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HomeMy WebLinkAboutTAFT PLACE - FDP180028 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTi TAFT PLACE (4101 South Taft Hill Road) Fort Collins, Colorado FINAL DRAINAGE & EROSION CONTROL REPORT Prepared by: North Star Design 700 Automation Drive, Unit I Windsor, Colorado 80550 Prepared for: Aweida Properties, Inc February 11, 2019 Project Number 385-01 ii February 11, 2019 Wes Lemarque City of Fort Collins Stormwater 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage & Erosion Control Report for Taft Place (4101 South Taft Hill Road) Dear Wes, I am pleased to submit for your review and approval, this Final Drainage & Erosion Control Report for a multi-use building at 4101 South Taft Hill Road (Taft Place) in Fort Collins. I certify that this report for the drainage design was prepared in accordance with the criteria in the City of Fort Collins Storm Drainage Manual. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, Patricia Kroetch, P.E. 700 Automation Drive, Unit I Windsor, CO 80550 Phone: 970-686-6939 Fax: 970-686-1188 iii TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................... iii 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location ...................................................................................................................1 1.2 Description of Property ............................................................................................1 2. DRAINAGE BASINS AND SUB-BASINS 2.1 Major Basin Description ..........................................................................................1 2.2 Sub-Basin Description .............................................................................................2 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations ..............................................................................................................2 3.2 Four Step Process to Minimize Adverse Impacts of Urbanization ..........................2 3.3 Development Criteria Reference and Constraints ...................................................3 3.4 Hydrologic Criteria ..................................................................................................4 3.5 Hydraulic Criteria ....................................................................................................4 4. DRAINAGE FACILITY DESIGN 4.1 General Concept ......................................................................................................4 4.2 Specific Flow Routing .............................................................................................5 4.3 Drainage Summary ..................................................................................................5 5. CONCLUSIONS 5.1 Compliance with Standards ....................................................................................6 5.2 Drainage Concept ....................................................................................................6 6. REFERENCES ....................................................................................................................7 APPENDICES A Vicinity Map B Hydrologic Computations C Hydraulic Calculations D Detention System Sizing Calculations E BMP Schedule and Cost Estimate F Erosion & Sediment Control Report G Figures & Tables 1 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location This site is located on the southwest corner of the intersection of West County Road 38E and South Taft Hill Road in the Southeast Quarter of Section 33, Township 7 North, Range 69 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. See the Vicinity Map in Appendix A of this report. This project is bounded on the north and east by existing arterial rights of ways and on the west and south by existing residences. 1.2 Description of Property The entire project consists of approximately 0.35 acres. This site was previously unplatted and was used for a single residence with a gravel driveway. There are some older trees on site that will be removed and volunteer grasses and weeds cover the site. The existing house and driveways have recently been removed. All of the surrounding area is large lot residential county development and are not part of a subdivision. There are no major drainageways, facilities or easements within or adjacent to the site. Proposed development on-site will include a single multi use building, a private drive with access to both CR 38E and Taft Hill Road, a parking area and sidewalks. Existing drainage patterns will be altered to route flow to a proposed underground detention system in the west portion of the site under the drive and parking which will release into the existing storm system near the northeast corner of the site. Irrigation of the site will be through a drip system connected to the potable water system. 2. DRAINAGE BASINS AND SUB-BASINS 2.1 Major Basin Description The proposed development lies within the Mail Creek Drainage Basin. The basin generally drains from west to east to the confluence of Mail Creek and Fossil Creek, and ultimately to Fossil Creek Reservoir. Three irrigation canals intercept stormwater to transport it out of the basin, but runoff spills into the basin when their capacity is exceeded. There are no irrigation facilities within this Basin which will influence or be 2 influenced by the local drainage design. This site is not within a FEMA defined floodway or floodplain. No previous drainage studies have been completed for this site. Stormwater detention and water quality enhancement are required for this site. 2.2 Sub-basin Description Runoff from this site currently flows to the existing streets on the north and east. Currently, there are small roadside ditches and driveway culverts that collect the water from this site. Both adjacent properties direct their runoff to the adjacent street and no runoff from those sites will impact this site. With the proposed drainage concept for this site, the runoff from the site will flow to an underground detention system located under the access drive and parking on the west side of the building. It is proposed to provide underground detention using a StormTech chamber system with underdrain. The sizing of this system was provided by Evan Fischgrund at Advanced Drainage Systems, Inc. and is provided in Appendix D. This detention facility will release the runoff at a composite historic rate into the existing storm system to the north of the site. Curb & gutter will be added to the adjacent streets therefore street runoff will no longer impact this site. 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the “City of Fort Collins Storm Drainage Design Criteria Manual” specifications. 3.2 Four Step Process to Minimize Adverse Impacts of Urbanization Because this site is small, the ability to disconnect impervious areas is difficult. The site does not benefit from disconnecting the impervious areas therefore this has not been accomplished on this site. Step 1. Employ Runoff Reduction Practices – reduction of runoff peaks, volumes, and pollutant loads as the site is developed by implementing Low-Impact Development (LID) strategies including: 3  Increase time of concentration by routing flows along the drive aisles and increasing the length of the flow path.  Routing runoff from the proposed site into the underground detention/water quality to promote infiltration and biological uptake.  Routing flows through filter material in the underground detention to increase time of concentration, promote infiltration and provide initial water quality. Step 2. Implement BMPs That Provide a Water Quality Capture Volume with Slow Release - The efforts outlined in Step 1 will facilitate the reduction of runoff. Runoff will be routed through the rain gardens and then to an underground detention storage facility that will provide attenuation prior to release into the public storm system to reduce the amount of runoff generated from the site through infiltration, and also treat the runoff prior to releasing it from the site. Step 3. Stabilize Streams - There are no major drainageways in or near this site therefore Step 3 it not directly applicable this project. However, this project will pay stormwater development fees and monthly stormwater utility fees which contribute to the City’s ongoing efforts to attain stream stability where and as needed. Step 4. Implement Site Specific and Other Source Control BMPs - This step applies to covering storage/handling areas and spill containment and control. Vehicle maintenance and washing during construction will be completed off site to prevent potential spills of vehicle fluids. Any handling of chemicals will be completed inside the building and will be handled per the applicable MSDS (material safety data sheet). Spills will be contained immediately and cleaned up using appropriate absorption materials. 