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HomeMy WebLinkAboutKAPPA KAPPA GAMMA ADDITION - BASIC DEVELOPMENT REVIEW - BDR170015 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE RELATED DOCUMENTAugust 18, 2017 Heather McDowell Water Utilities Engineer City of Fort Collins 281 North College Avenue Fort Collins, CO 80524 RE: Drainage and Erosion Control Letter – Kappa Kappa Gamma CSU House Expansion DRAINAGE The following letter explains the design and intent of the developed drainage plan for the Kappa Kappa Gamma CSU House Expansion. The scope of this project includes expanding the structure of the sorority house, adding additional parking, a water quality detention pond, and storm outlet structures to direct flow into the City storm sewer system. With an increase in imperviousness of 6,656 square feet over the existing conditions, this drainage letter provides enough information to approve the drainage design in lieu of a drainage report. The site is located at 729 South Shields Street in the northeast quarter of Section 15, Township 7 North, Range 69 West of the 6 th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. The project area lies on the north side of South Shields Street between West Plum Street and West Laurel Street. The project area ground cover consists entirely of soil type C. The site lies outside of any floodplains as shown in the attached FEMA Firmette. The total area of the site is 1.1 acres with existing and proposed imperviousness of 53% and 67% respectively. According to the Old Town Master Drainage Report any increase of imperviousness over 5,000 square feet will require onsite detention to account for the difference. The proposed site increases the imperviousness by 6,656 square feet. The additional 1,656 square feet will be accounted for in the detention pond as well as the water quality capture volume (WQCV) for the entire area draining to the pond. The undisturbed areas will be left in their historic conditions and not accounted for in the detention pond. The City of Fort Collins’ mass balance approach to detention was modified to incorporate a multi-stage outlet with variable outflow rates based on inflow, depth, and outflow. The Urban Drainage detention spreadsheet accomplishes this type of analysis and has been provided in the appendix. Page| 2 The WQCV and additional detention for the site will be treated in a rain garden pond on the north edge of the lot with an outlet that will discharge into the public storm sewer system. The release rate for the WQCV will be controlled by the underdrain orifice, while the additional volume release rate will be controlled by an above ground orifice plate. The outlet structure has been designed to release the WQCV in 12 hours at an average outflow of 0.02 cfs and the additional volume at an average outflow of 0.02 cfs. The Old Town Master Drainage Report specifies a 2-year historic release rate for the additional volume. The additional required volume was calculated using a mass balance method, which incorporates the City of Fort Collins’ IDF curve as inflow and the 2-yr historic release rate (0.02 cfs) as a constant outflow. Although the overall peak outflow of the detention pond is above the maximum 2-yr historic rate of 0.02 cfs, the outflow rate to drain the WQCV and the additional volume is 0.02 cfs. Any volume above the WQCV plus the additional volume will overtop the inlet structure and flow into the public storm sewer. The emergency overflow route from the pond will follow existing topography to South Shields Street, where it will drain into existing stormwater structures. The runoff generated by the site reaches the detention pond via overland flow, curb and gutter, and storm sewers. The parking lots drain to combination inlets in a sump condition. The capacity of these inlets can pass the 100-yr storm with a maximum of 6 inches of ponding. The inlets flow into 15” HDPE pipes at 0.5% slope. These pipes have the capacity to convey the 100-yr storm within the pipes. For complete calculations see the appendix materials. Below is a summary of the drainage basins, detention volumes, and outlet structure. Table 1: Drainage Basin Runoff Summary. DESIGN BASIN TOTAL AREA (ACRES) C2 C100 PERCENT IMPERVIOUS 2-YR RUNOFF (CFS) 100-YR RUNOFF (CFS) HISTORIC BASINS H1 0.43 0.87 1.0 90% 0.98 3.90 H2 0.36 0.35 0.4 21% 0.27 1.19 H3 0.28 0.48 0.6 37% 0.29 1.25 DEVELOPED BASINS P1 0.46 0.88 1.0 90% 1.17 4.62 P2 0.13 0.95 1.0 96% 0.34 1.25 P3 0.22 0.56 0.7 46% 0.34 1.48 OS1 0.04 0.35 0.4 21% 0.04 0.17 OS2 0.22 0.44 0.6 31% 0.25 1.10 DETENTION BASINS WQCV (P1-P3) 0.81 0.80 1.0 79% 1.70 7.34 2YR HIST (DEV-HIST-5000SQFT) 0.04 0.20 0.3 2% 0.02 0.09 Page| 3 Table 2: Detention Summary. DESIGN BASIN TOTAL AREA (ACRES) PERCENT IMPERVIOUS VOL REQ (ACRE-FT) VOL PROV (ACRE-FT) WQCV (P1-P3) 0.81 79% 0.017 0.017 2YR HIST (DEV-HIST-5000SQFT) 0.04 100% 0.008 0.008 ABOVE REQUIRED 0 0 0 0.021 TOTAL 0.85 - 0.025 0.046 Since runoff from proposed improvements is captured by a water quality detention pond and released into the public storm system, and offsite drainage follows historic patterns, this site complies with City requirements for stormwater criteria. EROSION CONTROL a. In the existing condition, the site is fully developed with paving, structures, mature trees, and is fully landscaped. Little to no erosion has been observed at the site beyond the normal migration of fine particles during larger storm events. All runoff flows to the existing public right-of-way in an unregulated manner. The site lies in a fully developed area of Ft. Collins and is surrounded on the north, south, and west by stabilized properties. To the east lies the Shield St. right-of-way. b. Construction stormwater management will be achieved through the implementation of standard BMPs as outlined in Volume 3 of the UDFCD manual. 1. The site will be bonded by silt fence 2. Vehicle tracking control will be installed at the construction entrance 3. Concrete Washout and Stabilized Staging Areas will be installed near the construction entrance 4. A permanent water quality and detention pond is proposed for this project. Inlet Protection will be installed at all newly constructed inlets and Outlet Protection will be installed at the pond outlet structure. 5. A Temporary Sediment Basin will be installed in the bottom of the pond during construction i. The SWMP Administrator for this project will be: ii. Potential Pollutant Sources: 1. All stockpiles will be controlled by silt fence. 2. Vehicle tracking will be managed by the VTC at the entrance and regular sweeping by the contractor. 3. No contaminated soils are expected on this project. 4. Wherever possible any loading/unloading will be achieved by use of the entrance to the site from Astor St. to the south. 5. A stabilized staging area will be provided for the laydown of incoming materials. Any point source pollutants or chemicals will be stored in construction trailers or temporary sheds on site. 6. Fueling will only occur in designated areas and a cleanup/spill kit will be made available at all times. Page| 4 7. Dust migration will be mitigated by frequent wetting of exposed soils. Saw cutting and other dust generating activities will also be managed with water applications. 8. Maintenance involving pollutants will be performed in designated areas with a cleanup/spill kit available at all times. 9. Waste materials will be isolated from any runoff areas, bounded by silt fence if necessary. Frequent removal of waste materials from the site in protected containers will be provided. 10. A concrete washout will be provided near the construction entrance 11. No batch plants are anticipated for this project. 12. A roll-off dumpster and portable toilet will be provided to accept waste from onsite labor 13. No other waste sources are anticipated on this project c. Permanent seeding and stabilization will be in accordance withte h Landscape Architecture design for this project, which will comply with all Ft. Collins regulations regarding planting, species type, mulching, and irrigation. d. Construction Sequence: 1. Installation of silt fence, vehicle tracking, concrete wash, dumpster, toilet, and stabilized staging area 2. Demolition phase. Removal of structural components, site flatwork, and trees. 3. Construction phase i. Install inlets, storm pipe, detention pond, and pond outlet structure ii. Protect inlets and outlets 4. Install temporary sediment basin 5. Seeding per Landscape plan 6. Mulching per Landscape plan 7. All construction BMPS to be inspected within 12 hours of any rain event. 8. Bi-Annual removal of sediment from permanent pond. e. Security calculations: TBD Sincerely, Baseline Engineering Corporation, Michael White, PE Page| 5 REFERENCES: 1. Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual, City of Fort Collins, Fort Collins, CO. February 2013. 2. Larimer County Stormwater Design Standards, Larimer County Engineering Department, Fort Collins, CO. June 20, 2005. 3. Urban Storm Drainage Criteria Manual, Volumes 1-2; Urban Drainage and Flood Control District, Denver, CO. January 2016. 4. Urban Storm Drainage Criteria Manual, Volumes 3; Urban Drainage and Flood Control District, Denver, CO. November 2010. Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 4/20/2017 Page 1 of 4 4491810 4491820 4491830 4491840 4491850 4491860 4491870 4491810 4491820 4491830 4491840 4491850 4491860 4491870 491780 491790 491800 491810 491820 491830 491840 491850 491860 491870 491880 491780 491790 491800 491810 491820 491830 491840 491850 491860 491870 491880 40° 34' 39'' N 105° 5' 49'' W 40° 34' 39'' N 105° 5' 45'' W 40° 34' 37'' N 105° 5' 49'' W 40° 34' 37'' N 105° 5' 45'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 20 40 80 120 Feet 0 5 10 20 30 Meters Map Scale: 1:484 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available 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 accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 74 Nunn clay loam, 1 to 3 percent slopes C 1.1 100.0% Totals for Area of Interest 1.1 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 4/20/2017 Page 3 of 4 Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 4/20/2017 Page 4 of 4 33 (11) Section 4.0 is amended to read as follows: 4.0 Intensity-Duration-Frequency Curves for Rational Method: The one-hour rainfall Intensity-Duration-Frequency tables for use the Rational Method of runoff analysis are provided in Table RA-7 and in Table RA-8. Table RA-7 -- City of Fort Collins Rainfall Intensity-Duration-Frequency Table for Use with the Rational Method (5 minutes to 30 minutes) 2-Year 10-Year 100-Year Duration (min) Intensity (in/hr) Intensity (in/hr) Intensity (in/hr) 5 2.85 4.87 9.95 6 2.67 4.56 9.31 7 2.52 4.31 8.8 8 2.4 4.1 8.38 9 2.3 3.93 8.03 10 2.21 3.78 7.72 11 2.13 3.63 7.42 12 2.05 3.5 7.16 13 1.98 3.39 6.92 14 1.92 3.29 6.71 15 1.87 3.19 6.52 16 1.81 3.08 6.3 17 1.75 2.99 6.1 18 1.7 2.9 5.92 19 1.65 2.82 5.75 20 1.61 2.74 5.6 21 1.56 2.67 5.46 22 1.53 2.61 5.32 23 1.49 2.55 5.2 24 1.46 2.49 5.09 25 1.43 2.44 4.98 26 1.4 2.39 4.87 27 1.37 2.34 4.78 28 1.34 2.29 4.69 29 1.32 2.25 4.6 30 1.3 2.21 4.52 34 Table RA-8 -- City of Fort Collins Rainfall Intensity-Duration-Frequency Table for Use with the Rational Method (31 minutes to 60 minutes) 2-Year 10-Year 100-Year Duration (min) Intensity (in/hr) Intensity (in/hr) Intensity (in/hr) 31 1.27 2.16 4.42 32 1.24 2.12 4.33 33 1.22 2.08 4.24 34 1.19 2.04 4.16 35 1.17 2.0 4.08 36 1.15 1.96 4.01 37 1.16 1.93 3.93 38 1.11 1.89 3.87 39 1.09 1.86 3.8 40 1.07 1.83 3.74 41 1.05 1.8 3.68 42 1.04 1.77 3.62 43 1.02 1.74 3.56 44 1.01 1.72 3.51 45 0.99 1.69 3.46 46 0.98 1.67 3.41 47 0.96 1.64 3.36 48 0.95 1.62 3.31 49 0.94 1.6 3.27 50 0.92 1.58 3.23 51 0.91 1.56 3.18 52 0.9 1.54 3.14 53 0.89 1.52 3.1 54 0.88 1.5 3.07 55 0.87 1.48 3.03 56 0.86 1.47 2.99 57 0.85 1.45 2.96 58 0.84 1.43 2.92 59 0.83 1.42 2.89 60 0.82 1.4 2.86 HISTORIC RUNOFF COEFFICIENTS Basin or Sub-Basin Total Area (acres) % Impervious Roof Area (acres) Paved Area (acres) Sidewalk Area (acres) Gravel Area (acres) Landscape Area (acres) Composite Runoff Coefficient, C (2 to 10-yr) Composite Runoff Coefficient, C (11 to 25-yr) Composite Runoff Coefficient, C (26 to 50-yr) Composite Runoff Coefficient, C ( 51 to 100-yr) H1 0.43 90% 0.02 0.37 0.04 0.87 0.96 1.00 1.00 H2 0.36 21% 0.04 0.03 0.29 0.35 0.39 0.42 0.44 H3 0.28 37% 0.06 0.05 0.17 0.48 0.53 0.58 0.60 Total 1.07 53% 0.12 0.45 0.00 0.00 0.50 0.60 0.66 0.72 0.75 DEVELOPED RUNOFF COEFFICIENTS Basin or Sub-Basin Total Area (acres) % Impervious Roof Area (acres) Paved Area (acres) Sidewalk Area (acres) Gravel Area (acres) Landscape Area (acres) Composite Runoff Coefficient, C (2 to 10-yr) Composite Runoff Coefficient, C (11 to 25-yr) Composite Runoff Coefficient, C (26 to 50-yr) Composite Runoff Coefficient, C ( 51 to 100-yr) P1 0.46 90% 0.05 0.37 0.04 0.88 0.97 1.00 1.00 P2 0.13 96% 0.05 0.07 0.95 1.00 1.00 1.00 P3 0.22 46% 0.07 0.04 0.11 0.56 0.62 0.67 0.70 OS1 0.04 21% 0.01 0.03 0.35 0.38 0.41 0.43 OS2 0.22 31% 0.04 0.03 0.15 0.44 0.49 0.53 0.55 Total 1.07 67% 0.21 0.52 0.00 0.00 0.34 0.71 0.78 0.85 0.89 DETENTION RUNOFF COEFFICIENTS Basin or Sub-Basin Total Area (acres) % Impervious HISTORIC TIME OF CONCENTRATION Basin or Sub-Basin Total Area (acres) C (2-yr) C (100-yr) Length (ft) Slope (%) Ti (2-yr) Ti (100-yr) Length (ft) Slope (%) Ground Cover Velocity (ft/sec) (manual input) Tt Total Tc (2-yr) Total Tc (100-yr) Tc Maximum** for Urbanized Basins = (Length/180)+10 Final Tc (2-yr)* Final Tc (100-yr) * H1 0.43 0.87 1.00 176 0.5 7.06 3.13 - - - - 0.00 7.06 3.13 10.98 7.06 5.00 H2 0.36 0.35 0.44 117 1.7 12.68 11.18 - - - - 0.00 12.68 11.18 10.65 10.65 10.65 H3 0.28 0.48 0.60 92 1.0 11.06 8.89 - - - - 0.00 11.06 8.89 10.51 10.51 8.89 Total DEVELOPED TIME OF CONCENTRATION Basin or Sub-Basin Total Area (acres) C (2-yr) C (100-yr) Length (ft) Slope (%) Ti (2-yr) Ti (100-yr) Length (ft) Slope (%) Ground Cover Velocity (ft/sec) (manual input) Tt Total Tc (2-yr) Total Tc (100-yr) Tc Maximum** for Urbanized Basins = (Length/180)+10 Final Tc (2-yr)* Final Tc (100-yr) * P1 0.46 0.88 1.00 137 3.2 3.28 1.49 - - - - 0.00 3.28 1.49 10.76 5.00 5.00 P2 0.13 0.95 1.00 105 2.5 2.12 1.41 - - - - 0.00 2.12 1.41 10.58 5.00 5.00 P3 0.22 0.56 0.70 128 5.8 6.34 4.69 - - - - 0.00 6.34 4.69 10.71 6.34 5.00 OS1 0.04 0.35 0.43 14 2.0 4.19 3.71 - - - - 0.00 4.19 3.71 10.08 5.00 5.00 OS2 0.22 0.44 0.55 72 3.5 6.89 5.74 - - - - 0.00 6.89 5.74 10.40 6.89 5.74 Total DETENTION TIME OF CONCENTRATION Basin or Sub-Basin Total Area (acres) C (2-yr) C (100-yr) Length (ft) Slope (%) Ti (2-yr) Ti (100-yr) Length (ft) Slope (%) Ground Cover Velocity (ft/sec) (manual input) Tt Total Tc (2-yr) Total Tc (100-yr) Tc Maximum** for Urbanized Basins = (Length/180)+10 Final Tc (2-yr)* Final Tc (100-yr) * WQCV (P1-P3) 0.81 0.80 1.00 137 3.2 4.41 1.49 315 0.5 PA 1.78 2.95 7.36 4.43 10.76 7.36 5.00 2YR HIST (DEV-HIST-5000SQFT) 0.038 0.20 0.25 - - - - - - - - - - 5.00 5.00 Total Time of Concentration - Total - Tc (minutes) Time of Concentration - Total - Tc (minutes) Basin Information Runoff Coefficients Time of Concentration - Initial Overland Flow - Ti (minutes) Time of Concentration - Channelized Flow - Tt (minutes) Time of Concentration - Total - Tc (minutes) (ASSUME MIN TIME) Basin Information Runoff Coefficients Time of Concentration - Initial Overland Flow - Ti (minutes) Time of Concentration - Channelized Flow - Tt (minutes) Basin Information Runoff Coefficients Time of Concentration - Initial Overland Flow - Ti (minutes) Time of Concentration - Channelized Flow - Tt (minutes) HISTORIC PEAK RUNOFF Basin or Sub-Basin Total Area (acres) C (2-yr) C (100-yr) Tc (2-yr) Tc (100-yr) I (2-yr) I (100-yr) Q (2-yr) Q (100-yr) H1 0.43 0.87 1.00 7 5 2.62 9.07 0.98 3.90 H2 0.36 0.35 0.44 11 11 2.15 7.50 0.27 1.19 H3 0.28 0.48 0.60 11 9 2.15 7.50 0.29 1.25 Total DEVELOPED PEAK RUNOFF Basin or Sub-Basin Total Area (acres) C (2-yr) C (100-yr) Tc (2-yr) Tc (100-yr) I (2-yr) I (100-yr) Q (2-yr) Q (100-yr) P1 0.46 0.88 1.00 5 5 2.88 9.96 1.17 4.62 P2 0.13 0.95 1.00 5 5 2.88 9.96 0.34 1.25 P3 0.22 0.56 0.70 6 5 2.75 9.52 0.34 1.48 OS1 0.04 0.35 0.43 5 5 2.88 9.96 0.04 0.17 OS2 0.22 0.44 0.55 7 6 2.62 9.07 0.25 1.10 Total DETENTION PEAK RUNOFF Basin or Sub-Basin Total Area (acres) C (2-yr) C (100-yr) Tc (2-yr) Tc (100-yr) I (2-yr) I (100-yr) Q (2-yr) Q (100-yr) WQCV (P1-P3) 0.81 0.80 1.00 7 5 2.62 9.07 1.70 7.34 2YR HIST (DEV-HIST-5000SQFT) 0.038 0.20 0.25 5 5 2.88 9.96 0.02 0.09 Total Basin Information Runoff Coefficients - C Time of Concentration - Tc (min) Rainfall Intensity - I (in/hr) Peak Discharge - Q (cfs) Basin Information Runoff Coefficients - C Time of Concentration - Tc (min) Rainfall Intensity - I (in/hr) Peak Discharge - Q (cfs) Basin Information Runoff Coefficients - C Time of Concentration - Tc (min) Rainfall Intensity - I (in/hr) Peak Discharge - Q (cfs) Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK = 5.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK = 0.020 ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK = 0.013 Height of Curb at Gutter Flow Line HCURB = 6.00 inches Distance from Curb Face to Street Crown TCROWN = 10.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX = 0.030 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW = 0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO = 0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET = 0.013 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX = 5.0 10.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX = 4.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow = SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) KAPPA KAPPA GAMMA SORORITY Type 13 Combo Inlet co3176-UD-Inlet_v4.05.xlsm, Type 13 Combo Inlet 8/18/2017, 10:38 AM Design Information (Input) MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above) alocal = 2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 3.1 4.9 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) = 3.00 3.00 feet Width of a Unit Grate Wo = 1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = 0.43 0.43 Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = 0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = 3.30 3.30 Grate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = 0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) = 3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert = 6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthroat = 5.25 5.25 inches Angle of Throat (see USDCM Figure ST-5) Theta = 0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet) Wp = 2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10) Cf (C) = 0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw (C) = 3.70 3.70 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co (C) = 0.66 0.66 Grate Flow Analysis (Calculated) MINOR MAJOR Clogging Coefficient for Multiple Units Coef = 1.00 1.00 Clogging Factor for Multiple Units Clog = 0.50 0.50 Grate Capacity as a Weir (based on Modified HEC22 Method) MINOR MAJOR Interception without Clogging Qwi = 1.1 3.2 cfs Interception with Clogging Qwa = 0.5 1.6 cfs Grate Capacity as a Orifice (based on Modified HEC22 Method) MINOR MAJOR Interception without Clogging Qoi = 5.7 7.0 cfs Interception with Clogging Qoa = 2.8 3.5 cfs Grate Capacity as Mixed Flow MINOR MAJOR Interception without Clogging Qmi = 2.3 4.4 cfs Interception with Clogging Qma = 1.1 2.2 cfs Resulting Grate Capacity (assumes clogged condition) QGrate = 0.5 1.6 cfs Curb Opening Flow Analysis (Calculated) MINOR MAJOR Clogging Coefficient for Multiple Units Coef = 1.00 1.00 Clogging Factor for Multiple Units Clog = 0.17 0.17 Curb Opening as a Weir (based on Modified HEC22 Method) MINOR MAJOR Interception without Clogging Qwi Autodesk Storm and Sanitary Analysis Water Quality Capture Volume, WQCV 1. Determine the WQCV in Watershed Inches WQCV = a (0.91I 3 -1.19I 2 +0.78I ) Where: WQCV = Water Quality Capture Volume, watershed inches a = coefficient corresponding to WQCV drain time I = Imperviousness (%/100) Drain Time (hrs) Coefficient (a ) 12 0.8 24 0.9 40 1.0 Coefficient, a 0.80 Imperviousness, I 79 WQCV = 0.26 watershed inches 2. Determine the required storage volume in Acre-Feet V = (WQCV/12)A Where: V = Required Storage Volume, acre-feet A = Tributary catchment area upstream, acres Area, A 0.81 acres V = 0.017 acre-feet Drain Time Coefficients Input 1.00 (Assume 100% impervious) 1.00 (Max C = 1.0) 0.02 cfs 0.038 acres (6,656-5,000=1,656 sqft) Results 0.008 Rainfall Duration (min) Rainfall Intensity (in/hr) Qin (cfs) Volumein (ft 3 ) Qout (cfs) Volumeout (ft 3 ) Volume detained (acre-feet) 5 9.96 0.38 113.54 0.02 6.00 0.002 10 7.74 0.29 176.47 0.02 12.00 0.004 15 6.52 0.25 222.98 0.02 18.00 0.005 20 5.61 0.21 255.82 0.02 24.00 0.005 25 4.97 0.19 283.18 0.02 30.00 0.006 30 4.52 0.17 309.17 0.02 36.00 0.006 35 4.08 0.16 325.58 0.02 42.00 0.007 40 3.74 0.14 340.63 0.02 48.00 0.007 45 3.45 0.13 354.31 0.02 54.00 0.007 50 3.23 0.12 367.99 0.02 60.00 0.007 55 3.03 0.12 380.30 0.02 66.00 0.007 60 2.86 0.11 391.25 0.02 72.00 0.007 65 2.71 0.10 402.19 0.02 78.00 0.007 70 2.59 0.10 413.14 0.02 84.00 0.008 75 2.48 0.09 424.08 0.02 90.00 0.008 80 2.38 0.09 433.66 0.02 96.00 0.008 85 2.29 0.09 443.23 0.02 102.00 0.008 90 2.21 0.08 452.81 0.02 108.00 0.008 95 2.13 0.08 461.02 0.02 114.00 0.008 100 2.06 0.08 470.59 0.02 120.00 0.008 105 2.00 0.08 478.80 0.02 126.00 0.008 110 1.94 0.07 487.01 0.02 132.00 0.008 115 1.88 0.07 493.85 0.02 138.00 0.008 120 1.84 0.07 502.06 0.02 144.00 0.008 Detention Volume Requirement (acre-feet) Detention Volume - Mass Balance Method 100-yr Storm for Additional Impervious Above 5000 SQFT Released at the 2-yr historic rate Runoff Coefficient, C = Frequency Factor, Cf = 2-yr Release, Qout = Area = Project: Basin ID: Depth Increment = 5025 ft Required Volume Calculation Media Surface -- 0.00 -- -- -- 261 0.006 Selected BMP Type = RG 5,025.50 -- 0.50 -- -- -- 300 0.007 137 0.003 Watershed Area = 0.85 acres 5,026.00 -- 1.00 -- -- -- 603 0.014 360 0.008 Watershed Length = 300 ft 5,028.50 -- 3.50 -- -- -- 712 0.016 2,010 0.046 Watershed Slope = 0.020 ft/ft 5,029.00 -- 4.00 -- -- -- 1,095 0.025 2,461 0.057 Watershed Imperviousness = 79.00% percent -- -- -- -- Percentage Hydrologic Soil Group A = 0.0% percent -- -- -- -- Percentage Hydrologic Soil Group B = 0.0% percent -- -- -- -- Percentage Hydrologic Soil Groups C/D = 100.0% percent -- -- -- -- Desired WQCV Drain Time = 12.0 hours -- -- -- -- Location for 1-hr Rainfall Depths = User Input -- -- -- -- Water Quality Capture Volume (WQCV) = 0.018 acre-feet -- -- -- -- Excess Urban Runoff Volume (EURV) = 0.066 acre-feet -- -- -- -- 2-yr Runoff Volume (P1 = 0.82 in.) = 0.044 acre-feet 0.82 inches -- -- -- -- 5-yr Runoff Volume (P1 = 1.14 in.) = 0.066 acre-feet 1.14 inches -- -- -- -- 10-yr Runoff Volume (P1 = 1.4 in.) = 0.083 acre-feet 1.40 inches -- -- -- -- 25-yr Runoff Volume (P1 = 1.81 in.) = 0.114 acre-feet 1.81 inches -- -- -- -- 50-yr Runoff Volume (P1 = 2.27 in.) = 0.146 acre-feet 2.27 inches -- -- -- -- 100-yr Runoff Volume (P1 = 2.86 in.) = 0.191 acre-feet 2.86 inches -- -- -- -- 500-yr Runoff Volume (P1 = 4.7 in.) = 0.326 acre-feet 4.70 inches -- -- -- -- Approximate 2-yr Detention Volume = 0.041 acre-feet -- -- -- -- Approximate 5-yr Detention Volume = 0.062 acre-feet -- -- -- -- Approximate 10-yr Detention Volume = 0.075 acre-feet -- -- -- -- Approximate 25-yr Detention Volume = 0.090 acre-feet -- -- -- -- Approximate 50-yr Detention Volume = 0.103 acre-feet -- -- -- -- Approximate 100-yr Detention Volume = 0.122 acre-feet -- -- -- -- -- -- -- -- Stage-Storage Calculation -- -- -- -- Zone 1 Volume (User Defined) = 0.017 acre-feet -- -- -- -- Zone 2 Volume (User Defined - Zone 1) = 0.008 acre-feet -- -- -- -- Zone 3 Volume (User Defined - Zones 1 & 2) = 0.001 acre-feet -- -- -- -- Total Detention Basin Volume = 0.026 acre-feet -- -- -- -- Initial Surcharge Volume (ISV) = N/A ft^3 -- -- -- -- Initial Surcharge Depth (ISD) = N/A ft -- -- -- -- Total Available Detention Depth (Htotal ) = user ft -- -- -- -- Depth of Trickle Channel (HTC) = N/A ft -- -- -- -- Slope of Trickle Channel (STC ) = N/A ft/ft -- -- -- -- Slopes of Main Basin Sides (Smain ) = user H:V -- -- -- -- Basin Length-to-Width Ratio (RL/W ) = user -- -- -- -- -- -- -- -- Initial Surcharge Area (AISV ) = user ft^2 -- -- -- -- 1 User Defined Stage-Area Boolean for Message 1 Equal Stage-Area Inputs Watershed L:W 1 CountA 0 Calc_S_TC H_FLOOR L_FLOOR_OTHER 0.00 ISV 0.00 ISV 0.00 Floor 0.00 Floor 1.61 Zone 1 (User) 1.61 Zone 1 (User) 2.16 Zone 2 (User) 2.16 Zone 2 (User) 2.22 Zone 3 (User) 2.22 Zone 3 (User) DETENTION BASIN STAGE-STORAGE TABLE BUILDER UD-Detention, Version 3.07 (February 2017) 0.000 0.015 0.030 0.045 0.060 0.000 0.010 0.020 0.030 0.040 0.00 1.00 2.00 3.00 4.00 Volume (ac-ft) Area (acres) Stage (ft.) Area (acres) Volume (ac-ft) 0 100 200 300 400 0 5 10 15 20 0.00 1.00 2.00 3.00 4.00 Area (sq.ft.) Length, Width (ft.) Stage (ft) Length (ft) Width (ft) Area (sq.ft.) CO3176-UD-Detention_v3.07.xlsm, Basin 8/18/2017, 8:12 AM Project: Basin ID: Stage (ft) Zone Volume (ac-ft) Outlet Type Zone 1 (User) 1.61 0.017 Filtration Media Zone 2 (User) 2.16 0.008 Circular Orifice Zone 3 (User) 2.22 0.001 Weir&Pipe (Circular) 0.026 Total User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Calculated Parameters for Underdrain Underdrain Orifice Invert Depth = 2.00 ft (distance below the filtration media surface) Underdrain Orifice Area = 0.0 ft2 Underdrain Orifice Diameter = 0.625 inches Underdrain Orifice Centroid = 0.03 feet User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP) Calculated Parameters for Plate Invert of Lowest Orifice = N/A ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = N/A ft2 Depth at top of Zone using Orifice Plate = N/A ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feet Orifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet Orifice Plate: Orifice Area per Row = N/A inches Elliptical Slot Area = N/A ft2 User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Row 1 (optional) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional) Stage of Orifice Centroid (ft) N/A N/A N/A N/A N/A N/A N/A N/A Orifice Area (sq. inches) N/A N/A N/A N/A N/A N/A N/A N/A Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional) Stage of Orifice Centroid (ft) N/A N/A N/A N/A N/A N/A N/A N/A Orifice Area (sq. inches) N/A N/A N/A N/A N/A N/A N/A N/A User Input: Vertical Orifice (Circular or Rectangular) Calculated Parameters for Vertical Orifice Zone 2 Circular Not Selected Zone 2 Circular Not Selected Invert of Vertical Orifice = 1.61 N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = 0.00 N/A ft2 Depth at top of Zone using Vertical Orifice = 2.16 N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = 0.02 N/A feet Vertical Orifice Diameter = 0.375 N/A inches User Input: Overflow Weir (Dropbox) and Grate (Flat or Sloped) Calculated Parameters for Overflow Weir Zone 3 Weir Not Selected Zone 3 Weir Not Selected Overflow Weir Front Edge Height, Ho = 2.16 N/A ft (relative to basin bottom at Stage = 0 ft) Height of Grate Upper Edge, Ht = 2.16 N/A feet Overflow Weir Front Edge Length = 4.00 N/A feet Over Flow Weir Slope Length = 16.00 N/A feet Overflow Weir Slope = 0.00 N/A H:V (enter zero for flat grate) Grate Open Area / 100-yr Orifice Area = 14.26 N/A should be > 4 Horiz. Length of Weir Sides = 16.00 N/A feet Overflow Grate Open Area w/o Debris = 44.80 N/A ft2 Overflow Grate Open Area % = 70% N/A %, grate open area/total area Overflow Grate Open Area w/ Debris = 22.40 N/A ft2 Debris Clogging % = 50% N/A % User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate Zone 3 Circular Not Selected Zone 3 Circular Not Selected Depth to Invert of Outlet Pipe = 2.50 N/A ft (distance below basin bottom at Stage = 0 ft) Outlet Orifice Area = 3.14 N/A ft2 Circular Orifice Diameter = 24.00 N/A inches Outlet Orifice Centroid = 1.00 N/A feet Half-Central Angle of Restrictor Plate on Pipe = N/A N/A radians User Input: Emergency Spillway (Rectangular or Trapezoidal) Calculated Parameters for Spillway Spillway Invert Stage= 3.50 ft (relative to basin bottom at Stage = 0 ft) Spillway Design Flow Depth= 0.18 feet Spillway Crest Length = 12.00 feet Stage at Top of Freeboard = 3.68 feet Spillway End Slopes = 3.00 H:V Basin Area at Top of Freeboard = 0.02 acres Freeboard above Max Water Surface = 0.00 feet Routed Hydrograph Results Design Storm Return Period = WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year One-Hour Rainfall Depth (in) = 0.53 1.07 0.82 1.14 1.40 1.81 2.27 2.86 4.70 Calculated Runoff Volume (acre-ft) = 0.018 0.066 0.044 0.066 0.083 0.114 0.146 0.191 0.326 OPTIONAL Override Runoff Volume (acre-ft) = Inflow Hydrograph Volume (acre-ft) = 0.018 0.065 0.043 0.065 0.082 0.114 0.146 0.191 0.325 Predevelopment Unit Peak Flow, q (cfs/acre) = 0.00 0.00 0.01 0.09 0.25 0.66 0.98 1.44 2.74 Predevelopment Peak Q (cfs) = 0.0 0.0 0.0 0.1 0.2 0.6 0.8 1.2 2.3 Peak Inflow Q (cfs) = 0.3 1.1 0.7 1.1 1.3 1.8 2.3 3.0 5.1 Peak Outflow Q (cfs) = 0.019 1.0 0.6 1.0 1.8 2.8 3.0 3.6 7.1 Ratio Peak Outflow to Predevelopment Q = N/A N/A N/A 13.8 8.7 4.9 3.7 3.0 3.0 Structure Controlling Flow = Filtration Media Overflow Grate 1 Overflow Grate 1 Overflow Grate 1 Overflow Grate 1 Overflow Grate 1 Overflow Grate 1 Overflow Grate 1 Overflow Grate 1 Max Velocity through Grate 1 (fps) = N/A 0.02 0.02 0.0 0.0 0.1 0.1 0.1 0.2 Max Velocity through Grate 2 (fps) = N/A N/A N/A N/A N/A N/A N/A N/A N/A Time to Drain 97% of Inflow Volume (hours) = 12 17 18 17 17 16 16 15 12 COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1 Vert Orifice 2 Count_Underdrain = 1 0.11(diameter = 3/8 inch) 1 2 1 Count_WQPlate = 0 0.1(4diameter = 7/16 inch) Count_VertOrifice1 = 1 0.18(diameter = 1/2 inch) Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean Count_VertOrifice2 = 0 0.2(4diameter = 9/16 inch) 2 1 5yr, <72hr 0 Count_Weir1 = 1 0.29(diameter = 5/8 inch) >5yr, <120hr 0 Count_Weir2 = 0 0.(36 diameter = 11/16 inch) Max Depth Row Count_OutletPipe1 = 1 0.42(diameter = 3/4 inch) WQCV 144 Watershed Constraint Check Count_OutletPipe2 = 0 0.(50 diameter = 13/16 inch) 2 Year 221 Slope 0.020 COUNTA_2 (Standard FSD Setup)= 1 0.58(diameter = 7/8 inch) EURV 222 Shape 2.43 MaxPondDepth_Error? FALSE 0.(67 diameter = 15/16 inch) 5 Year 222 Hidden Parameters & Calculations 0.76 (diameter = 1 inch) 10 Year 225 Spillway Depth (diameter 0.86 = 1-1/16 inches) 25 Year 227 0.18 WQ Plate Flow at 100yr depth = 0.00 (0.diameter 97 = 1-1/8 inches) 50 Year 228 CLOG #1= 35% (diameter 1.08 = 1-3/16 inches) 100 Year 229 1 Z1_Boolean Cdw #1 = 1.15 (1.diameter 20 = 1-1/4 inches) 500 Year 236 1 Z2_Boolean Cdo #1 = 1.07 (diameter 1.32 = 1-5/16 inches) Zone3_Pulldown Message 1 Z3_Boolean Overflow Weir #1 Angle = 0.000 (1.diameter 45 = 1-3/8 inches) 1 Opening Message CLOG #2= #VALUE! (diameter 1.59 = 1-7/16 inches) Draintime Running Cdw #2 = #VALUE! (1.diameter 73 = 1-1/2 inches) Outlet Boolean Outlet Rank Total (1 to 4) Cdo #2 = #VALUE! (diameter 1.88 = 1-9/16 inches) Vertical Orifice 1 1 1 2 Overflow Weir #2 Angle = #VALUE! (2.diameter 03 = 1-5/8 inches) Vertical Orifice 2 0 0 Boolean Underdrain Q at 100yr depth = 0.02 (diameter 2.20 = 1-11/16 inches) Overflow Weir 1 1 2 0 Max Depth VertOrifice1 Q at 100yr depth = 0.00 (2.diameter 36 = 1-3/4 inches) Overflow Weir 2 0 0 0 500yr Depth VertOrifice2 Q at 100yr depth = 0.00 (diameter 2.54 = 1-13/16 inches) Outlet Pipe 1 1 2 0 Freeboard EURV_draintime_user = (2.diameter 72 = 1-7/8 inches) Outlet Pipe 2 0 0 1 Spillway Count_User_Hydrographs 0 (diameter 2.90 = 1-15/16 inches) 1 Spillway Length CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches) Button Visibility Boolean FALSE Time Interval CountA_4 (100yr Only) = 1 (use 3.29 rectangular openings) 1 Button_Trigger 0 Underdrain 0 WQCV Plate 0 EURV-WQCV Plate 0 EURV-WQCV VertOrifice 0 Outlet 90% Qpeak 1 Outlet Undetained S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis minimum bound maximum bound UD-Detention, Version 3.07 (February 2017) Detention Basin Outlet Structure Design 0 1 2 3 4 5 6 7 8 0.1 1 10 FLOW [cfs] TIME [hr] 500YR IN 500YR OUT 100YR IN 100YR OUT Outflow Hydrograph Workbook Filename: .\CO3176-Det Pond Outflow Hydrographs.xlsx Storm Inflow Hydrographs The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program. SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK Time Interval TIME WQCV [cfs] EURV [cfs] 2 Year [cfs] 5 Year [cfs] 10 Year [cfs] 25 Year [cfs] 50 Year [cfs] 100 Year [cfs] 500 Year [cfs] 5.31 min 0:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:05:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Hydrograph 0:10:37 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Constant 0:15:56 0.01 0.05 0.03 0.05 0.06 0.08 0.11 0.14 0.23 0.941 0:21:14 0.04 0.13 0.09 0.13 0.16 0.22 0.28 0.37 0.62 0:26:33 0.09 0.33 0.22 0.33 0.42 0.57 0.73 0.94 1.58 0:31:52 0.26 0.91 0.61 0.91 1.14 1.57 2.00 2.59 4.36 0:37:10 0.29 1.06 0.70 1.06 1.33 1.82 2.33 3.03 5.13 0:42:29 0.27 1.00 0.66 1.00 1.26 1.73 2.21 2.88 4.88 0:47:47 0.25 0.91 0.60 0.91 1.14 1.57 2.01 2.62 4.44 0:53:06 0.22 0.80 0.52 0.80 1.01 1.39 1.78 2.33 3.95 0:58:25 0.18 0.68 0.44 0.68 0.86 1.18 1.52 1.99 3.40 1:03:43 0.16 0.60 0.39 0.60 0.75 1.04 1.33 1.74 2.97 1:09:02 0.14 0.54 0.35 0.54 0.68 0.94 1.20 1.57 2.68 1:14:20 0.11 0.43 0.28 0.43 0.55 0.76 0.98 1.28 2.20 1:19:39 0.09 0.34 0.22 0.34 0.44 0.61 0.79 1.04 1.79 1:24:58 0.06 0.25 0.16 0.25 0.32 0.45 0.59 0.78 1.36 1:30:16 0.05 0.18 0.12 0.18 0.23 0.33 0.43 0.57 1.00 1:35:35 0.03 0.13 0.09 0.13 0.17 0.24 0.31 0.42 0.73 1:40:53 0.03 0.11 0.07 0.11 0.14 0.19 0.25 0.33 0.57 1:46:12 0.02 0.09 0.06 0.09 0.11 0.16 0.20 0.27 0.47 1:51:31 0.02 0.08 0.05 0.08 0.10 0.14 0.18 0.23 0.40 1:56:49 0.02 0.07 0.04 0.07 0.09 0.12 0.15 0.20 0.35 2:02:08 0.02 0.06 0.04 0.06 0.08 0.11 0.14 0.18 0.32 2:07:26 0.02 0.06 0.04 0.06 0.07 0.10 0.13 0.17 0.29 2:12:45 0.01 0.04 0.03 0.04 0.05 0.07 0.10 0.13 0.22 2:18:04 0.01 0.03 0.02 0.03 0.04 0.05 0.07 0.09 0.16 2:23:22 0.01 0.02 0.01 0.02 0.03 0.04 0.05 0.07 0.12 2:28:41 0.00 0.02 0.01 0.02 0.02 0.03 0.04 0.05 0.08 2:33:59 0.00 0.01 0.01 0.01 0.01 0.02 0.03 0.03 0.06 2:39:18 0.00 0.01 0.00 0.01 0.01 0.01 0.02 0.02 0.04 2:44:37 0.00 0.01 0.00 0.01 0.01 0.01 0.01 0.02 0.03 2:49:55 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.02 2:55:14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 3:00:32 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 3:05:51 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:11:10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:16:28 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:21:47 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:27:05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:32:24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:37:43 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:43:01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:48:20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:53:38 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:58:57 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:04:16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:09:34 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:14:53 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:20:11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:25:30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:30:49 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:36:07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:41:26 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Summary Stage-Area-Volume-Discharge Relationships The user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically. The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points. Stage Area Area Volume Volume Total Outflow [ft] [ft^2] [acres] [ft^3] [ac-ft] [cfs] 0.00 261 0.006 0 0.000 0.00 1.00 597 0.014 360 0.008 0.02 1.61 629 0.014 736 0.017 0.02 2.00 646 0.015 984 0.023 0.02 2.15 653 0.015 1,088 0.025 0.02 2.50 668 0.015 1,320 0.030 17.12 3.00 690 0.016 1,659 0.038 32.09 3.50 712 0.016 2,010 0.046 33.82 4.00 1,095 0.025 2,461 0.057 49.48 UD-Detention, Version 3.07 (February 2017) 5028 SPILLWAY - 5028.5 TOP OF BERM - 5029 Detention Basin Outlet Structure Design Stage - Storage Description POND BOTTOM - 5025.0 5026 WQCV - 5026.61 5027 ADDITIONAL DET - 5027.15 5027.5 For best results, include the stages of all grade slope changes (e.g. ISV and Floor) from the S-A-V table on Sheet 'Basin'. Also include the inverts of all outlets (e.g. vertical orifice, overflow grate, and spillway, where applicable). UD-Detention Outflow Hydrographs WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year Time [hr] Time [min] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] Outflow2 - [cfs] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.09 5.31 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.18 10.62 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.27 15.93 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.35 21.24 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.44 26.55 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 1.93 0.53 31.86 0.02 0.02 0.02 0.02 0.02 0.02 1.30 3.61 7.10 0.62 37.17 0.02 0.02 0.02 0.02 0.34 2.78 3.05 2.42 3.23 0.71 42.48 0.02 0.64 0.02 0.64 1.84 0.76 1.36 3.02 5.87 0.80 47.79 0.02 1.01 0.02 1.01 0.49 2.04 2.32 2.03 2.80 0.89 53.10 0.02 0.54 0.10 0.54 1.26 0.71 1.13 2.26 4.41 0.97 58.41 0.02 0.70 0.62 0.70 0.47 1.41 1.66 1.55 2.17 1.06 63.72 0.02 0.47 0.20 0.47 0.89 0.66 0.97 1.74 3.36 1.15 69.03 0.02 0.50 0.39 0.50 0.41 0.98 1.18 1.19 1.70 1.24 74.34 0.02 0.32 0.17 0.32 0.55 0.47 0.66 1.14 2.23 1.33 79.65 0.02 0.29 0.21 0.29 0.27 0.58 0.71 0.74 1.06 1.42 84.96 0.02 0.17 0.10 0.17 0.28 0.26 0.37 0.63 1.27 1.50 90.27 0.02 0.15 0.10 0.15 0.15 0.30 0.37 0.40 0.56 1.59 95.58 0.02 0.11 0.07 0.11 0.16 0.17 0.22 0.36 0.71 1.68 100.89 0.02 0.10 0.06 0.10 0.11 0.18 0.23 0.26 0.39 1.77 106.20 0.02 0.08 0.05 0.08 0.10 0.13 0.17 0.24 0.47 1.86 111.51 0.02 0.07 0.05 0.07 0.09 0.13 0.16 0.20 0.31 1.95 116.82 0.02 0.06 0.04 0.06 0.08 0.11 0.14 0.19 0.35 2.04 122.13 0.02 0.06 0.04 0.06 0.07 0.10 0.13 0.17 0.28 2.12 127.44 0.02 0.05 0.03 0.05 0.06 0.08 0.10 0.13 0.24 2.21 132.75 0.02 0.03 0.02 0.03 0.04 0.06 0.08 0.10 0.15 2.30 138.06 0.02 0.02 0.02 0.02 0.03 0.04 0.05 0.07 0.13 2.39 143.37 0.02 0.02 0.02 0.02 0.02 0.03 0.04 0.05 0.09 2.48 148.68 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.04 0.07 2.57 153.99 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.05 2.66 159.30 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.03 2.74 164.61 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 2.83 169.92 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 2.92 175.23 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.01 180.54 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.10 185.85 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.19 191.16 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.27 196.47 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.36 201.78 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.45 207.09 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.54 212.40 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.63 217.71 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.72 223.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.81 228.33 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.89 233.64 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 3.98 238.95 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.07 244.26 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.16 249.57 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.25 254.88 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.34 260.19 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.43 265.50 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.51 270.81 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.60 276.12 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 N 89°30'00" W (281.00') N 00°30'00" E (169.00') S 89°30'00" E (273.00') S 00°30'00" W (93.92') S 00°30'00" W (30.00') L=24.94' R=71.00° Δ=56°30'32" L=21.08' R=60.00° Δ=56°30'32" N 89°30'00" W (281.00') N 00°30'00" E (169.00') S 89°30'00" E (273.00') S 00°30'00" W (93.92') S 00°30'00" W (30.00') L=24.94' R=71.00° Δ=56°30'32" L=21.08' R=60.00° Δ=56°30'32" DESIGN BASIN TOTAL AREA (ACRES) C2 C100 PERCENT IMPERVIOUS 2-YR RUNOFF (CFS) 100-YR RUNOFF (CFS) HISTORIC BASINS H1 0.43 0.87 1.0 90% 0.98 3.90 H2 0.36 0.35 0.4 21% 0.27 1.19 H3 0.28 0.48 0.6 37% 0.29 1.25 DEVELOPED BASINS P1 0.46 0.88 1.0 90% 1.17 4.62 P2 0.13 0.95 1.0 96% 0.34 1.25 P3 0.22 0.56 0.7 46% 0.34 1.48 OS1 0.04 0.35 0.4 21% 0.04 0.17 OS2 0.22 0.44 0.6 31% 0.25 1.10 DETENTION BASINS WQCV (P1-P3) 0.81 0.80 1.0 79% 1.70 7.34 2YR HIST (DEV-HIST-5000SQFT) 0.04 0.20 0.3 2% 0.02 0.09 4.69 281.43 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.78 286.74 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.87 292.05 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4.96 297.36 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.04 302.67 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.13 307.98 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.22 313.29 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.31 318.60 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.40 323.91 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.49 329.22 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.58 334.53 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.66 339.84 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.75 345.15 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.84 350.46 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 5.93 355.77 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 6.02 361.08 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 6.11 366.39 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 6.20 371.70 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 6.28 377.01 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 6.37 382.32 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 4:46:44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:52:03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:57:22 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:02:40 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:07:59 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:13:17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:18:36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:23:55 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:29:13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:34:32 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:39:50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:45:09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:50:28 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:55:46 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:01:05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:06:23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:11:42 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:17:01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:22:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 UD-Detention, Version 3.07 (February 2017) Detention Basin Outlet Structure Design 50YR IN 50YR OUT 25YR IN 25YR OUT 10YR IN 10YR OUT 5YR IN 5YR OUT 2YR IN 2YR OUT EURV IN EURV OUT WQCV IN WQCV OUT 0 0.5 1 1.5 2 2.5 0.1 1 10 100 PONDING DEPTH [ft] DRAIN TIME [hr] 500YR 100YR 50YR 25YR 10YR 5YR 2YR EURV WQCV 0.00 10.00 20.00 30.00 40.00 50.00 60.00 0 500 1,000 1,500 2,000 2,500 3,000 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 OUTFLOW [cfs] AREA [ft^2], VOLUME [ft^3] PONDING DEPTH [ft] User Area [ft^2] Interpolated Area [ft^2] Summary Area [ft^2] Volume [ft^3] Summary Volume [ft^3] Outflow [cfs] Summary Outflow [cfs] Time to Drain 99% of Inflow Volume (hours) = 13 18 18 18 18 18 18 18 17 Maximum Ponding Depth (ft) = 1.44 2.21 2.20 2.21 2.24 2.26 2.27 2.28 2.35 Area at Maximum Ponding Depth (acres) = 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Maximum Volume Stored (acre-ft) = 0.015 0.026 0.026 0.026 0.026 0.027 0.027 0.027 0.028 Detention Basin Outlet Structure Design UD-Detention, Version 3.07 (February 2017) KAPPA KAPPA GAMMA SORORITY LID - WATER QUALITY DETENTION POND Example Zone Configuration (Retention Pond) Surcharge Volume Length (LISV ) = user ft -- -- -- -- Surcharge Volume Width (WISV ) = user ft -- -- -- -- Depth of Basin Floor (HFLOOR ) = user ft -- -- -- -- Length of Basin Floor (LFLOOR ) = user ft -- -- -- -- Width of Basin Floor (WFLOOR ) = user ft -- -- -- -- Area of Basin Floor (AFLOOR ) = user ft^2 -- -- -- -- Volume of Basin Floor (VFLOOR ) = user ft^3 -- -- -- -- Depth of Main Basin (HMAIN ) = user ft -- -- -- -- Length of Main Basin (LMAIN ) = user ft -- -- -- -- Width of Main Basin (WMAIN ) = user ft -- -- -- -- Area of Main Basin (AMAIN ) = user ft^2 -- -- -- -- Volume of Main Basin (VMAIN ) = user ft^3 -- -- -- -- Calculated Total Basin Volume (Vtotal ) = user acre-feet -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- DETENTION BASIN STAGE-STORAGE TABLE BUILDER Optional Override Area (ft^2) Length (ft) Optional Override Stage (ft) Stage (ft) Stage - Storage Description Area (ft^2) Width (ft) KAPPA KAPPA GAMMA SORORITY LID - WATER QUALITY DETENTION POND UD-Detention, Version 3.07 (February 2017) Volume (ft^3) Volume (ac-ft) Area (acre) Optional User Override 1-hr Precipitation Total detention volume is less than 100-year volume. Example Zone Configuration (Retention Pond) CO3176-UD-Detention_v3.07.xlsm, Basin 8/18/2017, 8:12 AM = 0.1 1.0 cfs Interception with Clogging Qwa = 0.1 0.8 cfs Curb Opening as an Orifice (based on Modified HEC22 Method) MINOR MAJOR Interception without Clogging Qoi = 4.5 5.3 cfs Interception with Clogging Qoa = 3.8 4.4 cfs Curb Opening Capacity as Mixed Flow MINOR MAJOR Interception without Clogging Qmi = 0.7 2.0 cfs Interception with Clogging Qma = 0.6 1.6 cfs Resulting Curb Opening Capacity (assumes clogged condition) QCurb = 0.1 0.8 cfs Resultant Street Conditions MINOR MAJOR Total Inlet Length L = 3.00 3.00 feet Resultant Street Flow Spread (based on street geometry from above) T = 5.0 10.0 ft Resultant Flow Depth at Street Crown dCROWN = 0.0 0.0 inches Low Head Performance Reduction (Calculated) MINOR MAJOR Depth for Grate Midwidth dGrate = 0.279 0.429 ft Depth for Curb Opening Weir Equation dCurb = 0.09 0.24 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.48 0.76 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 1.00 1.00 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = 0.48 0.76 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition) Qa = 0.6 2.0 cfs WARNING: Inlet Capacity less than Q Peak for Minor and Major Storms Q PEAK REQUIRED = 1.2 4.6 cfs CDOT/Denver 13 Combination INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-Vert H-Curb W Lo (C) Lo (G) Wo WP CDOT/Denver 13 Combination Override Depths USE MAX CAPACITY SINCE IN SUMP: 4.4 CFS W/ 50% CLOGGING USE MAX CAPACITY SINCE IN SUMP: 3.5 CFS W/ 50% CLOGGING ADD GRATE & CURB OPENING MAX CAPACITY : 7.9 CFS W/ 50% CLOGGING co3176-UD-Inlet_v4.05.xlsm, Type 13 Combo Inlet 8/18/2017, 10:38 AM Roof Area (acres) Paved Area (acres) Sidewalk Area (acres) Gravel Area (acres) Landscape Area (acres) Composite Runoff Coefficient, C (2 to 10-yr) Composite Runoff Coefficient, C (11 to 25-yr) Composite Runoff Coefficient, C (26 to 50-yr) Composite Runoff Coefficient, C ( 51 to 100-yr) WQCV (P1-P3) 0.81 79% 0.17 0.48 0.00 0.00 0.16 0.80 0.88 0.96 1.00 2YR HIST (DEV-HIST-5000SQFT) 0.038 2% - - - - - 0.20 0.22 0.24 0.25 Basin Information Surface Type Runoff Coefficients Basin Information Surface Type Runoff Coefficients Basin Information Surface Type Runoff Coefficients of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 11, Sep 23, 2016 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 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. Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 4/20/2017 Page 2 of 4