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HomeMy WebLinkAboutCENTERPOINT PLAZA (RE-APPLICATION) - PDP - PDP150014 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE AND EROSION CONTROL REPORT FOR CENTERPOINT PLAZA Job Number 1028 July 14, 2015 FINAL DRAINAGE AND EROSION CONTROL REPORT FOR CENTERPOINT PLAZA Section 20, Township 7 North, Range 68 West Sixth Principal Meridian, Fort Collins, Colorado Design and Analysis Based Upon a Local Vertical Datum Prepared for: Mr. Sean Sjodin NexGen Properties, L.L.C. One Denver Tech Center 5251 DTC Parkway, Suite 8000 Greenwood Village, CO 80111 (303) 923-2442 Prepared by: RICK ENGINEERING COMPANY, INC. 4 Inverness Court East, Suite 300 Englewood, CO 80112 (303) 565-8080 JN 1028 July 14, 2015 CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT TABLE OF CONTENTS Subject Page 1.0 INTRODUCTION ................................................................................................................. 1 1.1 Site Location .............................................................................................................. 1 1.2 Site Description ......................................................................................................... 2 1.3 Purpose and Objectives ............................................................................................. 2 1.4 Previous Studies ........................................................................................................ 2 1.5 Methodologies and Procedures ................................................................................. 2 2.0 DRAINAGE BASIN AND SUBBASINS ............................................................................ 4 2.1 Major Basin Description ......................................................................................... 4 2.2 Sub-basin Description ............................................................................................. 4 3.0 DEVELOPED DRAINAGE PATTERNS ............................................................................5 4.0 STORMWATER DETENTION REQUIREMENTS ...........................................................6 5.0 POST-CONSTRUCTION STORMWATER MANAGEMENT .............................................................7 5.1 Water Quality ................................................................................................................... 7 6.0 LONG TERM MAINTENANCE ......................................................................................... 8 7.0 SUMMARY ........................................................................................................................... 9 8.0 ENGINEER’S STATEMENT ............................................................................................. 10 CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDICES APPENDIX A – FIGURES AND EXHIBITS ........................................................................... A-1 APPENDIX B – HYDROLOGIC DATA SHEETS................................................................... B-1 APPENDIX C – HYDRAULIC CALCULATIONS.................................................................. C-1 APPENDIX D – HYDRAULIC MODELS (STORM DRAIN)................................................. D-1 APPENDIX E – BMP CALCULATIONS ..................................................................................E-1 APPENDIX F – REFERENCE DOCUMENTATION................................................................F-1 LIST OF FIGURES Figure 1 - Location Map .................................................................................................................... 1 Figure 2 – FEMA FIRM ............................................................................................................. A-2 Figure 3 – Proposed Drainage Map ............................................................................................ A-3 CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 1 1.0 INTRODUCTION 1.1 Site Location Centerpoint Plaza (project site) is located in the northwest quarter of Section 20, Township 7 North, Range 68 West of the 6th Principal Meridian in the City of Fort Collins, Colorado. More specifically, the project site is bounded by Timberline Road on the west, Midpoint Drive on the north, Railroad Right of Way on the north and industrial development to the east as shown on the location map (Figure 1) below. Figure 1 - Location Map CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 2 1.2 Site Description The project site is a total of approximately 2.34 acres. Phase 1 development was completed in May of 2006. The Phase 2 area is approximately 1.57 acres. Vegetation on Phase 2 consists of native weeds and grasses. Onsite soils are Hydrologic Group C according to the Natural Resources Conservation Service (NRCS). The site is zoned E (Employment) and is adjacent to industrial development. The project site is within Flood Insurance Zone X, the areas determined to be outside the 500-year flood plain according to the FEMA Flood Insurance Rate Map, Community-Panel No 08069C-0983G. 1.3 Purpose and Objectives The purpose and objectives of this Drainage Report are to: 1. Provide supporting information required for the Site Plan drainage scheme, which meets or exceeds the City of Fort Collins Storm Drainage Design Criteria and Construction Standards and Erosion Control requirements defined in the Fort Collins Stormwater Manual, Section 1.3.3, Volume 3, Chapter 7 of the Fort Collins Amendments. 