3.3 Development Criteria Reference and Constraints The runoff from this site has been routed to conform to the requirements of the Mail Creek Drainage Basin and the City of Fort Collins Stormwater Department. There are no previous drainage studies for this or the adjacent sites. This site is highly constrained due to the small size of the site and the requirement for dedication of additional right of way for the adjacent arterial streets. Stormwater runoff detention is required for this site with on-site detention. The release rate from the site will be at the calculated composite release rate of 0.63 cfs. 4 3.4 Hydrologic Criteria Runoff computations were prepared for the 2-year minor and 100-year major storm frequencies utilizing the rational method. All hydrologic calculations associated with the basins are included in Appendix B of this report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub-basins. Detention volume was calculated using the predetermined composite release rate of 0.63 cfs. The FAA method for detention sizing was utilized to determine the required volume. Refer to the detention calculations included in Appendix D of this report. 3.5 Hydraulic Criteria Hydraulic elements have been designed per City of Fort Collins standards to adequately convey the 100-year storm runoff from this site to the proposed underground detention area. A proposed 12” storm pipe will convey the detained runoff from the site to an existing manhole located on the northwest corner of Taft Hill Road and CR 38E. Runoff from the adjacent streets will also be collected and conveyed to this existing manhole. The existing storm system is relatively shallow therefore the proposed storm pipes are smaller than the minimum City standard size of 15” in order to maximize the cover over the storm pipes. 4. DRAINAGE FACILITY DESIGN 4.1 General Concept The runoff from this site will surface flow to two on site low points on the entry drives. The runoff will then enter the underground detention and infiltrate into the subgrade in the water quality chambers. The flow will be attenuated and the detained runoff will discharge into the proposed inlet and storm pipe located in the northeast corner of the site on CR 38E. 4.2 Specific Flow Routing With this design, the site has been considered as a single basin which described in the following paragraph. 5 Basin 1 contains the entire site including the building, parking lot, sidewalks, entrance drives and underground detention. The runoff from this basin will flow north to one low point in the entrance drive from CR 38E and will flow east to another low point in the access drive from Taft Hill Road. Flow from both low points will flow to the underground detention via storm pipes. From here, the attenuated flow will release into the existing storm system at a rate of 0.63 cfs. Basin 1 is further divided into Basin 1A and Basin 1B in order to size the collection and conveyance systems to the detention pond. Basin 1A encompasses the west half of the site including the parking lot and the west half of the building. This basin contributes flows to Inlet 1 and Onsite Storm 1. Basin 1B encompasses the east half of the site including the east half of the building and the landscape areas. This basin contributes flows to Inlet 2 and then to Onsite Storm 2. The underground detention chamber system will release the detained runoff from the site at the rate of 0.63 cfs. This rate was calculated by determining the area of the site that is historically impervious and using the 2 year historic runoff rate (0.20 cfs) then determining the area of the site that is historically pervious and using the 100 year historic runoff rate (0.43 cfs). The composite of these 2 historic values was used as the allowable release rate from the detention storage. This totals an allowable release rate of 0.63 cfs. A drainage easement will be dedicated on the plat to encompass the detention storage system. Pipes are also shown on the plan to convey runoff from the west and the south to the existing storm system at the northwest corner of the intersection of Taft Hill Road and CR 38E. These pipes will fall within the right of ways and will not require separate drainage easements. The existing storm system is relatively shallow therefore the proposed storm pipes are smaller than the minimum City standard size of 15” in order to maximize the cover over the storm pipes. 4.3 Drainage Summary This site has been designed to meet or exceed the “City of Fort Collins Storm Drainage Design Criteria Manual” specifications. The proposed drainage design for this site has been designed to convey on-site runoff to the detention pond while minimizing future 6 maintenance. The site incorporates LID (Low Impact Development) volume in the chambers in addition to the detention volume. Refer to the end of Appendix E for a table indicating the sizing of the required volume for LID treatment. All drainage facilities proposed with this project, including the underground detention chambers, drain basins, inlets and storm pipe are private and will be owned and maintained by the property owner. The pipes and the storm manholes in the right of way will be owned and maintained by the City of Fort Collins. 5. CONCLUSIONS 5.1 Compliance with Standards All computations that have been completed within this report are in compliance with the “City of Fort Collins Erosion Control Reference Manual for Construction Sites”, the “City of Fort Collins Storm Drainage Design Criteria Manual”, and the “Urban Storm Drainage Criteria Manual”. 5.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for the collection and conveyance of on-site runoff to the underground detention system. Conveyance elements exist in County Road 36E to adequately convey detained runoff downstream. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit would be required. 7 6. REFERENCES 1. Urban Drainage and Flood Control District, “Urban Storm Drainage Criteria Manual”, 2001 Edition Volume 1 updated June 2001, January 2004 and April 2008; Volume 2 updated June 2001 and April 2008; and Volume 3 updated November and December 2010. 2. The Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual, adopted by the City Council of the City of Fort Collins, as referenced in Section 26-500 (c) of the Code of the City of Fort Collins. 3. ORDINANCE NO. 152, 2012 of the Council of the City of Fort Collins amending Chapter 26 of the Code of the City of Fort Collins and the Fort Collins Stormwater Criterial Manual to incorporate provisions implementing Low Impact Development (LID) Principles. APPENDIX A VICINITY MAP APPENDIX B HYDROLOGIC COMPUTATIONS North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 LOCATION: 4101 South Taft Hill Road PROJECT NO: 385-01 COMPUTATIONS BY: ppk DATE: 11/27/2018 Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria Recommended % Impervious from Urban Storm Drainage Criteria Manual % Runoff Impervious coefficient C Streets, parking lots (asphalt): 100% 0.95 Sidewalks: 96% 0.95 Gravel: 40% 0.50 Roofs: 90% 0.95 Lawns (flat <2%, heavy soil): 0% 0.20 SUBBASIN TOTAL TOTAL ROOF PAVED SIDEWALK GRAVEL LANDSCAPE % RUNOFF DESIGNATION AREA AREA AREA AREA AREA AREA AREA Impervious COEFF. (ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C) 1A 0.22 9,636 936 4681 1209 0 2,810 69% 0.73 1B 0.12 5320 1724 964 578 0 2,054 58% 0.58 Total to pond (Basin 1) 0.34 14,956 2,660 5,645 1,787 0 4,864 65% 0.71 Historic landscape 0.23 9,927 9,927 0% 0.20 Historic hardscape 0.12 5,029 1,370 1,572 690 1,397 0 80% 0.82 Historic Site 0.34 14,956 1,370 1,572 690 1,397 9,927 27% 0.41 Equations - Calculated C coefficients & % Impervious are area weighted C =  (Ci Ai) / At Ci = runoff coefficient for specific area, Ai Ai = areas