 and 5 into basin A3 if the inlets ever become clogged and do not drain. • Subbasin A10 includes the landscaped area to the west of Building 7. Flow is directed to several a 12-inch sumped area drain and piped to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the east into basin A9. • Subbasin Ai 1 includes the landscaped area around north and west sides of Building 6 and includes a picnic area and some sidewalk. Flow is directed to a 12-inch sumped area drain and piped to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the east into basin A9. • Subbasin Al includes the landscaped the green space to the west of Building 5. Two fl- inch sumped area drains collect runoff and the flow is piped to LID Pond 3. Flows for stone events greater than the 10-year event will pond in the sumped area and overflow to the south onto basin A6. • Subbasin A 13 includes the landscaped area to the south of Building 6. An 8-inch area drain collects runoff and the flow is piped to LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the east into basin A14. • Subbasin A] 4 contains the east portion of the parking lot, sidewalk, landscaped areas and LID Pond 3. The parking lot is sloped to drain to the east curb and gutter and discharge into the pond through curb cuts. An overflow in the pond allows for flows greater than the WQCV to discharge into the detention pond. • Subbasin A 15 includes a small landscaped area to the west of Building 2. Flow is collected in an 8-inch sumped area drain and piped directly into LID Pond 3. Flows for storm events greater than the 10-year event will pond in the sumped area and overflow to the north into basin A 14. • Subbasin A16 contains the bottom of the detention pond and the sidewalk along the east side of the site. The ponds outlet structure is connected to Horsetooth Storm System. An overflow spillway is located on the south side of the detention pond and is directed to Horsetooth Road. • Subbasin B1 contains the south portion of the site that drains offsite. This includes landscaped area, sidewalk and the entrance into the property. Runoff will sheet flow across the landscaped areas and road onto Horsetooth Road and be directed to the east along curb and gutter. The 100-year peak flow is 1.56 cfs. Housing Catalyst - Village on Horsetooth Page 9 of 19 • Subbasin B2 contains the east side of the detention ponds embankment. Flow from the embankment will be directed to the east into the Canal. The 100-year peak flow is 1.45 cfs. • Subbasin B3 contains the north portion of the site that drains offsite. This area exists because of the detention basins berm. Flow is directed to the north into a swale running west to east that discharges into the Canal. Minimal flow, 0.63 cfs for the 100-year event, will enter the Canal. • Subbasin B4 contains a small portion of the west side of the site that will be directed offsite and into the neighboring detention basin area. A berm was placed along the west side of the site keep flow from leaving the site and offsite flows from entering the site. The offsite flow, 0.12 cfs for the 100-year event, is the result of the berm. • Roof Subbasin RI's roof drains will surface discharge to the north into basin A6. • Roof Subbasin R2's roof drains will surface discharge to the west into basin A 13. • Roof Subbasin R3's roof drains will surface discharge to the north and east into basin A3. • Roof Subbasin R4's roof drains will surface discharge to the south into basin A3. • Roof Subbasin R5 will be piped into the storm system to the east of the building in basin Al2. • Roof Subbasin R6's roof drains will surface discharge to the east into basin A14. • Roof Subbasin R7's roof drains will surface discharge to the east into basin A 14. • Roof Subbasin R8's roof drains will surface discharge to the north into basin A2. • Roof Subbasin R9's roof drains will surface discharge to the north into basin Al. • Roof Subbasin R10's roof drains will surface discharge to the west into basin A10. Housing Catalyst - Village on Horsetooth Page 10 of 19 ' Table 2. Developed Basin Properties and Flows Coefficients Drainage Basin Design Point Area (acre) % Impervious Q-10 (cfs) Q-100 WO Runoff Coef C100. Al 1 1.04 57.0% 0.01 6.07 0.73 A2 2 0.52 48.4% 0.82 2.63 0.69 A3 3 0.75 73.6% 0.02 5.80 0.81 A4 4 0.11 2.0% 0.13 0.40 0.46 A5 5 0.01 2.0% 0.99 0.05 0.46 A6 6 0.26 80.5% 0.06 1.83 0.85 A7 7 0.02 2.0% 0.05 0.10 0.46 A8 8 0.12 1 16.5% 0.06 0.53 0.53 A9 9 0.95 18.7% 0.01 4.01 0.55 A10 10 0.08 5.6% 2.67 0.34 1 0.48 All 11 0.06 6.3% 0.06 0.30 0.49 Al2 12 0.04 25.8% 0.68 0.20 0.58 A13 13 0.02 2.0% 0.37 0.07 0.46 A14 14 0.91 62.9% 0.22 6.54 0.76 A15 15 0.04 29.6% 0.14 0.21 0.60 A16 16 0.80 14.5% 0.02 3.02 0.51 61 17 0.34 16.6% 0.70 1.56 0.54 B2 18 0.31 2.0% 0.44 1.45 0.46 B3 19 0.14 14.5% 0.71 0.63 0.53 134 20 0.03 2.0% 0.47 0.12 0.46 R1 21 0.17 90.0% 0.29 1.49 0.90 R2 22 0.10 90.0% 0.43 0.93 0.90 R3 23 0.17 90.0% 0.69 1.52 0.90 R4 24 0.11 90.0% 0.71 1.01 1 0.90 R5 25 0.07 90.0% 0.69 0.63 0.90 R6 26 0.10 1 90.0% 0.71 0.93 0.90 R7 27 0.17 90.0% 18.07 1.49 0.90 R8 28 0.17 90.0% 0.75 1.52 0.90 R9 29 0.17 90.0% 0.71 1.49 0.90 R10 1 30 0.17 90.0% 0.69 1.53 1 0.90 Total Site Flow 7.96 48.3 % 32.19 48.27 0.69 Total Offsite (B Basins) 0.82 1 10.2% 2.31 3.77 0.50 Total To LID Pond 1 1.38 65.1% 1.41 9.09 0.77 Total To LID Pond 2 0.69 58.6% 1.57 4.15 0.74 Total To LID Pond 3 4.26 55.6% 26.88 28.39 0.73 Total to Pond 7.14 52.6% 29.87 44.51 0.71 ' PROPOSED DETENTION POND AND LID As per the City's requirement, the 100-year runoff volume is captured in the detention pond and has an outflow rate equal to the historical 2-year flow rate of 2.21 cfs. This is accomplished ' through the installation of a restrictor plate on the 15 inch RCP outlet pipe. Only a small portion Housing Catalyst - Village on Horsetooth Page 11 of 19 of the sites area, 10.2%, was not designed to drain onsite into the LID and detention ponds. The bottom of the detention pond is at an elevation of 5105.30 feet and is 5.2 feet deep with a total volume of 3.73 acre-ft. The detention pond's emergency overflow spillway is located on the southern edge of the pond at an elevation of 5109.50 ft and will discharge to Horsetooth Road if the outlet structure of the pond is ever clogged or malfunctioning. The spillway was designed to be able to discharge the peak 100-year runoff rate of 44.51 cfs with 9 inches of head. For the 100- year storm event, the pond will have a maximum water surface elevation of 5108.94 ft, which is a pond volume of approximately 1.34 acre-feet. The difference of 0.56 ft between the 100-year water surface elevation and spillway bottom elevation is because of the tie in elevation of the spillway to Horsetooth Road. The top of pond was designed at 5110.50 ft to allow for 1 foot of freeboard above the spillway bottom. Access to the pond and outlet can be achieved by entering the pond from parking lot and driving along the pond bottom. The detention pond will have no water quality controls except for the grass surface which will provide filtration for the basin runoff flows. Three bioretention ponds, labeled LID Pond 1, 2, and 3, were designed to capture and treat the sites required WQCV. The WQCV is a total of 5,073 cf. All three LID Ponds have a depth of 1 foot. An overflow weir was designed for both LID Ponds 2 and 3 to discharge into the detention pond at the peak 100-year runoff rates that enter the ponds. LID Pond 1 and 2 will be connect by a culvert. The LID pond bottoms square footage have been sized so the ponds volume is equal to or greater than the required WQCV for the basins discharging to the ponds. The pond bottoms include 12 inches of amended soil media, 6 inches of squeegee, and a minimum of 10 inches of CDOT Type C gravel with an underdrain in the gravel section. Only the required LID area, the bottom of the ponds, will have the amended soil area. The table below outlines the water quality LID Pond details are in the Table 3 below. Only 1.04% of the sites impervious area is not captured and treated in LID Ponds and this is from the offsite basins. Table 3. Water Quality LID Pond Details Max Required Water Provided Amended % of WQCV Depth Quality LID Water Quality Soil Area treated in LID Volume LID Volume Pond ft c of sf LID Pond 1 1.00 1,216 1,238 1,238 102% LID Pond 2 1.00 557 764 764 137% LID Pond 3 1.00 3,267 3,281 3,281 100% Total 5,053 5,283 5,283 105% The underdrain pipe will have a very shallow slope and will tie into the outlet structure at a lower elevation than the outlet pipe creating a micropool in the outlet structure. The head from the higher elevations of the pond bottoms will force the underdrain to empty into the outlet structure and overflow into the outlet pipe. There should only be standing water up to the outlet pipes elevation of 5305.29 ft. Therefore, there will only be standing water in the gravel and squeegee portions of the amended soil areas of the LID Ponds, not in the amended soil media. The detention volume Housing Catalyst - Village on Horsetooth Page 12 of 19 includes the area above the overflow elevation for the LID Ponds because the LID ponds are hydraulically connected to the detention pond. HISTORIC/DEVELOPED BASIN COMPARISON The site contains one historical basin that drains to the east into the Pleasant Valley and Lake Canal. The developed site still drains primarily to the east, but instead of draining into the Canal, the runoff is collected and discharged into the Horsetooth storm sewer system. A very small portion of the site, 10.2%, drains offsite, a total of 3.77 cfs for the 100-year event. The existing site has a peak 100-year runoff rate of 28.78 cfs. As required by the City, the detention pond has a discharge rate of 2.21 cfs into the Horsetooth system, which is equivalent to the historical 2-year peak runoff rate. In the event that the detention pond outlet pipe is clogged, the pond's overflow spillway will safely convey flow onto Horsetooth at a peak rate of 44.51 cfs. The site's three LID ponds will treat 100% of the onsite required WQCV, with only 1.04% of the impervious area draining offsite. The LID ponds will have amended soils with an underdrain system to promote infiltration. STORMWATER POLLUTION PREVENTION/EROSION CONTROL TEMPORARY EROSION CONTROL A temporary erosion control plan is to be implemented for the site during construction of the proposed 10 building multi -family residential development. Temporary erosion control measures include, but are not limited to, slope and swale protection provided by the use of erosion control wattles/sediment control logs, inlet protection, vehicle tracking control at access points to the site. All temporary erosion control measures are to be removed after they are deemed unnecessary. Refer to the Erosion Control Plan and Details for the Village on Horsetooth for additional detailed information. PERMANENT EROSION CONTROL Chapter 2 of the Urban Drainage and Flood Control District's Urban Storm Drainage Criteria Manual Volume 3 (USDCM) provides guidelines for the selection of appropriate permanent ' structural BMPs for a site that is to be developed or redeveloped. The Village on Horsetooth is best characterized as a "conventional redevelopment" with over 1 acre of impervious area on the project site. The BMP decision tree for such sites is provided in Figure 2-2 of the USDCM. As ' previously stated, the site and surrounding vicinity is comprised of hydrologic soil group Type B soils, per the NRCS soil survey, with a depth to bedrock of greater than 5 feet. The existing percent vegetative density for the property is approximately 75%. The rainfall erodibility is K=0.28 for ' Type B soil and will cause rilling and gulling over longer distances and steeper slopes. Perimeter control will be the primary means of minimizing the extent of gulling. The site is located in the Foothills Stormwater Basin. The Foothill basin drains west to east through open channels and storm sewer that ultimately discharges into the Fossil Creek Reservoir Inlet Ditch. There are no irrigation canals passing through the site; however, the Pleasant Valley and Lake Canal flows south to the east of the site. No stormwater will be permitted to discharge into the canal. An earthen berm adjacent to the canal and to the east of the proposed detention pond will prevent onsite developed runoff from entering the canal, see grading plans. The drainage from Housing Catalyst - Village on Horsetooth ' Page 13 of 19 the detention pond will discharge to the City storm sewer system located on the south side of Horsetooth Road. Permanent erosion control measures include, but are not limited to, the constructed detention ponds, riprap pads placed for culvert and flared end section outlet protection, seeding and mulch placed to enable and established vegetative growth, etc. Long-term maintenance of these erosion control measures shall be the responsibility of the owner of the property. A general erosion control plan has been provided in the utility plans on sheet CE1.0. An erosion control escrow calculation is provided in Appendix D. STORMWATER MANAGEMENT CONTROLS The Stormwater Management Plan (SWMP) administrator is to be determined. According to the CDPHE Stormwater Fact Sheet — Construction, construction activities produce many different kinds of pollutants which may cause stormwater contamination problems. The main pollutant of concern at construction sites is sediment. Grading activities remove grass, rocks, pavement, and other protective ground covers, resulting in the exposure of underlying soil to the elements. The soil is then easily picked up by wind and/or washed away by rain or snowmelt. In addition, construction activities often require the use of toxic or hazardous materials such as fuel, fertilizers, pesticides, and herbicides, and building materials such as asphalt, sealants, and concrete, which may also pollute stormwater. These materials can be harmful to humans, plants, and aquatic life. Other pollution sources that could be present include: runoff from vehicle washing, vehicle maintenance and/or fueling, There are no known existing non-stormwater components of discharge (i.e., springs, landscape irrigation return flow, etc.), or any anticipated during construction. All Disturbed and Stored Soil: The total disturbed area will be approximately 8.3 acres. Soil stockpiles should be kept below the locally mandated maximum height of 10 feet and surrounded with sediment control devices. If the storage of these soils occurs over a period greater than 30 days, then consider temporarily seeding the soil to minimize soil loss to wind and water erosion. No phasing of grading activities is proposed. Silt fence around the perimeter of the property with prevent sediment and disturbed soils from being carried offsite. Inlet protection will be used on all inlets to prevent sediment and debris from entering the storm drain system. 2. Vehicle Tracking of Sediments: The majority of the existing site is unpaved. A temporary stabilized stone pad (Vehicle Tracking Control pad, VTC) will be provided at points of ingress and egress onto the unpaved area. The VTC is designed to reduce the amount of mud transported onto the roads by construction traffic. If the site is extraordinarily muddy, then consider designating an area to wash construction vehicles before they leave the site and enter the public right-of-way. A BMP such as this is a good way to avoid the costs associated Housing Catalyst - Village on Horsetooth Page 14 of 19 with street cleaning or accidentally discharging large amounts of sediment into other storm drain systems. Street sweeping will be conducted as necessary to remove sediment tracked on to pavement and adjacent streets. When in doubt, choose methods that prevent pollution rather than ones that force clean-up at the downstream end just before the stormwater enters the receiving waters. In other words, the most efficient construction site BMPs are those that prevent erosion from happening. 3. Management of Contaminated Soils: There are no known contaminated soils on site. If contaminated soils are found, the contractor shall report to the SWMP administrator and engineer to determine appropriate removal and/or mitigation measures. 4. Loading and Unloading Operations: Loading/unloading activities that may result in sediment tracking or spills will occur within the paved area of the site or a temporary gravel staging area will be provided in the area shown on the plans. ' 5. Outdoor Storage Activities: Materials storage and waste disposal will occur within a contained and secure area with the use of berms and silt fence around the storage areas and dumpsters for waste ' disposal. Coordinate location with SWMP administrator. 6. Vehicle and Equipment Maintenance and Fueling: ' Materials should be stored and handled in covered areas to prevent contact with stormwater, and chemicals should be stored within berms or secondary containment devices to prevent leaks and spills from entering stormwater runoff. 1 Spill Mana eg ment ' In general, the spill prevention and response plan must be kept on site at all times during construction and should include the following: ' a) Notification procedures to be used in the event of an accident. At the very least, the SWMP Administrator should be notified. Depending on the nature of the spill and the material involved, the Colorado Department of Health, ' downstream water users, or other agencies may also need to be notified. b) Instructions for clean-up procedures. c) Provisions for absorbents are to be made available for use in fuel areas, and ' for containers to be available for used absorbents. d) Procedures for properly washing out concrete trucks and other equipment in a manner and location so that the materials and wash water cannot discharge ' from the site and never into a storm drain system or stream. 1 Housing Catalyst - Village on Horsetooth ' Page 15 of 19 7. Significant Dust or Particulate Generating Processes: Disturbed areas not yet ready to be seeded, landscaped, paved, or otherwise stabilized shall be watered, or ripped as necessary to preclude visible dust emissions. Contractor shall make every effort to minimize particulate emissions and dust generation from vehicles performing the work (including but not limited to regular maintenance of construction equipment). Contractor to follow local and state dust ordinances at all times. 8. Routine Maintenance Activates Involving Fertilizer, Pesticides, Detergents, Fuels, Solvents, Oils, Etc: .Materials should be stored and handled in covered areas to prevent contact with stormwater, and chemicals should be stored within berms or secondary containment devices to prevent leaks and spills from entering stormwater runoff. 9. On -site Waste Management Practices (Waste Piles, Liquid Wastes, Dumpsters, etc): Materials storage, waste disposal, and vehicle maintenance and fueling can occur within an enclosed and secure area. The area can be enclosed with temporary fencing and accessed through a gate with a lock. 10. Concrete Truck/Equipment Washing: A concrete washout facility will be provided onsite. Properly wash out concrete trucks and other equipment in a manner and location (a minimum of 50 feet away from any inlet structures) so that the materials and wash water cannot discharge from the site, and never into a storm drain system or stream. 11. Dedicated Asphalt and Concrete Batch Plants: There will be no dedicated batch plant on site. 12. Non -industrial Waste Source Such as Workers Trash And Portable Toilets: Garbage cans shall be located at break areas and portable toilets shall be provided if onsite bathroom facilities cannot be used. Locate dumpsters and portable toilets away from drainage courses (minimum 50 feet from any inlet structures) and stake down toilets to prevent tipping. 13. Other Areas or Procedures where Potential Spills can Occur: Records of spills, leaks, or overflows that result in the discharge of pollutants must be documented and maintained. Record all spills that are responded to, even if they do not result in a discharge of pollutants. 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 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. More guidance is available on the web at www.colorado.gov. - The Division's toll -free 24-hour number for environmental hazards and chemical spills and releases is 1-877-518-5608. Housing Catalyst - Village on Horsetooth Page 16 of 19 ' SEQUENCE OF CONSTRUCTION ACTIVITIES Construction Start Date (This is the day you expect to begin disturbing soils, including grubbing, stockpiling, excavating, demolition, and grading activities): January 2017 Final Stabilization Date (this is when the site is finally stabilized. This means that all disturbed areas have been either built on, paved, or a uniform vegetative cover reaching over 70% of the initial vegetative density has been established.) Even if you are doing one part of the project, the estimated completion date must be for the overall project: June 2018 Construction Sequencing: (Detailed construction sequencing to be determined by the contractor) 1. Installation of temporary erosion and sediment control measures. This includes all sediment control logs, silt fencing, vehicle tracking pad, and inlet protection where land disturbing activities will occur. Implementations of individual BMPs is to coincide with construction to minimize the exposure of unprotected areas. Inlet protection will be installed as the storm sewers are constructed. Structural BMPs that do not become part of the permanent stormwater management plan are to be removed as the paving, landscaping, and other permanent groundcover installations are completed. 2. Sequence of all land disturbing activity. Overlot grading in preparation for pouring of new sidewalks and building foundations will occur early in the construction schedule. Additional land disturbance will occur around the site for utility installation and the construction of the new driveway approach and sidewalk. 3. Drainage facility construction. Construction of the detention pond, storm inlets and piping will occur early in the schedule. 4. Sediment basins, temporary channel stabilization. Sediment control logs or erosion control blankets will be installed on the banks of the vegetated detention pond and swale on the east side of the site. 5. Seedina All disturbed areas will be seeded upon completing of finish grading. Soil amendment will be required for the LID basin water quality treatment areas, see utility plans. Refer to the landscape plans for detailed planting and seeding schedule. Temporary seed mix to be as follows: SPECIES COMMON NAME VARIETY LBS/ACRE AGROPYRON SMITHI WESTERN WHEATGRASS ARRIBA 8.0 ARRHENATHERUM ELATES TALL OATGRASS 3.0 LOLIUM PERENNE PERENNIAL RYEGRASS PENNFINE 2.0 6. Mulchine Spread straw mulch uniformly over seeded areas at a rate of 90 lbs per 1000 square feet of ground. No more than 25% of the ground should be visible. Crimp or pinch mulch into soil 2-4 inches by using either a mulch anchoring tool, a farm disk operating on the contour of the slope, or by cleating with bulldozer tracks operating up and down the slopes (to prevent tracks from forming gullies). 7. Required maintenance activities (e.g. after -storm checks of all BMPs. etc.). All temporary sediment control BMPs shall be inspected after each rain event to ensure proper protection and to determine if cleaning is necessary. Final cleaning of all storm facilities shall be provided upon final stabilization of site. Housing Catalyst - Village on Horsetooth Page 17 of 19 CONCLUSIONS The goal of the Drainage and Erosion Control Report for the Housing Catalyst Village on Horsetooth is to describe appropriate controls and measures to improve water quality by reducing pollutants in stormwater discharges and ensure compliance with the requirements of the City of Fort Collins Erosion Control and Stormwater Standards and the UDFCD. The proposed drainage system presented in this report is designed to convey the 100-year peak stormwater runoff through the site to the proposed detention pond. Through calculations and review of the proposed storm drain system, there appears to be adequate capacity to convey the proposed flows. This report also proposes best management practices for erosion control, permanent landscaping, riprap, and on -site construction facilities. The proposed permanent structural BMP's on site, including the vegetated swales, water quality LID basins, and detention areas, capture the majority of the runoff discharged from the site and improve storm water quality by facilitating sedimentation and filtering while limiting erosion through slowed -release of runoff. Temporary BMP's to be employed during the construction of the proposed improvements include silt fence, sediment control logs, and rock socks at the downstream limits of disturbance, slope protection on the vegetated swales and LID basins, a concrete washout facility on site, street sweeping practices to eliminate tracked sediment, and construction of a temporary sedimentation basin in the proposed detention basin. These measures, along with the other standard Best Management Practices described in this report, will serve to reduce pollutants in the storm water runoff and satisfy the requirements of the City of Fort Collins Erosion Control Standards. It can therefore be concluded that development of the detention pond complies with all of the stormwater jurisdictional criteria and will not adversely affect the existing streets, storm drain system and/or detention/water quality facilities. Housing Catalyst - Village on Horsetooth Page 18 of 19 REFERENCES 1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood Control District, June 2001, January 2016. 2. City of Fort Collins Stormwater Criteria Manual, City of Fort Collins, December 2013. 3. "Geotechnical Investigation FCHA Village At Horsetooth 1506 West Horsetooth Road Fort Collins, Colorado', CTL Thompson Incorporated, Dated July 19, 2016. 4. City of Fort Collins Foothills Basin Master Plan, Retrieved from http://www.fcgov.com/ utilities/what-we-do/stormwater/drainage-basins/foothills-basin on August 8, 2016. Housing Catalyst - Village on Horsetooth Page 3 of 19 ' APPENDIX A - FIGURES W. DRAKE RD o � J J L~L Q H f6 ~ w W � � � W 2 L PROJECT J1 W. HORSETOOTH RD VILLAGE ON HORSETOOTH VICINITY MAP SCILLE: 1'=11M, 25 Old Town Square Suite 200 Fort Collins, CO 80520 Phone: 9702259099 Fan: 970:225:6963 APPENDIX B - HYDRAULIC/HYDROLOGIC ' COMPUTATIONS JVA Incorporated JVA Office: 25 Old Town Square, S 200 Fort Collins Fort Collins, CO 80524 Ph: (970) 225 9099 ' Version 2016 XT: 6/30/2016 Project Information: Job Name: VifteOnlHorsstoolll Job Number: 2595e Date: 5/8/2017 Designed by: LA Municipality: Forl G47iins, Soil Type: 8 Runoff Calculations: Minor Design Storm: 10 year Major Design Storm: 100 year Detention Calculations: Minor Storm Detention: 10 year plus 0 % WQCV Major Storm Detention: 100 year plus 0 % WQCV Detention Volume by: 55ac FAA>5ac FAA+20% Enter WQCV: 1,2116 Cf (GB, PR PLD, SFB. EDB,etc.) Allowable Release Rates (if applicable): Max release rate 1 cfs / acre? No Site Area: 7 96 acres Enter Offsite flows to bypass site (these will be added to the allowable release rates) Q10 = 0.00 cfs (bypass flows) I Q10allow = 2.21 cfs Q100 = 0.00 cfs (bypass flows) Q100allow = 2.21 cfs Rainfall Data Information: Enter City, Town, or County: Fort —Collins Frequency of Design Event One Hour Point Rainfall P1 2 yr 082 in 5 yr 1.14 in 10 yr 1.40 in 100 2.86 in Runoff Coefficient Calculations: Use UDFCD Equations? Yes Intensity Duration Values: I-D-F FortCollinslDF Do you need to Calc P1? H9m 2595c - Rational Calculations 2152017.xlsx INTRO Page 1 of 20 JVA Incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 Job Name: Village On Horsetooth Job Number: 2595c Date: 5/8/17 By: LAT Village On Horsetooth Historic Runoff Coefficient & Time of Concentration Calculations Location: FortCollins Minor Design Storm: 10 Major Design Storm: 100 Soil Type: B 2' "" 2 ,, I /° (°) Runoff Coeffs Initial Overland Time (t) Travel Time (t,) t,=Length/(Velocity tc Comp tc Urbanized Check t° x 60) ON Final Basin Design Pavad Adrives/co Aroof A gravel A plygnd A art. turf Aiscape (B Aiscape ATotal ATotal ImP u;;:rr Slope t ' Len th 9 Sloe P VeloL)lty]Time of Totalt - L/180 +g c ( )Name Point streets nc (sf) (sf) (sf) (sf) (sf) soil) (CID soil) (sf) (Tot (%) C2 CS C10 C100 ,, ., (min) ftl °,oJType of Land Surface K (fpConc Length 10 (min.) Min (sf) (sf) (sf) I t' + ti = tc (ft) t° S:,O 8,896 1 346,561 7.96 1 16.0% 1 0.14 0.15 0.25 0.53 ''_' 35.5 43 0.8% Paved areas 8 shallow 20 1.8 1.3 36.9 643 13.6 is paved swales I TOTAL SITE 117,418 I 530 I 8,896 161,172 I 0 I 0 1258,5451 0 1346,5611 7.96 1 16.0% 10.14 10.15 10.25 I 0.53 I Runoff Coeffs Rainfall Intensities in/hr Area Flow Rates (cfs) Time of Basin Design Name Point Conc C2 C5 C10 C100 2 5 10 100 A (sf)[Aotall02 05 010 0100 (tc)rotal )c H1 1 13.6 1 0.14 1 0.15 1 0.25 1 0.53 1.94 1 0.00 1 3.33 1 6.79 346,561 7.96 2.21 0.00 6.75 28.78 TOTAL SITE 346,561 7.96 2.21 0.00 6.75 28.78 I' 2595c - Rational Calculations 2152017.xlsx Historic Page 2 of 20 JVA incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 Village On Horsetooth Composite Runoff Coefficient Calculations Location: Fort Collins Minor Design Storm: 10 Major Design Storm: 100 Sal Type: B Job Name: Village On Horsetooth Job Number: 2595c Date: 518l17 By: LAT c v.l,,. -1a w-i r- l mccnrne rn.ma. s Basin Desl n Dale I 25% 2% 2% 1 (%) Runoff Co(. fs Basin Name Design Po1m A°°" .!nW. (an Aanvw` one can A,Asr., can (9f) • M,na (a() Aen.lun (5f) ^l.rapv le ` Aftosse , . l) Arow can Armor (8c) I% ( ) C2 C5 C10 ciao Al 1 16,105 111,490 18,856 45,451 1.04 57,0% 0.51 0.53 0.59 0.73 A2 2 6,271 4,876 293 11, 315 22.755 0.52 j 48.4% 0.43 0.45 0.52 0.89 A:i 3 15.483 9,296 7859 32,638 0.75 73.6% 0.65 0.68 0.72 0.81 A4 4 _ 4,630 4,630 0.11 2.0% 0.02 0.02 0.14 0.46 A5 5 503 503 0.01 2.0% 0.02 0.02 0.14 0.46 >� 6 5.296 4,089 1.813 11,197 0.26 80.5% 0.72 0.75 0.78 0.85 7 989 989 0.02 2.0% 0.02 0.02 0.14 0.46 - N 700 312 4,064 5,076 0.12 16.5% 0.15 0.15 0.26 0.53 9 858 650 2.777 31,128 41.413 0.96 18.7% 0.17 0.17 0.28 0.55 10 14I 3.439 3.586 0.08 5.6% 0.05 0.05 0.17 OAS All 11 309 2402 2,711 0.06 6.3% 0.06 0.06 0.18 0.49 Al2 IZ l3r, 1, 175 1,610 0.04 25.8% 0.23 0.24 0.33 0.58 A13 13 821 821 0.02 2.0% 0.02 0.02 0.14 0.46 A14 1.1 11153 -. 39,634 0,91 62.9% 0,56 0.58 0.63 0.76 A15 1S 111 SIBS 1,596 0.04 29.6% 0,26 0.28 0.36 060 A16 lc I959 2tl-79 35,065 0.80 10.5% 0.09 1 0.10 0.21 0.51 61 '- 666 1,56' 14,66D 0.34 16.6% OAS 0.15 0.26 0.54 82 n'. 'nJ 13.720 0.31 2.0% 0.02 0.02 0.14 0.46 R3 la a.. !14 6,077 0.14 14.5% 0,13 0.13 1 0.24 0.53 134 2n 1, 101 1,101 0.03 2.0% 0,02 0.02 0.14 0.46 Rt 21 7.2H9 7,289 0.17 90.0% 0.80 0.84 0.85 0.90 R2 22 4, 969 4,569 0.10 90.0% 0.80 0.84 0.85 0.90 R3 23 7451 7,451 0.17 90.0% 0.80 0.84 0.85 0.90 R4 24 4,929 4,929 0.11 90.0% 0.80 0.84 0.85 0.90 R5 25 10HO 3,080 0.07 90.0% 0.80 0.84 0.85 0.90 P6 26 -a9 4.549 0.10 90.0% 0.80 0.84 0.85 0.90 27 ';8 7,288 0.77 90.0% 0.80 0.84 0.85 0.90 28 �':l 7,451 0.17 90.0% 0.80 0.84 0.85 0.90 2595c - Rational Calculations 2152017.xlsx Developed C Page 3 of 20 JVA Incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 Village On Horsetooth Composite Runoff Coefficient Calculations Location: Fan Collin Minor Design Storm: 10 Major Design Storm: 100 Soil Type: B Job Name: Village On Horsetooth Job Number. 2595c Data 5l8/17 By LAT C Value ralculatea from DDFMCM Choirs, 6 Basin Desirin Data I (v/o)= ww%' 9W" 9901% 2591 25% 2% i(5„I Runoff Coeffs 'gave0 'tlnv,wc A, A� Anl Wie Aen. yn `�eraVe to ,12% A,- AT.. AT.. ImP Basin Name Design Point slraale (6f) one (all (9f) (Sf) (5f) (af) sell (Cl)(sd9 (91) (so) (%) C2 CS C10 C100 (at) (6f) Irp ... ,.. 7,268 0.17 90.0% 0.80 0.84 0.85 0.90 7,471 0.17 90.0% 0.80 0.84 0.85 0.90 Total She 60,983 50,091 61,325 5,189 2,777 0 166,193 0 346,558 7.96 48.3% 0.43 0.45 0.52 0.69 Total To LID Pond 1 16,105 10,490 14,739 0 0 0 18,856 0 60,190 1.38 65,1% 0.58 0.61 0.65 0.77 (Al, Re, R10) Total To LID Pond 2 6.271 41876 7,451 293 0 0 11,315 0 30.206 0.69 58.6% 0.52 0.55 0.60 0.74 (A2, Re) Total To LID Pond 3 (A3, A4, A5, A6, A7, A8, All, A70, All, Al2, A13, A14, 37,941 30,336 39.135 1.271 2.777 0 74.079 0 185,539 4.26 55.6% 0.49 0.52 0,58 0.73 At 5, R7, R2, R3, R4, R5, R6, R7 Total Of he 888 2,g30 0 294 0 0 32.168 0 35,558 0.82 10.2% 0.09 0.09 021 0.50 (81, 82, 83, 84) Total to Pond 80,317 47,861 81,325 4,896 2,777 0 134,025 0 311,000 7.14 52.6% 0.47 0.49 0.55 0.71 (All A and All R) Total for WOCV Calm 80,317 45,702 61,325 1,564 2,777 0 104.250 1 0 1 275,935 6.33 1 58.0% 1 0.52 1 0.54 0.59 0.74 Al-A15 and All R 8 Basin SITE Area of Total Total Area %Imllary (�) Impery Area 112 II2 10.2% 35,558 3,614 U6 558 1."% of Total Site Impervious Area not being detain. B Basin Area of Impervious I Total Site Area 98.96% of Total Sites Impervious Area being detained. 10.3% Total Site Area not being sent to Detention Pond. B Basin Area I Total Site Area 2595c - Rational Calculations 2152017 Ass Developed C Page 4 of 20 �� JVA Incorporated III\\/!//N 2501d Town square. S 20 tJ\`'"'Jl`III h97UCO 524P(0)5 099 Village On Horsetooth Time of Concentration Calculations Lpceuon Port C.11,ns Minor Design Storm: 10 Major Design Storm: f00 Soil Type. a Job Name: Valli On Haraetooth Job Number 25950 Del.: 5I8117 By. LAT Sub-Baeb Data In10al Overland Time (4) Traval Tone (4) Ik Comp to Urbanhed Ched 4 4=Length/lVebciyx0) ON Final Time at Tobl amity Deaign Arm C5 •,.. Smp. L La.ngln Slope vvI TyF. al Land Surface Q Vebtlty 4 Cone Length 4=(U180N Min Name Point (c) r^V1^ 1x,1 (min) tin Rp.) (Min) 10 (.in) 4+4=4 16) 4 Al t IN 0.0 66 2 2% 6.5 380 1 3% Paved amps 3 sn.0ow 0 23 2.8 9.3 446 12.6 9.3 Paved swalas A2 2 0.52 0.45 116 1 A 5 1 a% Pevad areas 6 mallow 20 2.4 1.0 12.6 275 11.5 11 S aved ,,wales A3 3 0.76 0.68 4.0 220 11% Pevad areas 3 snauow 0 21 17 5.7 265 11.5 57 aved swalas A4 4 0.11 002 8.3 46 1.9% Grassed amrvn, y 16 2.1 0.4 9.7 91 10.5 6] A5 5 0.01 0.02 ,. 5.9 31 1 0% Greased watanvey 15 L8 0.4 6.2 43 10.2 6.2 All B 0.26 0.75 0911, 7.1 90 0.8% Pevad aro.. 6 mi llow 0 1.7 OS 8.0 198 11.1 8.0 nd sw.les A] ] 0.02 0.02 39 as 10% Grassed wato., 15 I'S 0.7 66 72 10.4 5.0 A6 8 0.12 0.15 - � Zt n; t0% Pevad arena 5.hallnw 20 2.0 0.6 ].] 112 10.6 ]] even awalne A9 9 0.95 017 _. 9.0 125 2.0% Grassed webmay 15 2.1 10 100 170 10.9 10.0 A1O 10 ON 005 6.5 102 10% GA..d..in., 15 is 1_1 76 117 10.9 76 All 11 ON 0,06 2.0 67 12% Grassed walelwaY 15 15 OJ 27 72 10.4 50 Al2 12 0." 1 J 6.0 Grossed wame ' is 0.0 0.0 60 31 10.2 6.0 A13 13 0.02 0.02 1 6.5 Grassed vvme .y 16 1.2 1M 7.6 84 10.5 7.6 A14 14 0.91 0.58 .11 '^ 4.6 Pnvud tunas 5 0illnw vad.w,nlos 20 2.8 1.3 6a 261 115 5.8 AIS 15 0.04 0,28 4.2 61f 08x:, Grassed w.lerway 15 1.3 1.1 s3 105 10.6 5.3 A16 16 DAD 0.10 7.2 381 0 ]% Grassnd waterway 15 1.2 5.2 124 40 12.4 12.4 Bt iT 1 0.15 3: % r 5,0 139 115% Grassnd wm ., 15 1.0 2.3 7.3 170 10.9 7.3 82 18 0.31 0.02 .1 3.9 Grassed walnmay 15 0.0 0.0 39 24 10.1 5.0 63 19 0.14 0.13 54 .123 1511, Grassed wal.m 16 1.8 20 74 243 114 A4 54 20 0.03 0.02 3.9 Grassed wabroay 15 0.0 0.0 39 10 10.1 5.0 R1 21 0.17 Mad 3.2 Paved uMm 5 anminw 0 0.0 0.0 3.2 70 10.4 5.0 aved ,,.alma R2 22 0.10 064 - 3.2 Pawn aroas 5 ,,nand. 20 0.0 00 3.2 70 10.4 5'0 ay.c swalas R3 23 0.17 0.84 3.6 Pa-d amas S sh.allnw 0 0.0 0.9 3A 0 10.5 5.0 • o.o'd swabs R4 24 0.11 0.84 12 Paved amas 5 shallow 20 0.0 00 3.2 70 10.4 &0 a.reh ,,vase RS 26 0.07 0.84 2 ] Paved areas 5 Sn.11ow 20 00 0.0 2.7 50 10.3 5.0 avetl swnb•x R6 26 DAD 084 3.6 paved ernes x -:now+w n,i•. 20 0.0 0.0 3.6 90 10.5 5.0 R] 27 0.17 O.84 • 3.0 Pavcr 20 0.0 0.0 3.0 80 10.3 50 Ra 28 0.17 0.m 3.0 Paven .v c.,... 0 0.0 0.0 3.0 0 10.3 so ad + R9 29 0.17 084 30 Pavedalnas 1' 20 0.0 0.0 30 0 10.3 50 avedawah:. R10 0 0.17 O54 30 Paved areas 5 snan° w I 0 0.0 0.0 3.0 0 10.3 50 aved swalas 2595c - Rational Calculallons 2152017.xlsx Developed Te Page 5 of 20 11-4 ! ©. ! f!!! § ! ; : !!! , .........;;..�! `;;�.1�.�|�� ® :!�§!•!l;,,,tf=:;:| *. � � l�;�■;�#°��- •` ! ! w�� !!E ■! !! �!!!!�!!!�`!! ! ®� ; ,.. ., �I�III�IIIIIII�INII Ili!li��illillll�l -N1 �IilYillll�l l I � ilia �� Mill IIIII i10 illlil0iili01illYi 91BIIII�N�11�1911191�N11 a C Oeap Pam RR. RCaen e J a $ y j: a 8 + cnlaal w s s w i S N J D+ N w � f r w g a� 0 o Ei o $ $ $ m u Y = $ $ e $ u' $ ❑fcfal IM Type It - - _ Pipe Sizs W - - A Pipe MM.I Skye(%I Y Ppe Mw - - crag Mav Pipe aoa�ay (zeal t-aetn IR1 s E g m C o nlm�nl m Wal Time ml Li ME 11111 �B@ no so 11 I� 1111111111 I�111 I��1� I�I�� 1911 ■1191111�1111■�91111 E JVA Incorporated Job Name: Village On Homatcoth 25 Old Town Square, S 200 Jab Number 2595c Fort Collins, CO 80524 Date: 518/2017 Ph (970) 225 9099 By: LAT 0 Village On Horsetooth LID Water Quality Capture Volume (WQCV) Calculations (UDFCD Volume 3 Chapter 3) Location: Fort Collin Major Design Storm: 100 Soil Type: B WQCV=a((0.9113).(1.1912)*(0.781)) Where: WQCV = Water Quality Capture Volume (watershed inches) a = Drain Time Coefficient (see table below) I . Imperviousness (%/100) Drainage Time (hm) Coefficient, a 12 0.8 24 0.9 40 1.00 Rain Garden=12hours The on site required WQCV was split into 3 areas depending on which LID Pond the area was directed to. The Detention Pond Basin, Basin At 7. WQCV will be treated by grass filtration. The total required WQCV is the sum total of the three LID Ponds WQCV. LID POND 1 LID POND 2 LID POND 3 a= 0.80 a= 0.80 a= 0.80 1= 0.651 %/100 1= 0.586 %/100 1= 0.556 %/100 WQCV= 0.202 watershed Inches WQCV= 0.184 watershed Inches WQCV= 0.177 watershed inches V„d,,.-i=1.2'(WQCVn2)'A'43560 V„a,,,., -1.2'(WQCV/12)'A'43560 V,„,,,, 1.2•(WQCV/12)-A'43560 WQCV= 0.202 watershed Inches WGCV= 0.184 watershed inches WQCV= 0.177 watershed inches A = 1.38 acre A = 0.69 acre A = 4.26 acre V,.nu,nd = 1216 cf V„d,,. = 556 cf V,a„ „ed = 32B1 cf V,,,,,,,,,, = 0.028 acre -It V„ ,.w = 0.013 acre-ft 0.075 acre-0 Required WQCV for the Shaw 5053 of 11 II II II JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number 2595c Fort Collins, CO 80524 Date: 5/8/2017 Ph: (970) 225 9099 By: LAT 0 Village On Horsetooth LID Area and WQCV Design Calculations (UDFCD Volume 3 Chapter 4) Location'. For Collins Soil Type: u LID Pond 1 LID Pond 2 Required WQCV= 1,216 of Required WQCV= 556 cf Bottom Area= 1,238 sf Bottom Area= 764 sf Total Height of LID= 1.00 8 Total Height of LID= 1.0 it 'Provided Volume (H-A)= 1,238 of 'Provided Volume (H-A)= 764 of Area of Amended Soil= 1,238 sf Area of Amended Sell= 764 sf % Treated= 102% % Treated= 137% LID Pond 3 Required WQCV= 3,281 of Bottom Area= 3,281 sf Total Height of LID= 1.00 0 'Provided Volume (H-A)= 3,281 or Area of Amended Soil= 3.281 sf %Treated= 100% Provided volume only includes area above ameneded soil not entire pond volume at depth of pond Total WO Volume Required to be Treated by LID= 5.053 of (Entire Site WQCV includes detention pond which doesn't have WO Treatment) Total Volume Treated by LID Ponds= 5,283 of I LID1+LID2,LID3 Amended Soil Pond Volumes) On -Site Developed Area Treated by LID= 105% (Required 75% of WQCV to be Treated by LID) JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number: 2595c Fort Collins, CO 80524 Date: 518117 Ph: (970) 225 9099 By: LAT Village On Horsetooth Detention Pond Volume Calculations: FAA Procedure Based on FAA Procedure, par Federal Avialion Agency'Amon Drainage Manual Drainage Basin n Design Storm 10 year Composite "C" Factor 0.55 Time of Concentration Tc 1240 min (Max Tc) Basin Size 7.14 acre Release Rate Calculations Allowable Release Rate for Site 2 21 cfs (Historic Flows for Basin HI) Less Undetained OHsite Flows 0 00 cfs Allowable Release Rate for Pond 2.21 cfs Rainfall Intensity Calculations Point Hour Rainfall (P,) : 1.40 Cl= 28.5 Rainfall Intensity: FortCollinslDF C2= 10 1= C,'P,/(Cr+Ta)eCr C3= 0.789 Volume calculations Inflow Volume = C ' I ' A' time (sec) Outflow Volume = Alowable Release Rate time (sec) Storage Volume = Inflow Volume - Outflow Volume Detention Storage Calculations Time t (min) Intensity I (in/hr) now Vin (ft) Outflow Adjustment Factor in Average Outflow (cts) u ow VDut (ftaj orage Vstor (ft) 5.0 4.87 5,752 1.00 2.21 662 5,090 10.0 3.78 8,929 1.00 2.21 1,324 7,606 15.0 3.19 11,304 0.91 2.01 1,813 9,490 20.0 2.74 12,945 0.81 1.79 2.144 10.801 25.0 2.44 14410 0.75 1.65 2.475 11,935 30.0 2.21 15,662 0.71 1.56 2,806 12,856 35.0 2.00 16,569 0.68 1.49 3,137 13.432 40.0 1.83 17,320 0.66 1.44 3,468 13,852 45.0 1.69 17,997 0.64 1.41 3,799 14.198 50.0 1.58 18,6B6 0.62 1.38 4.130 14,556 55.0 1.48 19,255 0.61 1.35 14,794 60.0 1.40 19.843 0.60 1.33 15,052 65.0 1.32 20,314 0.60 1.31 15,192 70.0 1.26 20,791 0.59 1.30 15.337 75.0 1.20 21 235 0.58 1.29 15,451 80.0 1.15. 21,652 0.58 1.27 k77"70 15,537 85.0 1.10 22,045 0.57 1.26 15,598 90.0 1.05 22,415 0.57 1.25 15,639 95.0 1.01 22,767 0.57 1.25 15659 100.0 0.98 23,102 0.56 1.24 15.663 105.0 0.94 23,421 0.56 1.23 15,651 110.0 0.91 23,726 0.56 1.23 8,101 15,625 115.0 0.88 24,018 0.55 1.22 8.431 15,587 120.0 0.86 24,299 0.55 1.22 8762 15,536 125.0 0.83 24,569 0.55 1.21 9,093 15,475 130.0 0.81 24,829 0.55 121 9.424 15,405 135.0 0.79 25,080 0.55 1.20 9,755 15,324 140.0 0.77 25,322 0.54 1.20 10,086 15,236 145.0 0.75 25.557 0.54 1.20 10.417 15,140 150.0 0.73 25,794 0.54 1.19 10,748 15,036 155.0 0.71 26.004 0.54 1.19 11.079 14,925 160.0 0.69 26.218 0.54 1.19 11.410 14,808 165.0 0.68 26426 0.54 1.19 11,741 14,686 170.0 0.66 26,628 0.54 1.18 12,071 14,557 175.0 0.65 26,825 0.54 1.18 12,402 14,423 180.0 0.64 27,017 0.53 Intensity Equation 112,733 14,284 Max from FoCo CM Maximum Volume (R 15,663 0% WOCV 0 to Required 10Yr Volume 15,663 ft3 2595c - Radonal Calculations 2152017.xlsx Modified FAA-10-yr Page 12 of 20 JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, 5 200 Job Number: 2595c Fort Collins, CO 80524 Date: 518117 Ph: (970)225 9099 By: LAT Village On Horsetooth Detention Pond Volume Calculations: FAA Procedure eased an FAA Pmpedure, par Federal Avieeen Aaenq'Anpprl Drainage' Manual Drainage Basin A Design Storm 100 year Composite "C" Factor o 71 Time of Concentration Tc i 2 ao min (Max Tc) Basin Size 7 14 acre Release Rate Calculations Allowable Release Rate for Site 2 21 ds (Historic Flows for Basin H1) Less Undetalned Oflade Flows 000 cis Allowable Release Rate for Pond 2.21 cis Rainfall Intensity Calculations Point Hour Rainfall (Pi) : 2.86 C1= 28.5 Rainfall Intensity: FortColllnsIDF C2= 10 1= C1"P1/(C2*T0)AC3 C3= 0.789 Volume Calculations Inflow Volume = C " I • A " time (sec) Outflow Volume = Alowable Release Rate "time (sec) Storage Volume = Inflow Volume - Outflow Volume Detention Storage Calculations Time I (min) Intensity I (in/hr) Inflow Vln (ft') Outflow Adjustment Factorm Average Outflow (cfs) Ourflow Volt (it') Storage Valor (it) 5.0 9.95 15,173 1.00 2.21 662 14,512 10.0 7.72 23.545 1.00 2.21 1,324 22,222 15.0 6.52 29,828 0.91 2.01 1813 28.015 20.0 5.60 34,159 0.81 1.79 2,144 32,015 25.0 4.98 37,972 0.75 1.65 2,475 35,497 30.0 4.52 41,357 0.71 1.56 2.806 38.551 35.0 4.09 43,638 0.68 1.49 3,137 40,501 40.0 3.75 45,700 0.66 1.44 3,468 42,232 45.0 3.47 47,556 0.64 1.41 3,799 43,757 50.0 3.23 49,317 0.62 1.38 4,130 45,168 55.0 3.03 50,894 0.61 1.35 4,461 46,434 60.0 2.86 52,337 0,60 1.33 4,792 47,545 65,0 2.70 53.579 0.60 1.31 5.122 48.456 70.0 2.57 54.835 0.59 1,30 5,453 49.382 75.0 2.45 56.008 0.58 1.29 5,784 50,224 80.0 2.34 57,108 0.58 1.27 6115 50,992 85.0 2.24 58143 0.57 1.26 6,446 51.697 90.0 2.15 1 59121 0,57 1.25 8777 52,344 95.0 2.07 60,049 0.57 1.25 7.108 52.941 100.0 2.OD 60.932 0.56 1.24 7.439 53.493 105.0 1.93 61773 0.56 1.23 7770 54,004 110.0 1.87 62,578 0.56 1.23 8,101 54.477 115.0 1.81 63,349 0.55 1.22 8 431 54.917 120.0 1.75 64.089 0.55 122 8.762 55,326 125.0 1.70 64,800 0.55 1.21 9,093 55,707 13D.0 1.65 65486 0.55 1.21 9424 56,062 135.0 1.61 66,148 0.55 1.20 9,755 56,393 140.0 1.56 fib 787 0.54 1 1.20 10,086 1 56,701 145.0 1.52 1 67,406 0.54 1.20 10,417 56.9139 150.0 149 68,005 0.54 1.19 10,748 57,257 155.0 1.45 68,586 0.54 1.19 11,079 57,508 160.0 1.42 69.151 0.54 1.19 11.410 57.741 165.0 1.39 69,699 0.54 1.19 11,741 57,959 170.0 135 70,233 0.54 1.18 12,071 58161 175.0 1.33 70,752 0.54 1.18 12,402 58,350 180.0 1.30 71,259 0.53 ntensity Equation 1.18 12,733 58,525 Max from FoCo CM Maximum Volume Ile) 58,525 0% WOCV 0 ft3 Required 100Vr Volume 56,525 it' 2595c - Rational Calculations 2152017.xlsx Modified FAA-100-yr Page 13 of 20 JVA Incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 POND VOLUME CALCULATIONS - STAGE / STORAGE Pond Volume = Prismoidal Formula Volume Equation = (Al+A2+SQRT(A1'A2rD/3 Staae / Storaae Inout Table Job Name: Village On Horsetooth Job Number: 2595c Date: 518/17 By: LAT ELEVATION R DEPTH(D) ft AREA (Al) fe WEIGHTED AVG AREA(A2) a INCREMENTAL VOLUME ft, CUMMULATIVE VOLUME W 5105.25 0 0 5105.5 0.3 60 30 5 5 5106.0 0.5 2.070 1,065 414 419 5106.5 0.5 3.940 3,005 1,478 1,896 5107.0 0.5 9.931 6,936 3,354 5251 5107.5 0.5 18,178 14,055 6,924 12175 5108.0 0.5 30.681 24,430 12,079 24,254 51085 0.5 35.881 33,281 16,624 40.878 5109.0 0.5 45.161 40,521 20,216 61,094 5109.5 0.5 60,241 52,701 26,260 87,354 5110.0 0.5 75,323 67,782 33,821 121,175 5110.5 0.5 89.411 82,367 41,133 162,308 To of Pond 5110.50 5.25 TOTALVOLUMEJ 162,308 cf 3.726 ac-R Pond Volume Summary Table Required Volume (ft) Required Volume (ac-ft) Water Surface Elevation Water Depth V10+ 0% WQCV 15.663 c1 0.360 ac-ft 5107.64 ft 2.39 ft V100 + 0% WQCV 58.525 cf 1.344 ac-ft 5108.94 ft 3.69 It Volume Interpolation Calculations V10+ 0% WQCV V100 + 0% WQCV Vol I Elev Vol I Elev 12174.92 1 5107+50 40877.64 1 5108.50 15663.10 1 5107.64 1 58525.34 1 5108.94 24254.10 1 5108.00 1 61093.72 1 5109.00 2595c - Rational Calculations 2152017.xlsx Vol Pond Page 14 of 20 5111.0 5110.5 5110.0 5109.5 5109.0 Z O Q 5108.5 W > 5108D <O LL � w 5107.5 e: — 5107.0 5108.5 5106.0 5105.5 5105.0 5104.5 0 JVA Incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 Job Name: Village On Horsetooth Job Number. 2595c Date: 518117 By LAT STAGE VS. STORAGE 20000 40.000 60,000 80,000 100,000 120.000 140.000 160.000 180.000 POND VOLUME (CF) 2595c - Rational Calculations 2152017.xlsz Vol Pond Page 15 of 20 JVA Incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 ORIFICE PLATE AT OUTLET PIPE WORKSHEET Orifice Plate using Headwater above opening and Q=cA(2gH)^.5 C= 0.65 Summary of Available Pioe Releases Pie Dia Area Head H Q Outfall Pipe at centrold avail out in so (ft) (cfs) 12 0.79 3,14 7.25 is 1.23 3.01 11.10 18 1.77 2.89 15.65 24 3.14 2.64 26.59 30 4.91 2.39 39.54 36 7.07 2.14 53.87 Q=cA(2gH)^.5 C= 0.65 Iteration process Q 2.21 cis c 0.65 H,� 3.01 ft Needed Area 0.24 sf Using Area- determine Ao 0.24 sf Apipe 1.23 sf theta 4.188 rad Ao-calced 0.24 sf Job Name: Village On Horsetooth Job Number: 2595c Date: 5/8/17 By. LAT Qm,oa allowable release rate: 2.21 cis 100-yr Water Surface Elev: 108.94 ft Inv Elev at Outlet Struct: 5105.30 ft Outlet Pipe at Structure: 15 in A. = LApiPe(2 r_ B )j+[rsin�2 J* rco2 )JI m -0.31 ft distance above(+) or below(-) center m = r cos � 2 2 H 0.31 ft Height above pipe invert H = r+ m 2595c - Rational Calculations 2152017.xlsx Major Orifice Page 1 of 1 JVA Incorporated Job Name: Village On Horsetooth 011% 25 Old Town Square, S 200 Job Number: 2595c ' ``IIME,ME `� \� \III Ph: (970) 225 099Fort Collins, CO524 D By LAT17 0 ' Village On Horsetooth Emergency Overflow Spillway Calculations ' Broad -Crested Weir Equation -Trapezoidal Shape where: Q = Discharge (cfs) Q — CLH 3 +C'� H � z C = Weir Coeffecient L = Weir Length (ft) \ V l H = Average Weir Head (ft) H.V =Side Slope ' Calculations Knowns: Side Slopes (H:V) 4.00 Desired Spillway Head 0.75 It Weir Coefficient 3.087 Spillway Elevation 5609.50 ft 100-yr Pond Inflow 44.5 cfs Calculated Spillway 19.20 ft Use Spillway Length 20.50 ft Spillway Depth 1.00 ft Top of Berm Elevation 5610.5 ft Top of Berm Length 28.50 It Berm Width 6.0 ft 2595c - Rational Calculations 2152017.xlsx Page 17 of 20 8/28/06 11 JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number: 2595c Fort Collins, CO 80524 Date: 5/8/17 Ph: (970)225 9099 By: LAT 0 Village On Horsetooth LID Pond 2 Weir Overflow Broad -Crested Weir Equation -Trapezoidal Shape / l�� -here: O = Discharge (cfs) — CLH z +C H C = Weir Coeffecient Q — V JJJ L = Weir Length (ft) H = Average Weir Head (ft) H:V =Side Slope Calculations Knowns: Side Slopes (H:V) Desired Spillway Head Weir Coefficient Spillway Elevation 100-yr Pond Inflow Calculated Spillway Use Spillway Length Spillway Depth Top of Be" Elevation Top of Berm Length Berm Width 4.00 0.75 ft 3.087 5608.00 It 11.53 cfs 2.75 It 2.75 ft 1.00 ft 5609.0 It 10.75 ft 4.0 It 11 I 11 11 1 I 1 I 11 1 I 11 11 1 I 2595c - Rational Calculations 2152017.xlsx Page 18 of 20 8/28/06 1 II I' Village On Horsetooth LID Pond 3 Weir Overflow JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number: 2595c Fort Collins, CO 80524 Date: 5/8/17 Ph: (970) 225 9099 By: LAT 0 Broad -Crested Weir Equation -Trapezoidal Shape where: Q = Discharge (cfs) CLH a t C HT a C= Weir Coeffecient Q = \ V % L = Weir Length (ft) H = Average Weir Head (ft) H:V =Side Slope Calculations Knowns: Side Slopes (H:V) 4.00 Desired Spillway Head 0.75 ft Weir Coefficient 3.087 Spillway Elevation 5607.30 ft 100-yr Pond Inflow 22.31 cfs Calculated Spillway 8.13 ft Use Spillway Length 8.50 ft Spillway Depth 1.00 ft Top of Berm Elevation 5608.3 ft Top of Berm Length 16.50 ft Berm Width 4.0 ft 2595c - Raflonal Calculations 2152017.xlsx Page 19 of 20 8/28/06 , JVA Incorporated Job Name: Village On Horsetooth � � � I,IOMMI./1M�, 25 Old Town Square, S 200 Job Number: 2595c \% \% \"1 Fort Collins, CO 524 D Ph: (970) 225 099By: 17 LAT ' 0 Village On Horsetooth ' Emergency Overflow Spillway Calculations for between Buildings 4 and 5 ' Broad -Crested Weir Equation -Trapezoidal Shape where: O = Discharge (cfs) Q - CLHz +C� H �F72 L = Weir Length L =Weir Length (ft) (ft) t V l H = Average Weir Head (ft) H:V =Side Slope Calculations t Knowns: Side Slopes (H:V) Desired Spillway Head 0.25 ft Weir Coefficient 3.087 Spillway Elevation 5610.65 ft ' 100-yr Pond Inflow 4.00 cfs Calculated Spillway 8.37 ft ' Use Spillway Length 8.50 ft Spillway Depth 0.10 It ' Top of Berm Elevation 5610.75 ft Top of Berm Length 10.10 ft Berm Width 4.0 ft 1 I 2595c - Rational Calculations 2152017.xlsx Page 20 of 20 8/28106 1 JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number: 2595c Fort Collins, CO 80524 Date: 1/16/17 Ph: (970)225 9099 By: LAT FLOW CALCULATIONS - GRATE INLET SUMP CONDITION (Reference: Urban Drainage and Flood Control District Drainage Cntena Manual, 2001, V.1, Section 3.3.6) (Note: Spreadsheet assumes orifice condition for fully developed flow.) INLET TYPE: Combination Inlet BASIN: A3 Orifice Equation: Q = Cd'Ao'(2gH)A0.5 K = Clogging Coeffieent value for multiple inlets Adjust Ao (open area) due to clogging as follows: Effective Area Opening As = (1-C) Ao, where: C=K'Co/N N = Number of Inlets Cc = Single Inlet Clogging Factor: Co(grate)= 0.5 (50% clogging) Number of inlets: Inlet Dimensions and Effective Open Area: Grate Ooenlno: Allowable depth: Constants: Flow Calculations: Grate Flow: Total Intercepted Flow with an allowable depth of N- 2 Ao(g)= 2.32 V2 Total Ao(g) = 4.64 ftA2 K = 1.50 C = K•Co/N = 0.38 Aa(g) = (I-C)Ao - 2.90 ftA2 H - 9.0 in = g = 32.20 ff/sA2 Cd = 0.67 Q = Cd' Ae(g)' (2g'H)A0.5 Qg= 13.50 CFS Required Flow (Q 10 ) = 2.51 cfs Required Flow (Q 100 ) = 5.80 cfs 2595c - Rational Calculations 01132017.xlsx Grate-Sump(UDFCD) A7 N I Grate 2 1.5 3 1.75 4 1.88 5 1.94 6 1.97 7 1.98 8 1.99 0.75 ft 2 inlet(s) and 9 inches is 13.5 cfs Bypass = 0.0 cfs Bypass = 0.0 cis Page 1 of JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number: 2595c Fort Collins, CO 80524 Date: 1 /16117 Ph: (970)225 9099 By: LAT FLOW CALCULATIONS - GRATE INLET SUMP CONDITION (Reference: Urban Drainage and Flood Control District Drainage Criteria Manual, 2001, V.1, Section 3.3.6) (Note: Spreadsheet assumes orifice condition for fully developed flow.) INLET TYPE: Type 13 Inlet - Vane Grate BASIN: A6 Orifice Equation: O = Cd`Ao'(2gH)A0.5 K = Clogging Coefficent value for multiple inlets Adjust Ao (open area) due to clogging as follows: Effective Area Opening Ae = (1-C) Ao, where: C=K'Co/N N = Number of Inlets Co = Single Inlet Clogging Factor: Co(grate)= 0.5 (50%clogging) Number of inlets: Inlet Dimensions and Effective Open Area: Grate Ooenino: Allowable depth: Constants: Flow Calculations: Grate Flow: Total Intercepted Flow with an allowable depth of N= 2 Ao(g) = 1 32 W2 Total Ao(g) = 2.64 ftA2 K= 1,50 C = K'Co/N = 0.38 Ae(g) = (1-C)Ao = 1.65 ft-2 H = 2 0 in = g = 32.20 ftlsA2 Cd = 0.67 Q = Cd' Ae(g)' (2g'H)A0.5 Qg= 3.62 CFS Required Flow (Q 10 ) = 1.418 cis Required Flow (Q 100 ) = 3.17 cis N Grate 2 1.5 3 1,75 4 1,88 5 1.94 6 1.97 7 1.98 8 1.99 0.1666667 It 2 inlet(s) and 2 inches is 3.6 cis Bypass = 0.0 cis Bypass = 0.0 cfs 2595c - Rational Calculations 01132017.xlsx Grate-Sump(UDFCD) A6 Page 1 of 1 JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number 2595c Fort Collins, CO 80524 Date: 1/16/17 Ph: (970)225 9099 By: LAT Village On Horsetooth Green Space Basin A9: FAA Procedure BaW on FM Procedure. pm Fed"I Aviation Aaanoy WA K D,alneae- Manual Drainage Basin A<; Design Storm 100 year Composite'C' Factor 0,53 Time of Concentration Tc 12 10 min (Max Tc) Basin Size 080 acre Release Rate Calculations Allowable Release Rate for Site 1 68 Offs 10-Year pipe Flow rate Less Undetained OBsite Flows 0.00 cfs Allowable Release Rate for Pond 1,68 cfs Rainfall Intensity Calculations Point Hour Rainfall (P,) : 2.86 Cl- 28.5 Rainfall Intensity: FortCollinslDF C2= 10 1= C,'P,/(Cr*Te)^C, C3= 0.789 Volume Calculations Inflow Volume = C' I' A'time (sec) Outflow Volume = Alowable Release Rate' time (sec) Storage Volume = Inflow Volume - Outflow Volume Detention Storage Calculations Time t (min) Intensity I (In/hr) Inflow Vin (8e) Outflow Adjustment Factor no Average Outflow (cfs) Outflow Vout (it') Storage Vstor (Ra) 5.0 9.95 1263 1.00 1.68 503 760 10.0 7.72 1960 1.00 1.68 1,005 954 1&0 6.52 2483 0.90 1.51 1,362 1,120 20.0 5.60 2843 0.80 1.34 1,614 1230 25.0 4.98 3160 0.74 1.24 1865 1.296 30.0 4.52 3442 0.70 1.18 2,116 1,326 35.0 4.09 3.632 0.67 1.13 2,368 1.265 40.0 3.75 3804 0.65 1.09 2,619 1,185 45.0 3.47 3,958 0.63 1.06 2.870 1,088 50.0 3.23 4,105 0.62 1.04 3,121 983 55.0 3.03 4.236 0.61 1.02 3,373 863 60.0 2.86 4,356 0.60 1.01 3,624 732 65.0 2.70 4,459 0.59 0.99 3.875 584 70.0 2.57 4 564 0.59 0.98 4.127 437 75.0 2045 4,662 0.58 0.97 4,378 283 80.0 2.34 4 753 0.58 0.96 4,629 124 85.0 4 839 0.57 0.96 4,881 41 90.0 4 921 0.57 0.95 5,132 -211 95.0 4 998 0.56 0.94 5.383 -385 100.05 071 0.56 0.94 5 635 -563 105.05 141 0.56 0.93 5 886 -745 770.05208 0.56 0.93 6.737 -929 115.05273 0.55 0.93 6389 -1776 120.05 334 0.55 0.92 6 640 -1 30fi 125.05.393 0.55 0.92 B 891 -1 498 130.05 451 0.55 0.92 7 143 -1 692 135.01.6115,506 0.54 0.91 7 394 -1 889 140.0 1.56 5559 0.54 0.91 7,645 -2.087 145-0 1.52 5,610 0.54 0.91 7.897 1 -2,286 1%0 1.49 5,660 0.54 0.91 8.148 -2,488 155.0 1.45 5.709 0.54 0.90 8,399 -2,691 160.0 1.42 5.756 0.54 0.90 8,651 -2,895 165.0 1.39 5,801 0.54 0.90 8.902 .3,101 170.0 1.35 5,846 0.54 0.90 9,153 -3,308 175.0 1.33 51889 0.53 0.90 9,405 -3,516 180.0 1.30 5,931 0.53 ntensity Equation 0.89 9,65fi -3,725 Max from FoCo CM Maximum Volume IF) 1,326 0% WOCV 0 to Required 1(1 Volume 1,326 R' 2595C - Rational Calculations 01132017.xisx Modified FAA-100-yr A9 Page 1 of 1 JVA Incorporated 25 Old Town Square, S 200 Fort Collins, CO 80524 Ph: (970) 225 9099 BASIN A9 PONDING AREA VOLUME CALCULATIONS Pond Volume = Prismoidal Formula Volume Equation = (A1+A2+SQRT(A1'A2pD/3 Stage I Storaae Input Table Job Name: Village On Horsetooth Job Number: 2595c Date: 1116117 By: LAT ELEVATION It DEPTH (D) It AREA (At) fts WEIGHTED AVG AREA (A2) ft`' INCREMENTAL VOLUME ft3 CUMMULATIVE VOLUME ft' 10555 D 5109.75 0.3 1 e]"' 976 202 2D2 �1+0 r1 0.3 4 1 i1 3,001 730 932 5113 S 0.3 Z7 3 5,755 1,420 2,352 51 10 0.3 1 + !)'>s 9,215 2,288 4,640 5110 ? a 1 13,224 1,975 6,615 To of Pond 51165 1.15 TOTALVOLUMEJ 6,615 of 1 0.152 ac-ft Pond Volume Summary Table Required Volume (ft') Required Volume (ac-ft) Water Surface Elevation Water Depth V100 + 0"o WQCV 0.030 ac-ft 5110.07 ft 0.57 ft Volume Interpolation Calculations 0 0% WQCV V100 + 0% WQCV Vol Elev Vol Elev 0.00 5109.50 932.30 5110+00 0000 5109+50 1326.02 5110+07 202.02 5109,75 2352.44 5110.25 2595c - Rational Calculations 01132017.xlsx Vol Ponding Area A9 Page 1 of 2 JVA Incorporated Job Name: Village On Horsetooth 25 Old Town Square, S 200 Job Number: 2595c Fort Collins, CO 80524 Date: 1116117 Ph: (970) 225 9099 By: LAT FLOW CALCULATIONS - GRATE INLET SUMP CONDITION (Reference: Urban Drainage and Flood Control District Drainage Cntena Manual, 2001, VA, Section 3.3.6) (Note: Spreadsheet assumes orifice condition for fully developed flow.) INLET TYPE: 24" Area Drain BASIN: A9 Orifice Equation: Q = Cd'Ao'(2gH)A0.5 K = Clogging Coefficent value for multiple inlets Adjust Ao (open area) due to clogging as follows: Effective Area Opening As = (1-C) Ao, where: C=K'Co/N N = Number of Inlets Cc = Single Inlet Clogging Factor: Co(grate)= 0.5 (50%clogging) Number of inlets: Inlet Dimensions and Effective Open Area: Grate Ooenino: Allowable depth: Constants: Flow Calculations: Grate Flow: Total Intercepted Flow with an allowable depth of N= 2 Ao(g) = 1.6 ft-2 Total Ao(g) = 3.20 ftA2 K = 1.50 C = K'Co/N = 0.38 Ae(g) _ (1-C)Ao - 2.00 ft^2 H=2.0 in = g = 32.20 ftlsA2 Cd = 0.67 Q = Cd' Ae(g)' (2g`H)A0.5 Qg= 4.39 CFS Required Flow (Q 10 ) = 0.99 cfs Required Flow (Q 100 ) = 4.01 cfs N Grate 2 1.5 3 1.75 4 1.88 5 1.94 6 1.97 7 1.98 8 1.99 0.1666667 ft 2 inlet(s) and 2 inches is Bypass = Bypass = 4.39 cfs 0.0 cfs 0.0 cfs 2595c - Rational Calculations 01132017.xlsx Grate-Sump(UDFCO) A9 Page 1 of 1 APPENDIX C - REFERENCED DOCUMENTS III) lie S :ji9) ! Y� IH)) f I !I !'.H H � d • I) I H � ° i Fr �. o f di �i�EI aH �� w ii"l i! t f H2 J Y i 71 i I I 6 S )i, 13! Yi f' x �slHss! IiYYY t � ;� , 5�R a �I E t iJi! s I7 e ),�)� f f 9 f 3 e �• d i 'x I z s � �) l f I I I - ' 141 $J9 m ! ict q a ,ta � i t � 333 a �. ; gg - - �• Tll }pY r 4) $ F+ ail�:Tj�C llt': �$ Y� f ^)9° {,�14 e4 atR iLa #a3) o - £2P la l a: gi• iJY4 �]} 4 a pI R ) F -t 3$i co£Cyp-3 NiJJyIPI Y [F. Iia! JYHIafilt6(S Se �y�R Chfl3 - W ist Ufa 1'st i f J 6 olst fia•# IJ) a 2i3)tF I, R aF Y c d p) x= z Js ; 2ef£Y )`�a�.� ) ill M - J ;F. Y {{ a.. g) a� L i�£ fsit d xS dE is} , a°tFR Sta lia�$ '8 / !`° S }i: 7 H?{ 6 ; IySya�xiFS5 d a �R9gp TRk9 't All PIP l)f.,9°e sJ?IA 2{3� #R�.�) It@e)�8 a� I' 2ta 1�tiii�€ { }e)) l= Ft�l � i RIL �r �a� aF.) � 9l�xbD at putillf)l 1:laalt jitu fl2! aHl)4<,€i:P ! ah-, Hfll lit aYdlHla `iY ad RI )=RP s � a ! -t 0 a 1 CTL I THOMPSON 1 1 GEOTECHNICAL INVESTIGATION ' FCHA VILLAGE AT HORSETOOTH 1506 WEST HOREETOOTH ROAD FORT COLLINS, COLORADO , FORT COLLINS HOUSING AUTHORITY 1715 West Mountain Avenue ' Fort Collins, Colorado 80521 Attention: Kristin Fritz, AICP , Project No. FC07464-120 ' July 19, 2016 400 North Link Lane I Fort Collins, Colorado 80524 ' Telephone:970-206-9455 Fax:970-206-9441 SCOPE This report presents the results of our Geotechnical Investigation for the ' proposed FCHA Village at Horsetooth in Fort Collins, Colorado. The purpose of the investigation was to evaluate the subsurface conditions and provide founda- tion recommendations and geotechnical design criteria for the project. ' The report was prepared from data developed during field exploration, la- boratory testing, engineering analysis and experience with similar conditions. The report includes a description of subsurface conditions found in our explorato- ry borings and discussions of site development as influenced by geotechnical considerations. Our opinions and recommendations regarding design criteria and construction details for site development, foundations, floor systems, slabs - on -grade, lateral earth loads, pavements and drainage are provided. If the pro- posed construction changes, we should be requested to review our recommen- dations. Our conclusions are summarized in the following paragraphs. ' SUMMARY OF CONCLUSIONS t 1. Soils encountered in our borings consisted of interlayered sandy clay and clayey sand to the depths explored. Based on laboratory testing, the soils are generally non -expansive to low -swelling. No ' bedrock was encountered in our borings. 2. Groundwater was encountered at depths of 19 to 23 feet during ' drilling and was measured several days after drilling at depths of 19 to 22 feet. Existing groundwater levels are not expected to signifi- cantly affect the proposed construction. ' 3. We believe the proposed structures can be constructed on a spread footing foundation placed on natural, undisturbed soil and/or ' properly compacted fill. Foundation design and construction rec- ommendations are presented in this report. FORT COLLINS HOUSING AUTHORITY ' VILLAGE AT HORSETOOTH CTL I T PROJECT NO. FC07464-120 4. We believe slab -on -grade floors are appropriate for this site. Some movement of slab -on -grade floors should be anticipated. We ex- pect movements will be minor, on the order of 1 inch or less. If movement cannot be tolerated, structural floors should be consid- ered. 5. Pavement subgrade at this site will generally consist of A-4 and A- 2-4 materials according to AASHTO criteria, with expected poor to good subgrade support. Recommended section thicknesses and pavement materials are provided in this report. SITE CONDITIONS AND PROPOSED CONSTRUCTION The area of proposed development is on the north side of Horsetooth Road east of Big Ben Drive in Fort Collins, Colorado. An existing residence with horse stalls and associated pasture areas were located on site at the time of our investigation. The ground surface is generally flat; vegetation consisted of natural grasses, weeds and trees. A ditch runs along the eastern boundary of the proper- ty. We understand that the proposed construction will consist of nine apart- ment buildings having 96 units, a club house, and associated paved parking are- as and access drives. No below grade areas are planned. INVESTIGATION Subsurface conditions were investigated by drilling thirteen exploratory borings to depths of approximately 20 to 30 feet. Our representative observed drilling operations, logged the soil found in the borings, and obtained samples. Groundwater measurements were taken during and several days after drilling. Summary logs of the borings, including results of field penetration resistance tests, are presented on Figures 2 and 3. FORT COLLINS HOUSING AUTHORITY 'Z VILLAGE AT HORSETOOTH CTL I T PROJECT NO. FC07464-120 h ,i v OSLLHfro (N9C9bb 0594H OZ94H 06SC0bb 095LflDt OE548 0054E M99 S01 0 T Q J N m O J � O O1 3_ � o a 8 S o m x m � p � p P O V y NZ � 6 N d jp 2 U mR9 050[ h « 4 a + < 0 ■ » [ Z ■ X. « x 0 e k ' | L (\ ( _ _ I j , 3 a[B2 §m a c -2 2;FA 0,0 ■«':flm !� 3©4a --- f #` |k b/ r�9 ,, _OM. f3E& J! &> !; !2|}} !Eo «§ �]{k } ? - \!k} !7/ \0 cc » ( _ `ƒ c, ... n m 3 < 0M { �� k (\Ek #§w!& a! a! �#\! 0 m - %`k (�Jf / { U( //!! \3M !J� [ \ \� ;. §[}!! ¥° ; |0 ; \ / < - �® !} »[f ; ,[!| [ . a I! \§� §{}( kƒiM §]§ } !!J I | 3 0/$) J |0 \`� � » n 0 ■ ■ � 0 z ' Soil Map—Larimer County Area, Colorado 1 ' Map Unit Legend Larimer County Area, Colorado (CO644) ' Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3 Totals for Area of Interest 1 Altvan-Satanta loams, 0 to 3 &2 100.0 percent slopes 8.2 100.0 UNatural Resources Web Soil Survey all 1/2016 Conservation Service National Cooperative Soil Survey Page 3 of 3 4 7510 4 70V �l>7C aRi'?[n: 4t8)G31 49 71 G47J IW 53 W IWVFW 4487M z mWO 0. m O V N t m m p` O C m N N E !.: 00 N C m co1pm E N yaE 0 E m m'v E m �' Z i. c W umi m U a'n ro Emmc3 m ymN m.2nm Z UN L 0 OW 75 CQ m3 E gCvm 3 ¢ m4 NLE' Lm m 0 TmN p.Cmm m v''o E mo cm cv rnn �mm c m cyamTt - U c ata�Ommm EO`m `0 a vm � Ta m Lea ° m Eh m a2mmmm mv n ym .o -a yma m >NU m E Z to m oLE =m dy Em mm 'vCovym vamo o�2co( i r3 `mm�a �va«O• vms 0` J 0 A 15 n CC Lgo mME me m a no�!2 0 ON mc N O O tC NoU2 mm o n, m � U) E 0ammC mEm m FmJmym 7i eam wE= u E f� iv w w- �N H y E o z m m a m a m W m m >m z c o `o 0 o` W m n a c Y 2 J d m N h t7 i0 Q O ° 6 N N O Oi n O d Ql N 1� (� N Q p C• v N N f�l lht Q1 il] _N Y ♦ [ 1 2 ■ ■ ■ O O O ® ■ ■ ■ ■ ■ ■ O o N m m 3 m n m Q i N O y C pO O 0 N m O N y 6 m Q q O O N N N CI t♦1 d d N m Z W O\/ O `/ `( N Lo E, Q 3 K Factor, Whole Soil—Larimer County Area, Colorado K Factor, Whole Soil K Factor, Whole Soil— Summary by Map Unit — Larimer County Area, Colorado (CO6") Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 .28 7.7 100.0 to 3 percent slopes Totals for Area of Interest 7.7 100.0% Description Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by water. Factor K is one of six factors used in the Universal Soil Loss Equation (USLE) and the Revised Universal Soil Loss Equation (RUSLE) to predict the average annual rate of soil loss by sheet and rill erosion in tons per acre per year. The estimates are based primarily on percentage of silt, sand, and organic matter and on soil structure and saturated hydraulic conductivity (Ksat). Values of K range from 0.02 to 0.69. Other factors being equal, the higher the value, the more susceptible the soil is to sheet and rill erosion by water. "Erosion factor Kw (whole soil)" indicates the erodibility of the whole soil. The estimates are modified by the presence of rock fragments. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie -break Rule: Higher Layer Options (Horizon Aggregation Method): Surface Layer (Not applicable) LSUA Natural Resources Web Soil Survey 411111111111111 Conservation Service National Cooperative Soil Survey 1 1 1 10l26/2016 Page 3 of 3 1 ' Map Unit Description: Altvan-Satanta loams, 0 to 3 percent slopes—Larimer County Area, Colorado Larimer County Area, Colorado 3—Altvan-Satanta loams, 0 to 3 percent slopes Map Unit Setting National map unit symbol: jpw2 Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost -free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Altvan and similar soils: 45 percent Setanta and similar soils: 30 percent Minor components: 25 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Altvan Setting Landform: Benches, terraces Landform position (three-dimensional): Side slope, tread Down -slope shape: Linear Across -slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 10 inches: loam ' H2 - 10 to 18 inches: clay loam, loam, sandy clay loam H2 - 10 to 18 inches: loam, fine sandy loam, silt loam H2 - 10 to 18 inches: gravelly sand, gravelly coarse sand, coarse sand ' H3 - 18 to 30 inches: H3 - 18 to 30 inches, H3 - 18 to 30 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: ' Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches t Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None ' Calcium carbonate, maximum in profile: 10 percent I u[)A Natural Resources Web Soil Survey 8111/2016 Conservation Service National Cooperative Soil Survey Page 1 of 3 Map Unit Description: Altvan-Satanto loams, 0 to 3 percent slopes—Larimer County Area, Colorado Available water storage in profile: Very high (about 13.2 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Description of Satanta Setting Landform: Structural benches, terraces Landform position (three-dimensional): Side slope, tread Down -slope shape: Linear Across -slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile Hi - 0 to 9 inches: loam H2 - 9 to 18 inches: loam, clay loam, sandy clay loam H2 - 9 to 18 inches: loam, clay loam, fine sandy loam H2 - 9 to 18 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of pondirlg: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Minor Components Nunn Percent of map unit: 10 percent Larim Percent of map unit: 10 percent Lmm Natural Resources Web Soil Survey 811112016 011110 Conservation Service National Cooperative Soil Survey Page 2 of 3 Map Unit Descriptor: Altvan-Satanta loams, 0 to 3 percent slopes—Larimer County Area, Colorado Stoneham Percent of map unit: 5 percent Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 10, Sep 22, 2015 1 t i yDg Natural Resources Web Soil Survey 0" Conservation Service National Cooperative Soil Survey Page 3 of 3 ■S0 0 S _« Wo 0 � @ 0 0 � � g m � CL 2 � m � 1 1 t 1 1 1 1 1 1 1 1 FOOTHILLS BASIN Master Plan Water Quality Concepetual Alternatives t+AW P125)" c"7 Gam) , aU 5 TOOTH r fg'/ CIE VM ASSOCIATES I Lake Sherwood • Water Quality Treatment provided in Existing Lake Sherwood Parkwood East Pond R •Retrofit Existing Pond to accommodate Water Quality ^ •I a Volume. � \ Parkwood Southmoor Village Pond Lake • Retrofit Existing Pond to accommodate Water Quality Volume Warr.•. Lak� 1 i �I 1• r �1 Proposed Stream 1 \ Restoration �l Improvement Foothills Basin Boundary Proposed BMP Basin Type Flood Control Only Water Quality Only j Flood Control and Water Quality Proposed Improvements Fort Collins Nigh School Pond None • Retrofit Existing Pond to accommodate Water Quality Proposed Conceptual Coflindale PUD Pond Volume P..P^..d Water Quality Alternatives • Retrofit Existing Pond to accommodate Water Quality Proposed Water Quality Pond Volume Undeveloped Area Water Warren Lake . Water Quality Treatment - - Stream - Canal provided in Existng Warren _ - Lake rrl Parks w Proposed Stream Restoration and Habitat Improvements F�, Haw im., - zuoe ' Erosion and Sediment Control Escrow/Security Calculation for The City of Fort Collins ' 10/26/2016 Project: Village On Horsetooth Disturbed Acres: 8.00 BMP Amount Estimated Unit Total EROSION CONTROL BMPs Units Quantity Price Price ' Vehicle Tracking Control Pad each 1 $750.00 $750.00 Sediment Control Log L.F. 2100 $2.00 $4,200.00 Concrete Washout each 1 $1,200.00 $1,200.00 ' Outlet Protection each 9 $400.00 $3,600.00 Inlet Protection each 46 $400.00 $18,400.00 Construction Fence L.F. 1900 $1.00 $1,900.00 Street Sweeping and Cleaning LS 1 $2,000.00 $2,000.00 ' Silt Fence L.F. 1000 $1.50 $1,500.00 Sub -Total: $33,550.00 1.5 x Sub -Total: $50,325.00 ' Amount of security: $50,325.00 Reseeding Amount ' Seeding AC 4 $2,000.00 $8,000.00 Sub -Total: $8,000.00 ' 1.5 x Sub -Total: $12,000.00 Amount to Re -seed: $12,000.00 Miniumum Escrow Amount Minimum escrow amount: $3,000.00 ' Final E-scrow Amount Maximum between BMP, Reseedin and Minimum E-scrow Erosion Control Escrow: $50,325.00 ' The amount of the .security must be based on one and one-half times the estimate of the cost to install the approved measures, or one and one-half times the cost to re -vegetate the disturbed land to dry land grasses based upon unit cost determined by the City'.s Annual Revegetation and Stabilization Bid. ' whichever is greater. In no instance, will the amount of security be less than one thousand five hundred dollars ($1,500) for residential development or three thousand dollars ($3,000) for commercial development" 1 12/13/2016 3:27 PM VA2595c FCHA 1506 HorsetwthXReports\Drainage ReporhFiinal Drainage Report\Appendix D- Erosion Control\2595c Erosion Control Esa .xls APPENDIX D - EROSION CONTROL ESCROW A1aa.au.-- DEVELOPED RUNOFF TABLE mXWdaq Milan GwOn Pam Am pant % Imponw4w 0.10 Was o-im kM 10i Cords Class Al 1 t.d Sl0% 001 &OT O.b A2 3 as NfM ON 1.W am AS S an 718%, 002 Sm 0.31 M 4 all 20a 0.13 0 40 DO AS 5 0.m 20% ON Od 0.46 AS B 0.1E Sl a06 To ON AT 2 am z0% 0.05 0.10 DO AT B DID 1111 0.08 0.SO aw AP B 0.&5 1&T% OOl 6M am A10 10 am 50% 267 ON - -TA All 11 0.m &3% ON am an Al2 12 O.d S.0% O.Y 010 O.Y A13 13 am 2016 037 OOT am A14 14 a% RP% aII &SC an A1S 15 0. A.O% 014 011 O.m Aid 16 ON 10594 Om RST a51 61 17 ON 1604 Oro 1.56 O54 ez 1S oA1 2.016 60 145 0Ad 0 1O 0.14 ITEM, 0.71 LOT am Be m am zOu 047 112 0.4e --Ti-- 1 -FIT-m.a% a.29 1.w ON R2 21 0.10 man O43 Om ON 25 SIT 900% ON VLSI am b Ott WM aTt 1.1 93 \RS b 6.07 --6VM 0.m 0.03 am S 0.10 90.016 0.71 O.m 0.m w 27 0.17 90.06 17.97 1.0 DID RB 2e OTT man on 1.52 0m !0 S 0,17 90.01% 0,71 1. ON R10 30 0.17 90.0% 0..0 1.55 ON TWI Sol Flow Td 41 321P am O.A TOlal MN BMA an 10.21E vN 3.n am Tavel To LID Pond 1.36 ".1% 1.N S.d 0.TI Tptll To LED Pond CM an 1.117 Atb 0.74 TaYI To LED Pond i AIS 65.616 21m 211.19 O.72 TowlbPaN 7.14 92.0% N.67 41 0.71 LID POND DETAIL TABLE RECORDS PROMOED WATER WATER Allege POND MAX WAUTY WALLY SOL ID DEPTH UD WaLME UO VOLLM Ali (an (a) (a) (A) 1 1.0 1.216 1,236 12M 2 to S37 764 764 3 1.0 am am 3261 TOTAL 5,053 5,283 a203 UD/WOCV MMARY OC CAPTURED 8 BASINS 6ONSM 1 . EA NOT CAPTURED 1.d2 HEATED BY -0 IWi S AREA TREATED BY II . fi2 I) I EL GEND mmmmmmmm PROPOSED DRAINAGE BASIN BOIIN3AAY (BUS BASIN) TOP OF DETENTON POND y OVERFLOW LOCATION -w DIRECTION OF FLOW (PROPOSED) DIRECTION a FLOW (EIaSTINO) 0 BASIN DESIGN POINT A BRAINAGE BASIN IOENTIPCATON BUBBIE 5 I. A = DE1£LWEO BASH ITMA MIN .$ =RUNOFF COaROFNi I.0 = NDA ACID$ -- VILLAGE ON HORSETOOTH FINAL DEVELOPMENT PLAN FORTCOLLINS. CO HOUSING GTALYST 1715 W Al Awnw Foil Onto. CO 50521 p. 970.4162910 WARCHITIECTIARE NA. INCORPORATED 25 pd Twm Sewn, SuI41m Fu1 Cwlm,. CO 80524 diI6IxALaITE mug No DESCRIPTION DATE REVISIONS No DESCRIPTION DATE DEVELOPED DRAINAGE MAP SEAL: PRal"N., R1602B DRAWW Br: Fxbm R6MB%rn &v: BACLCRH DRAWING NUMBER: C1.5 Nr M/�„ 5M E BIN � IW M �ffi 1111rr1 Ix/ SW x/5 ,91x M-13A xOLgxG IR Ci I20 ` cYM6 0 e . s1EPlus> rcpgwE s y n 18PF.Prxum u s sErxx \ uxC sveomW 1 wr10 siRy ,o \ WT 9 PwWs> wz flEt. W. 9309612 oy. 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UT I / I A OEMIOHD 8s5M OEBICN410]N MB N.N BY, CIM IH I I ; � N \\1j1� 5 IA OPNWLE Bl9N pFNIfIfA1pN BII®IE 5 . XI w WEfFlCEM JpB NIABER. ZM5E r 1 +�\ ` 1 I I/ I L. MEA ACPES WiE. WMMIB it IY iI i/� .56P".' 1`` N j�/yI©rvaixc Irl i if Lvx \ I FE I I I l I 11 / ` / r ^11 ^ I BW1. 9M. P�IC °A40 V% ILLI �SJBBI SHED mmmmw / .'IGN EIkV: 511 0 �tiI--II�R—tiI�--M�—M11—M—Y-��I--M BY p1,5109IR (x RCP ♦ '✓�\� ` ____ ___ ♦__ _______________ _ _ _ _ ' `R 51 `-W HORSETOOTH ROAD R� -`A __ _ _________ ' o 1 .9, N" IS flCP ` �!' SWgl1• / J•' 31@Dp' 15' RCP M A tlWx 1✓•I EIEV 5110ffi' _ ___ ______________ HJ FIEVi1WX' ' ' ® ro a 0 m Ew nee3,an' EIrv3,Wx• SGV£ M IFET SHEET xIMBERR FIG 2 HISTORIC RUNOFF TABLE 8�4! OF9tll IAG 2 ra IW ra RUHOFi POM (�) RUMMi PEMc 006F5 !as) (cEs) am M 1 ]88 121 1R.I3 O51 ]OEM ]MM R21 P8.]A OSJ