2. Provide the onsite Federal Emergency Management Agency (FEMA) Special Flood Hazard Areas (SFHA). 3. Determine the onsite detention requirements for the runoff volume difference between the 100-year developed inflow rate and the 2-year historic release rate. 4. Determine the required onsite drainage improvements to convey the runoff through the project site. 1.4 Previous Studies 1. Anderson Consulting Engineers, Inc, Spring Creek Master Drainage Plan, Baseline Hydrologic Analysis, Volumes I & II, Fort Collins, Colorado, May 5, 2003. 2. Anderson Consulting Engineers, Inc, Hydrologic modeling and Hydraulic Analyses for Spring Creek Downstream of Edora Park, Fort Collins, Colorado, October 21, 2005. CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 3 3. DMW Civil Engineers, Inc, Final Drainage Report for Centerpoint Plaza First Replat, Fort Collins, Colorado, October 28, 2008. 1.5 Methodologies and Procedures 1. Drainage design criteria is based on the City of Fort Collins Storm Drainage Design Criteria and Construction Standards and Erosion Control requirements defined in the Fort Collins Stormwater Manual, Section 1.3.3, Volume 3, Chapter 7 of the Fort Collins Amendments 2. Hydrologic Criteria The rational method has been used to estimate peak storm water runoff form the project site. An initial 10-year and major 100-year design storms have been used to evaluate the proposed drainage system. Calculations made as part of the investigation, along with other supporting material, are contained in Appendix B. Rainfall intensity data for the rational method has been taken from the intensity data tables contained in the City of Fort Collins Storm Drainage Design Criteria and Construction Standards manual (see Figure 3- 1a). Composite coefficients were generated using Table 3-3 and 3-4 of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards manual. 3. Hydraulic Criteria Spreadsheets from the Urban Storm Drainage Criteria Manual have been used to analyze the capacity of proposed pipes and swales for the site. Various spreadsheets using City of Fort Collins criteria have been used in the design of the proposed detention ponds. CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 4 2.0 DRAINAGE BASINS AND SUBBASINS 2.1 Major Basin Description The Centerpoint Plaza site is within the Spring Creek Drainage Basin, as identified by the City of Fort Collins Master Drainage Plan, but not within any regulatory floodplains designated by either the City or FEMA. Spring Creek is a major watercourse that flows from Spring Canyon Dam at Horsetooth Reservoir to its confluence with the Poudre River. The Spring Creek drainage basin encompasses nearly nine square miles in central Fort Collins. The basin is dominated by residential development, but it also includes open space, parks and isolated areas of commercial and industrial development. 2.2 Sub-Basin Description Stormwater runoff from the project site drains overland generally from northwest to southeast at slopes ranging from 1.0% to 2.0%. Stormwater runoff from most of the site is conveyed to a water quality pond and routed via storm pipes to Spring Creek, located north of the site. Runoff not captured by the pond currently is conveyed from the site towards the southeast in a shallow swale adjacent to the railroad. CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 5 3.0 DEVELOPED DRAINAGE PATTERNS The developed site has been divided into nine (9) on-site and one (1) off-site drainage basins. Stormwater runoff will be conveyed overland to an onsite detention and water quality pond and released into existing stormwater utilities at the northwest corner of the site. Basins 1 (0.09 acres) and 2 (0.12 acres) are comprised primarily of asphaltic paving. Runoff from Basins 1 and 2 sheet flows across the paving, parking lot, and along concrete gutters from northwest to southeast. Stormwater runoff follows existing flow patterns and is conveyed to the southeast. The peak 10 and 100-year flows from Basin 1 are 0.3 and 0.9 cfs, respectively. The peak 10 and 1- 100-year flows from Basin 2 are 0.4 and 1.0 cfs, respectively. Basin 3 (1.30 acres) is comprised mostly of the existing building and parking lot, and includes existing landscaping, and proposed roof and parking. Runoff from Basin 3 follows existing flow patterns and flows from west to east. Runoff is conveyed in concrete trickle pans and gutters to Basin 4, and then to Basin 5. The peak 10 and 100-yr flows from Basin 3 are 4.1 and 11.5 cfs, respectively. Basin 4 (1.01·acres) is currently primarily grassed meadow, but was modeled as developed. Runoff was modeled as flowing east to west, conveyed by pans and gutters to Basin 5. The peak 10 and 100-yr flows from Basin 4 are 4.2 and 10.1 cfs, respectively. Basin 5 (0.09 acres) is composed primarily of a grassed swale. Runoff is conveyed to the south and into a storm drain pipe discharging in the Pond. Basin also conveys runoff from Basins 3 and 4 to the storm pipe. The peak 10 and 100-yr flows from Basin 5 are 0.02 and 0.4 cfs, respectively. The combined peak 10 and 100-yr flows from Basins 3, 4, and 5 are 7.5 20.7 and cfs, respectively CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 6 Basin 6 (1.18 acres) is a combination of developed and undeveloped areas, but was modeled as fully developed. Runoff was modeled as flowing east to west, conveyed by pans, gutters and sheet flow to Basin 7 and then to the Pond. The peak 10 and 100-yr flows from Basin 6 are 4.9 and 11.7 cfs, respectively Basin 7 (0.33 acres) is composed primarily of paving and roof. Runoff from Basins 6 and 7 is conveyed via sheet flow and gutters to an 8-foot wide concrete sidewalk culvert and into the Pond. The peak 10 and 100-yr flows from Basin 7 are 1.5 and 3.3 cfs, respectively. The combined peak 10 and 100-yr flows from Basins 6 and 7 are 6.2 and 14.7 cfs, respectively Basin 8 (0.73 acres) is composed primarily of roof and paving. Runoff is conveyed by pans, sheet flow, and gutters to a 6-foot wide curb opening into the Pond. The peak 10 and 100-yr flows from Basin 8 are 2.6 and 6.6 cfs, respectively. Basin 9 (0.21 acres) is composed primarily of grassed slopes, and the Pond. Runoff is conveyed by sheet flow and pans to the existing outlet structure, and then to Spring Creek. The peak 10 and 100-yr flows from Basin 9 are 0.4 and 1.0 cfs, respectively. The combined peak 10 and 100-yr flows from Basins 3 through 9 are 15.3 and 42.0 cfs, respectively 4.0 STORMWATER DETENTION REQUIREMENTS The drainage report for Phase 1 called for a Detention Pond which lies in Phase 2. The City of Fort Collins Stormwater department has indicated that detention is not required for this development providing that proper drainage facilities exist to convey the un-detained flows to either Spring Creek to the north of Skunk Pond far to the east. Due to the fact that a majority of the downstream facilities to Skunk Pond are inadequate and would require upgrading it was found to be more economical to convey un-detained flows to Spring Creek to the north. An Amendment to the Phase 1 Drainage plan was approved with this concept in the DMW Civil Engineers Final Drainage Report 0805.00-CPR, dated October 28, CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 7 2008. This project reconfigures the approved Phase 1 Pond and provides the same water quality capture volume and complies with the original Phase 1 drainage report. 5.0 POST-CONSTRUCTION STORMWATER MANAGEMENT In order to provide treatment of stormwater runoff, stormwater quality best management practices (BMPs) have been incorporated into the proposed site improvements. BMPs utilized on this site and shown on the Proposed Drainage Map have been designed utilizing the guidelines provided in the Urban Storm Drainage Criteria Manual, Volume 3 (USDCM Vol. 3), including the “Four Step Process to Minimize Adverse Impacts of Urbanization” as listed below:  Step 1. Employ runoff reduction practices  Step 2. Implement BMPs that provide a water quality capture volume with slow release  Step 3. Stabilize drainageways  Step 4. Implement Site Specific and other source control BMPs The post-construction stormwater quality BMPs proposed for this project include: 5.1 Water Quality A Structural Best Management Practices (BMPs) are proposed for the project site to improve runoff as recommended by the Urban Storm Drainage Criteria Manual and as described in the Fort Collins Stormwater Management Manual, Volume 3-Best Management Practices (BMPs). The detention pond incorporates an extended detention basin for water quality purposes. An extended detention basin (EDB) is a sedimentation basin which uses a much smaller outlet that extends the emptying time of the more frequent occurring storm runoff events to facilitate pollutant removal. Soluble pollutant removal can be somewhat enhanced by providing a small wetland marsh or ponding area in the basin’s bottom to promote biological uptake. The detention basin planting will meet the City of Fort Collins CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 8 Detention Pond Landscape Guidelines which will help facilitate successful biological uptake. The basins are considered to be “dry” because they are designed not to have a significant permanent pool of water remaining between storm runoff events. Extended Detention Basin’s may develop wetland vegetation and sometimes shallow pools in the bottom portions of the facilities. The water quality pond for the project site has been designed to provide 4,704 cubic feet of water quality capture and with a water surface elevation of 4909.17. Release of the captured water is controlled by a steel plate with one column of six 5/8” diameter circular perforations. The outlet structure itself and 36” diameter RCP outlet pipe convey flows in excess of the water quality capture volume north to Spring Creek. The pond will reach a maximum water surface elevation of 4910.50 to discharge these flows through the outlet structure. The parking lot serves as an emergency overflow and any excess runoff is conveyed off-site to the southeast towards Skunk Pond. CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 9 6.0 LONG TERM MAINTENANCE The proper functioning of the drainage systems described in this report is dependent on the owner providing, annual and continuous maintenance to the drainage improvements. The firm responsible for the ownership, operation, scheduled and unscheduled maintenance and liability of drainage improvements and common areas detailed on this report is: NexGen Properties or an Officially Designated Entity by NexGen; Mr. Sean Sjodin NexGen Properties, L.L.C. One Denver Tech Center 5251 DTC Parkway, Suite 8000 Greenwood Village, CO 80111 (303) 923-2442 Maintenance guidelines and a checklist is provided within Appendix E. Refer to Chapter 6 of the Urban Storm Drainage Criteria Manual, Volume 3 for maintenance of the site’s stormwater quality BMPs (grass swales, grass buffers, bioretention areas, etc.). CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 10 7.0 SUMMARY  The supporting information required for the Site Plan drainage scheme is being provided within the report.  The onsite Federal Emergency Management Agency (FEMA) Special Flood Hazard Areas (SFHA) have been shown on the drainage figures of the report.  The offsite and onsite peak discharges for the 100-year storm event have been calculated. The 2-year and 10-year event was calculated for comparison of pre- development and post-development discharges.  The required onsite drainage improvements to convey the runoff through the project site have been calculated and are shown in the figures of the report. CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 11 8.0 ENGINEER’S STATEMENT The drainage design concept presented in this Drainage Report assures that drainage affecting the project will be handled in a manner that does not conflict with any federal, state, and/or county regulations intended to protect adjacent properties and/or the project itself from adverse impacts during design storm events specified in the current regulations. Disclaimer – Any deviations from the drainage scheme and hydraulic design presented herein, or any variations in climatic or watershed conditions may affect the functionality and other hydrologic or hydraulic characteristics of this project and nullify the results presented herein. CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT 7/14/2015 Page 12 WORKS CITED  Anderson Consulting Engineers, Inc, Spring Creek Master Drainage Plan, Baseline Hydrologic Analysis, Volumes I & II, Fort Collins, Colorado, May 5, 2003.  Anderson Consulting Engineers, Inc, Hydrologic modeling and Hydraulic Analyses for Spring Creek Downstream of Edora Park, Fort Collins, Colorado, October 21, 2005.  DMW Civil Engineers, Inc, Final Drainage Report for Centerpoint Plaza First Replat, Fort Collins, Colorado, October 28, 2008.  Urban Drainage and Flood Control District, Urban Storm Drainage Criteria Manual, Volume 1 and 2. June 2001, Revised April 2008.  Urban Drainage and Flood Control District, Urban Storm Drainage Criteria Manual, Volume 3 – Best Management Practices. November 2010.  Stantec, Topographic Map.  United States Department of Agriculture – Natural Resouce Conservation Service, Web Soil Survey. <http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm>.  National Oceanic and Atmospheric Administration (NOAA), NOAA Atlas 14 Point Precipitation Frequency Estimates: CO. <http://hdsc.nws.noaa.gov/hdsc/pfds/ pfds_map_cont.html?bkmrk=co>.  Federal Emergency Management Agency (FEMA), National Flood Insurance Program (NFIP); Flood Insurance Rate Map (FIRM) 08069C-0983G.  Bentley, StormCAD V8i. November 9, 2009.  Bentley, FlowMaster v. 8.01. November 9, 2006. L:\1028_CenterpointPlaza_DrainageReport_FtCollins_20150713.DOCX CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDIX A – FIGURES AND EXHIBITS PageA-1 ‹ CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDIX B – HYDROLOGIC DATA SHEETS PageB-1 Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 9 Area = 0.21 Acres Percent Imperviousness = 20.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.55 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.26 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.26 N/A 0.25 33.90 1 2 3 4 5 500 Computed Tc = 33.90 Regional Tc = 12.78 User-Entered Tc = 12.78 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 3.79 inch/hr Peak Flowrate, Qp = 0.44 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.74 cfs Rainfall Intensity at User-Defined Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.74 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 9 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:44 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 9 Area = 0.21 Acres Percent Imperviousness = 20.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.34 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.26 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.26 N/A 0.25 33.90 1 2 3 4 5 500 Computed Tc = 33.90 Regional Tc = 12.78 User-Entered Tc = 12.78 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 2.35 inch/hr Peak Flowrate, Qp = 0.17 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.28 cfs Rainfall Intensity at User-Defined Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.28 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 9 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:43 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 8 Area = 0.73 Acres Percent Imperviousness = 20.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.55 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.26 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.26 N/A 0.25 33.90 1 2 3 4 5 500 Computed Tc = 33.90 Regional Tc = 12.78 User-Entered Tc = 12.78 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 3.79 inch/hr Peak Flowrate, Qp = 1.53 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 2.56 cfs Rainfall Intensity at User-Defined Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 2.56 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 8 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:45 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 8 Area = 0.73 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 2.53 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 2.41 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 2.53 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 8 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:42 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 7 Area = 0.33 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 2.14 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 1.87 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 2.14 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 7 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:51 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 7 Area = 0.33 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 1.14 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 1.09 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 1.14 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 7 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:41 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 6 Area = 1.18 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 7.67 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 6.68 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 7.67 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 6 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:51 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 6 Area = 1.18 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.09 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 3.90 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.09 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 6 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:40 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 5 Area = 0.09 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.51 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 5 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:50 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 5 Area = 0.09 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.30 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 5 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:39 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 4 Area = 1.01 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 6.56 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 5.71 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 6.56 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 4 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:50 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 4 Area = 1.01 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 3.50 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 3.34 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 3.50 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 4 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:36 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 3 Area = 1.30 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 8.45 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 7.36 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 8.45 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 3 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:49 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 3 Area = 1.30 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.51 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 4.30 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.51 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 3 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:39 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 2 Area = 0.12 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.78 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.68 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.78 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 2 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:52 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 2 Area = 0.12 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.42 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.40 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.42 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 2 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:38 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 1 Area = 0.09 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.84 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0100 500 0.82 N/A 0.73 11.44 1 2 3 4 5 500 Computed Tc = 11.44 Regional Tc = 12.78 User-Entered Tc = 11.44 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.30 cfs Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 1 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:37 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 1 Area = 0.09 Acres Percent Imperviousness = 95.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 100 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.89 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.82 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.0200 500 0.82 N/A 0.92 9.10 1 2 3 4 5 500 Computed Tc = 9.10 Regional Tc = 12.78 User-Entered Tc = 9.10 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.51 cfs Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 1 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:52 AM Project Title: Catchment ID: I. Catchment Hydrologic Data Catchment ID = 1 Area = 0.09 Acres Percent Imperviousness = 100.00 % NRCS Soil Type = C A, B, C, or D II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3 Design Storm Return Period, Tr = 10 years (input return period for design storm) C1 = 28.50 (input the value of C1) C2= 10.00 (input the value of C2) C3= 0.786 (input the value of C3) P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.92 Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) 5-yr. Runoff Coefficient, C-5 = 0.90 Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.) Illustration NRCS Land Heavy Tillage/ Short Nearly Grassed Type Meadow Field Pasture/ Bare Swales/ Lawns Ground Waterways Conveyance 2.5 5 7 10 15 Calculations: Reach Slope Length 5-yr NRCS Flow Flow ID S L Runoff Convey- Velocity Time Coeff ance V Tf ft/ft ft C-5 fps minutes input input output input output output Overland 0.4000 500 0.90 N/A 3.42 2.44 1 2 3 4 5 500 Computed Tc = 2.44 Regional Tc = 12.78 User-Entered Tc = 5.00 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = 6.33 inch/hr Peak Flowrate, Qp = 0.52 cfs Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.32 cfs Rainfall Intensity at User-Defined Tc, I = 5.46 inch/hr Peak Flowrate, Qp = 0.45 cfs (Sheet Flow) 20 Shallow Paved Swales Sum CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Centerpoint Plaza 1 Paved Areas & UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:30 AM CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDIX C – HYDRAULIC CALCULATIONS Page C-1 Project = Inlet ID = Design Information (Input) MINOR MAJOR Type of Inlet Inlet Type = Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal = 3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 1.6 2.3 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) = N/A N/A feet Width of a Unit Grate Wo = N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = N/A N/A Grate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = N/A N/A Grate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) = 5.00 5.00 feet Height of Vertical Curb Opening in Inches Hvert = 6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat = 6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 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 Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw (C) = 3.00 3.00 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co (C) = 0.67 0.67 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition) Qa = 0.0 0.0 cfs Q PEAK REQUIRED = 16.0 31.0 cfs INLET IN A SUMP OR SAG LOCATION Enter Your Project Name Here Enter Your Inlet ID Here CDOT Type R Curb Opening H-Vert H-Curb W Lo (C) Lo (G) Wo WP Override Depths UD-Inlet_v3.14.xlsm, Inlet In Sump 7/13/2015, 12:06 PM CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDIX D – HYDRAULIC MODELS (STORM DRAIN) PageD-1 CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDIX E – BMP CALCULATIONS Page E-1 Sheet 1 of 4 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 85.0 % B) Tributary Area's Imperviousness Ratio (i = Ia / 100 ) i = 0.850 C) Contributing Watershed Area Area = 2.970 ac D) For Watersheds Outside of the Denver Region, Depth of Average d6 = 1.60 in Runoff Producing Storm E) Design Concept (Select EURV when also designing for flood control) F) Design Volume (1.2 WQCV) Based on 40-hour Drain Time VDESIGN = 0.108 ac-ft (VDESIGN = (1.0 * (0.91 * i 3 - 1.19 * i 2 + 0.78 * i) / 12 * Area * 1.2) G) For Watersheds Outside of the Denver Region, VDESIGN OTHER = 0.400 ac-ft Water Quality Capture Volume (WQCV) Design Volume (VWQCV OTHER = (d 6*(VDESIGN /0.43)) H) User Input of Water Quality Capture Volume (WQCV) Design Volume VDESIGN USER = ac-ft (Only if a different WQCV Design Volume is desired) I) Predominant Watershed NRCS Soil Group J) Excess Urban Runoff Volume (EURV) Design Volume For HSG A: EURVA = (0.1878i - 0.0104)*Area EURV = ac-f t For HSG B: EURVB = (0.1178i - 0.0042)*Area For HSG C/D: EURVC/D = (0.1043i - 0.0031)*Area 2. Basin Shape: Length to Width Ratio L : W = 3.0 : 1 (A basin length to width ratio of at least 2:1 will improve TSS reduction.) 3. Basin Side Slopes A) Basin Maximum Side Slopes Z = 4.00 ft / ft (Horizontal distance per unit vertical, 4:1 or flatter preferred) 4. Inlet A) Describe means of providing energy dissipation at concentrated inflow locations: Design Procedure Form: Extended Detention Basin (EDB) Centerpoint Plaza Rick Engineering Company July 13, 2015 Pond Outlet Structure RKF Choose One Excess Urban Runoff Volume (EURV) Choose One A B C / D Water Quality Capture Volume (WQCV) UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM Sheet 2 of 4 Designer: Company: Date: Project: Location: 5. Forebay A) Minimum Forebay Volume VFMIN = 0.007 ac-ft (VFMIN = 2% of the WQCV) B) Actual Forebay Volume VF = ac-ft C) Forebay Depth DF = in (DF = 18 inch maximum) D) Forebay Discharge i) Undetained 100-year Peak Discharge Q100 = cfs ii) Forebay Discharge Design Flow QF = cfs (QF = 0.02 * Q 100) E) Forebay Discharge Design F) Discharge Pipe Size (minimum 8-inches) Calculated DP = in G) Rectangular Notch Width Calculated WN = in 6. Trickle Channel A) Type of Trickle Channel F) Slope of Trickle Channel S = 0.0100 ft / ft 7. Micropool and Outlet Structure A) Depth of Micropool (2.5-feet minimum) DM = ft B) Surface Area of Micropool (10 ft 2 minimum) A M = sq ft C) Outlet Type D) Depth of Design Volume (EURV or 1.2 WQCV) Based on the Design H = feet Concept Chosen Under 1.E. E) Volume to Drain Over Prescribed Time WQCV = 0.333 ac-ft F) Drain Time TD = hours (Min TD for WQCV= 40 hours; Max T D for EURV= 72 hours) G) Recommended Maximum Outlet Area per Row, (Ao) A o = square inches H) Orifice Dimensions: i) Circular Orifice Diameter or Dorifice = inches ii) Width of 2" High Rectangular Orifice Worifice = inches I) Number of Columns nc = number J) Actual Design Outlet Area per Row (Ao) A o = square inches K) Number of Rows (nr) nr = number L) Total Outlet Area (Aot) A ot = square inches M) Depth of WQCV (HWQCV) H Sheet 3 of 4 Designer: Company: Date: Project: Location: 8. Initial Surcharge Volume A) Depth of Initial Surcharge Volume DIS = in (Minimum recommended depth is 4 inches) B) Minimum Initial Surcharge Volume VIS = cu ft (Minimum volume of 0.3% of the WQCV) C) Initial Surcharge Provided Above Micropool Vs= cu ft 9. Trash Rack A) Type of Water Quality Orifice Used B) Water Quality Screen Open Area: At = Aot * 38.5*(e -0.095D ) At = square inches C) For 1-1/4"", or Smaller, Circular Opening (See Fact Sheet T-12): i) Width of Water Quality Screen and Concrete Opening (Wopening) W opening = inches ii) Height of Water Quality Screen (HTR) H TR = inches iii) Type of Screen, Describe if "Other" D) For Circular Opening (greater than 1-1/4" diameter) OR 2" High Rectangular Opening (See Fact Sheet T-12): i) Width of Water Quality Screen Opening (Wopening) W opening = ft ii) Height of Water Quality Screen (HTR) H TR = ft iii) Type of Screen, Describe if "Other" v) Cross-bar Spacing inches vi) Minimum Bearing Bar Size RKF Design Procedure Form: Extended Detention Basin (EDB) July 13, 2015 Centerpoint Plaza Pond Outlet Structure Rick Engineering Company Choose One Circular (up to 1-1/4" diameter) Circular (greater than 1-1/4" diameter) OR Rectangular (2" high) Choose One S.S. Well Screen with 60% Open Area* Other (Describe): Choose One Aluminum Amico-Klemp SR Series (or equal) Other (Describe): UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM Sheet 4 of 4 Designer: Company: Date: Project: Location: 10. Overflow Embankment A) Describe embankment protection for 100-year and greater overtopping: B) Slope of Overflow Embankment ZE = ft / ft (Horizontal distance per unit vertical, 4:1 or flatter preferred) 11. Vegetation 12. Access A) Describe Sediment Removal Procedures Notes: Centerpoint Plaza Pond Outlet Structure Design Procedure Form: Extended Detention Basin (EDB) July 13, 2015 Rick Engineering Company RKF Choose One Irrigated Not Irrigated UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT APPENDIX F – REFERENCE DOCUMENTATION Page F-1 This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA WQCV = feet (Estimate using actual stage-area-volume relationship and VWQCV) N) Ensure Minimum 40 Hour Drain Time for WQCV TD WQCV = hours Centerpoint Plaza July 13, 2015 Rick Engineering Company Design Procedure Form: Extended Detention Basin (EDB) (flow too small for berm w/ pipe) Pond Outlet Structure RKF Choose One Wall with Rect. Notch Berm With Pipe Choose One Orifice Plate Other (Describe): Choose One Concrete Soft Bottom Wall with V-Notch Weir UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM