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Home My WebLink AboutPROSPECT AND COLLEGE HOTEL - PDP190014 - SUBMITTAL DOCUMENTS - ROUND 3 - STORMWATER MANAGEMENT PLANPreliminary Stormwater Management Report for Prospect and College Hotel Fort Collins, CO Prepared For Saunders Commercial Development Company 1705 17th Street, Suite 350 Denver, CO, 80202 6/17/2020 Project No. 18111 June 17, 2020 City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80521 Reference: Preliminary Drainage and Erosion Control Report for Prospect and College Hotel A Portion of Lot 2 of Fox Shopping Center Subdivision Fort Collins, Colorado Dear Staff: Sanderson Stewart is pleased to submit this Preliminary Drainage and Erosion Control Report for your review. This report accompanies the Project Development Plan (PDP) submittal for the proposed Prospect and College Hotel in Fort Collins, Colorado. This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM), and serves to document the stormwater impacts associated with the proposed project. We understand that review by the City is to assure general compliance with standardized criteria contained in the FCSCM. If you should have any questions as you review this report, please feel free to contact me at 970/488- 0169 or by email at csonnier@sandersonstewart.com. Sincerely, Charles Sonnier, PE Senior Engineer/Project Manager CERTIFICATION I hereby state that this Preliminary Drainage Report has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community of professional engineers. The analysis has been prepared utilizing procedures and practices specified by the City of Fort Collins and within the standard accepted practices. __________________________________________ ___________________________ Charles Sonnier, P.E. Date Prospect and College Hotel June 17, 2020 Page 1 Project No. 18111 June 17, 2020 Project No. 18111 PRELIMINARY (PDP) STORMWATER MANAGEMENT REPORT FOR PROSPECT AND COLLEGE HOTEL A PORTION OF LOT 2 OF FOX SHOPPING CENTER SUBDIVISION FORT COLLINS, COLORADO I. Overview Narrative The proposed project is an infill development that will include the construction of a new multi-level hotel building and supporting infrastructure improvements. The purpose of this report is to identify the required stormwater management and water quality facilities for the developed site. The design standards governing this project are the Fort Collins Stormwater Criteria Manual (FCSCM), Dec 2018 and the Mile High Flood District’s Urban Storm Drainage Criteria Manual (USDCM), Volume 1-3. II. General Project Location The subject property is located at 1623 South College Avenue, Fort Collins, Colorado, 80525 (Site) in the Northeast Quarter of Section 23, Township 7 North, in Range 69 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. The Site lies within a portion of Lot 2 of the Fox Shopping Center Subdivision and is approximately situated at the southwest corner of South College Avenue and West Prospect Road. The property is bounded on the north by West Prospect Road and Schraders Gas Station, to the west and south by commercial businesses (Fox Shopping Center and Choice Center) and to the east by South College Avenue. III. Existing Site Information The proposed Prospect and College Hotel is located on a portion of existing Lot 2 of Fox Shopping Center Subdivision. The site has a net area of approximately 2.0083 acres and is located within the City limits of Fort Collins. Currently, the property accommodates an existing retail building occupied by Chuck E. Cheese and Fort Collins Furniture and Mattress consisting mostly of asphalt parking lot and rooftop. Major Basin Description The project site lies within the Spring Creek Basin which stormwater from the project site ultimately flows to. Spring Creek is a major watercourse that flows from Spring Canyon Dam at Horsetooth Reservoir to the Cache La Poudre River. This basin encompasses nearly nine square miles in central Fort Collins. The basin mostly contains residential development but also includes parks, open space and areas of commercial and industrial development. Sub-Basin Description` The property itself slopes generally to the north and east with stormwater runoff entering into an existing 20-foot Type R curb inlet along South College Avenue adjacent to the Schraders Gas Station. The City has stated that the downstream stormwater piping cannot accept 100% of the “historic” runoff and, due to that, the crown of College Avenue overtops with excess runoff that flows overland and to the east on a circuitous flow path to Spring Creek. The existing site provides no detention or water quality treatment of existing storm runoff prior to entering the College Avenue storm line system. Prospect and College Hotel June 17, 2020 Page 2 Project No. 18111 According to the NRCS website, the site consists mainly of Fort Collins and Altvan-Satanta loams with a classification of Type B & C soils. Refer to Appendix A for soil classification information. According to the Flood Insurance Rate Map (FIRM) for Larimer County, Colorado, Panel No. 979 of 1420, Map No. 08069C0979H, revised May 2, 2012, the proposed development is outside of any special flood hazard areas (see Appendix A). IV. Project Description The proposed project will consist of a new 6-story hotel building with approximately 83,356 square-feet of gross floor area and supporting utilities consisting of storm sewer, sanitary sewer and waterline improvements. Surface improvements include a new paved parking lot, landscaped areas and concrete sidewalk surrounding the buildings. Part of the City of Fort Collins required improvements will include the extension of utility services from existing sewer, water, and storm drain that are not located within the boundary of Lot 2. This project also proposes the removal all existing surface improvements, including the existing Chuck E. Cheese building, within Lot 2 in order to accommodate the proposed improvements. Off-site improvements will mainly consist of a stormwater outfall pipe to convey stormwater from the site to the existing drainage channel to the west. V. Drainage Design Criteria A. Regulations/Development Criteria The design standards governing this project are the Fort Collins Stormwater Criteria Manual (FCSCM), Dec 2018 and the Mile High Flood District’s Urban Storm Drainage Criteria Manual (USDCM), Volume 1-3. B. Four-Step Process The overall stormwater management strategy employed with the proposed project utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices Several techniques have been utilized with the proposed development to facilitate the reduction of runoff peak rates, volumes, and pollutant loads as the site is developed from the current use by implementing multiple Low Impact Development (LID) strategies. Proposed techniques include providing landscaped island and buffer areas throughout the site to reduce the overall impervious area, to minimize directly connected impervious areas (MDCIA), providing a central StormTech filtration system to help slow runoff rates and grading the site such that runoff is routed over a longer distance to reduce the time of concentration prior to the ultimate outfall point. Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with Slow Release The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban development of this intensity will still generate stormwater runoff that will require additional BMPs and water quality. The majority of stormwater runoff from the site will ultimately be intercepted and treated using a StormTech filtration system prior to the ultimate outfall point with the remaining to be treated via a grassed lined drainage channel that the site discharges to. Prospect and College Hotel June 17, 2020 Page 3 Project No. 18111 Step 3 – Stabilize Streams There are no major drainageways within the subject property, however, the proposed outfall discharges off-site into an existing grassed drainage channel to the west. Proposed stabilization and treatment to the stream at the outfall will include a concrete flared end section, a concrete trickle pan, and a turf reinforcement mat (TRM) to help prevent erosion. Step 4 – Implement Site Specific and Other Source Control BMPs The proposed project will improve upon site specific source controls compared to historic conditions: The proposed development will provide LID and water quality treatment; thus, eliminating sources of potential pollution previously left exposed to weathering and runoff processes. C. Hydrological Criteria 1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the FCSCM, serve as the source for all hydrologic computations associated with the proposed development. Tabulated data contained in Table 3.4-1 has been utilized for Rational Method runoff calculations. 2. The Rational Method has been employed to compute stormwater runoff utilizing coefficients and calculation methods contained in Chapter 5, Section 3.2 of the FCSCM. 3. Three separate design storms have been utilized to address distinct drainage scenarios. A fourth design storm has also been computed for comparison purposes. The first design storm considered is the 80th percentile rain event, which has been employed to design the project’s water quality features. The second event analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The third event considered is the “Major Storm,” which has a 100-year recurrence interval. A fourth storm, the 10-year event, was also computed for comparison purposes only. 4. No other assumptions or calculation methods have been used with this development that are not referenced by current City of Fort Collins criteria. 5. The City has noted in the original concept meeting held in 2018 that detention will not be required, however, LID techniques to improve water quality should be implemented where possible. D. Hydraulic Criteria 1. All drainage facilities proposed with the project are designed in accordance with criteria outlined in the FCSCM and/or the USDCM. 2. As stated above, the subject property is not located in a City designated floodplain. The proposed project does not propose to modify any natural drainageways. E. Modifications of Criteria 1. The proposed development is not requesting any modifications to criteria at this time. Prospect and College Hotel June 17, 2020 Page 4 Project No. 18111 VI. Proposed Drainage Facilities A. General Concept The intent of the proposed design is to safely and adequately convey the minor and major design storm given the site’s existing constraints and off-site flooding concerns by the City that were previously mentioned. 1. As stated, one of the main objectives of the project drainage design was to capture and re-direct a portion of the site’s existing runoff to the west that would otherwise convey to the east, in an effort to assist the City in reducing the routine flooding that occurs at the southwest corner of South College Avenue and West Prospect Road. Based on initial calculations, over half of the existing peak flows would be redirected to the west drainage channel that would have otherwise flowed to South College Avenue drainage system. 2. Other than the portion of the site to be re-directed to the west, the remaining small portion of the site is proposed to generally maintain historic drainage patterns, with this runoff being directed into the existing College Avenue storm line system. The proposed site will reduce overall site imperviousness and will provide water quality treatment in an onsite StormTech filtration system. The overflows beyond what will be treated by the StormTech system will be treated though an off-site, 1,200-foot long, grassed drainage channel that the re-directed flow ultimately discharges to. A more detailed description of the projects sub- basins and drainage patterns is provided below. B. Specific Details The proposed storm drainage system will collect runoff via sheet flow and curb and gutter and convey to proposed area and curb inlets. The storm drain piping will then convey the collected stormwater to the south and west to an existing drainage channel that ultimately flows to Spring Creek approximately 1,200 feet to the south of the discharge point. Water quality flows from the run-off captured by the proposed storm system will be diverted to an on-site StormTech filtration system intended to meet the low impact development (LID) requirements. An off-site easement will be needed to encompass the proposed outfall storm piping from the Site to the west drainage channel. An MOU between the City and Developer will need to be established for hard and soft cost sharing of this outfall. Permission to discharge into the west channel will also need to be obtained from the owners of the easement the drainage channel is contained within. 1. There are seven total on-site sub-basins and two off-site sub-basins for the project. A detailed description of each sub-basin and the drainage system within them is described as follows: Basin 1: This basin is approximately 0.37 acres and includes on-site flows, mainly from south but north of the raised pedestrian walk. This basin consists generally of asphalt and concrete surfaces with minor landscaping. This basin flows via sheet flow and curb and gutter to a combination inlet located on the west side of the main landscape island and has a total composite imperviousness of 85%. Basin 2: This basin is comprised of approximately 0.37 acres and includes on-site flows generally from the west of the proposed building and from the main landscape island itself. This basin also flows to a combination inlet on the east side of the main Prospect and College Hotel June 17, 2020 Page 5 Project No. 18111 landscaped island, via sheet flow and curb and gutter, and consists mainly of asphalt and concrete surfaces with minor landscaping. This sub-basin has a total composite imperviousness of 77%. Basin 3: This 0.28-acre sub-basin is lies to the north of the site and includes on and off-site flows. The design point is a Type 13 area inlet located to the east of the sub- basin that stormwater coveys to by sheet and curb and gutter flow. This area is comprised of mostly asphalt with some elements of landscaping and concrete. This sub-basin has a total composite imperviousness of 88%. Basin 4: This small 0.16-acre sub-basin flows, via sheet and curb and gutter, to a combination inlet design point to the east of the sub-basin. This basin contains asphalt and concrete and has a composite imperviousness of 92%. Basin 5: This sub-basin consists of roof-top only and consist of approximately 0.32 acres. Flows from the roof are anticipated to connect directly to the underground storm piping. Total composite imperviousness is 90%. Basin 6: This small 0.30-acre sub-basin is located along the east of the property and adjacent to College Avenue. This sub-basin consists mainly of landscaping and sidewalk and will sheet flow historically to the west curb and gutter line of College Avenue then north to the existing 20-foot Type R inlet. This basin has a composite imperviousness of 47%. Basin 7: This basin is approximately 0.20 acres and includes on-site flows, mainly from east and south of the raised pedestrian walk. This basin consists generally of asphalt and concrete surfaces with minor landscaping. This basin flows via sheet flow and curb and gutter to a flume in a landscape island at the southwest portion of the site and has a total composite imperviousness of 85%. Basin OS-1: These off-site flows generate from the existing Fox Shopping Center building rooftop and parking lot to the west of the project site. This 0.89-acre area flows into Basin 2 and has a composite imperviousness of 91%. Basin OS-2: These off-site flows also generate from the existing Fox Shopping Center building rooftop and parking lot to the west of the project site. This 0.35-acre area flows into Basin 3 and has a composite imperviousness of 86%. 2. Final design details, and construction documentation shall be provided to the City of Fort Collins for review prior to Final Development Plan approval. 3. Stormwater facility Standard Operating Procedures (SOP) will be provided by the City of Fort Collins in the Development Agreement. C. Low Impact Development (LID) The LID requirement option for this project is treating at least 75% of the new and/or modified impervious areas which translates to approximately 67,954 square feet of area to be treated. Proposed on-site LID treatment intended to meet this requirement is an on-site StormTech filtration system. Prospect and College Hotel June 17, 2020 Page 6 Project No. 18111 1. StormTech Filtration System A StormTech filtration system is proposed to treat approximately 85% of the new and/or modified impervious area and the WQCV equal to 100% of the site. Approximately 74,488 square feet of contributory area (from new and/or modified impervious area) would convey to the StormTech facility, however, the WQCV was calculated assuming 100% of the site to equal approximately 0.064 acre-ft or 2,809 cubic-feet of volume to be treated. Based on this WQCV, the number of StormTech chambers were determined form a chamber sizing spreadsheet provided by the City of Fort Collins. It was calculated that thirty-Eight (38) ADS StormTech SC-740 chambers were required to contain the WQCV. The FAA method was also used to calculate the water quality storage volume that was determined to be 720 cubic feet which did not govern the design and, therefore, 38 chambers were used. Total storage with aggregate was calculated to be 2,846 cubic feet which was greater than the calculated WQCV of 2,809 cubic feet. Water quality flow is intended to flow into these chambers and treated through the ADS geotextile fabric before entering into the base stone layer beneath the chambers. A weir to divert the 100-year water quality peak flow rate is proposed to be installed in MH 3. Based on a peak water quality flow rate of 2.56 cfs through a 36-inch pipe, the top of weir elevation was calculated to be 4989.16 which is also the elevation of where the top of chambers is proposed to be set. Based on these elevations, the invert of the 6-inch perforated underdrain to be set in the base stone is calculated to be 4986.16. The underdrain is proposed to be installed flat to the outfall point within the large drainage channel to the west. Please see preliminary LID Treatment Exhibit, Water Quality Capture Volume (WQCV) computations and StormTech information provided in the Appendix D. VII. Variance Requests (if necessary) The proposed development is not requesting any variances at this time. VIII. Erosion Control Erosion and sediment control will be achieved through construction control measure to include various BMPs selected from the FCSCM such as silt fencing, vehicle tracking devices, inlet/outlet protection and curb protection, concrete washout, vehicle tracking control and stabilized staging areas. Preliminary BMP locations are shown in the corresponding Preliminary Utility Plans associated with this report. A separate Erosion Control Report and Erosion Control Plans will be provided at Final Development Plan submittal. IX. Conclusion The proposed drainage system design will provide safe conveyance of the minor and major storm events while providing increased water quality treatment compared to the existing condition. A substantial improvement to the routine flooding at College and Prospect is also anticipated. Prospect and College Hotel June 17, 2020 Page 7 Project No. 18111 A. Compliance with Standards 1. The drainage design proposed with the proposed project complies with the City of Fort Collins’ Stormwater Criteria Manual. 2. The drainage design proposed with this project complies with requirements for Spring Creek Basin. 3. The drainage plan and stormwater management measures proposed with the proposed development are compliant with all applicable State and Federal regulations governing stormwater discharge. 4. The erosion control materials that will be submitted with the final plans will comply with the requirements set forth by the City of Fort Collins’ Stormwater Criteria Manual and the Urban Storm Drainage Criteria Manual. B. Drainage Concept 1. The drainage design proposed with this project will effectively limit any potential flooding and/or damage associated with runoff quantities while effectively treating runoff through water quality mitigation features. 2. The drainage concept for the proposed will assist in reducing the routine flooding that currently occurs at the southwest corner of West Prospect Road and South College Avenue. Prospect and College Hotel June 17, 2020 Page 8 Project No. 18111 REFERENCES 1. City of Fort Collins, December 2018, Fort Collins Stormwater Criteria Manual. 2. Mile High Flood District, 2001 (November 2010 with some sections updated April 2018), Urban Storm Drainage Criteria Manual, Volume 3, Stormwater Quality. 3. United States Department of Agriculture Natural Resources Conservation Service; Web Soil Survey; accessed on-line September 2019. 4. Federal Emergency Management Agency; FEMA Flood Map Service Center; accessed on-line September 2019. APPENDICES 1. Appendix A - Site Information a. Vicinity Map b. Existing Site Aerial c. ALTA/NSPS Land Title Survey d. Proposed Site Plan e. NRCS Soils Data f. FEMA Map 2. Appendix B – Existing and Proposed Imperviousness a. Existing versus Proposed Impervious Area Exhibit 3. Appendix C – Rational Method Calculations a. Storm Criteria b. Rational Method Calculations 4. Appendix D – LID Information a. LID Treatment Exhibit b. WQCV Calculations c. StormTech Calculations and System Layout 5. Appendix E – Drainage Basin Map a. Drainage Basin Map APPENDIX A Prospect and College Hotel – Fort Collins, CO 18111 Map data ©2019 Google 1000 ft Google Maps Page 1 of 1 https://www.google.com/maps/@40.5677659,-105.0800875,15.37z 9/4/2019 Midtown Fort Collins Hotel Existing Site Aerial 600 ft N ➤➤ N © 2018 Google © 2018 Google © 2018 Google 0 30 SCALE: 1:30 30 15 60 PROJECT DEVELOPMENT PLAN NORTH FILE: PROJECT NO: CAD: QUALITY ASSURANCE: DRAWING HISTORY DATE DESCRIPTION FORT COLLINS, COLORADO 80525 SITE PLAN PROSPECT AND COLLEGE HOTEL 1623 SOUTH COLLEGE AVENUE FORT COLLINS, COLORADO C3.1 JET 18111_SITE_PROD.DWG ICS/LMH 2019/09/16 FIRST PDP SUBMITTAL 2020/02/26 2020/06/17 - - - - SECOND PDP SUBMITTAL THIRD PDP SUBMITTAL - - - - - - 18111 PLAN NOTES 1 NEW ASPHALT PAVING NEW CONCRETE WALK NEW ACCESSIBILITY RAMP NEW 4" PAINTED YELLOW STRIPE AT 3' O.C. (TYP.) NEW PAINTED INTERNATIONAL DISABLED SYMBOL NEW 4" PAINTED YELLOW PARKING STRIPE (TYP.) NEW CONCRETE DRIVE APPROACH PER CDOT STANDARDS NEW PRE-CAST PIN DOWN CONCRETE PARKING STOP NEW ADA SIGNAGE IN FRONT OF ALL ADA SPACES (TYP.) NEW TRASH PAD AND ENCLOSURE (SEE ARCH. FOR DETAILS) 2 3 4 5 6 7 8 9 10 CITY OF FORT COLLINS, COLORADO UTILITY PLAN APPROVAL APPROVED: CHECKED BY: CHECKED BY: Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 1 of 3 4490490 4490520 4490550 4490580 4490610 4490640 4490670 4490700 4490730 4490490 4490520 4490550 4490580 4490610 4490640 4490670 4490700 4490730 493320 493350 493380 493410 493440 493470 493500 493320 493350 493380 493410 493440 493470 493500 40° 34' 2'' N 105° 4' 44'' W 40° 34' 2'' N 105° 4' 36'' W 40° 33' 54'' N 105° 4' 44'' W 40° 33' 54'' N 105° 4' 36'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,310 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes 3.2 38.4% 4 Altvan-Satanta loams, 3 to 9 percent slopes 1.0 11.9% 35 Fort Collins loam, 0 to 3 percent slopes 3.8 45.1% 76 Nunn clay loam, wet, 1 to 3 percent slopes 0.4 4.6% Totals for Area of Interest 8.4 100.0% Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 3 of 3 Larimer County Area, Colorado 35—Fort Collins loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlnc Elevation: 4,020 to 6,730 feet Mean annual precipitation: 14 to 16 inches Mean annual air temperature: 46 to 48 degrees F Frost-free period: 143 to 154 days Farmland classification: Prime farmland if irrigated Map Unit Composition Fort collins and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Fort Collins Setting Landform: Interfluves Down-slope shape: Linear Across-slope shape: Linear Parent material: Pleistocene or older alluvium derived from igneous, metamorphic and sedimentary rock and/or eolian deposits Typical profile Ap - 0 to 4 inches: loam Bt1 - 4 to 9 inches: clay loam Bt2 - 9 to 16 inches: clay loam Bk1 - 16 to 29 inches: loam Bk2 - 29 to 80 inches: loam Properties and qualities Slope: 0 to 3 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 (0.20 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: 12 percent Salinity, maximum in profile: Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 2e Map Unit Description: Fort Collins loam, 0 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 1 of 2 Land capability classification (nonirrigated): 4c Hydrologic Soil Group: C Ecological site: Loamy Plains (R067BY002CO) Hydric soil rating: No Minor Components Nunn Percent of map unit: 10 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: Loamy Plains (R067BY002CO) Hydric soil rating: No Vona Percent of map unit: 5 percent Landform: Interfluves Landform position (two-dimensional): Backslope, footslope Landform position (three-dimensional): Side slope, base slope Down-slope shape: Linear Across-slope shape: Linear Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Map Unit Description: Fort Collins loam, 0 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 2 of 2 Larimer County Area, Colorado 3—Altvan-Satanta loams, 0 to 3 percent slopes Map Unit Setting National map unit symbol: jpw2 Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Altvan and similar soils: 45 percent Satanta and similar soils: 30 percent Minor components: 25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform: 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 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 Map Unit Description: Altvan-Satanta loams, 0 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 1 of 3 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 Hydric soil rating: No Description of Satanta Setting Landform: Terraces, structural benches Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 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 ponding: 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 Hydric soil rating: No Minor Components Nunn Percent of map unit: 10 percent Hydric soil rating: No Larim Percent of map unit: 10 percent Hydric soil rating: No Map Unit Description: Altvan-Satanta loams, 0 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 2 of 3 Stoneham Percent of map unit: 5 percent Hydric soil rating: No Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Map Unit Description: Altvan-Satanta loams, 0 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 3 of 3 Larimer County Area, Colorado 4—Altvan-Satanta loams, 3 to 9 percent slopes Map Unit Setting National map unit symbol: jpwf Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Farmland of statewide importance Map Unit Composition Altvan and similar soils: 55 percent Satanta and similar soils: 35 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform: Fans, benches, terraces Landform position (three-dimensional): Base slope, side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 16 inches: clay loam, loam, sandy clay loam H2 - 9 to 16 inches: loam, fine sandy loam, silt loam H2 - 9 to 16 inches: gravelly sand, gravelly coarse sand, coarse sand H3 - 16 to 31 inches: H3 - 16 to 31 inches: H3 - 16 to 31 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: Properties and qualities Slope: 6 to 9 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Map Unit Description: Altvan-Satanta loams, 3 to 9 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 1 of 3 Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 13.7 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No Description of Satanta Setting Landform: Terraces, structural benches Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 14 inches: loam, clay loam, sandy clay loam H2 - 9 to 14 inches: loam, clay loam, fine sandy loam H2 - 9 to 14 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: Properties and qualities Slope: 3 to 6 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Hydric soil rating: No Minor Components Nunn Percent of map unit: 6 percent Hydric soil rating: No Larimer Percent of map unit: 4 percent Map Unit Description: Altvan-Satanta loams, 3 to 9 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 2 of 3 Hydric soil rating: No Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Map Unit Description: Altvan-Satanta loams, 3 to 9 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 3 of 3 Larimer County Area, Colorado 76—Nunn clay loam, wet, 1 to 3 percent slopes Map Unit Setting National map unit symbol: jpxq Elevation: 4,800 to 5,600 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 Nunn, wet, and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn, Wet Setting Landform: Alluvial fans, stream terraces Landform position (three-dimensional): Base slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 10 inches: clay loam H2 - 10 to 47 inches: clay loam, clay H2 - 10 to 47 inches: clay loam, loam, gravelly sandy loam H3 - 47 to 60 inches: H3 - 47 to 60 inches: H3 - 47 to 60 inches: Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat poorly drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table: About 24 to 36 inches Frequency of flooding: Rare Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 19.8 inches) Interpretive groups Land capability classification (irrigated): 2w Map Unit Description: Nunn clay loam, wet, 1 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 1 of 2 Land capability classification (nonirrigated): 3s Hydrologic Soil Group: C Hydric soil rating: No Minor Components Heldt Percent of map unit: 6 percent Hydric soil rating: No Dacono Percent of map unit: 3 percent Hydric soil rating: No Mollic halaquepts Percent of map unit: 1 percent Landform: Swales Hydric soil rating: Yes Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Map Unit Description: Nunn clay loam, wet, 1 to 3 percent slopes---Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/30/2019 Page 2 of 2 Report—Physical Soil Properties Three values are provided to identify the expected Low (L), Representative Value (R), and High (H). Physical Soil Properties–Larimer County Area, Colorado Map symbol and soil name Depth Sand Silt Clay Moist bulk density Saturated hydraulic conductivity Available water capacity Linear extensibility Organic matter Erosion factors Wind erodibility group Wind erodibility index Kw Kf T In Pct Pct Pct g/cc micro m/sec In/In Pct Pct 3—Altvan- Satanta loams, 0 to 3 percent slopes Altvan 0-10 -42- -38- 16-20- 23 1.20-1.30 -1.40 4.23-9.17-14.11 0.14-0.16-0. 18 0.0- 1.5- 2.9 1.0- 1.5- 2.0 .28 .28 3 5 56 10-18 -35- -38- 20-28- 35 1.20-1.30 -1.40 4.23-9.17-14.11 0.15-0.16-0. 17 3.0- 4.5- 5.9 0.5- 0.8- 1.0 .32 .32 18-30 -45- -43- 8-12- 15 1.30-1.40 -1.50 4.23-9.17-14.11 0.12-0.14-0. 15 0.0- 1.5- 2.9 0.5- 0.8- 1.0 .43 .43 30-60 -96- - 2- 0- 3- 5 1.50-1.55 -1.60 141.14-423.07- 705.00 0.02-0.03-0. 04 Physical Soil Properties–Larimer County Area, Colorado Map symbol and soil name Depth Sand Silt Clay Moist bulk density Saturated hydraulic conductivity Available water capacity Linear extensibility Organic matter Erosion factors Wind erodibility group Wind erodibility index Kw Kf T In Pct Pct Pct g/cc micro m/sec In/In Pct Pct 4—Altvan- Satanta loams, 3 to 9 percent slopes Altvan 0-9 -42- -38- 16-20- 23 1.20-1.30 -1.40 4.23-9.17-14.11 0.14-0.16-0. 18 0.0- 1.5- 2.9 1.0- 1.5- 2.0 .28 .28 3 5 56 9-16 -35- -38- 20-28- 35 1.20-1.30 -1.40 4.23-9.17-14.11 0.15-0.16-0. 17 3.0- 4.5- 5.9 0.5- 0.8- 1.0 .32 .32 16-31 -45- -43- 8-12- 15 1.30-1.40 -1.50 4.23-9.17-14.11 0.12-0.14-0. 15 0.0- 1.5- 2.9 0.5- 0.8- 1.0 .43 .43 31-60 -96- - 2- 0- 3- 5 1.50-1.55 -1.60 141.14-423.07- 705.00 0.02-0.03-0. 04 0.0- 1.5- 2.9 0.0- 0.3- 0.5 Physical Soil Properties–Larimer County Area, Colorado Map symbol and soil name Depth Sand Silt Clay Moist bulk density Saturated hydraulic conductivity Available water capacity Linear extensibility Organic matter Erosion factors Wind erodibility group Wind erodibility index Kw Kf T In Pct Pct Pct g/cc micro m/sec In/In Pct Pct 35—Fort Collins loam, 0 to 3 percent slopes Fort collins 0-4 36-43- 50 28-38- 48 16-19- 26 1.44-1.47 -1.50 4.23-9.17-42.34 0.15-0.15-0. 17 1.7- 2.1- 3.5 1.0- 1.5- 2.0 .43 .43 5 5 56 4-9 30-42- 45 20-26- 50 20-32- 35 1.45-1.49 -1.53 1.41-2.82-14.11 0.15-0.16-0. 16 2.3- 4.6- 5.1 0.5- 0.8- 1.0 .32 .32 9-16 30-42- 45 20-26- 50 20-32- 35 1.45-1.49 -1.53 1.41-9.17-14.11 0.15-0.16-0. 16 2.1- 4.2- 4.9 0.5- 0.8- 1.0 .28 .28 16-29 35-47- 50 20-32- 38 20-21- 30 1.48-1.50 -1.51 1.41-9.17-14.11 0.15-0.15-0. 16 1.5- 1.7- 3.3 0.0- 0.3- 0.5 .43 .43 29-80 35-47- 50 20-32- 38 20-21- 30 1.48-1.50 -1.51 Physical Soil Properties This table shows estimates of some physical characteristics and features that affect soil behavior. These estimates are given for the layers of each soil in the survey area. The estimates are based on field observations and on test data for these and similar soils. Depth to the upper and lower boundaries of each layer is indicated. Particle size is the effective diameter of a soil particle as measured by sedimentation, sieving, or micrometric methods. Particle sizes are expressed as classes with specific effective diameter class limits. The broad classes are sand, silt, and clay, ranging from the larger to the smaller. Sand as a soil separate consists of mineral soil particles that are 0.05 millimeter to 2 millimeters in diameter. In this table, the estimated sand content of each soil layer is given as a percentage, by weight, of the soil material that is less than 2 millimeters in diameter. Silt as a soil separate consists of mineral soil particles that are 0.002 to 0.05 millimeter in diameter. In this table, the estimated silt content of each soil layer is given as a percentage, by weight, of the soil material that is less than 2 millimeters in diameter. Clay as a soil separate consists of mineral soil particles that are less than 0.002 millimeter in diameter. In this table, the estimated clay content of each soil layer is given as a percentage, by weight, of the soil material that is less than 2 millimeters in diameter. The content of sand, silt, and clay affects the physical behavior of a soil. Particle size is important for engineering and agronomic interpretations, for determination of soil hydrologic qualities, and for soil classification. The amount and kind of clay affect the fertility and physical condition of the soil and the ability of the soil to adsorb cations and to retain moisture. They influence shrink-swell potential, saturated hydraulic conductivity (Ksat), plasticity, the ease of soil dispersion, and other soil properties. The amount and kind of clay in a soil also affect tillage and earthmoving operations. Moist bulk density is the weight of soil (ovendry) per unit volume. Volume is measured when the soil is at field moisture capacity, that is, the moisture content at 1/3- or 1/10-bar (33kPa or 10kPa) moisture tension. Weight is determined after the soil is dried at 105 degrees C. In the table, the estimated moist bulk density of each soil horizon is expressed in grams per cubic centimeter of soil material that is less than 2 millimeters in diameter. Bulk density data are used to compute linear extensibility, shrink-swell potential, available water capacity, total pore space, and other soil properties. The moist bulk density of a soil indicates the pore space available for water and roots. Depending on soil texture, a bulk density of more than 1.4 can restrict water storage and root penetration. Moist bulk density is influenced by texture, kind of clay, content of organic matter, and soil structure. Physical Soil Properties---Larimer County Area, Colorado Midtown Hotel Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 1 of 6 Saturated hydraulic conductivity (Ksat) refers to the ease with which pores in a saturated soil transmit water. The estimates in the table are expressed in terms of micrometers per second. They are based on soil characteristics observed in the field, particularly structure, porosity, and texture. Saturated hydraulic conductivity (Ksat) is considered in the design of soil drainage systems and septic tank absorption fields. Available water capacity refers to the quantity of water that the soil is capable of storing for use by plants. The capacity for water storage is given in inches of water per inch of soil for each soil layer. The capacity varies, depending on soil properties that affect retention of water. The most important properties are the content of organic matter, soil texture, bulk density, and soil structure. Available water capacity is an important factor in the choice of plants or crops to be grown and in the design and management of irrigation systems. Available water capacity is not an estimate of the quantity of water actually available to plants at any given time. Linear extensibility refers to the change in length of an unconfined clod as moisture content is decreased from a moist to a dry state. It is an expression of the volume change between the water content of the clod at 1/3- or 1/10-bar tension (33kPa or 10kPa tension) and oven dryness. The volume change is reported in the table as percent change for the whole soil. The amount and type of clay minerals in the soil influence volume change. Linear extensibility is used to determine the shrink-swell potential of soils. The shrink-swell potential is low if the soil has a linear extensibility of less than 3 percent; moderate if 3 to 6 percent; high if 6 to 9 percent; and very high if more than 9 percent. If the linear extensibility is more than 3, shrinking and swelling can cause damage to buildings, roads, and other structures and to plant roots. Special design commonly is needed. Organic matter is the plant and animal residue in the soil at various stages of decomposition. In this table, the estimated content of organic matter is expressed as a percentage, by weight, of the soil material that is less than 2 millimeters in diameter. The content of organic matter in a soil can be maintained by returning crop residue to the soil. Organic matter has a positive effect on available water capacity, water infiltration, soil organism activity, and tilth. It is a source of nitrogen and other nutrients for crops and soil organisms. Erosion factors are shown in the table as the K factor (Kw and Kf) and the T factor. 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 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 indicates the erodibility of the whole soil. The estimates are modified by the presence of rock fragments. Erosion factor Kf indicates the erodibility of the fine-earth fraction, or the material less than 2 millimeters in size. Physical Soil Properties---Larimer County Area, Colorado Midtown Hotel Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 2 of 6 Erosion factor T is an estimate of the maximum average annual rate of soil erosion by wind and/or water that can occur without affecting crop productivity over a sustained period. The rate is in tons per acre per year. Wind erodibility groups are made up of soils that have similar properties affecting their susceptibility to wind erosion in cultivated areas. The soils assigned to group 1 are the most susceptible to wind erosion, and those assigned to group 8 are the least susceptible. The groups are described in the "National Soil Survey Handbook." Wind erodibility index is a numerical value indicating the susceptibility of soil to wind erosion, or the tons per acre per year that can be expected to be lost to wind erosion. There is a close correlation between wind erosion and the texture of the surface layer, the size and durability of surface clods, rock fragments, organic matter, and a calcareous reaction. Soil moisture and frozen soil layers also influence wind erosion. Reference: United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. (http://soils.usda.gov) Physical Soil Properties---Larimer County Area, Colorado Midtown Hotel Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 3 of 6 PROJECT LOCATION APPENDIX B Prospect and College Hotel – Fort Collins, CO 18111 EXHIBIT B NORTH 50 0 SCALE:1" = 100' 50 100 SURFACE AREA (SF) % IMPERV. IMPERV. AREA (SF) ROOFTOP 15,080 90 13,572 CONCRETE 13,930 90 12,537 ASPHALT 47,300 100 47,300 LANDSCAPE 16,604 2 332 TOTAL 92,914 73,741 EXISTING PROPOSED SURFACE AREA (SF) % IMPERV. IMPERV. AREA (SF) ROOFTOP 22,032 90 19,829 CONCRETE 7,928 90 7,135 ASPHALT 54,615 100 54,615 LANDSCAPE 8,339 2 167 TOTAL 92,914 81,746 APPENDIX C Prospect and College Hotel – Fort Collins, CO 18111 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 2.0 Runoff Methodologies 3.1 Rational Formula Page 3 2.0 Runoff Methodologies There are two runoff analysis methodologies that are approved by the City: the Rational Method and the Stormwater Management Model (SWMM). In general, the chosen methodology should follow the basin size limitations listed in Table 2.0-1 below. SWMM must also be used to assess the performance of multiple detention basins in parallel or in series in a particular watershed. The City is the determining authority with respect to the appropriate methodology to use under uncertain circumstances. Please note that the Colorado Urban Hydrograph Procedure (CUHP) is not allowed to be utilized for hydrology analysis for Fort Collins area projects because this procedure is calibrated using Denver/Boulder rainfall data. Table 2.0-1: Runoff Calculation Method Project Size Runoff Calculation Method < 5 acres Rational Method Required 5-20 acres Rational Method or SWMM Accepted ≥ 20 acres SWMM Required Reference: Drainage Report submittal requirements must be prepared in accordance with the criteria set forth in Chapter 2: Development Submittal Requirements. 3.0 Rational Method 3.1 Rational Formula The methodology and theory behind the Rational Method is not covered in this Manual as this subject is well described in many hydrology reference books. However, the Rational Method procedure is generally provided in the following sections. Runoff coefficient calculations, rainfall data, and the time of concentration formula are specific to the City and are included below. The Rational Formula is represented by the following equation: 𝐐𝐐 = 𝐂𝐂𝐂𝐂𝐂𝐂 Equation 5-1 Where: Q = Peak Rate of Runoff, cfs C = Runoff Coefficient, dimensionless I = Rainfall Intensity, in/hr A = Area of the Basin or Sub-basin, acres FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.2 Runoff Coefficients Page 4 3.2 Runoff Coefficients Runoff coefficients used for the Rational Method are determined based on either overall land use or surface type across the drainage area. For Overall Drainage Plan (ODP) submittals, when surface types may not yet be known, land use shall be used to estimate flow rates and volumes. Table 3.2-1 lists the runoff coefficients for common types of land uses in the City. Table 3.2-1. Zoning Classification - Runoff Coefficients Land Use Runoff Coefficient (C) Residential Urban Estate 0.30 Low Density 0.55 Medium Density 0.65 High Density 0.85 Commercial Commercial 0.85 Industrial 0.95 Undeveloped Open Lands, Transition 0.20 Greenbelts, Agriculture 0.20 Reference: For further guidance regarding zoning classifications, refer to the Land Use Code, Article 4. For a Project Development Plan (PDP) or Final Plan (FP) submittals, runoff coefficients must be based on the proposed land surface types. Since the actual runoff coefficients may be different from those specified in Table 3.2-1, Table 3.2-2 lists coefficients for the specific types of land surfaces. FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.2 Runoff Coefficients Page 5 Table 3.2-2. Surface Type - Runoff Coefficients Surface Type Runoff Coefficients Hardscape or Hard Surface Asphalt, Concrete 0.95 Rooftop 0.95 Recycled Asphalt 0.80 Gravel 0.50 Pavers 0.50 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope < 2% 0.10 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.20 Lawns, Clayey Soil, Flat Slope < 2% 0.20 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 0.35 3.2.1 Composite Runoff Coefficients Drainage sub-basins are frequently composed of land that has multiple surface types or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: ( ) t n i i i A C xA C ∑ = = 1 Equation 5-2 Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (Ai), dimensionless Ai = Area of Surface with Runoff Coefficient of Ci, acres or square feet n = Number of different surfaces to be considered At = Total Area over which C is applicable, acres or square feet 3.2.2 Runoff Coefficient Frequency Adjustment Factor The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapotranspiration and other losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.3 Time of Concentration Page 6 applied to the composite runoff coefficient. These frequency adjustment factors, Cf, are found in Table 3.2-3. Table 3.2-3. Frequency Adjustment Factors Storm Return Period (years) Frequency Adjustment Factor (Cf) 2, 5, 10 1.00 25 1.10 50 1.20 100 1.25 3.3 Time of Concentration 3.3.1 Overall Equation The next step to approximate runoff using the Rational Method is to estimate the Time of Concentration, Tc, or the time for water to flow from the most remote part of the drainage sub-basin to the design point under consideration. The Time of Concentration is represented by the following equation: 𝐓𝐓𝐜𝐜 = 𝐓𝐓 𝐢𝐢 + 𝐓𝐓𝐭𝐭 Equation 5-3 Where: Tc = Total Time of Concentration, minutes Ti = Initial or Overland Flow Time of Concentration, minutes Tt = Channelized Flow in Swale, Gutter or Pipe, minutes 3.3.2 Overland Flow Time Overland flow, Ti, can be determined by the following equation: 𝐓𝐓𝐢𝐢 = 𝟏𝟏.𝟖𝟖𝟖𝟖(𝟏𝟏.𝟏𝟏−𝐂𝐂𝐂𝐂𝐂𝐂𝐟𝐟)√𝐋𝐋 √𝐒𝐒 𝟑𝟑 Equation 3.3-2 Where: C = Runoff Coefficient, dimensionless Cf = Frequency Adjustment Factor, dimensionless L = Length of Overland Flow, feet S = Slope, percent CXCF PRODUCT OF CXCF CANNOT EXCEED THE VALUE OF 1 OVERLAND FLOW LENGTH L=200’ MAX IN DEVELOPED AREAS L=500’ MAX IN UNDEVELOPED AREAS FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 7 3.3.3 Channelized Flow Time Travel time in a swale, gutter or storm pipe is considered “channelized” or “concentrated” flow and can be estimated using the Manning’s Equation: 𝐕𝐕 = 𝟏𝟏.𝟒𝟒𝟒𝟒 𝐧𝐧 𝐑𝐑𝟐𝟐/𝟑𝟑 𝐒𝐒𝟏𝟏/𝟐𝟐 Equation 5-4 Where: V = Velocity, feet/second n = Roughness Coefficient, dimensionless R = Hydraulic Radius, feet (Hydraulic Radius = area / wetted perimeter, feet) S = Longitudinal Slope, feet/feet And: 𝐓𝐓𝐭𝐭 = 𝐋𝐋 𝐕𝐕𝐂𝐂𝐕𝐕𝐕𝐕 Equation 5-5 3.3.4 Total Time of Concentration A minimum Tc of 5 minutes is required. The maximum Tc allowed for the most upstream design point shall be calculated using the following equation: 𝐓𝐓𝐜𝐜 = 𝐋𝐋 𝟏𝟏𝟖𝟖𝐕𝐕 + 𝟏𝟏𝐕𝐕 Equation 3.3-5 The Total Time of Concentration, Tc, is the lesser of the values of Tc calculated using Tc = Ti + Tt or the equation listed above. 3.4 Intensity-Duration-Frequency Curves for Rational Method The two-hour rainfall Intensity-Duration-Frequency curves for use with the Rational Method is provided in Table 3.4-1 and Figure 3.4-1. TC • A MINIMUM TC OF 5 MINUTES IS REQUIRED IN ALL CASES. • A MAXIMUM TC OF 5 MINUTES IS TYPICAL FOR SMALLER, URBAN PROJECTS. FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 8 Table 3.4-1. IDF Table for Rational Method Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) 5 2.85 4.87 9.95 39 1.09 1.86 3.8 6 2.67 4.56 9.31 40 1.07 1.83 3.74 7 2.52 4.31 8.80 41 1.05 1.80 3.68 8 2.40 4.10 8.38 42 1.04 1.77 3.62 9 2.30 3.93 8.03 43 1.02 1.74 3.56 10 2.21 3.78 7.72 44 1.01 1.72 3.51 11 2.13 3.63 7.42 45 0.99 1.69 3.46 12 2.05 3.50 7.16 46 0.98 1.67 3.41 13 1.98 3.39 6.92 47 0.96 1.64 3.36 14 1.92 3.29 6.71 48 0.95 1.62 3.31 15 1.87 3.19 6.52 49 0.94 1.6 3.27 16 1.81 3.08 6.30 50 0.92 1.58 3.23 17 1.75 2.99 6.10 51 0.91 1.56 3.18 18 1.70 2.90 5.92 52 0.9 1.54 3.14 19 1.65 2.82 5.75 53 0.89 1.52 3.10 20 1.61 2.74 5.60 54 0.88 1.50 3.07 21 1.56 2.67 5.46 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 9 Figure 3.4-1. Rainfall IDF Curve – Fort Collins Prospect College Hotel Fort Collins, Colorado LAND USE AND IMPERVIOUSNESS 6/16/2020 Proj No. 18111 Surface Type Runoff Coefficients % Impervious Asphalt 0.95 100% 2-Year Cf 1.00 Concrete 0.95 90% 10-Year Cf 1.00 Rooftop 0.95 90% 100-Year Cf 1.25 Gravel 0.50 40% Landscape < 2% 0.10 2% Landscape 2-7% 0.15 2% BASIN IMPERVIOUS CALCS Developed Conditions Total Area, A Total Area, A 2-Year 10-Year 100-Year % Basin Basin Description sf Acres Asphalt Rooftop Concrete Landscape Composite Composite Composite Composite Design Point Area (sf) Area (sf) Area (sf) Area (sf) Runoff Coefficient Runoff Coefficient Runoff Coefficient Impervious, I 1 B-1 (On-Site Only) 16,117 0.37 10,798 0 3,223 2,096 0.84 0.84 1.00 85% 2 B-2 16,071 0.37 8,465 0 4,259 3,347 0.77 0.77 0.97 77% 3 B-3 (On-Site Only) 12,360 0.28 9,728 0 1,266 1,366 0.86 0.86 1.00 88% 4 B-4 6,904 0.16 5,553 0 844 507 0.89 0.89 1.00 92% 5 B-5 14,016 0.32 0 14,016 0 0 0.95 0.95 1.00 90% 6 B-6 13,079 0.30 0 0 6,707 6,372 0.54 0.54 0.67 47% 7 B-7 8,712 0.20 5,837 0 1,742 1,133 0.84 0.84 1.00 85% O1 OS-1 38,950 0.89 21,552 6,803 8,531 2,064 0.90 0.90 1.00 91% O2 OS-2 15,415 0.35 7,780 2,179 3,878 1,578 0.86 0.86 1.00 86% 1 OS-1 and B-1 55,067 1.26 32,350 6,803 11,754 4,160 0.89 0.89 1.00 89% 3 OS-2 and B-3 27,775 0.64 17,509 2,179 5,143 2,944 0.86 0.86 1.00 87% Fort Collins Rational Spreadsheet_2-10-100-Yr.xlsx Prospect College Hotel Fort Collins, Colorado 6/16/2020 Proj# 18111 Note: Assumed C-value for flow over grassy surfaces is 0.25 (0.31 for 100-yr) Assumed C-value for flow over hard surfaces is 0.95 (1.00 for 100-yr) TIME OF CONCENTRATION CALCULATIONS INITIAL FLOW - Ti Channelized Flow - Tt C*Cf C*Cf C*Cf INIT. INIT. Trvl 1 Trvl 1 Trvl 1 2-Yr Tc* = 10-Yr Tc* = 100- Yr Tc* = BASIN Is Length 2-yr Cf= 10-yr Cf= 100-yr Cf= L1 S1 Ti 2-yr Ti 10-yr Ti 100-yr L 2 V T2 Sum Ti +Tt Sum Ti +Tt Sum Ti +Tt Design Point >200' ? Flow path material 1 1 1.25 (ft) (%) (min) (min) (min) (ft) (f/s) (min) (min) (min) (min) 1 NO 2 0.95 0.95 1.00 200.00 0.01 4.06 4.06 2.70 0.00 0.00 0.00 5.0 5.0 5.0 2 NO 2 0.95 0.95 1.00 183.00 0.02 2.97 2.97 1.98 0.00 0.00 0.00 5.0 5.0 5.0 3 NO 2 0.95 0.95 1.00 115.00 0.02 2.40 2.40 1.60 0.00 0.00 0.00 5.0 5.0 5.0 4 NO 2 0.95 0.95 1.00 134.00 0.01 3.04 3.04 2.03 0.00 0.00 0.00 5.0 5.0 5.0 5 NO 2 0.95 0.95 1.00 100.00 0.01 2.81 2.81 1.87 0.00 0.00 0.00 5.0 5.0 5.0 6 NO 2 0.95 0.95 1.00 95.00 0.03 1.90 1.90 1.27 0.00 0.00 0.00 5.0 5.0 5.0 7 NO 3 0.95 0.95 1.00 172.00 0.01 3.85 3.85 2.57 0.00 0.00 0.00 5.0 5.0 5.0 O1 NO 2 0.95 0.95 1.00 200.00 0.01 4.02 4.02 2.68 120.00 2.96 0.67 5.0 5.0 5.0 O2 NO 2 0.95 0.95 1.00 200.00 0.01 3.88 3.88 2.59 0.00 0.00 0.00 5.0 5.0 5.0 2 1 NO 2 0.95 0.95 1.00 200.00 0.01 4.02 4.02 2.68 67.00 2.52 0.44 5.0 5.0 5.0 3 NO 2 0.95 0.95 1.00 200.00 0.01 3.88 3.88 2.59 180.00 3.80 0.79 5.0 5.0 5.0 2 * If time of concentration was less than 5 minutes, 5 minutes was used. TRVL 2 Fort Collins Rational Spreadsheet_2-10-100-Yr.xlsx Prospect College Hotel Fort Collins, Colorado 6/16/2020 Proj# 18111 STORM DRAINAGE CALCULATION AREA C2 C10 C100 Tc* Tc* Tc* I 2 I 10 I 100 Q Q Q BASIN Basin Description 2-Yr 10-Yr 100-Yr 2-yr 10-yr 100-yr Design Point (acres) (min) (min) (min) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1 B-1 (On-Site Only) 0.37 0.84 0.84 1.00 5.0 5.0 5.0 2.85 4.87 9.95 0.89 1.51 3.68 2 B-2 0.37 0.77 0.77 0.97 5.0 5.0 5.0 2.85 4.87 9.95 0.81 1.39 3.55 3 B-3 (On-Site Only) 0.28 0.86 0.86 1.00 5.0 5.0 5.0 2.85 4.87 9.95 0.69 1.18 2.82 4 B-4 0.16 0.89 0.89 1.00 5.0 5.0 5.0 2.85 4.87 9.95 0.40 0.69 1.58 5 B-5 0.32 0.95 0.95 1.00 5.0 5.0 5.0 2.85 4.87 9.95 0.87 1.49 3.20 6 B-6 0.30 0.54 0.54 0.67 5.0 5.0 5.0 2.85 4.87 9.95 0.46 0.78 2.00 7 B-7 0.20 0.84 0.84 1.00 5.0 5.0 5.0 2.85 4.87 9.95 0.48 0.82 1.99 O1 OS-1 0.89 0.90 0.90 1.00 5.0 5.0 5.0 2.85 4.87 9.95 2.31 3.94 8.90 O2 OS-2 0.35 0.86 0.86 1.00 5.0 5.0 5.0 2.85 4.87 9.95 0.87 1.49 3.52 1 OS-1 and B-1 1.26 0.89 0.89 1.00 5.0 5.0 5.0 2.85 4.87 9.95 3.19 5.45 12.58 3 OS-2 and B-3 0.64 0.86 0.86 1.00 5.0 5.0 5.0 2.85 4.87 9.95 1.56 2.67 6.34 * If time of concentration was less than 5 minutes, 5 minutes was used. Basin Characteristics Intensities Sub-basin Fort Collins Rational Spreadsheet_2-10-100-Yr.xlsx APPENDIX D Prospect and College Hotel – Fort Collins, CO 18111 Prospect & College Hotel Water Quality Capture Volume (WQCV) Calculations Total Area of New and/or Modified Impervious Area Contributory to Stormtech = 87,469 sq-ft 2.008 Acres a= 0.8 12-Hour Drain Time I= 90% WQCV= 0.321 Watershed-Inches A= 2.008 Acres V= 0.064 Acre-Feet Therefore; 2,809 cubic-feet of WQCV is required to be treated � = �� 12 � x 1.2 �� = �(0.91� � − 1.19� � + 0.78� Prospect College Hotel Fort Collins, CO Vault ID In-Flow, WQ (cfs) Chamber Type Mimimum No. of Chambersd Minimum Release Ratee (cfs) Required Chamber Volume by FAA Method (cf) Mimimum No. of Chambersf Provided Number of Chambers Provided Release Ratee (cfs) Provided Chamber Volumeg (cf) Total Installed Chamber Volumeh (cf) S1 2.56 SC-740 38 0.90 720 10 38 0.90 1744 2846 Note: "Chamber Volume" refers to the open volume within the vaults. "Installed Chamber Volume" refers to the total volume provided, including the surrounding aggregates. a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. b. Volume within chamber only, not accounting for void spaces in surrounding aggregate. c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit. In-Flow WQ d. Number of chambers required to provide full WQCV within total installed system, including aggregate. C 0.89 e. Release rate per chamber times number of chambers. i 1.43 in/hr f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage). A 2.01 acres g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume. h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV. SC-160 SC-310 MC-3500 25.0 34.0 77 84.4 85.4 86 12.0 16.0 45 14.7 20.2 43.2 6.9 14.7 109.9 15.0 29.3 175 0.35 gpm/sf 7.48052 gal 0.133681 cf 0.002228 cfs *Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Report SC-160 SC-310 MC-3500 0.011426 0.015724 0.033687 Chamber Flow Rate SC-740 Flow Rate/chamber (cfs) 0.023586 45.9 Chamber/Aggregate Volume (cf) 74.9 Chamber Product SC-740 Design Storm WQ Required Detention Volume Developed "C" 0.9 Quantity Detention 720 Area 2.01 acres Max Release Rate 0.9 cfs Time Time Ft.Collins WQ Intensity Q 100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft3) (ft3) (ft3) 5 300 1.43 2.6 776 270 506 10 600 1.11 2.0 1205 540 665 15 900 0.94 1.7 1530 810 720 20 1200 0.81 1.5 1758 1080 678 25 1500 0.72 1.3 1954 1350 604 30 1800 0.65 1.2 2117 1620 497 35 2100 0.59 1.1 2241 1890 351 40 2400 0.54 1.0 2344 2160 184 45 2700 0.50 0.9 2442 2430 12 50 3000 0.46 0.8 2496 2700 -204 55 3300 0.44 0.8 2627 2970 -343 60 3600 0.41 0.7 2670 3240 -570 65 3900 0.39 0.7 2751 3510 -759 70 4200 0.37 0.7 2811 3780 -969 75 4500 0.35 0.6 2849 4050 -1201 80 4800 0.33 0.6 2865 4320 -1455 85 5100 0.32 0.6 2952 4590 -1638 90 5400 0.31 0.6 3028 4860 -1832 95 5700 0.29 0.5 2990 5130 -2140 100 6000 0.28 0.5 3039 5400 -2361 105 6300 0.27 0.5 3077 5670 -2593 110 6600 0.26 0.5 3104 5940 -2836 115 6900 0.3 0.5 3745 6210 -2465 120 7200 0.25 0.5 3256 6480 -3224 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Sunday, Feb 23 2020 Weir Sizing Circular Diameter (ft) = 3.00 Invert Elev (ft) = 4988.56 Slope (%) = 0.20 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 2.56 Highlighted Depth (ft) = 0.60 Q (cfs) = 2.560 Area (sqft) = 1.01 Velocity (ft/s) = 2.52 Wetted Perim (ft) = 2.79 Crit Depth, Yc (ft) = 0.50 Top Width (ft) = 2.40 EGL (ft) = 0.70 0 1 2 3 4 5 Elev (ft) Depth (ft) Section 4987.00 -1.56 4988.00 -0.56 4989.00 0.44 4990.00 1.44 4991.00 2.44 4992.00 3.44 Reach (ft) 2013 ADS, INC. FOR STORMTECH INSTRUCTIONS, DOWNLOAD THE INSTALLATION APP IMPORTANT - NOTES FOR THE BIDDING AND INSTALLATION OF THE SC-740 SYSTEM 1. STORMTECH SC-740 CHAMBERS SHALL NOT BE INSTALLED UNTIL THE MANUFACTURER'S REPRESENTATIVE HAS COMPLETED A PRE-CONSTRUCTION MEETING WITH THE INSTALLERS. 2. STORMTECH SC-740 CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH SC-310/SC-740/DC-780 CONSTRUCTION GUIDE". 3. CHAMBERS ARE NOT TO BE BACKFILLED WITH A DOZER OR AN EXCAVATOR SITUATED OVER THE CHAMBERS. STORMTECH RECOMMENDS 3 BACKFILL METHODS: x STONESHOOTER LOCATED OFF THE CHAMBER BED. x BACKFILL AS ROWS ARE BUILT USING AN EXCAVATOR ON THE FOUNDATION STONE OR SUBGRADE. x BACKFILL FROM OUTSIDE THE EXCAVATION USING A LONG BOOM HOE OR EXCAVATOR. 4. THE FOUNDATION STONE SHALL BE LEVELED AND COMPACTED PRIOR TO PLACING CHAMBERS. 5. JOINTS BETWEEN CHAMBERS SHALL BE PROPERLY SEATED PRIOR TO PLACING STONE. 6. MAINTAIN MINIMUM - 6" (150 mm) SPACING BETWEEN THE CHAMBER ROWS. 7. EMBEDMENT STONE SURROUNDING CHAMBERS MUST BE A CLEAN, CRUSHED, ANGULAR STONE 3/4-2" (20-50 mm). 8. THE CONTRACTOR MUST REPORT ANY DISCREPANCIES WITH CHAMBER FOUNDATION MATERIALS BEARING CAPACITIES TO THE SITE DESIGN ENGINEER. 9. ADS RECOMMENDS THE USE OF "FLEXSTORM CATCH IT" INSERTS DURING CONSTRUCTION FOR ALL INLETS TO PROTECT THE SUBSURFACE STORMWATER MANAGEMENT SYSTEM FROM CONSTRUCTION SITE RUNOFF. NOTES FOR CONSTRUCTION EQUIPMENT 1. STORMTECH SC-740 CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH SC-310/SC-740/DC-780 CONSTRUCTION GUIDE". 2. THE USE OF CONSTRUCTION EQUIPMENT OVER SC-740 CHAMBERS IS LIMITED: x NO EQUIPMENT IS ALLOWED ON BARE CHAMBERS. x NO RUBBER TIRED LOADERS, DUMP TRUCKS, OR EXCAVATORS ARE ALLOWED UNTIL PROPER FILL DEPTHS ARE REACHED IN ACCORDANCE WITH THE "STORMTECH SC-310/SC-740/DC-780 CONSTRUCTION GUIDE". x WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT CAN BE FOUND IN THE "STORMTECH SC-310/SC-740/DC-780 CONSTRUCTION GUIDE". 3. FULL 36" (900 mm) OF STABILIZED COVER MATERIALS OVER THE CHAMBERS IS REQUIRED FOR DUMP TRUCK TRAVEL OR DUMPING. USE OF A DOZER TO PUSH EMBEDMENT STONE BETWEEN THE ROWS OF CHAMBERS MAY CAUSE DAMAGE TO THE CHAMBERS AND IS NOT AN ACCEPTABLE BACKFILL METHOD. ANY CHAMBERS DAMAGED BY THE "DUMP AND PUSH" METHOD ARE NOT COVERED UNDER THE STORMTECH STANDARD WARRANTY. CONTACT STORMTECH AT 1-888-892-2694 WITH ANY QUESTIONS ON INSTALLATION REQUIREMENTS OR WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT. SC-740 STORMTECH CHAMBER SPECIFICATIONS 1. CHAMBERS SHALL BE STORMTECH SC-740. 2. CHAMBERS SHALL BE ARCH-SHAPED AND SHALL BE MANUFACTURED FROM VIRGIN, IMPACT-MODIFIED POLYPROPYLENE COPOLYMERS. 3. CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418-16a, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". 4. CHAMBER ROWS SHALL PROVIDE CONTINUOUS, UNOBSTRUCTED INTERNAL SPACE WITH NO INTERNAL SUPPORTS THAT WOULD IMPEDE FLOW OR LIMIT ACCESS FOR INSPECTION. 5. THE STRUCTURAL DESIGN OF THE CHAMBERS, THE STRUCTURAL BACKFILL, AND THE INSTALLATION REQUIREMENTS SHALL ENSURE THAT THE LOAD FACTORS SPECIFIED IN THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS, SECTION 12.12, ARE MET FOR: 1) LONG-DURATION DEAD LOADS AND 2) SHORT-DURATION LIVE LOADS, BASED ON THE AASHTO DESIGN TRUCK WITH CONSIDERATION FOR IMPACT AND MULTIPLE VEHICLE PRESENCES. 6. CHAMBERS SHALL BE DESIGNED, TESTED AND ALLOWABLE LOAD CONFIGURATIONS DETERMINED IN ACCORDANCE WITH ASTM F2787, "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". LOAD CONFIGURATIONS SHALL INCLUDE: 1) INSTANTANEOUS (<1 MIN) AASHTO DESIGN TRUCK LIVE LOAD ON MINIMUM COVER 2) MAXIMUM PERMANENT (75-YR) COVER LOAD AND 3) ALLOWABLE COVER WITH PARKED (1-WEEK) AASHTO DESIGN TRUCK. 7. REQUIREMENTS FOR HANDLING AND INSTALLATION: x TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS. x TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 2´. x TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED IN SECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO 550 LBS/IN/IN. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73 F / 23 C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLD OR YELLOW COLORS. 8. ONLY CHAMBERS THAT ARE APPROVED BY THE SITE DESIGN ENGINEER WILL BE ALLOWED. UPON REQUEST BY THE SITE DESIGN SHEET OF DATE: PROJECT #: DRAWN: CHECKED: THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS. 4640 TRUEMAN BLVD HILLIARD, OH 43026 ADVANCED DRAINAGE SYSTEMS, INC. 1-800-733-7473 R REV DRW CHK DESCRIPTION MIDTOWN HOTEL FORT COLLINS, CO EF N/A 2 6 70 INWOOD ROAD, SUITE 3 | ROCKY HILL | CT | 06067 860-529-8188 |888-892-2694 | WWW.STORMTECH.COM Detention Retention Water Quality NOTES MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECH SHEET #7 FOR MANIFOLD SIZING GUIDANCE. DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD COMPONENTS IN THE FIELD. THE SITE DESIGN ENGINEER MUST REVIEW ELEVATIONS AND IF NECESSARY ADJUST GRADING TO ENSURE THE CHAMBER COVER REQUIREMENTS ARE MET. THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION IS PROVIDED. NOT FOR CONSTRUCTION PROPOSED ELEVATIONS MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED): 4997.16 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC): 4991.16 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC): 4990.66 MINIMUM ALLOWABLE GRADE (TOP OF RIGID CONCRETE PAVEMENT): 4990.66 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT): 4990.66 TOP OF STONE: 4989.66 TOP OF SC-740 CHAMBER: 4989.16 12" x 12" TOP MANIFOLD INVERT: 4987.70 12" BOTTOM CONNECTION INVERT: 4986.76 24" ISOLATOR ROW INVERT: 4986.67 BOTTOM OF SC-740 CHAMBER: 4986.66 UNDERDRAIN INVERT: 4986.16 BOTTOM OF STONE: 4986.16 PROPOSED LAYOUT 38 STORMTECH SC-740 CHAMBERS 4 STORMTECH SC-740 END CAPS 6 STONE ABOVE (in) 6 STONE BELOW (in) 40 % STONE VOID 3365 INSTALLED SYSTEM VOLUME (CF) (PERIMETER STONE INCLUDED) (COVER STONE INCLUDED) (BASE STONE INCLUDED) 1656 SYSTEM AREA (SF) 308.70 SYSTEM PERIMETER (ft) 142.75' 136.82' SHEET OF DATE: PROJECT #: DRAWN: CHECKED: THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS. 4640 TRUEMAN BLVD HILLIARD, OH 43026 ADVANCED DRAINAGE SYSTEMS, INC. 1-800-733-7473 R REV DRW CHK DESCRIPTION MIDTOWN HOTEL FORT COLLINS, CO EF N/A 3 6 ACCEPTABLE FILL MATERIALS: STORMTECH SC-740 CHAMBER SYSTEMS PLEASE NOTE: 1. THE LISTED AASHTO DESIGNATIONS ARE FOR GRADATIONS ONLY. THE STONE MUST ALSO BE CLEAN, CRUSHED, ANGULAR. FOR EXAMPLE, A SPECIFICATION FOR #4 STONE WOULD STATE: "CLEAN, CRUSHED, ANGULAR NO. 4 (AASHTO M43) STONE". 2. STORMTECH COMPACTION REQUIREMENTS ARE MET FOR 'A' LOCATION MATERIALS WHEN PLACED AND COMPACTED IN 6" (150 mm) (MAX) LIFTS USING TWO FULL COVERAGES WITH A VIBRATORY COMPACTOR. 3. WHERE INFILTRATION SURFACES MAY BE COMPROMISED BY COMPACTION, FOR STANDARD DESIGN LOAD CONDITIONS, A FLAT SURFACE MAY BE ACHIEVED BY RAKING OR DRAGGING WITHOUT COMPACTION EQUIPMENT. FOR SPECIAL LOAD DESIGNS, CONTACT STORMTECH FOR COMPACTION REQUIREMENTS. 4. ONCE LAYER 'C' IS PLACED, ANY SOIL/MATERIAL CAN BE PLACED IN LAYER 'D' UP TO THE FINISHED GRADE. MOST PAVEMENT SUBBASE SOILS CAN BE USED TO REPLACE THE MATERIAL REQUIREMENTS OF LAYER 'C' OR 'D' AT THE SITE DESIGN ENGINEER'S DISCRETION. NOTES: 1. CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418-16a, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". 2. SC-740 CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787 "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". 3. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR ASSESSING THE BEARING RESISTANCE (ALLOWABLE BEARING CAPACITY) OF THE SUBGRADE SOILS AND THE DEPTH OF FOUNDATION STONE WITH CONSIDERATION FOR THE RANGE OF EXPECTED SOIL MOISTURE CONDITIONS. 4. PERIMETER STONE MUST BE EXTENDED HORIZONTALLY TO THE EXCAVATION WALL FOR BOTH VERTICAL AND SLOPED EXCAVATION WALLS. 5. REQUIREMENTS FOR HANDLING AND INSTALLATION: x TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS. x TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 2´. x TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED IN SECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO 550 LBS/IN/IN. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73 F / 23 C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLD OR YELLOW COLORS. MATERIAL LOCATION DESCRIPTION AASHTO MATERIAL CLASSIFICATIONS COMPACTION / DENSITY REQUIREMENT D FINAL FILL: FILL MATERIAL FOR LAYER 'D' STARTS FROM THE TOP OF THE 'C' LAYER TO THE BOTTOM OF FLEXIBLE PAVEMENT OR UNPAVED FINISHED GRADE ABOVE. NOTE THAT PAVEMENT SUBBASE MAY BE PART OF THE 'D' LAYER. ANY SOIL/ROCK MATERIALS, NATIVE SOILS, OR PER ENGINEER'S PLANS. CHECK PLANS FOR PAVEMENT SUBGRADE REQUIREMENTS. N/A PREPARE PER SITE DESIGN ENGINEER'S PLANS. PAVED INSTALLATIONS MAY HAVE STRINGENT MATERIAL AND PREPARATION REQUIREMENTS. C INITIAL FILL: FILL MATERIAL FOR LAYER 'C' STARTS FROM THE TOP OF THE EMBEDMENT STONE ('B' LAYER) TO 18" (450 mm) ABOVE THE TOP OF THE CHAMBER. NOTE THAT PAVEMENT SUBBASE MAY BE A PART OF THE 'C' LAYER. GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35% FINES OR PROCESSED AGGREGATE. SHEET OF DATE: PROJECT #: DRAWN: CHECKED: THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS. 4640 TRUEMAN BLVD HILLIARD, OH 43026 ADVANCED DRAINAGE SYSTEMS, INC. 1-800-733-7473 R REV DRW CHK DESCRIPTION MIDTOWN HOTEL FORT COLLINS, CO EF N/A 4 6 INSPECTION & MAINTENANCE STEP 1) INSPECT ISOLATOR ROW FOR SEDIMENT A. INSPECTION PORTS (IF PRESENT) A.1. REMOVE/OPEN LID ON NYLOPLAST INLINE DRAIN A.2. REMOVE AND CLEAN FLEXSTORM FILTER IF INSTALLED A.3. USING A FLASHLIGHT AND STADIA ROD, MEASURE DEPTH OF SEDIMENT AND RECORD ON MAINTENANCE LOG A.4. LOWER A CAMERA INTO ISOLATOR ROW FOR VISUAL INSPECTION OF SEDIMENT LEVELS (OPTIONAL) A.5. IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3. B. ALL ISOLATOR ROWS B.1. REMOVE COVER FROM STRUCTURE AT UPSTREAM END OF ISOLATOR ROW B.2. USING A FLASHLIGHT, INSPECT DOWN THE ISOLATOR ROW THROUGH OUTLET PIPE i) MIRRORS ON POLES OR CAMERAS MAY BE USED TO AVOID A CONFINED SPACE ENTRY ii) FOLLOW OSHA REGULATIONS FOR CONFINED SPACE ENTRY IF ENTERING MANHOLE B.3. IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3. STEP 2) CLEAN OUT ISOLATOR ROW USING THE JETVAC PROCESS A. A FIXED CULVERT CLEANING NOZZLE WITH REAR FACING SPREAD OF 45" (1.1 m) OR MORE IS PREFERRED B. APPLY MULTIPLE PASSES OF JETVAC UNTIL BACKFLUSH WATER IS CLEAN C. VACUUM STRUCTURE SUMP AS REQUIRED STEP 3) REPLACE ALL COVERS, GRATES, FILTERS, AND LIDS; RECORD OBSERVATIONS AND ACTIONS. STEP 4) INSPECT AND CLEAN BASINS AND MANHOLES UPSTREAM OF THE STORMTECH SYSTEM. NOTES 1. INSPECT EVERY 6 MONTHS DURING THE FIRST YEAR OF OPERATION. ADJUST THE INSPECTION INTERVAL BASED ON PREVIOUS OBSERVATIONS OF SEDIMENT ACCUMULATION AND HIGH WATER ELEVATIONS. 2. CONDUCT JETTING AND VACTORING ANNUALLY OR WHEN INSPECTION SHOWS THAT MAINTENANCE IS NECESSARY. SUMP DEPTH TBD BY SITE DESIGN ENGINEER (24" [600 mm] MIN RECOMMENDED) CATCH BASIN OR MANHOLE SC-740 ISOLATOR ROW DETAIL NTS STORMTECH HIGHLY RECOMMENDS FLEXSTORM PURE INSERTS IN ANY UPSTREAM STRUCTURES WITH OPEN GRATES COVER ENTIRE ISOLATOR ROW WITH ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE 8' (2.4 m) MIN WIDE SC-740 CHAMBER OPTIONAL INSPECTION PORT SC-740 END CAP SHEET OF DATE: PROJECT #: DRAWN: CHECKED: THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS. 4640 TRUEMAN BLVD HILLIARD, OH 43026 ADVANCED DRAINAGE SYSTEMS, INC. 1-800-733-7473 R REV DRW CHK DESCRIPTION MIDTOWN HOTEL FORT COLLINS, CO EF N/A 5 6 UNDERDRAIN DETAIL NTS A A B B SECTION A-A SECTION B-B FOUNDATION STONE BENEATH CHAMBERS FOUNDATION STONE BENEATH CHAMBERS DUAL WALL PERFORATED HDPE UNDERDRAIN ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE STORMTECH END CAP ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE STORMTECH CHAMBER OUTLET MANIFOLD STORMTECH END CAP STORMTECH CHAMBERS NUMBER AND SIZE OF UNDERDRAINS PER SITE DESIGN ENGINEER 4" (100 mm) TYP FOR SC-310 & SC-160LP SYSTEMS 6" (150 mm) TYP FOR SC-740, DC-780, MC-3500 & MC-4500 SYSTEMS PART # STUB A B C SC740EPE06T / SC740EPE06TPC 6" (150 mm) 10.9" (277 mm) 18.5" (470 mm) --- SC740EPE06B / SC740EPE06BPC --- 0.5" (13 mm) SC740EPE08T /SC740EPE08TPC 8" (200 mm) 12.2" (310 mm) 16.5" (419 mm) --- SC740EPE08B / SC740EPE08BPC --- 0.6" (15 mm) SC740EPE10T / SC740EPE10TPC 10" (250 mm) 13.4" (340 mm) 14.5" (368 mm) --- SC740EPE10B / SC740EPE10BPC --- 0.7" (18 mm) SC740EPE12T / SC740EPE12TPC 12" (300 mm) 14.7" (373 mm) 12.5" (318 mm) --- APPENDIX E Prospect and College Hotel – Fort Collins, CO 18111 0.89 OS-1 0.90 1.00 0.37 B-2 0.77 0.97 0.32 B-5 0.95 1.00 0.37 B-1 0.84 1.00 0.35 OS-2 0.86 1.00 0.28 B-3 0.86 1.00 0.30 B-6 0.54 0.67 0.16 B-4 0.89 1.00 0.20 B-7 0.84 1.00 PROJECT DEVELOPMENT PLAN FILE: PROJECT NO: CAD: QUALITY ASSURANCE: DRAWING HISTORY DATE DESCRIPTION FORT COLLINS, COLORADO 80525 DRAINAGE PLAN PROSPECT AND COLLEGE HOTEL 1623 SOUTH COLLEGE AVENUE FORT COLLINS, COLORADO C6.1 JET 18111_DRAINAGE_PROD.DWG ICS/LMH 2019/09/16 FIRST PDP SUBMITTAL 2020/02/26 2020/06/17 - - - - SECOND PDP SUBMITTAL Date: Included N/A Include name of project, date, name of design engineer Statement of compliance with the manual FP Final copies required to be stamped and signed by Colorado licensed PE Section, Township, Range Vicinity Map Roadways within and adjacent to site Names of surrounding developments Master Drainage Basin where site is located Existing stormwater drainage facilities and drainage patterns Existing irrigation facilities (if applicable) Existing land uses Existing ground cover and/or vegetation type Existing soils info Reference/discussion regarding pertinent Master Drainage Basin and any improvements planned for the area General basin characteristics Existing and planned land uses within the Master Drainage Basin Irrigation facilities that influence or are influenced by the local drainage (if applicable) Refer to Floodplain Checklists for requirements Proposed land uses and/or project summary Site acreage Discussion of proposed drainage plan, specific details that may include drainage issues at specific design points Conveyance of minor and major stormwater systems to an existing stormwater conveyance Detention basin and outlet design; summary table for each detention basin WQCV design LID systems and design Maintenance access to the drainage facilities Easements/tracts for drainage purposes Reference to any previous drainage studies for the area Four‐Step process outlined and discussed Using CoFC rainfall data for 2‐yr and 100‐yr recurrence intervals Using proper design storm recurrences (2‐yr and 100‐yr) Runoff calculation method Detention calculation method FP Street Capacity discussion FP Inlet Capacity discussion PDP and FP Drainage Report Checklist Project Name: General Location & Existing Site Info Master Drainage Basin Info Floodplain Information Cover Letter Project Description Proposed Drainage Facilities Drainage Design Criteria Page 1 of 2 Date: Included N/A PDP and FP Drainage Report Checklist Project Name: FP Pipe network models discussion FP Swale or channel sizing/capacity discussion FP Emergency spillway sizing discussion Included variance request form Statement of compliance with all erosion control materials that are to be provided with final plans FP Separate Erosion Control Report and Plans submitted Statement of compliance with manual, master drainage plans, floodplain regs, other state/federal regs Summary conclusion of drainage concept and effectiveness of design Referenced criteria, master plans, technical info Hydologic calculations: historic and developed runoff Detention basin volume calculations SDI data spreadsheet (meets detention drain time criteria) SWMM models (if applicable) LID exhibit and calculations Floodplain maps Soil survey information FP Street capacity FP Inlet sizing and capacity FP Storm pipe network models FP Erosion protection (i.e. riprap calculations) FP Swale or channel sizing FP Outlet structure design FP Spillway design Drainage map Conclusion References Appendices Variance Requests Erosion Control Page 2 of 2 THIRD PDP SUBMITTAL - - - - - - 18111 CITY OF FORT COLLINS, COLORADO UTILITY PLAN APPROVAL APPROVED: CHECKED BY: CHECKED BY: CHECKED BY: CHECKED BY: CHECKED BY: CITY ENGINEER DATE WATER & WASTEWATER UTILITY DATE STORMWATER UTILITY DATE PARKS & RECREATION DATE TRAFFIC ENGINEER DATE ENVIRONMENTAL PLANNER DATE 0 30 SCALE: 1:30 30 15 60 NORTH C2 C100 BASIN # AREA C2 = 2 YR RUNOFF COEFFICIENT C100 = 100 YR RUNOFF COEFFICIENT SC740EPE12B / SC740EPE12BPC --- 1.2" (30 mm) SC740EPE15T / SC740EPE15TPC 15" (375 mm) 18.4" (467 mm) 9.0" (229 mm) --- SC740EPE15B / SC740EPE15BPC --- 1.3" (33 mm) SC740EPE18T / SC740EPE18TPC 18" (450 mm) 19.7" (500 mm) 5.0" (127 mm) --- SC740EPE18B / SC740EPE18BPC --- 1.6" (41 mm) SC740EPE24B* 24" (600 mm) 18.5" (470 mm) --- 0.1" (3 mm) ALL STUBS, EXCEPT FOR THE SC740EPE24B ARE PLACED AT BOTTOM OF END CAP SUCH THAT THE OUTSIDE DIAMETER OF THE STUB IS FLUSH WITH THE BOTTOM OF THE END CAP. FOR ADDITIONAL INFORMATION CONTACT STORMTECH AT 1-888-892-2694. * FOR THE SC740EPE24B THE 24" (600 mm) STUB LIES BELOW THE BOTTOM OF THE END CAP APPROXIMATELY 1.75" (44 mm). BACKFILL MATERIAL SHOULD BE REMOVED FROM BELOW THE N-12 STUB SO THAT THE FITTING SITS LEVEL. NOTE: ALL DIMENSIONS ARE NOMINAL NOMINAL CHAMBER SPECIFICATIONS SIZE (W X H X INSTALLED LENGTH) 51.0" X 30.0" X 85.4" (1295 mm X 762 mm X 2169 mm) CHAMBER STORAGE 45.9 CUBIC FEET (1.30 mñ) MINIMUM INSTALLED STORAGE* 74.9 CUBIC FEET (2.12 mñ) WEIGHT 75.0 lbs. (33.6 kg) *ASSUMES 6" (152 mm) STONE ABOVE, BELOW, AND BETWEEN CHAMBERS PRE-FAB STUBS AT BOTTOM OF END CAP FOR PART NUMBERS ENDING WITH "B" PRE-FAB STUBS AT TOP OF END CAP FOR PART NUMBERS ENDING WITH "T" PRE-CORED END CAPS END WITH "PC" SC-740 TECHNICAL SPECIFICATION NTS 90.7" (2304 mm) ACTUAL LENGTH 85.4" (2169 mm) INSTALLED LENGTH BUILD ROW IN THIS DIRECTION A A C B 51.0" (1295 mm) 30.0" (762 mm) 12.2" 45.9" (1166 mm) (310 mm) 29.3" (744 mm) OVERLAP NEXT CHAMBER HERE (OVER SMALL CORRUGATION) START END 70 INWOOD ROAD, SUITE 3 | ROCKY HILL | CT | 06067 860-529-8188 |888-892-2694 | WWW.STORMTECH.COM Detention Retention Water Quality 24" (600 mm) HDPE ACCESS PIPE REQUIRED USE FACTORY PRE-FABRICATED END CAP PART #: SC740EPE24B TWO LAYERS OF ADS GEOSYNTHETICS 315WTK WOVEN GEOTEXTILE BETWEEN FOUNDATION STONE AND CHAMBERS 5' (1.5 m) MIN WIDE CONTINUOUS FABRIC WITHOUT SEAMS 70 INWOOD ROAD, SUITE 3 | ROCKY HILL | CT | 06067 860-529-8188 |888-892-2694 | WWW.STORMTECH.COM Detention Retention Water Quality MOST PAVEMENT SUBBASE MATERIALS CAN BE USED IN LIEU OF THIS LAYER. AASHTO M145ï A-1, A-2-4, A-3 OR AASHTO M43ï 3, 357, 4, 467, 5, 56, 57, 6, 67, 68, 7, 78, 8, 89, 9, 10 BEGIN COMPACTIONS AFTER 12" (300 mm) OF MATERIAL OVER THE CHAMBERS IS REACHED. COMPACT ADDITIONAL LAYERS IN 6" (150 mm) MAX LIFTS TO A MIN. 95% PROCTOR DENSITY FOR WELL GRADED MATERIAL AND 95% RELATIVE DENSITY FOR PROCESSED AGGREGATE MATERIALS. ROLLER GROSS VEHICLE WEIGHT NOT TO EXCEED 12,000 lbs (53 kN). DYNAMIC FORCE NOT TO EXCEED 20,000 lbs (89 kN). B EMBEDMENT STONE: FILL SURROUNDING THE CHAMBERS FROM THE FOUNDATION STONE ('A' LAYER) TO THE 'C' LAYER ABOVE. CLEAN, CRUSHED, ANGULAR STONE AASHTO M43ï 3, 357, 4, 467, 5, 56, 57 NO COMPACTION REQUIRED. A FOUNDATION STONE: FILL BELOW CHAMBERS FROM THE SUBGRADE UP TO THE FOOT (BOTTOM) OF THE CHAMBER. CLEAN, CRUSHED, ANGULAR STONE AASHTO M43ï 3, 357, 4, 467, 5, 56, 57 PLATE COMPACT OR ROLL TO ACHIEVE A FLAT SURFACE. 2,3 18" (450 mm) MIN* 8' (2.4 m) MAX 6" (150 mm) MIN D C B A 12" (300 mm) MIN 6" 51" (1295 mm) 12" (300 mm) TYP (150 mm) MIN 30" (760 mm) DEPTH OF STONE TO BE DETERMINED BY SITE DESIGN ENGINEER 6" (150 mm) MIN *TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR, INCREASE COVER TO 24" (600 mm). PAVEMENT LAYER (DESIGNED BY SITE DESIGN ENGINEER) SC-740 END CAP EXCAVATION WALL (CAN BE SLOPED OR VERTICAL) PERIMETER STONE (SEE NOTE 5) SUBGRADE SOILS (SEE NOTE 4) ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE ALL AROUND CLEAN, CRUSHED, ANGULAR STONE IN A & B LAYERS 70 INWOOD ROAD, SUITE 3 | ROCKY HILL | CT | 06067 860-529-8188 |888-892-2694 | WWW.STORMTECH.COM Detention Retention Water Quality 11.60' 9.00' *INVERT ABOVE BASE OF CHAMBER ITEMDESCRIPTION ON INVERT* MAX FLOW PART TYPE LAYOUT 24" BOTTOM PREFABRICATED END CAP/TYP OF ALL 24" BOTTOM CONNECTIONS AND 0.10" PREFABRICATED END CAP A ISOLATOR ROWS MANIFOLD B 12" X 12" TOP, ADS N-12 12.50" PIPE CONNECTION C 12" BOTTOM CONNECTION 1.20" NYLOPLAST (INLET W/ ISO ROW) D 30" DIAMETER (24" SUMP MIN) 2.3 CFS IN NYLOPLAST (OUTLET) E 30" DIAMETER (DESIGN BY ENGINEER)2.0 CFS OUT UNDERDRAIN F 6" ADS N-12 DUAL WALL PERFORATED HDPE UNDERDRAIN ISOLATOR ROW (SEE DETAIL) PLACE MINIMUM 12.50' OF ADS GEOSYNTHETICS 315WTK WOVEN GEOTEXTILE OVER BEDDING STONE AND UNDERNEATH CHAMBER FEET FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWS BED LIMITS F B C A E D 015'30' ENGINEER OR OWNER, THE CHAMBER MANUFACTURER SHALL SUBMIT A STRUCTURAL EVALUATION FOR APPROVAL BEFORE DELIVERING CHAMBERS TO THE PROJECT SITE AS FOLLOWS: x THE STRUCTURAL EVALUATION SHALL BE SEALED BY A REGISTERED PROFESSIONAL ENGINEER. x THE STRUCTURAL EVALUATION SHALL DEMONSTRATE THAT THE SAFETY FACTORS ARE GREATER THAN OR EQUAL TO 1.95 FOR DEAD LOAD AND 1.75 FOR LIVE LOAD, THE MINIMUM REQUIRED BY ASTM F2787 AND BY SECTIONS 3 AND 12.12 OF THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS FOR THERMOPLASTIC PIPE. x THE TEST DERIVED CREEP MODULUS AS SPECIFIED IN ASTM F2418 SHALL BE USED FOR PERMANENT DEAD LOAD DESIGN EXCEPT THAT IT SHALL BE THE 75-YEAR MODULUS USED FOR DESIGN. 9. CHAMBERS AND END CAPS SHALL BE PRODUCED AT AN ISO 9001 CERTIFIED MANUFACTURING FACILITY. PROJECT INFORMATION ADS SALES REP PROJECT NO. SALES NAME SALES NUMBER SALES EMAIL ENGINEERED PRODUCT MANAGER EPM NAME EPM NUMBER EPM EMAIL MIDTOWN HOTEL FORT COLLINS, CO ADVANCED DRAINAGE SYSTEMS, INC. R Chamber Flow Rate Conversion (gpm/sf to cfs) Flow Rate* 1 cf = 1 gallon = 1 GPM = Width (in) 51.0 Length (in) 85.4 Height (in) 30.0 Floor Area (sf) 30.2 Chamber Volume (cf) StormTech Chamber Data Chamber Dimensions SC-740 Chamber Configuration Summary Total Required WQ Volume (cf) Individual Chamber Release Ratea (cfs) Individual Chamber Volumeb (cf) Individual Installed Chamber Volumec (cf) 2809 0.024 45.90 74.90 55 0.87 1.48 3.03 22 1.53 2.61 5.32 56 0.86 1.47 2.99 23 1.49 2.55 5.20 57 0.85 1.45 2.96 24 1.46 2.49 5.09 58 0.84 1.43 2.92 25 1.43 2.44 4.98 59 0.83 1.42 2.89 26 1.4 2.39 4.87 60 0.82 1.4 2.86 27 1.37 2.34 4.78 65 0.78 1.32 2.71 28 1.34 2.29 4.69 70 0.73 1.25 2.59 29 1.32 2.25 4.60 75 0.70 1.19 2.48 30 1.30 2.21 4.52 80 0.66 1.14 2.38 31 1.27 2.16 4.42 85 0.64 1.09 2.29 32 1.24 2.12 4.33 90 0.61 1.05 2.21 33 1.22 2.08 4.24 95 0.58 1.01 2.13 34 1.19 2.04 4.16 100 0.56 0.97 2.06 35 1.17 2.00 4.08 105 0.54 0.94 2.00 36 1.15 1.96 4.01 110 0.52 0.91 1.94 37 1.16 1.93 3.93 115 0.51 0.88 1.88 38 1.11 1.89 3.87 120 0.49 0.86 1.84 1.41-9.17-14.11 0.15-0.15-0. 16 1.5- 1.7- 3.3 0.0- 0.3- 0.5 .43 .43 76—Nunn clay loam, wet, 1 to 3 percent slopes Nunn, wet 0-10 -35- -34- 27-31- 35 1.25-1.30 -1.35 1.41-2.82-4.23 0.15-0.18-0. 20 3.0- 4.5- 5.9 2.0- 3.0- 4.0 .24 .24 5 6 48 10-47 -28- -30- 35-43- 50 1.20-1.25 -1.30 0.42-2.32-4.23 0.15-0.17-0. 18 6.0- 7.5- 8.9 0.0- 1.0- 2.0 .24 .24 47-60 -36- -39- 15-25- 35 1.20-1.25 -1.30 1.41-2.82-4.23 0.10-0.14-0. 18 0.0- 1.5- 2.9 0.0- 0.3- 0.5 .24 .37 Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Physical Soil Properties---Larimer County Area, Colorado Midtown Hotel Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 6 of 6 .05 .05 Satanta 0-9 -43- -40- 10-18- 25 1.30-1.35 -1.40 4.23-9.17-14.11 0.14-0.16-0. 18 0.0- 1.5- 2.9 1.0- 1.5- 2.0 .32 .32 5 5 56 9-14 -38- -36- 18-27- 35 1.35-1.38 -1.40 4.23-9.17-14.11 0.15-0.17-0. 19 3.0- 4.5- 5.9 0.5- 0.8- 1.0 .32 .32 14-60 -42- -38- 10-20- 30 1.35-1.43 -1.50 4.23-9.17-14.11 0.14-0.17-0. 19 0.0- 1.5- 2.9 0.5- 0.8- 1.0 .37 .37 Physical Soil Properties---Larimer County Area, Colorado Midtown Hotel Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 5 of 6 0.0- 1.5- 2.9 0.0- 0.3- 0.5 .05 .05 Satanta 0-9 -43- -40- 10-18- 25 1.30-1.35 -1.40 4.23-9.17-14.11 0.14-0.16-0. 18 0.0- 1.5- 2.9 1.0- 1.5- 2.0 .32 .32 5 5 56 9-18 -38- -36- 18-27- 35 1.35-1.38 -1.40 4.23-9.17-14.11 0.15-0.17-0. 19 3.0- 4.5- 5.9 0.5- 0.8- 1.0 .32 .32 18-60 -42- -38- 10-20- 30 1.35-1.43 -1.50 4.23-9.17-14.11 0.14-0.17-0. 19 0.0- 1.5- 2.9 0.5- 0.8- 1.0 .37 .37 Physical Soil Properties---Larimer County Area, Colorado Midtown Hotel Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 4 of 6 accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/21/2019 Page 2 of 3 CHECKED BY: CHECKED BY: CHECKED BY: CITY ENGINEER DATE WATER & WASTEWATER UTILITY DATE STORMWATER UTILITY DATE PARKS & RECREATION DATE TRAFFIC ENGINEER DATE ENVIRONMENTAL PLANNER DATE 11 NEW BIKE RACKS 12 COURT YARD TRANSFORMER PAD GENERATOR SET AREA LUGGAGE OFF LOADING SPACE VINE FENCE 13 14 15 16 NOTE: -EXISTING UNDERGROUND INSTALLATIONS & PRIVATE UTILITIES SHOWN ARE INDICATED ACCORDING TO THE BEST INFORMATION AVAILABLE TO THE ENGINEER. THE ENGINEER DOES NOT GUARANTEE THE ACCURACY OF SUCH INFORMATION. SERVICE LINES (WATER, POWER, GAS, STORM, SEWER, TELEPHONE & TELEVISION) MAY NOT BE STRAIGHT LINES OR AS INDICATED ON THE PLANS. STATE LAW REQUIRES CONTRACTOR TO CALL ALL UTILITY COMPANIES BEFORE EXCAVATION FOR EXACT LOCATIONS. -UNLESS OTHERWISE SPECIFIED, ALL CONSTRUCTION LAYOUT AND STAKING SHALL BE PERFORMED UNDER THE RESPONSIBLE CHARGE OF A LAND SURVEYOR LICENSED IN THE STATE WHERE THE PROJECT IS LOCATED AND BY A PARTY CHIEF OR ENGINEERING TECHNICIAN EXPERIENCED IN CONSTRUCTION LAYOUT AND STAKING TECHNIQUES AS ARE REQUIRED BY THE SPECIFIC TYPE OF WORK BEING PERFORMED. 17 CONCRETE DRAIN PAN 18 PARKING WHEEL STOP 19 NEW CURB AND GUTTER 20 NEW RAISED PEDESTRIAN WALK 21 COLORED CONCRETE 22 FIRE LANE, NO PARKING SIGNS 23 LIGHT POLES 24 RAMP TO LOADING SPACE 25 PEDESTRIAN CROSSWALK 26 2' SIDEWALK CHASE AND FLUME