of surface with runoff coefficient of Ci n = number of different surfaces to consider At = total area over which C is applicable; the sum of all Ai's Flow.xls Cval North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 LOCATION: 4101 South Taft Hill Road PROJECT NO: 385-01 COMPUTATIONS BY: ppk DATE: 11/27/2018 2-yr storm Cf = 1.00 FINAL REMARKS tc DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 POINT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) 1 1A 0.22 0.73 41 2.0 3.4 80 1.0 0.016 2.0 0.66 4.0 121 10.7 5.0 1 1B 0.12 0.58 40 1.0 5.9 152 0.5 0.016 1.4 1.78 7.7 192 11.1 7.7 1 Total to pond (Basin 1) 0.34 0.71 40 1.0 4.5 152 0.5 0.016 1.4 1.78 6.3 192 11.1 6.3 Historic landscape 0.23 0.20 158.5 2.2 15.7 0 1.0 0.020 1.6 0.00 15.7 158.5 10.9 10.9 Historic hardscape 0.12 0.82 158.5 2.2 4.8 0 1.0 0.020 1.6 0.00 4.8 158.5 10.9 5.0 Historic Site 0.34 0.41 158.5 2.2 12.0 0 1.0 0.020 1.6 0.00 12.0 158.5 10.9 10.9 EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 minutes TIME (ti) TRAVEL TIME / GUTTER OR CHANNEL FLOW (tt) tc CHECK (URBANIZED BASIN) STANDARD FORM SF-2 TIME OF CONCENTRATION - 2 YEAR SUB-BASIN DATA INITIAL /OVERLAND Flow.xls TOC-2 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 LOCATION: 4101 South Taft Hill Road PROJECT NO: 385-01 COMPUTATIONS BY: ppk DATE: 11/27/2018 100-yr storm Cf = 1.25 FINAL REMARKS tc DESIGN SUBBASIN(s) Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10 POINT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min) (1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14) 1 1A 0.22 0.73 0.91 41 2.0 1.7 80 1.0 0.016 2.0 0.66 2.4 121 10.7 5.0 1 1B 0.12 0.58 0.73 40 1.0 4.2 152 0.5 0.016 1.4 1.78 6.0 192 11.1 6.0 1 Total to pond (Basin 1) 0.34 0.71 0.88 40 1.0 2.5 152 0.5 0.016 1.4 1.78 4.3 192 11.1 5.0 Historic landscape 0.23 0.20 0.25 158.5 2.2 14.8 0 1.0 0.020 1.6 0.00 14.8 158.5 10.9 10.9 Historic hardscape 0.12 0.82 1.00 158.5 2.2 1.7 0 1.0 0.020 1.6 0.00 1.7 158.5 10.9 5.0 Historic Site 0.34 0.41 0.51 158.5 2.2 10.2 0 1.0 0.020 1.6 0.00 10.2 158.5 10.9 10.2 EQUATIONS: tc = ti + tt ti = [1.87 (1.1 - CCf ) L 0.5 ] / S 1/3 tt = L/Vel. Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 minutes TIME OF CONCENTRATION - 100 YR STANDARD FORM SF-2 SUB-BASIN DATA TIME (ti) INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW (tt) tc CHECK (URBANIZED BASIN) Flow.xls TOC-100 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (2-YEAR) LOCATION: 4101 South Taft Hill Road PROJECT NO: 385-01 COMPUTATIONS BY: ppk DATE: 11/27/2018 2-yr storm, Cf = 1.00 TOTAL REMARKS Design Tributary A C*Cf tc i Q (2) from Q (2) Q(2)tot Sub-basin (new) Design Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) 1 1A 0.22 0.73 5.0 2.85 0.5 0.46 1 1B 0.12 0.58 7.7 2.44 0.2 0.17 1 Total to pond (Basin 1) 0.34 0.71 6.3 2.62 0.6 0.64 Historic landscape 0.23 0.20 10.9 2.14 0.1 0.10 Historic hardscape 0.12 0.82 5.0 2.14 0.2 0.20 Allowable release rate Historic Site 0.34 0.41 10.9 2.14 0.3 0.30 Q = Cf C iA Q = peak discharge (cfs) C = runoff coefficient Cf = frequency adjustment factor i = rainfall intensity (in/hr) from IDF curve A = drainage area (acres) DIRECT RUNOFF CARRY OVER Flow.xls Q2 North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (100-YEAR) LOCATION: 4101 South Taft Hill Road PROJECT NO: 385-01 COMPUTATIONS BY: ppk DATE: 11/27/2018 100-yr storm, Cf = 1.25 TOTAL REMARKS Des. Area A C*Cf tc i Q (100) from Q (100) Q(100)tot (new) Design Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs) 1 1A 0.22 0.91 5.0 9.95 2.0 2.01 1 1B 0.12 0.73 6.0 9.31 0.8 0.83 1 Total to pond (Basin 1) 0.34 0.88 5.0 9.95 3.0 3.02 Historic landscape 0.23 0.25 10.9 7.63 0.43 0.43 Allowable release rate Historic hardscape 0.12 1.00 5.0 7.63 0.88 0.88 Historic Site 0.34 0.51 10.2 7.63 1.34 1.34 Q = C iA Q = peak discharge (cfs) C = runoff coefficient I = rainfall intensity (in/hr) from IDF curve A = drainage area (acres) DIRECT RUNOFF CARRY OVER Flow.xls Q100 APPENDIX C HYDRAULIC CALCULATIONS 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 3' Curb Inlet High Flow Grate Inlet Capacity Chart High Hood Setting (8.47" Curb Setting) Mid Hood Setting (6.47" Curb Setting) Low Hood Setting (4.47" Curb Setting) 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 3' Curb Inlet High Flow Grate Inlet Capacity Chart High Hood Setting (8.47" Curb Setting) Mid Hood Setting (6.47" Curb Setting) Low Hood Setting (4.47" Curb Setting) System Input Summary Rainfall Parameters Rainfall Return Period: 100 Rainfall Calculation Method: Formula One Hour Depth (in): 9.95 Rainfall Constant "A": 28.5 Rainfall Constant "B": 10 Rainfall Constant "C": 0.786 Rational Method Constraints Minimum Urban Runoff Coeff.: 0.20 Maximum Rural Overland Len. (ft): 500 Maximum Urban Overland Len. (ft): 300 Used UDFCD Tc. Maximum: Yes Sizer Constraints Minimum Sewer Size (in): 12.00 Maximum Depth to Rise Ratio: 0.90 Maximum Flow Velocity (fps): 18.0 Minimum Flow Velocity (fps): 2.0 Backwater Calculations: Tailwater Elevation (ft): 53.00 Manhole Input Summary: Given Flow Sub Basin Information Element Name Ground Elevation (ft) Total Known Flow (cfs) Local Contribution (cfs) Drainage Area (Ac.) Runoff Coefficient 5yr Coefficient Overland Length (ft) Overland Slope (%) Gutter Length (ft) Gutter Velocity (fps) Detention 55.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Storm 1 54.35 2.01 2.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Manhole Output Summary: Local Contribution Total Design Flow Element Name Overland Time Elevation Loss Coefficients Given Dimensions Element Name Sewer Length (ft) Downstream Invert (ft) Slope (%) Upstream Invert (ft) Mannings n Bend Loss Lateral Loss Cross Section Rise (ft or in) Span (ft or in) Storm 1 24.10 52.60 0.7 52.77 0.010 0.03 0.00 CIRCULAR 12.00 in 12.00 in Sewer Flow Summary: Full Flow Capacity Critical Flow Normal Flow Element Name Flow (cfs) Velocity (fps) Depth (in) Velocity (fps) Depth (in) Velocity (fps) Froude Number Flow Condition Flow (cfs) Surcharged Length (ft) Comment Storm 1 3.89 4.95 7.26 4.05 6.12 4.99 1.39 Supercritical 2.01 0.00 A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe). If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer. If the sewer is pressurized, full flow represents the pressurized flow conditions. Sewer Sizing Summary: Existing Calculated Used 0.00 2.40 4.80 7.20 9.60 12.00 14.40 16.80 19.20 21.60 24.00 52.36 52.66 52.96 53.26 53.56 53.86 54.16 54.46 54.76 HGL EGL System Input Summary Rainfall Parameters Rainfall Return Period: 100 Rainfall Calculation Method: Formula One Hour Depth (in): 9.95 Rainfall Constant "A": 28.5 Rainfall Constant "B": 10 Rainfall Constant "C": 0.786 Rational Method Constraints Minimum Urban Runoff Coeff.: 0.20 Maximum Rural Overland Len. (ft): 500 Maximum Urban Overland Len. (ft): 300 Used UDFCD Tc. Maximum: Yes Sizer Constraints Minimum Sewer Size (in): 12.00 Maximum Depth to Rise Ratio: 0.90 Maximum Flow Velocity (fps): 18.0 Minimum Flow Velocity (fps): 2.0 Backwater Calculations: Tailwater Elevation (ft): 53.00 Manhole Input Summary: Given Flow Sub Basin Information Element Name Ground Elevation (ft) Total Known Flow (cfs) Local Contribution (cfs) Drainage Area (Ac.) Runoff Coefficient 5yr Coefficient Overland Length (ft) Overland Slope (%) Gutter Length (ft) Gutter Velocity (fps) Detention 55.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Storm 2 54.27 0.83 0.83 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Manhole Output Summary: Local Contribution Total Design Flow Element Name Overland Time Elevation Loss Coefficients Given Dimensions Element Name Sewer Length (ft) Downstream Invert (ft) Slope (%) Upstream Invert (ft) Mannings n Bend Loss Lateral Loss Cross Section Rise (ft or in) Span (ft or in) Storm 2 68.50 52.63 0.4 52.90 0.010 0.03 0.00 CIRCULAR 12.00 in 12.00 in Sewer Flow Summary: Full Flow Capacity Critical Flow Normal Flow Element Name Flow (cfs) Velocity (fps) Depth (in) Velocity (fps) Depth (in) Velocity (fps) Froude Number Flow Condition Flow (cfs) Surcharged Length (ft) Comment Storm 2 2.94 3.74 4.57 3.02 4.36 3.22 1.09 Supercritical 0.83 0.00 A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe). If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer. If the sewer is pressurized, full flow represents the pressurized flow conditions. Sewer Sizing Summary: Existing Calculated Used 0.00 6.80 13.60 20.40 27.20 34.00 40.80 47.60 54.40 61.20 68.00 52.39 52.69 52.99 53.29 53.59 53.89 54.19 54.49 54.79 HGL EGL System Input Summary Rainfall Parameters Rainfall Return Period: 100 Rainfall Calculation Method: Formula One Hour Depth (in): 9.95 Rainfall Constant "A": 28.5 Rainfall Constant "B": 10 Rainfall Constant "C": 0.786 Rational Method Constraints Minimum Urban Runoff Coeff.: 0.20 Maximum Rural Overland Len. (ft): 500 Maximum Urban Overland Len. (ft): 300 Used UDFCD Tc. Maximum: Yes Sizer Constraints Minimum Sewer Size (in): 12.00 Maximum Depth to Rise Ratio: 0.90 Maximum Flow Velocity (fps): 18.0 Minimum Flow Velocity (fps): 2.0 Backwater Calculations: Tailwater Elevation (ft): 53.00 Manhole Input Summary: Given Flow Sub Basin Information Element Name Ground Elevation (ft) Total Known Flow (cfs) Local Contribution (cfs) Drainage Area (Ac.) Runoff Coefficient 5yr Coefficient Overland Length (ft) Overland Slope (%) Gutter Length (ft) Gutter Velocity (fps) Type R Inlet 54.17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Storm 3 54.17 0.63 0.63 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Manhole Output Summary: Local Contribution Total Design Flow Element Name Elevation Loss Coefficients Given Dimensions Element Name Sewer Length (ft) Downstream Invert (ft) Slope (%) Upstream Invert (ft) Mannings n Bend Loss Lateral Loss Cross Section Rise (ft or in) Span (ft or in) Storm 3 92.20 52.14 0.5 52.60 0.010 0.03 0.00 CIRCULAR 12.00 in 12.00 in Sewer Flow Summary: Full Flow Capacity Critical Flow Normal Flow Element Name Flow (cfs) Velocity (fps) Depth (in) Velocity (fps) Depth (in) Velocity (fps) Froude Number Flow Condition Flow (cfs) Surcharged Length (ft) Comment Storm 3 3.28 4.18 3.96 2.78 3.56 3.23 1.23 Supercritical 0.63 0.00 A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe). If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer. If the sewer is pressurized, full flow represents the pressurized flow conditions. Sewer Sizing Summary: Existing Calculated Used 0.00 9.20 18.40 27.60 36.80 46.00 55.20 64.40 73.60 82.80 92.00 51.94 52.14 52.34 52.54 52.74 52.94 53.14 53.34 53.54 53.74 53.94 54.14 HGL EGL Program: UDSEWER Math Model Interface 2.1.1.4 Run Date: 11/28/2018 9:18:38 AM UDSewer Results Summary Project Title: Taft Place public storm Project Description: Default system System Input Summary Rainfall Parameters Rainfall Return Period: 100 Rainfall Calculation Method: Formula One Hour Depth (in): 9.95 Rainfall Constant "A": 28.5 Rainfall Constant "B": 10 Rainfall Constant "C": 0.786 Rational Method Constraints Minimum Urban Runoff Coeff.: 0.20 Maximum Rural Overland Len. (ft): 500 Maximum Urban Overland Len. (ft): 300 Used UDFCD Tc. Maximum: No Sizer Constraints Minimum Sewer Size (in): 12.00 Maximum Depth to Rise Ratio: 0.90 Maximum Flow Velocity (fps): 18.0 Minimum Flow Velocity (fps): 2.0 Backwater Calculations: Tailwater Elevation (ft): 52.00 Manhole Input Summary: Given Flow Sub Basin Information Element Name Ground Elevation (ft) Total Known Flow (cfs) Local Contribution (cfs) Drainage Area (Ac.) Runoff Coefficient 5yr Coefficient Overland Length (ft) Overland Slope (%) Gutter Length (ft) Gutter Storm 4-2 54.40 0.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.26 Storm 4-3 55.40 0.50 0.50 0.00 0.00 0.00 0.00 0.00 0.00 1.26 Storm 4-1 55.00 0.50 0.50 0.00 0.00 0.00 0.00 0.00 0.00 1.26 Manhole Output Summary: Local Contribution Total Design Flow Element Name Overland Time (min) Gutter Time (min) Basin Tc (min) Intensity (in/hr) Local Contrib (cfs) Coeff. Area Intensity (in/hr) Manhole Tc (min) Peak Flow (cfs) Comment OUTFALL 1 0.00 0.00 0.00 0.00 0.00 0.08 45.69 0.20 3.63 Storm 5-2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.63 Storm 5-1 0.00 0.00 0.00 0.00 2.00 0.00 0.00 0.00 2.63 Storm 4-2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.50 Storm 4-3 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 0.50 Storm 4-1 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 0.50 Sewer Input Summary: Elevation Loss Coefficients Given Dimensions Element Name Sewer Length (ft) Downstream Invert (ft) Slope (%) Upstream Invert (ft) Mannings n Bend Loss Lateral Loss Cross Section Rise Existing Calculated Used Element Name Peak Flow (cfs) Cross Section Rise Span Rise Span Rise Span Area (ft^2) Comment Storm 5-2 3.63 CIRCULAR 12.00 in 12.00 in 15.00 in 15.00 in 12.00 in 12.00 in 0.79 Existing height is smaller than the suggested height. Existing width is smaller than the suggested width. Exceeds max. Depth/Rise Storm 5-1 2.63 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Storm 4-2 0.50 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Storm 4-3 0.50 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Storm 4-1 0.50 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size. Sewer sizes should not decrease downstream. All hydraulics where calculated using the 'Used' parameters. Grade Line Summary: Tailwater Elevation (ft): 52.00 Invert Elev. Downstream Manhole Losses HGL EGL Element Name Downstream (ft) Upstream (ft) Bend Loss (ft) Lateral Loss (ft) Downstream (ft) Upstream (ft) Downstream (ft) Friction Loss (ft) Upstream (ft) Storm 5-2 51.85 52.07 0.00 0.00 52.85 53.43 53.18 0.58 53.76 Storm 5-1 52.07 52.14 0.01 0.00 53.59 53.66 53.77 0.07 53.83 Storm 4-2 52.09 52.30 0.00 0.00 53.75 53.76 53.76 0.01 53.77 Storm 4-3 52.30 52.76 0.00 0.00 53.76 53.78 53.77 0.02 53.78 Storm 4-1 52.09 52.70 0.00 0.00 53.75 53.78 53.76 0.02 53.78 Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a sewer. Bend loss = Bend K * V_fi ^ 2/(2*g) 0.00 19.00 38.00 57.00 76.00 95.00 114.00 133.00 152.00 171.00 190.00 51.49 51.89 52.29 52.69 53.09 53.49 53.89 54.29 54.69 55.09 HGL EGL 0.00 17.80 35.60 53.40 71.20 89.00 106.80 124.60 142.40 160.20 51.53 51.83 52.13 52.43 52.73 53.03 53.33 53.63 53.93 54.23 54.53 54.83 HGL EGL 0.00 6.90 13.80 20.70 27.60 34.50 41.40 48.30 55.20 62.10 51.53 51.83 52.13 52.43 52.73 53.03 53.33 53.63 53.93 54.23 54.53 54.83 HGL EGL APPENDIX D DETENTION SIZING CALCULATIONS MINIMUM DETENTION VOLUME REQUIRED FAA METHOD (100-YEAR) LOCATION: 4101 South Taft Ave PROJECT NO: 385-01 COMPUTATIONS BY: PPK SUBMITTED BY: North Star Design, Inc. DATE: 11/27/2018 Equations: A trib. To pond = 0.34 acre QD = CiA C100 = 0.88 Vi = T*CiA = T*QD Developed C*A = 0.3 acre Vo =K*QPO*T QPO = 0.63 cfs S = Vi - Vo K = 1 (from fig 2.1) Rainfall intensity from City of Fort Collins IDF Curve Storm Rainfall QD Vol. In Vol. Out Storage Storage Duration, T Intensity, i (cfs) Vi Vo SS (min) (in/hr) (ft3) (ft3) (ft3) (ac-ft) 5 9.95 3.0 893 189 704 0.016 10 7.72 2.3 1386 378 1008 0.023 20 5.60 1.7 2011 756 1255 0.029 30 4.52 1.4 2434 1134 1300 0.030 40 3.74 1.1 2686 1512 1174 0.027 50 3.23 1.0 2899 1890 1009 0.023 60 2.86 0.9 3081 2268 813 0.019 70 2.62 0.8 3292 2646 646 0.015 80 2.38 0.7 3418 3024 394 0.009 90 2.22 0.7 3587 3402 185 0.004 100 2.05 0.6 3680 3780 -100 -0.002 110 1.93 0.6 3811 4158 -347 -0.008 120 1.80 0.5 3878 4536 -658 -0.015 130 1.60 0.5 3734 4914 -1180 -0.027 140 1.40 0.4 3519 5292 -1773 -0.041 150 1.20 0.4 3231 5670 -2439 -0.056 160 1.15 0.3 3303 6048 -2745 -0.063 170 1.10 0.3 3357 6426 -3069 -0.070 180 1.05 0.3 3393 6804 -3411 -0.078 Required Storage Volume: 1300 ft3 0.030 acre-ft WATER QUALITY POND SIZE LOCATION: 4101 South Taft Ave PROJECT NO: 385-01 COMPUTATIONS BY: PPK SUBMITTED BY: North Star Design, Inc. DATE: 11/27/2018 From Urban Storm Drainage Criterial Manual Use: 12-hour drain time a=0.80 Required Storage Water Quality Capture Volume = WQCV = [required storage] * [Area] 12 Trib. % Imperv. Req. Storage WQCV WQCV WQ Flow area from Fig. EDB-2 (To column 1) (To column 2) (ac) (in. of runoff) (ac-ft) (cu-ft) (cfs) POND 0.34 65 0.254 0.007 314 0.33 a * [0.91 (i 3) - 1.19 (i 2) + 0.78(i)] 123456 7 8910 11 12 13 Req'd Flow Chamber Chamber Chamber Ch. Volume Min # of Total Req'd Volume Min # of # of Chambers Storage Provided Storage Provided WQ Volume WQ Type Release Volume w/ Aggregate Chambers Release Rate FAA Method Chambers Req'd in Req'd Chambers in Chambers & Agg (cf) (cfs) (cfs) (cf) (cf) incl. aggregate (cfs) (cf) w/ FAA method(Greater of Column 7 (cf) (cf) (Column 1/ (Column 4* (Column 9/ or Column 10) (Column 5 * Column 11) (Column 6 * Column 11) Column 6) Column 7) Column 6) 314 0.33 SC-160 0.011426 6.85 15 21 0.24 31 3 21 144 315  StormTec Chamber Summary Table Information provided by StormTec Project: Chamber Model - SC-160 Units - Imperial Number of chambers - 72 Voids in the stone (porosity) - 40 % Base of STONE Elevation - 5152.60 ft Amount of Stone Above Chambers - 6 in Amount of Stone Below Chambers - 4 in Area of system - 1447 sf Min. Area - Height of System Incremental Single Chamber Incremental Total Chamber Incremental Stone Incremental Ch & St Cumulative Chamber Elevation (inches) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (feet) 22 0.00 0.00 48.23 48.23 1357.21 5154.43 21 0.00 0.00 48.23 48.23 1308.98 5154.35 20 0.00 0.00 48.23 48.23 1260.74 5154.27 19 0.00 0.00 48.23 48.23 1212.51 5154.18 18 0.00 0.00 48.23 48.23 1164.28 5154.10 17 0.00 0.00 48.23 48.23 1116.04 5154.02 16 0.05 3.69 46.76 50.45 1067.81 5153.93 15 0.13 9.68 44.36 54.04 1017.36 5153.85 14 0.29 20.92 39.86 60.79 963.32 5153.77 13 0.44 31.82 35.51 67.32 902.54 5153.68 12 0.54 38.82 32.71 71.53 835.21 5153.60 11 0.62 44.38 30.48 74.86 763.69 5153.52 10 0.68 49.01 28.63 77.64 688.83 5153.43 9 0.74 52.98 27.04 80.02 611.19 5153.35 8 0.78 56.40 25.67 82.08 531.16 5153.27 7 0.82 59.39 24.48 83.87 449.09 5153.18 6 0.86 61.95 23.46 85.40 365.22 5153.10 5 0.89 64.42 22.47 86.88 279.82 5153.02 4 0.00 0.00 48.23 48.23 192.93 5152.93 3 0.00 0.00 48.23 48.23 144.70 5152.85 2 0.00 0.00 48.23 48.23 96.47 5152.77 1 0.00 0.00 48.23 48.23 48.23 5152.68 4101 South Taft Avenue 1068 sf min. area StormTech SC-160 Cumulative Storage Volumes Include Perimeter Stone in Calculations Click Here for Metric Detention Pond Outlet Sizing (100 yr event) LOCATION: Taft Place PROJECT NO: 385-01 COMPUTATIONS BY: PPK SUBMITTED BY: North Star Design, Inc. DATE: 11/27/2018 Submerged Orifice Outlet: release rate is described by the orifice equation, Qo = CoAo sqrt( 2g(h-Eo)) where Qo = orifice outflow (cfs) Co = orifice discharge coefficient g = gravitational acceleration = 32.2 ft/s Ao = effective area of the orifice (ft2) Eo = greater of geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) Qo = 0.63 cfs outlet pipe dia = D = 12.0 in Invert elev. = 5152.60 ft Eo = 5152.78 ft h = 5154.4 ft - 100 yr WSEL Co = 0.62 solve for effective area of orifice using the orifice equation Ao = 0.099 ft2 = 14.2 in2 orifice dia. = d = 4.25 in Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering ) d / D = 0.35 kinematic viscosity, u = 1.22E-05 ft2/s Reynolds no. = Red = 4Q/(pdu) = 1.86E+05 Co = (K in figure) = 0.62 check Use d = 4.25 in A o = 0.099 ft 2 = 14.19 in 2 Q max = 0.63 cfs Stormwater Facility Name: Facility Location & Jurisdiction: User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined Watershed Slope = 0.008 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs] Watershed Length‐to‐Width Ratio = 1.00 L:W 0.00 0 0.00 0.00 Watershed Area =0.34acres 0.50 365 0.50 0.28 Watershed Imperviousness = 65.0% percent 1.00 835 1.00 0.44 Percentage Hydrologic Soil Group A =0.0%percent 1.50 1,164 1.50 0.56 Percentage Hydrologic Soil Group B = 100.0% percent 1.83 1,357 1.83 0.63 Percentage Hydrologic Soil Groups C/D = 0.0% percent 2.25 1,646 2.25 0.71 User Input 17 User Input: Detention Basin Characteristics WQCV Design Drain Time = 12.00 hours After completing and printing this worksheet to a pdf, go to: https://maperture.digitaldataservices.com/gvh/?viewer=cswdif, create a new stormwater facility, and attach the pdf of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period = WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year One‐Hour Rainfall Depth = 0.53 0.98 1.36 1.71 2.31 2.91 3.67 in Calculated Runoff Volume = 0.006 0.017 0.026 0.035 0.052 0.069 0.091 acre‐ft OPTIONAL Override Runoff Volume = acre‐ft Inflow Hydrograph Volume = 0.005 0.016 0.026 0.035 0.051 0.068 0.090 acre‐ft Time to Drain 97% of Inflow Volume = 111 1222 hours Time to Drain 99% of Inflow Volume = 1111222 hours Maximum Ponding Depth = 0.19 0.55 0.83 1.05 1.43 1.78 2.20 ft Maximum Ponded Area = 0.003 0.009 0.016 0.020 0.026 0.030 0.037 acres Maximum Volume Stored = 0.000 0.003 0.006 0.010 0.019 0.028 0.042 acre‐ft Stormwater Detention and Infiltration Design Data Sheet Taft Place SW corner of Taft Hill Road and CR 38E, Fort Collins, CO Location for 1‐hr Rainfall Depths (use dropdown): Workbook Protected Worksheet Protected Det Pond Drain time check_FC_Rainfall.xlsm, Design Data 11/27/2018, 4:37 PM Doing_Clear_FoYes CountA= 1 0123 #N/A #N/A 0123 #N/A #N/A Check Data Set 1 Check Data Set 1 Stormwater Detention and Infiltration Design Data Sheet Area Discharge 0 0.5 1 1.5 2 2.5 0.1 1 10 FLOW [cfs] TIME [hr] 100YR IN 100YR OUT 50YR IN 50YR OUT 25YR IN 25YR OUT 10YR IN 10YR OUT 5YR IN 5YR OUT 2YR IN 2YR 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] 100YR 50YR 25YR 10YR 5YR 2YR WQCV Det Pond Drain time check_FC_Rainfall.xlsm, Design Data 11/27/2018, 4:37 PM APPENDIX E BMP SCHEDULE & COST ESTIMATE Project: Disturbed Acres: 0.35 EROSION CONTROL BMPs Units Estimated Quantity Unit Price Total Price L.F. 426 $3.00 $1,278.00 each 5 $85.00 $425.00 each $180.00 $0.00 each 3 $255.00 $765.00 each 1 $1,500.00 $1,500.00 each 1 $1,200.00 $1,200.00 Sub-Total: $5,168.00 1.5 x Sub-Total: $7,752.00 Amount of security: $7,752.00 Total Acres x Price/acre: $420.00 $1,200.00 Sub-Total: $420.00 1.5 x Sub-Total: $630.00 Amount to Re-seed: $630.00 Minimum escrow amount: $3,000.00 Erosion Control Escrow: $7,752.00 Miniumum Escrow Amount Taft Place (4101 South Taft Hill Road) Unit Price of Seeding per acre: “The amount of the security must be based on one and one-half times the estimate of the cost to install the approved measures, or one and one-half times the cost to re-vegetate the disturbed land to dry land grasses based upon unit cost determined by the City's Annual Revegetation and Stabilization Bid, whichever is greater. In no instance, will the amount of security be less than one thousand five hundred dollars ($1,500) for residential development or three thousand dollars ($3,000) for commercial development” Rock Sock Vehicle Tracking Control Pad Final Escrow Amount Erosion and Sediment Control Escrow/Security Calculation for The City of Fort Collins BMP Amount Silt Fence Concrete Washout Reseeding Amount Rock Berm Inlet Protection 11/27/2018 3:55 PM N:\385-01 South Taft site\drainage\FC Escrow.xls APPENDIX F EROSION & SEDIMENT CONTROL REPORT EROSION & SEDIMENT CONTROLS 1. Written Analysis An Erosion and Sediment Control Plan is included herewith. It should be noted, however, that any such Erosion and Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed or modified in conjunction with construction activities. It is imperative to appropriately reflect the current site conditions at all times. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 - Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing along the disturbed perimeter, gutter protection in the adjacent roadways and inlet protection at proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. Grading and Erosion Control Notes can be found on Sheet 2 of the Utility Plans. In addition to this report and the plan sheets, the Contractor shall be aware of and adhere to the applicable requirements outlined all Development Agreements pertaining to this property. Also, the Site Contractor for this project will be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division - Stormwater Program, before commencing any earth disturbing activities. The Contractor shall also develop a comprehensive Storm Water Management Plan (SWMP) conforming to applicable requirements including descriptions of the ongoing activities, inspections and maintenance of construction BMPs. • The site is approximately .35 acres all of which will undergo earthmoving operations. The existing site has existing ground cover (volunteer grasses and weeds) on approximate 45% - 50% of the site as the site has been historically used for storage of materials and vehicles for adjacent properties. Runoff from this site currently discharges to the adjacent roadside dtiches. With the proposed development, this site will also be sloped to drain to two low points and into two proposed inlets. The runoff will then enter the proposed detention pond and be released to the existing storm system in County Road 38E as the historic flow path dictates. The soils on this site are classified by the USGS Soil Survey as Altvan Satanta Loam (100%) which is classified in the hydrologic group B. The B soils are described as having 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. The rainfall erodibility is deemed to be moderate and the wind erodibility is deemed to be moderate. The site is surrounded by developed sites including streets, residences and paved areas. The construction shall utilize silt fence around the perimeter to control sediment transport from rainfall and from wind. The silt fence that is located in the proposed pavement areas will be removed prior to placing new pavement. Rock socks will be utilized in the existing curb and proposed curbs to capture sediments that are not fully contained by the silt fence placement. The locations of the rock socks will be in the areas of concentrated flow such as in the existing curb and on the concrete pans. The site will also utilize a vehicle tracking control pad to minimize sediment from being tracked onto adjacent pavements. Sediment that is tracked will be removed and placed within the site or permanently disposed of offsite. A concrete washout will be used on site during the concrete placement. All hardened concrete will be disposed of offsite. These BMP’s have not been located on the site map due to the fact that the site is very small and these BMP’s will need to be placed by the contractor in locations that are most beneficial and will minimize disruption of adjacent traffic. Permanent erosion control consists of covering the soils with a building, concrete walks, pavement, landscape mulch and sod. No soil will be left exposed to erosion after the construction is complete. Refer to the landscape plan for areas of and instructions for placement of sod and soil amendments required prior to placement of sod. Refer to Appendix for the timing of the construction phases and the sequential installation of all BMP phasing for this site. Refer to the Appendix for the Erosion Control Surety calculations. 2. SWMP contact information Permit holder: Name: Address: Phone Number: Email Address: Appointed agent: Name: Address: Phone Number: Email Address: 3. Identification and location of all potential pollution sources Potential Pollutant Source Activity Potential Pollutant Generated Applicable to this project Control Measure Disturbed Areas Sediment X Silt Fence, Rock Socks Soil stockpiles Sediment X Silt Fence, Rock Socks Travel to adjacent public streets Tracked sediment X Tracking Pad, street sweeping Contaminated soils Sediment, chemicals Possible Remove contaminated soils from site ** Loading and unloading chemicals Chemicals Unloading of building materials Trash, debris, track out X Trash dumpsters, Waste Management Firm ** Outdoor storage of chemicals Chemicals On site equipment maintenance Oil, grease On site equipment fueling Diesel, gasoline X Containment berm ** Dust generating activities Particulates, sediment X Water truck Use of fertilizer, pesticides, herbicides Fertilizer, pesticides Use of detergents, solvents, oils Detergents, solvents, oil X If spilled, remove contaminated soils from site ** Waste Chemicals, trash, debris X Waste Management Firm Concrete wash Concrete, sediment, wash water X Remove hardened concrete, dispose of offsite ** On site equipment washing Detergents, oil On site asphalt batch plant Asphaltic cement, sediment On site concrete batch plant Cement, sediment Portable toilets Domestic sewage X Waste Management Firm ** Refer to Section 5 for additional Materials Handling & Spill Prevention BMP 4. Best Management Practices (BMP’s) for Stormwater Pollution Prevention Structural Practices for Erosion and Sediment Control Structural practices for the site will consist mainly of silt fence and rock sock filters and are described in detail in the following paragraphs. These BMP's are expected to change as the construction progresses and it is the responsibility of the contractor to ensure appropriate BMP's are in place and/or removed at the appropriate time in the construction sequence. All temporary and permanent erosion and sediment control practices must be maintained and repaired as needed to assure continued performance of their intended function. Silt fence and rock sock filters shall be in place prior to commencement of construction activities. During clearing and grubbing necessary for silt fence installation, all cleared material shall be placed on the uphill side so that if erosion occurs from the cleared material, the sediment will be trapped and not transported downstream. Rock socks shall be implemented in the existing curb line as shown on the Drainage & Erosion Control Plan. A vehicle tracking pad will be installed at a location most beneficial to the site construction as determined by the contractor. Vehicles will not be permitted in the excavated area if soil is muddy. Gravel sub base will be placed and compacted in the areas indicated for pavement following excavation. All BMP's shall be installed per the details shown on the construction plan set. Temporary & Permanent Structural BMP’s: Refer to table in Section 3 for purpose of Structural BMP noted below Structural BMP Approximate location on site Applicable to this Project Silt Fence Site perimeter, refer to site map X Rock Socks At existing sidewalk culverts, in existing gutters, refer to site map X Earthen diversion dams Vegetated swales Sediment trap/pond Pipe slope drains Geogrid Inlet/outlet protection Culverts Refer to site map X Riprap Erosion control mats Inlet protection Vehicle Tracking Control Pad At site entrance, refer to site map X Concrete Washout To be located by Contractor X Non-Structural Practices for Erosion and Sediment Control: Soils exposed during the earthwork phase and landscape prep phase shall be kept in a roughened condition by ripping or disking along land contours until mulch, vegetation, or other permanent erosion control is installed. No large amount of soils (in excess of 15 yards) will be allowed to be stock piled on site. Overburden from the utility pipe trenching will be piled adjacent to trenches upstream of sediment controls and will be replaced in the trenches within 72 hours. Excess excavated materials from the demolition and grading phases of the project that cannot be reused on site will be exported as it is excavated. This includes any asphalt pavement from the existing site that is to be removed. In the current pre construction state the site enables tracking of silt onto the adjacent streets during wet conditions. During construction activities the street will be monitored for foreign debris tracked out of the site and mechanical sweeping and clean up will be performed as needed. No area shall remain exposed by land disturbing activity for more than thirty (30) days before required temporary or permanent erosion control (e.g. seed/mulch, landscaping, etc.) is installed. Temporary & Permanent non-structural BMP’s: Refer to table in Section 3 for purpose of Non Structural BMP noted below Non-Structural BMP Approximate location on site Applicable to this Project Surface roughening Entire site X Soil stockpile height limit (less than 10’) Perimeter vegetative buffer Minimization of site disturbance Mulch Seed & mulch stockpiles after 30 days Preservation & protection of existing vegetation & trees Good site housekeeping (routine cleanup of trash & constr debris) Entire Site X Sweeping & scraping of hardscape areas On and off site pavements X Heavy equip staged on site, properly maintained & inspected daily (no onsite maintenance) Staging area X 5. Material Handling & Spill Prevention Refer to table in Section 3 Materials Handling & Spill Prevention BMP Approximate location on site Applicable to this Project Portable toilets, anchored & located away from drainages Contractor to determine X Fuel storage located in bulk tanks with secondary containment & spill kit Mobile fueling performed at least 200 feet away from drainages & fully attended Contractor to determine X Fertilizers, form oil, solvents, cleaners, detergent stored in 55 gal or smaller containers, kept in storage units Contractor to determine X Dumpsters containing used chemicals containers & liquid wastes kept covered Contractor to determine X Equipment cleaning (on site) uses no detergents & flows to onsite retention basin In case of a release of fuel or other chemicals, absorbent booms or earthen berms will be immediately constructed to contain the spill & prevent runoff to adjacent surface waters Location of spill X MSDS sheets for onsite chemicals will be kept at the construction trailer to facilitate spill response & cleanup Contractor to determine X B) Dedicated Asphalt or Concrete Batch Plant: Not proposed with this development C) Vehicle Tracking Pad: Vehicle tracking control pad shall be installed wherever construction vehicle access routes intersect paved public roads. Vehicle tracking control pads shall be installed to minimize the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface. Any mud tracked to public roads shall be removed on a daily basis and after any significant storm that causes sediment to be transported. It is unlawful to track sediment/mud onto public streets and may be enforced by the City of Fort Collins, by the State of Colorado or by the EPA. D) Waste Management and Disposal: Portable toilets will be anchored & periodically maintained by waste management company. Dumpsters on site will be covered & periodically emptied by waste management company. Concrete waste will be allowed to harden and then will be removed from site. No vehicle or equipment washing activities will occur on site. Location of the concrete washout is shown on the site map. The washout will be sufficiently deep to accommodate all anticipated concrete truck wash water. Waste concrete will be allowed to harden and be removed from site periodically as the washout reaches 50% of its capacity. Truck wash water will not be allowed to reach the curb & gutter or any other water course. E) Groundwater and Stormwater Dewatering: No groundwater was encountered during soils exploration therefore ground water is not anticipated to be an issue. If groundwater is encountered a groundwater discharge permit shall be obtained and a detailed report shall be completed describing the location and the route of where pumped groundwater will be conveyed and the measures taken to prevent the transport of any pollutants to downstream waters. 6. BMP Implementation A) Phased BMP Implementation BMP’s are expected to change as the construction progresses and it is the responsibility of the contractor to ensure appropriate BMP’s are in place and/or removed at the appropriate time in the construction sequence. A construction sequence schedule has been included on the Drainage & Erosion Control Plan and included in the construction plans for this site. All BMP’s shall be inspected and repaired or replaced as required to satisfy the conditions of the Stormwater Discharge Permit. All BMP’s must be maintained and repaired as needed to assure continued performance of their intended function. Refer to Appendix E for the BMP schedule and estimated costs. B) Inspection & Maintenance: It is required that routine site inspections are performed to effectively address maintenance and repair of Best Management Practices (BMP's). The site inspections are to performed by the contractor or an inspector designated by the administrator at a minimum of once every fourteen (14) calendar days on active construction sites and after any significant storm event (an event causing runoff). As part of the site inspections the inspector is required to keep documentation of all inspections and BMP maintenance, including an updated Site Map indicating new BMP's or the removal of BMP's since the previous inspection. Any maintenance, repair, or necessary installation of BMP's that are noted during the inspection must be completed within seven (7) calendar days from the date of the inspection. 7. Soil Amendments, Permanent Seeding & Mulching A) Soil Amendments Soil in the Rain Gardens shall be amended per the City of Fort Collins Bioretention Sand Media Specifications found at: http://www.fcgov.com/utilities/img/site_specific/uploads/Bioretention_Sand_Media_Specs.pdf Soil treatment in the detention area will be to spread imported or stockpiled topsoil to a minimum depth of four inches over areas to be planted. B) Permanent Seeding The following seed mix shall be applied at the rates indicated in the bioswale and in the water quality pond. Other landscaped areas on site shall be treated per the landscape plan. Mulch shall be applied after seeding as the notes indicate below. Drill seed specified mix in two passes, each at right angles to each other. Drill half of the seed in each pass. If areas are too wet or steep to drill seed, broadcast seed in two opposite directions. Restore fine grade after seeding, and cover seed to depth of 1/4 inch by raking or dragging. Firm seeded areas with a roller weighing maximum of 100 lbs. per foot of width. Ground cover shall be considered established when 70% of the seed has been germinated. At the point that the seed is considered established, the temporary erosion control measures may be removed. C) Mulching All planted areas should be mulched preferably immediately following planting, but in no case later than 14 days from planting. Mulch conserves water and reduces erosion. The most common type of mulch used is hay or grass that is crimped into the soil to hold it. However, crimping may not be practical on slopes steeper than 3:1. The following guidelines should be followed with mulching: • Only weed-free and seed-free straw mulch should be used (grass hay often contains weedy exotic species). Mulch should be applied at 2 tons/acre and adequately secured by crimping, tackifier, netting, or blankets. • Crimping is appropriate on slopes of 3:1 or flatter and must be done so as to tuck mulch fibers into the soil 3 to 4 inches deep. • Tackifier or netting and blankets anchored with staples should be used on slopes steeper than 3:1. • Hydraulic mulching may also be used on steep slopes or where access is limited. Wood cellulose fibers mixed with water at 2,000 to 2,500 pounds/acre and organic tackifier at 100 pounds per acre should be applied with a hydraulic mulcher. APPENDIX G FIGURES AND TABLES FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 8 Table 3.4-1. IDF Table for Rational Method Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) 5 2.85 4.87 9.95 39 1.09 1.86 3.8 6 2.67 4.56 9.31 40 1.07 1.83 3.74 7 2.52 4.31 8.80 41 1.05 1.80 3.68 8 2.40 4.10 8.38 42 1.04 1.77 3.62 9 2.30 3.93 8.03 43 1.02 1.74 3.56 10 2.21 3.78 7.72 44 1.01 1.72 3.51 11 2.13 3.63 7.42 45 0.99 1.69 3.46 12 2.05 3.50 7.16 46 0.98 1.67 3.41 13 1.98 3.39 6.92 47 0.96 1.64 3.36 14 1.92 3.29 6.71 48 0.95 1.62 3.31 15 1.87 3.19 6.52 49 0.94 1.6 3.27 16 1.81 3.08 6.30 50 0.92 1.58 3.23 17 1.75 2.99 6.10 51 0.91 1.56 3.18 18 1.70 2.90 5.92 52 0.9 1.54 3.14 19 1.65 2.82 5.75 53 0.89 1.52 3.10 20 1.61 2.74 5.60 54 0.88 1.50 3.07 21 1.56 2.67 5.46 36 RAINFALL INTENSITY-DURATION-FREQUENCY CURVE 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 0.00 10.00 20.00 30.00 40.00 50.00 60.00 STORM DURATION (minutes) RAINFALL INTENSITY (inches/hour) 2-Year Storm 10-Year Storm 100-Year Storm Figure RA-16 City of Fort Collins Rainfall Intensity-Duration-Frequency Curves (13) Section 5.0 is deleted in its entirety. (14) Section 6.0 is deleted in its entirety. (15) Section 7.0 is deleted in its entirety. (16) Section 7.1 is deleted in its entirety. (17) Section 7.2 is deleted in its entirety. (18) Section 7.3 is deleted in its entirety. (19) Section 8.0 is deleted in its entirety. (20) Table RA-1 is deleted in its entirety. 40 Table RO-10 Rational Method Minor Storm Runoff Coefficients for Zoning Classifications Description of Area or Zoning Coefficient R-F 0.3 U-E 0.3 L-M-In 0.55 R-L, N-C-L 0.6 M-M-N, N-C-M 0.65 N-C-B 0.7 Business: C-C-N, C-C-R, C-N, N-C, C-S 0.95 R-D-R, C-C, C-L 0.95 D, C 0.95 H-C 0.95 C-S 0.95 Industrial: E 0.85 I 0.95 Undeveloped: R-C, T 0.2 P-O-L 0.25 For guidance regarding zoning districts and classifications of such districts please refer to Article Four of the City Land Use Code, as amended. 41 Table RO-11 Rational Method Runoff Coefficients for Composite Analysis Character of Surface Runoff Coefficient Streets, Parking Lots, Drives: Asphalt 0.95 Concrete 0.95 Gravel 0.5 Roofs 0.95 Recycled Asphalt 0.8 Lawns, Sandy Soil: Flat <2% 0.1 Average 2 to 7% 0.15 Steep >7% 0.2 Lawns, Heavy Soil: Flat <2% 0.2 Average 2 to 7% 0.25 Steep >7% 0.35 (4) A new Section 2.9 is added, to read as follows: 2.9 Composite Runoff Coefficient Drainage sub-basins are frequently composed of land that has multiple surfaces or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: ( ) t n i i i A C A C ∑ = = 1 * (RO-8) Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (Ai) Ai = Area of Surface with Runoff Coefficient of Ci, acres or feet2 n = Number of different surfaces to be considered At = Total Area over which C is applicable, acres or feet2 (5) A new Section 2.10 is added, to read as follows: 42 2.10 Runoff Coefficient Adjustment for Infrequent Storms The runoff coefficients provided in tables RO-10 and RO-11 are appropriate for use with the 2-year storm event. For storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapo-transpiration and other losses that have a proportionally smaller effect on storm runoff. This adjustment is applied to the composite runoff coefficient. These frequency adjustment factors are found in Table RO-12. Table RO-12 Rational Method Runoff Coefficients for Composite Analysis Storm Return Period (years) Frequency Factor Cf 2 to 10 11 to 25 26 to 50 51 to 100 1.00 1.10 1.20 1.25 Note: The product of C times Cf cannot exceed the value of 1, in the cases where it does a value of 1 must be used (6) Section 3.1 is deleted in its entirety. (7) Section 3.2 is deleted in its entirety. (8) Section 3.3 is deleted in its entirety. (9) A new Section 4.3 is added, to read as follows: 4.3 Computer Modeling Practices (a) For circumstances requiring computer modeling, the design storm hydrographs must be determined using the Stormwater Management Model (SWMM). Basin and conveyance element parameters must be computed based on the physical characteristics of the site. (b) Refer to the SWMM Users’ Manual for appropriate modeling methodology, practices and development. The Users’ Manual can be found on the Environmental Protection Agency (EPA) website (http://www.epa.gov/ednnrmrl/models/swmm/index.htm). (c) It is the responsibility of the design engineer to verify that all of the models used in the design meet all current City criteria and regulations. 4.3.1 Surface Storage, Resistance Factors, and Infiltration Table RO-13 provides values for surface storage for pervious and impervious surfaces and the infiltration rates to be used with SWMM. Table RO-13 also lists the appropriate infiltration decay rate, zero detention depth and resistance factors, or Manning’s “n” values, for pervious and impervious surfaces to be used for SWMM modeling in the city of Fort Collins. 55 0.87 1.48 3.03 22 1.53 2.61 5.32 56 0.86 1.47 2.99 23 1.49 2.55 5.20 57 0.85 1.45 2.96 24 1.46 2.49 5.09 58 0.84 1.43 2.92 25 1.43 2.44 4.98 59 0.83 1.42 2.89 26 1.4 2.39 4.87 60 0.82 1.4 2.86 27 1.37 2.34 4.78 65 0.78 1.32 2.71 28 1.34 2.29 4.69 70 0.73 1.25 2.59 29 1.32 2.25 4.60 75 0.70 1.19 2.48 30 1.30 2.21 4.52 80 0.66 1.14 2.38 31 1.27 2.16 4.42 85 0.64 1.09 2.29 32 1.24 2.12 4.33 90 0.61 1.05 2.21 33 1.22 2.08 4.24 95 0.58 1.01 2.13 34 1.19 2.04 4.16 100 0.56 0.97 2.06 35 1.17 2.00 4.08 105 0.54 0.94 2.00 36 1.15 1.96 4.01 110 0.52 0.91 1.94 37 1.16 1.93 3.93 115 0.51 0.88 1.88 38 1.11 1.89 3.87 120 0.49 0.86 1.84 Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g). Friction loss is always Upstream EGL - Downstream EGL. Excavation Estimate: The trench side slope is 1.0 ft/ft The minimum trench width is 2.00 ft Downstream Upstream Element Name Length (ft) Wall (in) Bedding (in) Bottom Width (ft) Top Width (ft) Trench Depth (ft) Cover (ft) Top Width (ft) Trench Depth (ft) Cover (ft) Volume (cu. yd) Comment Storm 5-2 56.20 2.00 4.00 4.33 6.33 3.66 2.00 4.33 2.63 0.96 25.08 Storm 5-1 12.35 2.00 4.00 4.33 0.00 2.63 0.97 4.33 2.53 0.86 3.30 (ft or in) Span (ft or in) Storm 5-2 56.20 51.85 0.4 52.07 0.013 0.03 0.00 CIRCULAR 12.00 in 12.00 in Storm 5-1 12.35 52.07 0.6 52.14 0.013 0.05 0.00 CIRCULAR 12.00 in 12.00 in Storm 4-2 42.80 52.09 0.5 52.30 0.013 0.05 0.00 CIRCULAR 12.00 in 12.00 in Storm 4-3 91.40 52.30 0.5 52.76 0.013 0.05 0.00 CIRCULAR 12.00 in 12.00 in Storm 4-1 121.70 52.09 0.5 52.70 0.013 0.05 0.00 CIRCULAR 12.00 in 12.00 in Sewer Flow Summary: Full Flow Capacity Critical Flow Normal Flow Element Name Flow (cfs) Velocity (fps) Depth (in) Velocity (fps) Depth (in) Velocity (fps) Froude Number Flow Condition Flow (cfs) Surcharged Length (ft) Comment Storm 5-2 2.26 2.88 12.00 4.62 12.00 4.62 0.00 Pressurized 3.63 56.20 Storm 5-1 2.77 3.52 8.34 4.51 9.34 4.01 0.80 Pressurized 2.63 12.35 Storm 4-2 2.53 3.22 3.52 2.61 3.62 2.50 0.95 Pressurized 0.50 42.80 Storm 4-3 2.53 3.22 3.52 2.61 3.62 2.50 0.95 Pressurized 0.50 91.40 Storm 4-1 2.53 3.22 3.52 2.61 3.62 2.50 0.95 Pressurized 0.50 121.70 A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe). If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer. If the sewer is pressurized, full flow represents the pressurized flow conditions. Sewer Sizing Summary: Velocity (fps) OUTFALL 1 55.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Storm 5-2 54.20 3.63 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Storm 5-1 54.17 2.63 2.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Element Name Peak Flow (cfs) Cross Section Rise Span Rise Span Rise Span Area (ft^2) Comment Storm 3 0.63 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size. Sewer sizes should not decrease downstream. All hydraulics where calculated using the 'Used' parameters. Grade Line Summary: Tailwater Elevation (ft): 53.00 Invert Elev. Downstream Manhole Losses HGL EGL Element Name Downstream (ft) Upstream (ft) Bend Loss (ft) Lateral Loss (ft) Downstream (ft) Upstream (ft) Downstream (ft) Friction Loss (ft) Upstream (ft) Storm 3 52.14 52.60 0.00 0.00 53.00 53.00 53.01 0.06 53.07 Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a sewer. Bend loss = Bend K * V_fi ^ 2/(2*g) Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g). Friction loss is always Upstream EGL - Downstream EGL. Overland Time (min) Gutter Time (min) Basin Tc (min) Intensity (in/hr) Local Contrib (cfs) Coeff. Area Intensity (in/hr) Manhole Tc (min) Peak Flow (cfs) Comment Type R Inlet 0.00 0.00 0.00 0.00 0.00 0.02 40.44 1.92 0.63 Storm 3 0.00 0.00 0.00 0.00 0.63 0.00 0.00 0.00 0.63 Sewer Input Summary: Element Name Peak Flow (cfs) Cross Section Rise Span Rise Span Rise Span Area (ft^2) Comment Storm 2 0.83 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size. Sewer sizes should not decrease downstream. All hydraulics where calculated using the 'Used' parameters. Grade Line Summary: Tailwater Elevation (ft): 53.00 Invert Elev. Downstream Manhole Losses HGL EGL Element Name Downstream (ft) Upstream (ft) Bend Loss (ft) Lateral Loss (ft) Downstream (ft) Upstream (ft) Downstream (ft) Friction Loss (ft) Upstream (ft) Storm 2 52.63 52.90 0.00 0.00 53.00 53.28 53.15 0.27 53.42 Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a sewer. Bend loss = Bend K * V_fi ^ 2/(2*g) Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g). Friction loss is always Upstream EGL - Downstream EGL. (min) Gutter Time (min) Basin Tc (min) Intensity (in/hr) Local Contrib (cfs) Coeff. Area Intensity (in/hr) Manhole Tc (min) Peak Flow (cfs) Comment Detention 0.00 0.00 0.00 0.00 0.00 0.02 42.82 1.08 0.83 Storm 2 0.00 0.00 0.00 0.00 0.83 0.00 0.00 0.00 0.83 Sewer Input Summary: Element Name Peak Flow (cfs) Cross Section Rise Span Rise Span Rise Span Area (ft^2) Comment Storm 1 2.01 CIRCULAR 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 12.00 in 0.79 Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size. Sewer sizes should not decrease downstream. All hydraulics where calculated using the 'Used' parameters. Grade Line Summary: Tailwater Elevation (ft): 53.00 Invert Elev. Downstream Manhole Losses HGL EGL Element Name Downstream (ft) Upstream (ft) Bend Loss (ft) Lateral Loss (ft) Downstream (ft) Upstream (ft) Downstream (ft) Friction Loss (ft) Upstream (ft) Storm 1 52.60 52.77 0.00 0.00 53.11 53.37 53.50 0.13 53.63 Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a sewer. Bend loss = Bend K * V_fi ^ 2/(2*g) Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g). Friction loss is always Upstream EGL - Downstream EGL. (min) Gutter Time (min) Basin Tc (min) Intensity (in/hr) Local Contrib (cfs) Coeff. Area Intensity (in/hr) Manhole Tc (min) Peak Flow (cfs) Comment Detention 0.00 0.00 0.00 0.00 0.00 0.04 45.85 0.16 2.01 Storm 1 0.00 0.00 0.00 0.00 2.01 0.00 0.00 0.00 2.01 Sewer Input Summary: