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HomeMy WebLinkAboutDrainage Reports - 03/03/20179 FINAL DRAINAGE REPORT Columbine Residences -Lot 1, Centre for Advanced Technology 241h Filing City of Fort Collins Approved Plans Approved by. _ - Dak-A — 3 -17 Prepared for: R4 Architects 226 Remington Street, Unit 3 Fort Collins, CO 80524 970-224-0630 Prepared by: Interwest Consulting Group 1218 West Ash, Suite A Windsor, Colorado 80550 (970)460-8488 January 11, 2017 Job Number 1278-069-00 INTERWEST . CONSULT I N G GROUP December 23, 2016 Ms. Heather McDowell City of Fort Collins Stormwater 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage Report for Columbine Residences -Lot 1 Dear Heather, I am pleased to submit for your review and approval, this Final Drainage Report for the Columbine Residences -Lot 1 development. 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 with variance request as noted. Review comments dated December 2, 2016 from the City of Fort Collins Stormwater Engineering Department have been addressed in this report. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. ' Sincerely, Erika Schneider, P.E. Colorado Professional tEngineer No. 41777 Reviewed By: Michael Oberlander, P.E., LEED AP Colorado Professional Engineer No. 34288 ' 1218 WEST ASH, SUITE C WINDSOR, COLORADO 80550 tit. 970.674.3300 • FAX. 970.674.3303 TABLE OF CONTENTS TABLEOF CONTENTS............................................................................................................ iii ' 1. GENERAL LOCATION AND DESCRIPTION................................................................ 1 1.1 Location...........................................................................................................................1 1.2 Description of Property................................................................................................. 1 ' 2. DRAINAGE BASINS AND SUB-BASINS.......................................................................... 2 2.1 Major Basin Description................................................................................................ 2 2.2 Sub -Basin Description................................................................................................... 2 ' 3. DRAINAGE DESIGN CRITERIA...................................................................................... 2 3.1 Regulations......................................................................................................................2 3.2 Directly Connected Impervious Area (DCIA) Discussion .......................................... 2 3.3 Development Criteria Reference and Constraints...................................................... 3 3.4 Hydrologic Criteria........................................................................................................ 4 3.5 Hydraulic Criteria.......................................................................................................... 4 ' 3.6 Floodplain Regulations Compliance............................................................................. 5 3.7 Modifications of Criteria .... :.......................................................................................... 5 ' 4. DRAINAGE FACILITY DESIGN....................................................................................... 5 4.1 General Concept............................................................................................................. 5 4.2 Specific Flow Routing.................................................................................................... 5 4.3 Drainage Summary........................................................................................................ 6 ' 5. CONCLUSIONS....................................................................................................................7 5.1 Compliance with Standards.......................................................................................... 7 5.2 Drainage Concept ......................... :..................................................... ............................ 7 6. REFERENCES...................................................................................................................... 7 ' APPENDIX A VICINITY MAP AND DRAINAGE PLAN APPENDIX B HYDROLOGIC COMPUTATIONS ' APPENDIX C HYDRAULIC COMPUTATIONS APPENDIX D WATER QUALITY AND LID CALCULATIONS APPENDIX E DETENTION POND CALCULATIONS ' APPENDIX F SOILS INFORMATION, FEMA FIRMETTE, FIGURES & TABLES iii 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location ' The proposed project is located northeast of the intersection of Centre Avenue and Worthington Circle in Fort Collins, Colorado and is the Centre for Advanced Technology 24"' Filing. More specifically it is in the SW 1/4 of Section 23, Township 7 North, Range 69 West of the 6`h P.M., City of Fort Collins, County of Larimer, State of Colorado. Please refer to the vicinity map in Appendix A. Larimer Canal No. 2 bounds the site on the north and the New Mercer Ditch on the south and west. CSURF property is located to the east of the site. 1.2 Description of Property The property is approximately 8.2 acres in size and will consist of 17 single family paired homes. The site will be served by a private drive which accounts for the majority of the proposed pavement area. The land currently slopes to the northeast at about 0.6%. The majority of the land is currently vacant. The majority of the ground cover is native grasses. There are no offsite flows onto the property. The existing soil type on -site consists of Altvan-Satanta loams (21 %) and Nunn clay loam (79%) which are classified as Type B and C, respectively, by the Natural Resources Conservation Service. Soil information is located in Appendix G. The property is not located within a City of Fort Collins Floodplain or FEMA 100-year floodplain (FEMA FIRM Panel 08069C0987G, effective May 2, 2012). 1 2. DRAINAGE BASINS AND SUB -BASINS ' 2.1 Major Basin Description ' The proposed development lies within the Spring Creek Master Drainage Basin. ' 2.2 Sub -basin Description The existing site drains to the northeast and discharges directly into Larimer Canal No. 2. 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. Where applicable, the criteria established in the ' "Urban Storm Drainage Criteria Manual' (UDFCD), developed by the Denver Regional Council of Governments, has been used. 3.2 Directly Connected Impervious Area (DCIA) Discussion ' Urban Drainage and Flood Control District (UDFCD) recommends a Four Step Process for receiving water protection that focuses on reducing runoff volumes, treating the water ' quality capture volume (WQCV), stabilizing drainageways and implementing long-term source controls. The Four Step Process applies to the management of smaller, frequently ' occurring events. ' Step 1: Employ Runoff Reduction Practices To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement Low Impact Development (LID) strategies, including Minimizing Directly Connected ' Impervious Areas (MDCIA). ' Runoff for the majority of the site will be routed through rain gardens before entering the water quality and detention pond thereby reducing runoff from impervious surfaces over ' permeable areas to slow runoff and increase the time of concentration and promote infiltration. 1 2 ' 'Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release The rain gardens help reduce total runoff by allowing the water to infiltrate. The water ' quality and detention pond located to the east of the project is designed to allow sediments to settle while incorporating a slow release. Step 3: Stabilize Drainageways Natural Drainageways are subject to bed and bank erosion due to increases in frequency, duration, rate and volume of runoff during and following development. Because the site will drain to a proposed water quality and detention pond and release into an existing storm system in Centre Avenue, bank stabilization is unnecessary with this project. Step 4: Implement Site Specific and Other Source Control BMPs Proactively controlling pollutants at their source by preventing pollution rather than removing contaminants once they have entered the stormwater system or receiving waters is important when protecting storm systems and receiving waters. This can be accomplished through site specific needs such as construction site runoff control, post - construction runoff control and pollution prevention / good housekeeping. It will be the responsibility of the contractor to develop a procedural best management practice for the site. 3.3 Development Criteria Reference and Constraints The runoff from this site has been routed to conform to the requirements of the City Stormwater Department. Water quality facilities are required for the new construction proposed on the site. Water quality will be met through the use of two rain gardens and a water quality pond. Fifty percent of the site runoff is required to be treated using the standard water quality treatment as described in the Fort Collins Stormwater Manual, Volume 3 Best ' Management Practices (BMPs) and runoff reduction practices (LID techniques) are also required. No less than seventyfive percent (75%) of any newly developed or redeveloped area, and any modification on a previously developed area for which a construction permit is required under City codes and regulations, must be treated using one or a combination of LID techniques. ' 3 ' The project adds 149,824 sf of new impervious area. Using the rain garden LID ' technique, 113,464 sf of new impervious area (76%) will be treated which exceeds the 50% water quality treatment and the 75% LID treatment requirements. In addition, 100% of the entire site will be treated with standard water quality capture volume in the water ' quality and extended detention pond. Please refer to Appendix D for LID calculations and. 3.4 Hydrologic Criteria The City of Fort Collins Rainfall Intensity -Duration —Frequency Curves (Figure RA-16 of ' the City of Fort Collins Storm Drainage Design Criteria Manual) is used for all hydrologic computations associated with this project. Runoff computations were ' prepared for the 2-year and 10-year minor and 100-year major storm frequency utilizing the rational method. All hydrologic calculations associated with the basins are included ' in Appendix B of this report. Please refer to Appendix A for the Drainage Plan depicting drainage basins and design points. ' Water quality volume was calculated using the method recommended in the "Urban Storm Drainage Criteria Manual". Water quality capture volume calculations are located ' in Appendix D. ' 3.5 Hydraulic Criteria All hydraulic calculations are prepared in accordance with the City of Fort Collins ' Drainage Criteria. All calculations are included in Appendix C of this. Storm systems were analyzed using StormCAD software. 1 4 4. 3.6 Floodplain Regulations Compliance The site is not within a City of Fort Collins floodway or a FEMA special flood hazard area (Panel 08069C0987G). Therefore, a completed "City of Fort Collins Floodplain Review Checklist for 50% Submittals" has not been included with this report. 3.7 Modifications of Criteria There are no modifications to criteria for this project at this time. DRAINAGE FACILITY DESIGN 4.1 General Concept The majority of the proposed development will be collected and conveyed to the proposed water quality and detention pond on the eastern most portion of the site. The pond outfall will discharge to a 15-inch storm pipe and into the existing storm sewer in Centre Avenue located east of the site. This system discharges into Spring Creek. An emergency overflow spillway will be constructed and will be designed to pass the 100- year flow. The driveway is located over the New Mercer Ditch where a box culvert will be installed to maintain flow for the ditch. The roadside ditch adjacent to Worthington Circle along the ditch will pass through the proposed culvert under the driveway. The box culvert is sized to match the downstream culvert at Centre. 4.2 Specific Flow Routing A summary of the drainage patterns within each basin is provided in the following paragraphs. Basin A includes the middle portion of the site. Runoff from this basin will sheet to a 2- foot wide concrete pan that directs flow to Rain Garden A located at design point A. The rain garden will discharge to storm system A that will convey flow to the water quality and detention pond located to the east. E Basins B-E includes the portion of the site adjacent to the drive aisle. These basins sheet flow to the drive aisle where flow will be conveyed to Rain Garden B via a 4' sidewalk culvert. This rain garden will discharge to storm system A that will convey flow to the water quality and detention pond located to the east. These basins account for all of the new pavements proposed. Basins F and G are adjacent to the outer boundary of the site. These two basins sheet to the 2-foot wide concrete pans located at the back side of the duplexes. The pans direct flow to the detention pond located to the east. ' Basin H is located to the east and includes the water quality and detention pond. Runoff from this basin will sheet to the pond. The pond outfall will discharge to a 15-inch storm system (B) and into the existing storm sewer in Centre Avenue located east of the site. This system discharges into Spring Creek. The hydraulic grade line at the existing system was assumed to be the top of the existing pipe (5037.5 ft.). ' 76% of the sites runoff will be treated for water quality in the rain gardens. 100 % of the site will be treated using standard water quality capture volume in the onsite water quality and extended detention pond. Onsite detention is provided for the runoff volume difference between the 100-year developed inflow rate and the 2-year historic release rate. ' The historic release rate is for this basin is 2.4 cfs. Water will be released through an orifice plate to a storm system that enters the existing storm system in Centre Ave and ' eventually into Spring Creek. Please refer to Appendix D for water quality capture and detention volume calculations and pond volume table. 4.3 Drainage Summary Drainage facilities located outside of the right of way (including, water quality and detention pond, rain gardens, proposed storm drain systems, and the pond outlet system) will be maintained by the property owners. 6 ' S. 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 and the Storm Drainage Design Criteria Manual. 5.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for stormwater quantity and quality treatment of proposed impervious areas. Conveyance elements will be designed during the final report to pass required ' flows and to minimize future maintenance. ' The design minimizes impacts to other utilities and properties and maintains the existing drainage flow paths as much as possible. The design will effectively control damage from storm runoff originating from the site. The recommended BMPs are sufficient to ' reduce runoff peaks, volumes and pollutant loads from the impervious areas of the site. ' If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit will be required. 6. REFERENCES' ' 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March, 2011. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria ' Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated September 1999. II APPENDIX A VICINITY MAP AND DRAINAGE PLAN 0 A ❑ O \v/ 0 ❑ 0 SITE ���� _ 1100 MEN u WORTHIGTON AVENUE RESIDENCES VICINITY MAP SCALE: 1 "=800' -'/ Np.2 NA� ♦" ��'�.��� UNPLA 77ED ECA -//-/ /!��♦, _ \�-� RIMR ' UACE 2' WIDE-� MTURK CONCRETE PAN --�� ♦ aw j ♦, tow\ \ \ \ \ 40 V HABITAT i �' BUFFER � � Flow�L ` \ OQOFMOY OAORDW \ 9BLMY -- - - ZONE _ ----' _, f� / 00 ow F \ F1EV-M.3 Opp 4*0 or 101111" op too 00 /.... _ r / 1W 6 B[RY EIEV-N.] GONOKIE ` r t 1.13 w74 , [' 0=mm■Y Flo I � I r ♦♦ ♦ ♦ 1' wT1cv wsa-eos7.7 • ` wTlcv�w,s ACrR J RAN A.. tOD-YR WeMe0AQ3 I I B TOTAE vaUYE-1.16 AC-R I I ♦ 1 I _ Q RESEAOTS UNPLA7TBD ♦ cOH I I Z' VIDE y SPRLwAY-IXM-e010.J Tor a eats I I III ♦ ♦ vAN ♦ N j l �► A i PROPERTY UWE I ` a 1.10 w UNDE Ds7 IT m I � ♦ ♦ II ♦ _1/ 1 —I 1 I I 1 N O N. IR iI STORM B Ru y c HABITAT so BUFFER DOME 00 20' UWE DRANIIQ • AN IMMON NBNW MDIo AERAER MP \ UOLRY EA$DMI#T. \ // / CONCRETE WIDE _ PAN— i _ \ \ \ //' Iuww. \ \ ° / �j s$iE •r 1�`_ R C.A.T. T17/ \ \ \o ' / ' aS EASCIENT n' LEGEND C£NTR EN EVUE PROPOSED ONNW.GE BASW DN0El1NE \ \ / / r_ D"NA�MN-RGE B0.5R--FEB • . OO O !% \ • D..S B MINORSfONM RUNOFF COEFFCIEM . r` I `` OflNNAGE BA91NAflEA DESIGN POINT w \ DION OF OVREAND D '/// PRELIMINARY � Q NOT FOR CONSTRUCTION 12.456 SF � (7 Za N . p m m O W W �0c�v Im.008 SF Retl'm WO/DrlenUon Puntll ) N rctm = z z 0 a 0 U Jm z 0La IL p Z U Z Nores. W a a I. SEE LANDSCAPE PIAN FOR PLANINGSTHROUGHOUT THESRE X 0 LL p N 2. THE TDP OF FOUNDATION ELEVATION SHOWN 15 HIGHER N THAN THE MINIMUM ELEVATION REOUINCp FOR PROTECN itO FROM THE IDOYR STORM w z J z LL w U = N o z� � IV) o a U O 40 20 O 40 BO Z SCALE'. 1' = 40 t ILI 2 IwIEnE V ? NEow a w W z z m ? 7.0 J d CALL UTILITY NOTIFICATION CENTER OF COLORADO O oil U O GALL 2-BUSINESS DAYS IN ADVANCE LL BEFORE YOU DIG, GRADE. OR EXCAVATE FDR THE MARKING D UNDERGROUND MEMBER UTIUTES r a Z w L APPROVED BY THE NEW MERCER DITCH COMPANY _ CZ G Q N m W RANDY OUSTAFSON, PRESIDENT DALE a IJy Z N O y W u CITY OF FORT COLLINS, COLORAD0 UTILITY PLAN APPROVAL APPROVED: REQY • CITY On NORM .0 DATE CHECKED BY: 342M WATER * WASTEMIER URUn DATE CHECKED BY: '^ F��Sh� STONYWATER UTILITYDATE CHECKED BY: PANS • RECREARON DATE PROD. NO. 127"GB CHECKED BY: TRAFFw �� DATE 15 CHECKED BY: ENVIRONMENTAL PLANNER DATE APPENDIX B HYDROLOGIC COMPUTATIONS 0 J ' m Q MM~ li } CQ G N W ' Q _Z Q (A Y R Q W R C C C C C m N a) N N U 0 UU"O'D w w 0 w 0 Id fL1 0f0 C7 (7 C7 C7 C7 co IC fC f0 fC fC � O N M CO CO n a COM _0 V 7 Y] I-: OI O O N 4 N Q O 0^ W N M O V M n tD n V N M O 0 m n m m o (P n m N G1 O O O O t0 O O C O O) CM p a 0'? 0 M E ui co r� r1l co vi M ui r u C GD N GD IO <O <O N O M E N m CO O O IO M ui n V O n O] O) m O) f0 t0 M n O O O O O O O O O U O tV O) N f0 O OD m O W In n n t0 n Id: 7 M If1 U o 0 0 0 0 0 0 0 0 CO N ID O Y Ncc W O to W n Q . O O O O CO C � W Q a < m U a W lL (7 2 F- FO N C � C C a o co d N a Interest Consulting Group RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: Worthington Residences (CSURF) PROJECT NO: 1278-069-00 COMPUTATIONS BY: as DATE: 3/16(2016 Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volume I Recommended % Impervious from Table RO-3 Urban Storm Drainage Criteria Manual, Volume I coefficient Impervious C 0.95 100 0.95 96 0.95 90 0.50 40 0.20 0 Type C Soils Runoff Streets, parking lots (asphalt) Sidewalks (concrete) Roofs Pavers Heavy Soil (Flat, <2%) SUBBASIN DESIGNATION TOTAL AREA (ac.) TOTAL AREA (sq.ft) ROOF AREA (sgJQ PAVED AREA (sq.ft) PAVERS AREA (sq.ft) SIDEWALK AREA (sq.ft) LANDSCAPE AREA (sq.ft) RUNOFF COEFF. (C) % Impervious REMARKS Existing Lot 6.75 293.818 0 0 0 0 293,818 0.20 0 Historic %I Proposed Lot 6.75 293.818 88.921 27,865 0 33,038 143,994 0.58 48 Calc'd % I Total New Impervious Area. 149,825 at 1 Equations - Calculated C coefficients & % Impervious are area weighted C=L(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 1 12.12.16 Final FC FIowCSURF.xIs Interwest Consulting Group RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: Worthington Residences (CSURF) PROJECT NO: 1278-069-00 - COMPUTATIONS BY: es DATE: 1211212016 Recommended Runoff Coefficients from Table RC-11 of City of Fort Collins Stormwater Code, Volume I Recommended % Impervious from Table RO-3 Urban Storm Drainage Criteria Manual, Volume I coefficient Impervious C 0.95 100 0.95 96 0.95 90 0.50 40 0.20 0 Type C Soils Runoff Streets, parking lots (asphalt) Sidewalks (concrete) Roofs Gravel or Pavers Landscape Areas (Flat, heavy) SUBBASIN DESIGNATION TOTAL AREA (ac.) TOTAL AREA (w.n) ROOF AREA (sq.f0 PAVED AREA (sQ.h) GRAVEUPAVERS AREA (w.lt) SIDEWALK AREA (s4.lp LANDSCAPE AREA (W In RUNOFF COEFF. (C) % Impemlous REMARKS E%LOT 6.75 M'818 0 0 0 0 293,818 0.20 0 Used to Determine 2- r Historic A 0.57 24,828 12,206 0 0 250 12,372 0.5B 45 Rain Garden B 0.60 26,214 4,634 7,145 0 8,830 5.605 0.79 76 C 1.00 43,422 13,565 7,M 0 9,633 13,135 0.72 66 D 0.54 23,398 4,487 5,712 0 4,105 9,093 0.66 59 E 1.13 49,325 17,669 7,919 0 10,220 13,518 0.74 68 F 1.15 50,076 18,829 0 0 0 31,248 048 34 G 0.66 28,713 11,095 0 0 0 17,619 0,49 35 H 1.10 47,842 6,438 0 0 0 41,404 0.30 12 6-E 3.27 142,358 40.355 27.865 32,788 41,351 0.73 67 Rain Garden A-E 3.64 167.187 52.560 27,865 0 33,038 53.723 0.71 64 Developed Area Treated by LID TOTAL 6.75 293,818 $8.921 27,865 0 33,038 143.994 0.58 48 Total Lot Equations - Calculated C coefficients 8 % Impervious are area weighted C=£(Ci Ai)/At Ci = runoff coefficient for specific area, At 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 At's 12-12-16 Final FC Flow-CSURF.xis a LL N Z W O C% LL z op aU C LL F O N W F A } m z E z `o O m Pula � O ¢1 p Oce0< Co .j a. 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U L] .9 N Y ¢ Q W ¢ 0 O N N J m N m n V N 4 ^ m � U O V N n m N O N V N N O ° H 'y _O U ¢ O W 0 ° i C E m 'c- ¢ O m 'o OQ[ O a U O O N n m m O N< N N Q N N O O m O O m m m N N N f0 N b O _ tG Oi m m m m t0 tp OI Oi IG YIR N O N m E tO N o n n m N w I` U N N N n m N O O N N m O O ID N (O m NM M. n U 0 0 c o 0 0 0 00 00 o n No rN Q — n N N 0 10 0 O 0--0- _mN 1D N m r w 0 = C -1 0 W J d 'x Q C] U O W LL (J m H F a o w m 0 U W ¢ G o a M� APPENDIX C HYDRAULIC CALCULATIONS 0 0 3 Worksheet for 4' SW Culvert Flow Element: Rectangular Channel Friction Method: Manning Formula Solve For: Discharge Input Data `" Roughness Coefficient: 0.013 Channel Slope: 0.02000 ft/ft Normal Depth: 0.60 ft Bottom Width: 4.00 ft Discharge: 23.17 ft'/s Flow Area: 2.40 ft' Wetted Perimeter: 5.20 ft Top Width: 4.00 ft Critical Depth: 1.01 ft Critical Slope: 0.00424 ft/ft Velocity: 9.65 ft/s Velocity Head: 1.45 ft Specific Energy: 2.05 ft Froude Number: 2.20 Flow Type: Supercritical GVF Input Data Downstream Depth: 0.00 ft Length: 0.00 ft Number Of Steps: 0 GVF Output Data Upstream Depth: 0.00 ft Profile Description: N/A Profile Headloss: 0.00 ft Downstream Velocity: 0.00 ft/s Upstream Velocity: 0.00 ft/s Normal Depth: 0.60 ft Critical Depth: 1.01 ft Channel Slope: 0.02000 ft/ft Critical Slope: 0.00424 ft/ft Cross Section for 4' SW Culvert Project Description Flow Element: Rectangular Channel Friction Method: Manning Formula Solve For: Discharge Section Data Roughness Coefficient: 0.013 Channel Slope: 0.02000 ftfft Normal Depth: 0.60 ft Bottom Width: 4.00 ft Discharge: 23.17 ft /s 0.60 tt 4 nn it j V' 5 Q M: 1 ' Interwest Consulting Group 1218 W. Ash, Suite C ' Inlet Flow Calculation for Area Inlets Windsor, CO 80550 Project: Columbine Residences ' Job Number: 1278-069-00 Calculations by : es Date : 12/15/2016 Objective: to determine capacity of Type C area inlet with close mesh grate NZ WSEL Geometry at inlet ' Grate Dimensions and information: Close Mesh Grate Width (W): 2.625 feet Length (L): 3.3542 feet ' Open Area (A): 6.6944 sq It Reduction Factor (F): 50% Grate Flow: ' Use the orifice equation Q; = C*A*SQRT(2*g*H) to find the ideal inlet capacity.* *See Hydraulic Design Handbook by McGraw-Hill for verificaiton of equation use and C value ' C = Orifice discharge coefficient= 0.67 A = Orifice area (ft) - open area of grate g = gravitational constant = 32.2 fUs2 H = head on grate centroid, ponding depth (feet) ' Then multiply by the reduction factor for the allowable capacity. QG = Qi * (1-F) At Rain Garden ' DETERMINE CAPACITY OF TYPE C INLET AT DP A H = 0.5 It Single Type C Inlet A= 1*A = 6.69 ft2 ' Q; = C*A*SQRT(2*g*H) 25.45 cfs QG= Q;*F = 12.73 cfs USE : Single Type C Inlet Pagel Worksheet for Basin F 2' pan and swale Flow Element: Irregular Section Friction Method: Manning Formula Solve For: Normal Depth Input Data Channel Slope: 0.00400 ft/ft Discharge: 4.40 ft3/s Current Roughness Weighted Methc ImprovedLotters Open Channel Weighted Roughnes: ImprovedLotters Closed Channel Weighted Roughne Hortons Roughness Coefficient: 0.014 Water Surface Elevation: 0.49 ft Elevation Range: 0.00 to 1.08 It Flow Area: 1.50 ft' Wetted Perimeter: 5.08 ft Top Width: 4.96 ft Normal Depth: 0.49 ft Critical Depth: 0.47 ft Critical Slope: 0.00451 ft%ft Velocity: 2.94 fus Velocity Head: 0.13 ft Specific Energy: 0.62 ft Froude Number: 0.95 Flow Type: Subcritical (-0+05.0, 1.08) (-0+01.0, 0.08) 0.030 (-0+0170 0:08)_(0+01 0.008) 0013r '�� " (0+01.0, 0.08) (0+03.5, 0.84) 0.030 ' Worksheet for Basin F 2' pan and swale -0+05.0 1.08 0+00 0 0.00 0+03.5 0.84 Cross Section for Basin F 2' pan and swale Project Description Flow Element: Irregular Section Friction Method: Manning Formula Solve For: Normal Depth Section Data Roughness Coefficient: 0.014 Channel Slope: 0.00400 ft/ft Normal Depth: 0.49 ft Elevation Range: 0.00 to 1.08 ft Discharge: 4.40 ft'/S 0 49 ft I i446tt V 5 L H: 1 n Z W cl M H W J Z i' w a- } H N a C'd O' N O 0 O (9 N Din d C N A j a N > C 0 U Q U m€ 0 yc N C C LLI d O a N N n Cl) O N ■0 N C 10 07 �Uia y > C � U Q E O mN d c c W ' N O 1 a` u I o 0 0 1 wr-• I o0o I +� aw 1 00o I C9 ❑ I I I I � Ht7 i o0o i � 0) ro --• l 0 0 0 l N t U 1 I $4 J� H W O O O n U co 1 1 0 — — — — I — — — I I N U I U ro I M� r 0) G 1 0 0 O I �.i wI I Q a.i I H r1 H a 'O W w 1 C c cr 2 rJ U op I roro N W 1 0 0 0 a.� ro H H C Ico I >. 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T. 7TN / p�T� NOW union II DIRW COMPANY IWGATIUN LATERAL E�Poray Tod / I 'RA OtY100,0 LAI�N59A110N 10 BE RET10�' 3 (W 12%`30N1 m.rm t1F Rv CAI TD vairY L0GAt10Q 3 I M' DRANAGE• ..ID 0 "+OD _ TIE 13114�9115050 51�51 STA RI145s to 31d111 ul-a E 31150114.71 LSTDNt B STA 10a353 • 10Lga9 1RRwAT1oN ` PRwmTM(1 P, UTILITY CROSSINGS LATERAL Pros �� \ TO BE NNO ED \ I� \ UNP/a TTEO I,\ 1 STORM SYSTEM B PLAN AMA • STORK B S7AIDa3B3 Nil EX TELE PRWGGTD 5010 Sz: (XtAOE I STmm B STA EX GAS 0t10.9 100-TR iq mss v 1s' RCP • S-0.3R 1512 LF 15 RCP a 5.0.3i 1A•3aaD 1G.q LF 15' RCP e S-a3R 50Xt 10100 11a00 12a00 13.00 STORM SYSTEM B PROFILE 40 20 O 40 90 HORIZONTAL SCALE: 1 " = 40 VERTICAL SCALE: I"= 4' / { NDrEs: �/ 1. RCPSTORM SHALL BECLAS4111WRN WATER i1G1li JOINi5 UBrM Cgg31 BEDDING PER STORM WATER pETAIL D I. CL.tiS B It0 PPE MIDPoIMI. 2. CL STATIONINGANDNORTHNGMNOE NGSATFESISMIDP WOFENDOF / SFRUCTUREATMCNVLNE 3 ALL OTHER STATIONING AND NORDIING AND EASTMJGS IS CENTER OF STRUCTURE q EXVTUI INFORMATRNJTOBEWRIFIEDBYCONiR MRPRRMTOCONSiRUC N \ 5 PIPE LENGIRSINCWDE FES. S ALL STORM SEWERS ARE PRVATE >. ALL STORMWATER FACILITIES WIP AP. STORM SEWER. MANHOLES AND BEDDING) SMALL BE CONSTRUCTED IN ACCORDANCE W Dll CITY OF FORTCOIlINS STANDARDSAND SPECIFICATIONS. B. SEE UTILITY RAN FOR OUTER BOLJNDARY COORDINATES. m F V Z 0 °m DO C O w0.4 µl FUN C N N N C = Z Z 0 d U 07m a p Ld IL a z U Z a CFO IAI ¢ a CrO t0 LL N N z� w� UE .. RI Ot � J a W ` GZ o p rc a N 0� L w ( Z_ i m: 7t w J O m IL Qb J IL W N N i iY fA CAu UTILITY NOTIFICATION CENTER CC CaoRADO O QA O CALL 2-WSTNE55 DAYS IN ADVANCE LL BEFORE YW DIG. GRADE. OR EXCAVATE FOR THE NAMING OF UNDERGRDLND MEMBER UTRJTIES. a b II II APPROVED BY THE NEW MERCER DITCH n COMPANY W J ee G ® O Id 2 O m WDW Y U RANDY WSTAFSON, PRESIDENT DATE CITY OF FORT COLLINS, COLORADO a uUi a O U UTILITY PLAN APPROVAL APPROVED:YR..... CITY ENGINEER DATE .Y O CHECKED BY: 3A2r0 WATER A WASTEWATER UDLITY DATE ` .� c CHECKED BY: ~FORA -` gt sTIIWAIER UTILITY NEMAL CHECKED BY: PROD. NO. 12713UB9 PARKS A RECREATION DALE CHECKED BY: TRAFTTC ENGNCER DAIS CHECKED BY: ENVIRONMENTAL PLANNER DATE NORTHTensar International Corporation ' 5401 St. Wendel-Cynthiana Road TensaE, AMERICAN Poseyville, Indiana 47633 GREEN® Tel. 800.772.2040 Fax 812.867.0247 www.nagreen.com Erosion Control Materials Design Software Version 5.0 Channel Computations Project Parameters Specify nnin 's n: .03 Discharge: 4.7 Peak eriod: 4 hane: 02 Bottomth: eft Slo e: .25 i htSlo e: .25 xistiannel Bend:end icient Kb :100 etarClass A - Ee etT ix Sod & Bunche etDensit : ood 75-95% Soil Type: lay Loam Channel Lining Options Protection Type Pennanent Material Type Matting Type P300 Mannin 's N value for selected Product 0.03 Cross -Sectional Area (A) A=AL+AB+AR= 4.4 AL = 1/2 * De th2 * ZL = 0.13 AB = Bottom Width * Depth = 4.13 AR = 1/2 * De th2 * ZR = 0.13 Wetted Perimeter (P) P=PL+PB+PR= 6.13 PL = Depth * ZL2 + 1)0.5 = 1.06 PB = Channel Bottom Width = 4 PR = Depth * ZR2 + 1)0.5 1.06 Hydraulic Radius (R) R=A/P= 0.72 Flow (Q) = 1.486 / n * A * R2/3 * S1/2 = 24.7 Velocity (V) V= /A= 5.62 Channel Shear Stress (Te) Td = 62.4 * Depth * Slope = 1.29 Channel Safety Factor = T / Td 1.55 Effective Stress on Blanket(Tdb) Te = Td * 0-CF * ns/n 2 = 1.21 CF = 0 ns = 0.03 Soil Safety Factor Allowable Soil Shear (Ta) 0 Soil Safet Factor = Ta / Te = 0 Conclusion: Stabilit of Mat STABLE Conclusion: Stability of Underlying soil STABLE Material Type Matting Type I P300 Mannin 's N value for selected Product 1 0.03 Cross -Sectional Area (A) A=AL+AB+AR= 1 4.4 AL = 1/2 * De th2 * ZL = 0.13 AB = Bottom Width * Depth = 4.13 AR = 1/2 * De th2 * ZR = 0.13 Wetted Perimeter (P) P=PL+PB+PR= 6.13 PL = Depth * ZL2 + 1)0.5 = 1.06 PB = Channel Bottom Width = 4 PR = Depth * ZR2 + 1)0.5 1.06 Hydraulic Radius (R) R 0.72 =A/P= Flow (Q) =1.4861n*A*R2/3*S1/2= 24.7 Velocity (V) V = / A = 5.62 Channel Shear Stress (Te) Td = 62.4 * Depth * Slope = 1.29 Channel Safety Factor = T / Td 6.2 Effective Stress on Blanket(Tdb) Te = Td * 1-CF * ns/n 2 = 0.3 CF = 0.75 ns = 0.03 Soil Safety Factor Allowable Soil Shear (Ta) 2 Soil Safet Factor = Ta / Te Conclusion: Stability of Mat TABLE Conclusion: Stability of Underlying soil TABLE ' I Side Slope Liner Resul 11 APPENDIX D WATER QUALITY AND LID CALCULATIONS 10 No Text I LID Table 75% On -Site Treatment by LID Requirement New Impervious Area 149,824 SF Required Minimum Impervious Area to be Treated by LID (75%) 112,368 SF Rain Garden A Impervious Area Treated by Rain Garden (Basin A) 12,456 SF Rain Garden B Impervious Area Treated by Rain Garden (Basins B-E) 101,008 SF Actual % of New Impervious Area Treated by LID (100% of site treated in WQ/Detention Pond) 76 % Design Procedure Form: Rain Garden (RG) II Sheet 1 of 2 Designer: ES Company: INTERWEST Date: December 15, 2016 ' Project: Worthington Residences (CSURF) Location: RAIN GARDEN A (Center of Site) I. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, 1 = 45.0 (100% if all paved and roofed areas upstream of rain garden) 8) Tributary Area's Imperviousness Ratio (i . I,/100) 0.450 C) Water Quality Capture Volume (WOCV) for a 12-hour Drain Time WQCV = 0.15 watershed inches (WQCV=0.8"(0.91" h- 1A9-1°. 0.78- it D) Contributing Watershed Area (including rain garden area) Area = 24,828 sq ft E) Water Quality Capture Volume (WQCV) Design Volume Vwocv = 319 cu it Vol . (WQCV / 12) ' Area F) For Watersheds Outside of the Denver Region, Depth of da. in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWOCVO,nER = cu h Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VwWv USER. cu ft (Only if a different WOCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) Dwoc,. 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. disc per unit vertical) Z - 0.00 ft / R (Use "0" 4 rain garden has vertical walls) C) Mimimum Flat Surface Area AM,,, = 213 sq It D) Actual Flat Surface Area Am w, - 256 sq It E) Area at Design Depth (Top Surface Area) A,e, . 817 sq It F) Rain Garden Total Volume V,= 537 cu It (VT= ((A,w + Awe ) / 2) " Depth) 3 Growing Media Choose One O 1S" Rain Garden Growing media other (Explain): 4. Underdrain System rChonre Me 0 YES A) Are underdrains provided? Q NO B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = 3.4 It Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol,_ = 328 cu ft iii) Orifice Diameter, 3/8" Minimum Dr, = 0.37 in MININUM oIAME-FP ' 12-12-16 RG A (center).xlsm, RG 12121/2016, 8:04 AM Design Procedure Form: Rain Garden (RG) Sheet 2 of 2 Designer: ES Company: INTERWEST Date: December 15. 2016 Project: Worthington Residences (CSURF) Location: RAIN GARDEN A (Center of Site) 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric Choosy— Q YES A) Is an impermeable liner provided due to proximity Q NO of structures or groundwater contamination? 6. Inlet / Outlet Control Choose One Q Sheet Row- No Energy Dissipation Required A) Inlet Control Q Concentrated Flow- Energy Dissipation Provided I Chnnse One 7. Vegetation Q Seed (Plan for frequent weed control) Q Plantings Q Sand Grown or Other High Infiltration Sod B. Irrigation Choose One Q YES A) Will the rain garden be irrigated? Q NO Notes: 12-12-16 RG A (center).xlsm, RG 12/21/2016, 8:04 AM II Design Procedure Form: Rain Garden (RG) II Sheet 1 of 2 Designer: ES Company: INTERWEST 1 Date: December 15, 2017 Project: Worthington Residences (CSURF) Location: RAIN GARDEN B-E (Drive Aisle Area) 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, I„ = 67.0 % (100% 0 all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = I,/100) = 0.670 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV .- 0.21 watershed inches (WQCV- 0.8' (0.91- i3- 1.19 - i2. 0.76 - i) D) Contributing Watershed Area (including rain garden area) A ea = 142.358 sq It E) Water Quality Capture Volume (WQCV) Design Volume V. _ - 2,488 cu It Vol = (WOCV / 12) ' Area F) For Watersheds Outside of the Denver Region. Depth of d, = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VwocvoTRER = cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume Vwocv USER ^ cu ft (Only if a different WOCV Design Volume is desired) 2. Basin Geometry A) WOCV Depth (12-inch maximum) Dwocv = 12 in B) Rain Garden Side Slopes (Z - 4 min., hortz. dist per unit vertical) Z = 4.00 It / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area Aw„ = 1658 sq ft D) Actual Flat Surface Area Ate„ = 2100 sq ft E) Area at Design Depth (Top Surface Area) A,a, = 3400 sq ft F) Rain Garden Total Volume VT- 2.750 cu It (VT- ((ATM - Ar M,) / 2) ' Depth) 3. Growing Media Goose One O Ir Rain Garden Growing Media Q Other (Explaln): 4. Underdrain System A) Are urxlerdrains provided Oxwse One YES Q NO B) Underdrain system orifice diameter for 12 four drain time i) Distance From Lowest Elevation of the Storage y- 3A ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol,,= 2,568 cu It iii) Orifice Diameter, 318" Minimum De = 1.05 in 1 12-12-16 RG B (Drive Aisle area).xlsm, RG 1212112016, 8:04 AM Design Procedure Form: Rain Garden (RG) Sheet 2 of 2 Designer: ES Company: INTER W EST Date: December 15. 2017 Project: Worthington Residences (CSURF) Location: RAIN GARDEN B-E (Drive Aisle Area) 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric Chmw o1e Q YES A) Is an impermeable liner provided due to proximity Q NO of structures or groundwater contamination7 _ --- 6. Inlet / Outlet Control Choose One Q Sheet Flow- No Energy Dissipation Required A) Inlet Control Q Concentrated Flow- Energy Dissipation Provided rhnn, one 7. Vegetation Seed (Plan for frequent weed control) Q Plantings �Q Q Sand Crown or Other High Infiltration Sod B. Irrigation Choose One Q YES A) Will the rain garden be irrigated? Q NO Notes: 1 12.12.16 RG B (Drive Aisle area).xlsm, RG 12/21/2016, 8:04 AM e RAIN GARDEN SUMMARY Project Name: Project Number: Company: Designer: Date: WORTHINGTON AVENUE RESIDENCES 1278-069-00 INTERWEST CONSULTING GROUP ES 12/20/2016 RAIN GARDEN SUMMARY RAIN RAIN GARDEN RAIN GARDEN RAIN GARDEN RAIN RAIN FLAT AREA FLAT AREA GARDEN BASIN TOTAL GARDEN GARDEN REQUIRED PROVIDED VOLUME VOLUME DEPTH (SAND AREA) (SAND AREA) PROVIDED REQUIRED SF CF SF INCH CF A A 219 319 256 12 537 B-E B 1658 2488 2100 1 12 2750 `NU I t: rULL WA I 1=11 UUALI I Y h'hUVIUtU IN F'UNU; I MtFirUFit, NU I HLA I t UN KU VIVLb Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility POND Project Name: Worthington Residences (CSURF) Project Number: 1278-069-00 Company: INTERWEST CONSULTING GROUP Designer: ES Date: 12/15/2016 1. Basin Storage Volume A) Tributary Area's Imperviousness Ratio (i=la/100) B) Contributing Watershed Area (Area) C) Water Quality Capture Volume (WQCV) (WQCV =1.0`(0.91'f3-1.19`i2+0.78i)) D) Design Volume: Vol = WQCV/12 ` Area ` 1.2 2. Outlet Works A) Outlet Type (Check One) B) Depth at Outlet Above Lowevst Perforations (H) C) Required Maxiumum Outlet Area per Row, (Ao) (Figure EDB-3) D) Perforation Dimensions (enter one only) i) Circular Perforation Diameter OR ii) 2" Height Rectangular Perforation Width E) Number of Columns (nc, See Table 6a-1 for Maximum) F) Actual Design Outlet Area per Row (Ao) G) Number of Rows (nr) r u H) Total outlet Area (Aot)� 3. Trash Rack A) Needed Open Area: At = 0.5 ` (Figure 7 Value) ` Aot B) Type of Outlet Opening (Check One) C) For 2", or Smaller, Round Opening (Ref: Figure 6a) 1) Width of Trash Rack and Concrete Opening (Wconc) from Table 6a-1 ii) Height of Trash Rack Screen (HTR) = H - 2" for flange of top support iii) Type of Screen Based on Depth H) Describe if "other" iv) Screen Opening Slot Dimension, Describe if "other" v) Spacing of Support Rod (O.C.) Type and Size of Support rod (Ref: Table 6a-2) vi) Type and size of Holding Frame (Ref: Table 6a-2) la = 48 % i = 0.475 A = 6.75 acres 100% of the site WQCV = 0.199533 watershed inches Vol. = 0.134685 ac-ft x Orifice Plate Perforated Riser Pipe Other: H= 1.7ft Ao = 0.4 square inches D = 3/4 inches, OR W = inches nc = 1 number Ao = 0.44 square inches nr = 5 number Act = 2.2 square inches At = 74.82227 square inches x < 2" Diameter Round 2" High Rectangular Other: Wconc = 3 inches HTR = 18.4 inches x S.S. #93 VE Wire (US Filter) Other: x 0.139" (US Filter) Other: 3/4 inches #156 VEE 3/8" x 1.0" flat bar D) For 2" High Rectangular Opening (Refer to Figure 6b): 1) Width of rectangular Opening (W) W = inches ' ii) Width of Perforated Plate Opening (Wconc=W+12") Wconc = 12 inches iii) Width of Trashrack Opening (Wopening) Wopening = inches t from Table 6b-1 iv) Height of Trash Rack Screen (HTR) HTR = inches v) Type of Screen (based on Detph H) KlempTM KPP Series Alumin, (Describe if "other) Other: vi) Cross -bar Spacing (Based on Table 6b-1, KlempTM KPP inches Grating). Describe if "other" Other: vii) Minimum Bearing Bar Size (KlempTM Series, Table 6b-2) (Based on depth of WQCV surcharge) ' 4. Detention Basin length to width ratio (LAN) 5. Pre -sedimentation Forebay Basin - Enter design values A) Volume (5 to 10% of the Design Volume in 1 D) acre-feet B) Surface Area acres C) Connector Pipe Diameter inches (Size to drain this volume in 5-minutes under inlet control) D) Paved/Hard Bottom and Sides yes/no ' 6. Two -Stage Design A) Top Stage (DWQ = 2' minumum) DWQ = feet Storage = acre-feet B) Bottom Stage (DBS = DWQ + 1.5' min, DWQ + 3.0' max. DBS = feet Storage = 5% to 15% of Total WQCV) Storage = acre-feet Surf. Area = acres C) Micro Pool (Minimum Depth = the Larger of Depth = feet 0.5"Top Stage Depth or 2.5 feet) Storage = acre-feet ' Surf. Area = acres D) Total Volume: Voltot = Storage from 5A + 6A + 6B Voltot = 0 acre-feet Must be > Design Volume in 1 D ' 7. Basin Side Slopes (Z, horizontal distance per unit vertical) Z = (horizontal/vertical) Minimum Z = 4, flatter preferred ' 8. Dam Embankment Side Slopes (Z, horizontal distance per unit vertical) Z = (horizontal/vertical) Minimum Z = 4, flatter preferred 9. Vegetation (Check the method or describe "other") x Native Grass Irrigation Turf Grass Other: DRAINAGE CRITERIA MANUAL (V.3) STRUCTURAL BEST MANAGEMENT PRACTICES 1 1 ami O.E w m c 0.4 E d 0.2 M. M 0.02 �i SOLUTION: Required Area er WQCV i FAR 0.01 i 0. v.v-r U.w U. 1 V U.ZU U.4u U.bu 1.0 2.0 4.0, 6.0 Required Area p FIGURE EDB-3 Water Quality Outlet Sizing: Dry Extended Detention Basin With a 40=1-lour Drain Time of the Capture Volume 9-1-99 Urban Drainage and Flood Control Distrld. S43 Orifice 'Plate Perforation Sizina Circular Perforation Sizing Chart may be applied to orifice plate or vertical pipe outlet. Hole Die (in) • Hole Die (in) Min. Sc (in) Area per Row (sq In) n=i 7 n=2 .n=3 1 4 0.250 1 0.05 0.10 0.15 5 16 0.313 2 0.08 0.15 0.23 3 B 0.375 2 0.11 0.22 0.33 7 16 0.438 2 0.15 0.30 0.45 172 0.500 2 - 0.20 0.39 0.59 9 16 0.563 3 0.25 0.50 0.75 5 8 0:625 i 3 0.31 0.61 0.92 11 16 0.688 3 0.37 0.74 1.11 3 4 0.750 3 J2.40.88 1:33 13 16 0.813 3 0.52 1.04 1.56 7 8 0.875 3 0.60 1.20 1.80 15 16 0.938 3 0.69 1.38 2.07, 1 1.000 4 0.79 1.57 2.36 1 1 16 1.063 1 4 0.89 1.77 :2.68 1 1 8 1.125 4 0.99 1.99 2.98 1 3 16 1.188 4 1.11 2.22 3.32 1 1 4 1.250 4 1.23 2.45 3.68 1 5 16 .1.313 4 1.35 2.71 4.06. 1 3 8 1.375 4 1.48 Z97 4.45 1 7 16 1.438 4 1.62 3.25 4.87 1 '1 2 1.5D0 _ 4 1.77 153 5.30 1 9 16 1.563 4 1.92 3.83 5.75 1 5 8 1.625 1 4 2.07 4.15 6.22 1 11 16 1.688 4 2.24 4:47' 6.71 1 :3 4 1.750 4 2.41 4.81 7.22, 1 1316 1.813 4 2.58 5.16 7.74 1 7 8 1.875 4 2.76 5.52 8.28 1 15 16 1.938 4 2.95 5:90 9.84 2 2.000 4 3.14 6.28 9.42' n =. Number of columns of perforations Minimum steel plate thickness. 1/4' 5/16 ' 3/8.' *-Designer may interpolate to ;the nearest -32ndinch to better "match the ;required area. 'If desired. Rectangular Perforation Sizina Only one column of rectangular perforations allowed. Rectangular Height = 2 inches Rectangular Width (inches) -. Required Area per Row (sq in 2" Urban Drainage and Flood Control District Drainage Criteria Manual (V.3) n* Dstal1&de9 Rectan ular Hole Width .- Min. Steel Thickness 5" 1 4 6» 1 4 7" 5 32 8" 5/16. " Figure 5 WQCV Outlet Orifice Perforation Sizing Table 6a-1: Standardized WQCV Outlet Design Using 2" Diameter Circular Openings. Minimum Width (Wco„ .) of Concrete Opening fora Well -Screen -Type Trash Rack. See Figure 6-a for Explanation of Terns. Maximum Dia. Width of TZ11Per Column of Holes as a Function of Water Depth H of Circular Maximum ��°g (inches) H=2.0'=4.0' H=5.0' H=6.0' Number of Columns < 0.25, 3 in.3 in. 34n=ini 3 i4< 0. 3 in. in 3 in.4_< 0.75 3' in. 6 in.7< 1.00 6 in..in 9 in.< 1.25 9 in.2< 1.50 12 in. 15 in. 18 in 18 in< 1.75 18 in. 21 in. 21 in. 24 inI< 2.00 21 in. 24 in. 27 in. 30 ini Table 6a-2: Standardized WQCV Outlet Design Using 2" Diameter. Circular Openings. US FilterTM Stainless Steel We117Screen (or.equal) Trash Rack Design Specifications. Max. Width Screen #93 VEE Support Rod Support RMod,Carbon Steel Frame of Opening Wire Slot Opening Type On-Cent Type Spacing 9" 0.139 #156 VEE '/."'/,'k1.01latbar 18"0.139 TE.074"x.50" 1"24" 0.139 TE.074' x05" I"1.0"x ! %"anle 2T' 0.139 TE,.074"x.75" 1" 1:03" 1.0"x 1'r4"an le 30" 0.139 TE..074"X1.0" 1" 1.155" 1'/.`kl%"an e 36" 0.139 TE.074"x1.0" F, 1;155" 1 !/,`k li4"an e 42" 0.139 TE .105"z1A" 1" 1.155" 1 '/.`k ", _ e US Filter, St. Paul, Minnesota, USA DESIGN EXAMPLE: Given: A, WQCV outlet with three columns of 5/8 inch (0.625 in) diameter openings: Water Depth Wabove the lowest opening of 3.5 feet Find: The dimensions for a well screen trash rack within the mounting frame. Solution From Table 6a-1 with an outlet opening diameter of 0.75 inches (i.e., rounded up fro& 5/8'.inch actual diameter of the opening) and the Water Depth H = 4 feet (i.e., rounded up from 3.5 feet). The. minimum width for each column of openings is 6 incligs. Thus, the total width is W Can. .= 36. = 18 inches. The total height, after adding the 2 feet below the lowest row of openings, and subtracting 2 inches for the flange of the top support channel, is 64 inches, Thus, Trash rack dimensions within the mounting frame =18 inches wide x 64 inches high From Table 66-2 select the ordering specifications for an 18", or less, wide opening trash rack using -US' Filter (or equal). stainless steel well -screen with #93 VEE wire, 0. 139" openings between wires, TE .074" x .5tY'support rods on 1.0" on -center spacing; total rack thickness of 0.655" and'/." x 1.0" welded carbon steel frame. ' Table 6a No Text APPENDIX E DETENTION POND CALCULATIONS E Interwest Consulting Group DETENTION VOLUME CALCULATIONS Rational Volumetric (FAA) Method 100-Year Event LOCATION: Worthington Residences (CSURF) PROJECT NO: 1278-069-00 COMPUTATIONS BY: es DATE: 12/15/2016 Equations: Area trib. to pond = 6.75 acre Developed flow = Qp = CIA C (100) = 0.73 Vol. In = Vi = T C I A = T Qp Developed C A = 4.9 acre Vol. Out = Vo =K QPo T Release rate, Opo = 2.40 cfs storage = S = Vi - Vo K = 1 (from fig 2.1) Rainfall intensity from City of Fort Collins IDF Curve with updated (3.67) rainfall Storm Duration, T (min) Rainfall Intensity, 1 (in/hr) Qp (cfs) Vol. In Vi (ft) Vol. Out Vo (ft) Storage S (ft) Storage S (ac-ft) 5 9.95 49.0 14698 720 13978 0.32 10 7.77 38.2 22944 1440 21504 0.49 20 5.62 27.7 33210 2880 30330 0.70 30 4.47 22.0 39603 4320 35283 0.81 40 3.74 18.4 44196 5760 38436 0.88 50 3.23, 15.9 47768 7200 40568 0.93 60 2.86 14.1 50691 8640 42051 0.97 70 2.57 12.7 53166 10080 43086 0.99 80 2.34 11.5 55313 11520 43793 1 1.01 90 2.15 10.6 57212 12960 44252 1.02 100 1.99 9.8 58916 14400 44516 1.02 110 1.86 9.2 60463 15840 44623 1.02 120 1.75 8.6 61881 17280 44601 1.02 130 1.65 8.1 63191 18720 44471 1.02 140 1.56 7.7 64408 20160 44248 1.02 150 1.48 7.3 65547 21600 43947 1.01 160 1.41 6.9 66617 23040 43577 1.00 170 1.35 6.6 67626 24480 43146 0.99 180 1.29 6.4 68583 25920 42663 0.98 190 1.24 6.1 69491 1 27360 42131 0.97 200 1.19 5.9 70357 28800 41557 0.95 210 1.15 5.6 71184 30240 40944 0.94 Required Storage Volume: 44623 ft3 1.02 acre-ft 12-13-16 Final Detention-CSURF (100 perc wq) - Copy.xls,FAA-100yr Proposed Detention Pond - Stage/Storage LOCATION: Worthington Residences (CSURF) PROJECT NO: 1278-069-00 COMPUTATIONS BY: es SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 12/15/2016 V=1/3d(A+B+sgrt(A'B)) where V = volume between contours, ft3 d = depth between contours, ft A = surface area of contour wOCV- 100-yr INSEL (Spillway) - Top of Berm - POND Stage (ft) Surface Area (ft2) Incremental Storage (ac-ft) Total Storage (ac-ft) Detention Storage (ac-ft) 36.0 0 37.0 3500 0.03 0.03 37.7 9800 0.10 0.13 38.0 13100 0.08 0.21 0.00 38.5 17000 0.17 0.38 0.17 39.0 18700 0.20 0.59 0.38 40.0 22100 0.47 1.05 0.84 40.1 22500 0.05 1.10 0.90 40.2 22800 0.05 1.16 0.95 40.3 23200 0.07 1.23 1.02 41.3 27400 0.56 1.79 1.58 REQUIRED DETENTION VOL = 1.02 AC -FT TOTAL REQUIRED WQCV= 0.13 AC -FT 12-13-16 Final Detention-CSURF (100 perc wq) - Copy.xls Stormwater Detention and Infiltration Design Data Sheet Columbine Residences Stormwater Facility Name: Facility Location & Jurisdiction: Fort Collins, Colorado User (Input) Watershed Characteristics Watershed Slope = 0.009 Wit Watershed length -to -Width Ratio = 3.00 L:W Watershed Area = 6.75 acres Watershed Imperviousness= 48.0% percent Percentage Hydrologic Soil Group A = 0.0% percent Percentage Hydrologic Soil Group 8 = 21.0% percent Percentage Hydrologic Soil Groups C/D = 79.0% percent User Input: Detention Basin Characteristics WQCV Design Drain Time = 40.00 hours After completing and printing this worksheet to a pdf, go to: https://mapenure.digitaldotasemices.com/vh/?viewer=cswdif, create a new Stormwater facility, and attach the pdf of this worksheet to that record. Design Storm Return Period - Two -Hour Rainfall Depth = Calculated Runoff Volume = OPTIONAL Override Runoff Volume = Inflow Hydrograph Volume = Time to Drain 97%of Inflow Volume = Time to Drain 99%of Inflow Volume = Maximum Paneling Depth Maximum Forded Area Maximum Volume Stared = User Defined Stage (ftl User Defined Area Ift-21 User Defined Stage Iftl User Defined Discharge Icfs1 0.00 0 0.00 0.00 1.00 3,500 4.30 2.40 1.70 9,800 5.30 29.80 2.00 13,100 2.50 17,000 3.00 18,700 4.00 22,100 4.10 22,500 4.20 22,800 4.30 23,200 5.30 27,400 Routed Hvdroeraoh Results WQCV 2 YearR03368' 10 Year 25 Year 50 Year 100 Year 0.53 0.98 1.71 2.31 2,91 3,67 0.112 0,246 0,605 0.940 1.249 1.677 0.112 0.246 0.605 0.940 1.248 1.676 3 4 7 9 10 12 3 5 8 10 11 13 1.16 1.72 2.60 3.26 3.81 4.40 0.112 0.228 0.398 0.449 0.493 0.542 0.055 0.150 1 0.293 1 0.436 1 0.715 1 0.977 1.281 In acre ft acre-ft acre-ft hours hours it acres acre-ft SOI_Design Data_FC Rainfall Columbine.xlsm, Design Data 2/15/2017, 7:16 AM Stormwater Detention and Infiltration Design Data Sheet 35 30 25 30 5 0 0.1 1 10 TIME [hr] 5 4.5 a 3.5 F 3 e V z 2.5 0 z S 2 1.5 1 0.5 0 0.1 1 30 100 DRAIN TIME (hr) SDI Design Data_FC_Rainfall Columbinenlsm, Design Data 2/15/2017, 7:16 AM Stormwater Detention and Infiltration Design Data Sheet Columbine Residences Stormwater Facility Name: Facility Location &Jurisdiction: Fort Collins, Colorado User (Input) Watershed Characteris Watershed Slope= Watershed Length -to -Width Ratio= Watershed Area = Watershed Imperviousness= Percentage Hydrologic Soil Group A= Percentage Hydrologic Soil Group B= Percentage Hydrologic Soil Groups C/D = 0.009 3.00 6.75 48.0% 0.0% 21.0% 79.0% User Input: Detention Basin Characteristics WQCV Design Drain Time = 40.00 hours After completing and printing this worksheet to a pdf, go to: h"os://mayerture.digitaldatasemices.com/vh/?viewer=cswdlf. create a new stormwater facility, and attach the pdf of this worksheet to that record. Design Storm Return Period Two -Hour Rainfall Depth Calculated Runoff Volume OPTIONAL Override Runoff Volume Inflow Hydrograph Volume rime to Drain 97%of Inflow Volume: Time to Drain 99%of Inflow Volume Maximum Pending Depth Maximum Fondled Area+ Maximum Volume Stored User Defined Stage Ift) User Defined Area Ift^2) User Defined Stage [ftl User Defined Discharge ids] 0.00 0 0.00 0.00 1.00 3,500 4.30 2.40 1.70 9,800 5.30 29.80 2.00 13,1D0 2.50 17,000 3.00 18,700 4.00 22,100 4.10 22,500 4.20 22,800 4.30 23,200 5.30 27,400 Rnutpd Hvdrnpranh RpcuAc W QCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year D.53 0.98 1.36 1.71 2.31 2.91 3.67 0.112 0.246 0.430 0.605 0.940 1.249 1.677 0.112 0.246 0.430 0,605 0.940 1.248 1.676 3 4 6 7 9 10 12 3 5 6 8 10 11 13 1.16 1.72 2.21 2.60 3.26 3.81 4.40 0.112 0.228 0.338 0.398 0.449 0,493 0.542 0.055 0.150 0.293 0.436 1 0,715 1 0.977 1.281 n acre-ft acre-ft acre-ft lours lours t cres acre-ft SDI_Design_Data_FC Rainfall Columbine.xlsm, Design Data 2115/2017, 7:16 AM Stormwater Detention and Infiltration Design Data Sheet e 50YR IN SOYR OUT —25YR IN 10YR IN 6 ■ . iv COC=C�C: C' 7■■111110■■ u ■■11111 ■■■11111.��■■1111 ■■11111 ■■■11111�\\�1111 ■■oll ^\�1111 0■■11111 EPA, �\6I4, ►11VM111111111111 M1��1���nnv1�■■■1■ , ��� ul�►1�,�►111,V1�■■■■1■ ■1��►vvav� SDI Design Data FC_Rainfall Columbine.xlsm, Design Data 2/15/2017, 7:16 AM POND 100-yr Event, Outlet Sizing ' LOCATION: Worthington Residences (CSURF) PROJECT NO: 1278-069-00 COMPUTATIONS BY: es SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 12/15/2016 Submerged Orifice Outlet: ' release rate is described by the orifice equation, Qo = COAO sgrt( 2g(h-E,)) where Q. = orifice ouff low (cfs) ' Co = orifice discharge coefficient g = gravitational acceleration = 32.20 1t/s Ao = effective area of the orifice (ft`) Eo = greater of geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) Qo = 2.40 cfs outlet pipe dia = D = 15.0 in ' Invert elev. = 5035.96 ft (inv. "D" on outlet structure) Eo = 5038.04 ft (downstream HGL for peak 100 yr flow - from FlowMaster) h = 5040.30 ft - 100 yr WSEL Co = 0.65 solve for effective area of orifice using the orifice equation ' Ao = 0.306 ft' 44.1 in` orifice dia. = d = 7.49 in ' Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering) d/ D = 0.50 kinematic viscosity, v = 1.22E-05 ft2/s Reynolds no. = Red = 4Q/(7tdv) = 4.01E+05 Co = (K in figure) = 0.65 check Use d = 7.5 in A,, = 0.307 n` = 44.18 in Qmax = 2.41 cfs orifice - 100yr, 12-13-16 Final Detention-CSURF (100 perc wq) - Copy.xls LOCATION: PROJECT NO: COMPUTATIONS BY SUBMITTED BY: DATE: Detention Pond Emergency Overflow Spillway Sizing Worthington Residences (CSURF) 1278-069-00 es INTERWEST CONSULTING GROUP 12/15/2016 top of berm Equation for flow over a broad crested weir Q=CLH"' where C = weir coefficient = 2.6 H = overflow height L = length of the weir b 4 spill elevation o L —♦ The pond has a spill elevation equal to the maximum water surface elevation in the pond Design spillway with 0.5 ft flow depth, thus H = 0.5 ft Size the spillway assuming that the pond outlet is completely clogged. Pond Q (100) = 29.8 cfs (peak flow into pond) Spill elev = 5040.30 ft Min top of berm elev.= 5041.30 Weir length required: L = 32 ft Use L = 32 ft v = 1.66 ft/s Ispillway, 12-13-16 Final Detention-CSURF (100 perc wq) - Copy.xls �ILw.sii� ae°°I r L, rs 'I ..waRp �Ya�u 1oIalnM PLAN r D .IA LL rN A B D 9 1��.IY.R Wltla 0p0 eI �rwu a�wlw+l � 1 •� III PWe'.1wb w C TIED munL ass I '�)uae 1• • .I ROE � NA am 1.. I I nw I e4 WW�uR�e •I.. J I nlp.wnT I• • H I �n I••H. RM[ MCA P AL MI Mo WEIR NIEEN $♦SEAT[ SECTION BA ,r LJ ` "" E*9' «, Do - To r of AB SECTION 0-0 J a .. , laB®IL7� INN ____— _ — vEwwwawaw aw.a<.aeew. :a: w i A roa s marn.n wu N .I w'-.+U+^.. 4lMY r 1� IRA 11. wiNlr. a iii `iiwesiWs wx.""a'wma+ro- wm r.. f� IS wrznn VICE.. .Awraw. rNau n.uR nw .Raa� — AgaNr. vNATauw � �,« WATER QUALITY yW�i w w as.w w ar a n .m +wo iwr Prr + ��FC OUTLET STRUCTURE DETAILS �,F �rR�, .�•a�•�� CITY OF FORT COLLINS UTILITIES ST08Yn me WAER CONSTNUCTiDv DhTAllS F.o. Boll eRo, rom cowus. Lro. eo5xz (11w) 221-67M Iasi ao w .wr Pe M MRYY .WME MIUM POMP MT d,.6oMa3 0' NIOEII RIBOI W/ P NRAzn ovisom NG 100-M MIL 9 z NNorth American Pipe Corporation AS SY M lr TYPE L WORM PM .U® ./ R• VETETATD Sll ANa .EDDm WIN e- rYP a . r WOE IXNOER 7 IM Y OOFMIJ QT aTxml �1 WpNR AND rAq G oanaW EMERGENCY OVERFLOW SPILLWAY W/ CONCRETE RIBBON NTS ASTM F768 PVC Highway Underdrain Pipe SOLVENT YIELD MUNICIPAL w ,aa m am nnm I WI fi }.al6t M OaSa am r . ]P.Tws WrM TYl r av Ivr m oueo uaw uTee 0]l4 :fill F NM. P.Iw .NeMIMEWn I,w I HOLES ROTATED IOC (FACING LP) IP P L —F. Y lI ♦ R \ y - Tor FLOW CONTROL PLATE DETAIL NTS nan�ngio ' wMP. snNeTe — O ema• Nm0 n S^NTure HOPE nbnE Ge14 12- MWlrp DeoM b Inlmum lY6 KW M No.etentmnSena Near NIIsena MI IRTn Clty OF.rl CO1Mh) Inlmum 6- TM[Y Lave, a M Gm i O.IMOam A'.. COOT W. a A9anG.Re/\ b• ` Aawe eM mmnm r rnNA La" a IN, \. PVC NPe COOT NP . ANngelc . uoftW.Y II II Inlmum.-PMp�yea HNC M, MOP1Mn.1 OepeMin, on UrWMPnO SIMI Cohih S) BIORETENTION / BIOSWALE CROSS SECTION CkyR�—QI'L_a1 f-^T? C.OIIIfIs �� STORMWAIER ! M E IMTE: "./I1J DCIAIL LjS --� w�a CONSTRUCTION DE, p — r STEEL ldl-YR f7fr CE PLATE 15' PIT, CUTLET PIPE 2I —dAMEMR OkIiICE 100-YR OUTLET ORIFICE PLATE DETAIL NTS Cfl'1. OF FORT COLLINS BIORETENTION SAND MEDIA SPECIFICATION PART 1 - CENTRAL A BIOREIENTKN SANG MEDIA (GSM) SHALL BE UNIFORMLY WDED. UNOGPACIED. FREE OF STO M STU PS. ROOTS. OR OTHER SKIM OB.ECTS LARGET TIM 1MO NCMES. NO OTHER MATERIALS OR SIASTAMDES SHALL SE MB® OR DUMPED YTIN THE BIOETDNTGN AREA THAT MAY BE HARMFUL TO PLANT GROWTH OR PROVE A M.MIDRANCE TO THE FARITYS FUNCTION AND MAINTENANCE- B. BSI SHALL WE FREE Of RANT OR S® MATERIAL OF NON-NATIVE, INVASIVE SPECIES OR WEEDS G FULLY MOED ISM SHALL BE TESTED PRIOR TO INSTALLATION! AND MEET THE FOLLCWING CRITERIA: 1. P-NDEX OF LESS THAN JO 2. PH U 15-6.5. SHOULD PH FALL OUTSIDE M THE ACCEPTABLE RANGE IT MAY BE MOORED WIN LYE (TO RAISE) OR IRON SU RATE PLUS SULFUR (TO LOITER). THE LIE OR WON SULFATE MUST BE MIXED UNIFORMLY NTO THE BSI PRIOR TO USE N THE BIIETENTION FACILITY. S CATION EXOHAKE WACTY (MC) GREATER TIMN 10 .. PNosoEHpRGUs (PHOSPHATE PllG6) NOT To E%LEEBD 69 PPM } BSM THAT FAILS TO MEET THE MINIMUM REOVNOIENTS SMALL LE REPLACED AT THE CONMACTOWS EI(PENg D. BSM SMALL BE CONSISTENCY MLY WORD E A DRUM MIXER. TION THE O' PEES WLL MOT H ALLONED. w)SMNG O' TE BSI ro A HGIIomcOus coNssTTNcr SMALL BE GOrE ro nE vTlsrAcnw of TIE OWNER. PART 2 - SDI!. MATERIALS A SAND 1. BSI SMALL CONSIST Of 61 SAND BY WOUME MEETING ASTM C-JJ. B. SHREDDED PAPER 1. BSI SMALL CONSIST OF 5-IM SHREDDED PAPER BY WLUE. I SHREDDED PAPER SHALL E LOOSELY PACKED. APPROXIMATE BUIX DENST' OF 50-100 LIS/CY. 3. SHREDDED PARR SHALL COMW OF LOOSE LEW PAPER, HOT SHREDDED PHONE BOOKS. AND SHALL BE TIORC1p0.Y AND MECHANICALLY AND M THESE D. OR LOAM PER USDA TETRIIRN. MIANGE WIN LEA THAN = GAY MATERIAL RABLY AT ITS SOURM PRIOR TO INQLANO TOPSOIL N THE MDL TOPSOE D ANY OTHER MATERIAL OELE1ElRKK5 TO RANT HEALTH. 2. LEAF CGMPOJT SHALL CGNSTBT a OA55 1 OROAMC LEAF cwwsr CdLSSTNG R AGED LE.VF M1ACH RESULTING TRW B0.000AL DEGRADATION AND MANSORUATI N OF PLANT-OERIVCp MATERIALS UNDER CONTROLLED CONDITIONS OE9QNED TO PROMOTE AEROBIC DECOMPOSITION. I THE MATERIAL SHALL BE WELL W1POSIFD. FREE OF VASE WEED SEEDS AND CONTAIN MATERIAL OF A GENERALLY HIARA NATURE CAPABE OF SUSTAINING GROWTH R VEGETATION. WITH NO MATERIALS TD)X TO PUNT GROWTH. A. COMPOST SHALL S: PROALUED BY A LOCAL US COMPOSTING COUNCIL SEAL OF TESTING ASSURANCE (STA) MEMBER. A COPY OF ME PNDNOEWS MOST RECENT INDEPENDENT STA TEST REPORT SMALL IN SUBMITTED TO AND APPROVED BY THE OWNER PRIOR TD DELVERY OF BSH TO THE PROJECT SITE I CNP(16T MATERIAL SHALL ALSO MEET THE FOLLOMNG CRITERIk a IM PERCENT OF THE MATERIAL SHALL PASS THROUGH! A 1/2 INCH SCREEN 0. PH OF THE MATERIAL SHALL BE BETWEEN &0 AND BA c. MOISTURE CONTENT SMALL BE BETWEEN 35 AND PA PERCENT Iw a MATURITY GREATER TUN BO PERCNT WT)RITYINOGEITIR E4 ER% AS PERCENTAGE 0' GEMINATON/MGOR. ICI+/IOa) • MATURITY INOCAIOR [%PRESSED AS TO M1.pOp1 RAIMaI < T2 1. MATURITY INOCATOR D%PRESSED AS AMYOMM/MIIRATETI RAIL <A n. MININKIM LToP�Eµ�T BASS SOLUBLE SALCONlENT S AUI BE NGREATER THAN 5BPARTS PER MLLGN OR o-5 MMMos/CM 1. PHOSPHORUS CONTENT SHALL IN NO GREATER THAN J26 PARTS PER MILLION j HEAVY METALS (MACE) SHALL NOT DCC® 0.5 PARTS PER M6LUN 4. CNEMICA CONTAMINANTS, MEET OR EXCEED HIS EPA CLASS A STAMIDARD. Q CAR 5 13. TABLE I a J IE IEL.S I. PATHOGENS, MEET OR EXCEED US EPA 0A55 A STANDARD. AO O 50132(A) LEVELS PART J - EXECUTION A GENERAL 1. REFER TO PRo.EGT SPECUTCATONS FOR EXCAVATION REQUIREMENTS. CITY OF FORT COLLINS. COLORADO RMETHOD i BLS! MATE AL SHALL BE SPREAD EVENLY N HGOZONTAL LAYERS, UTILITY PLAN APPROVAL z THICKNESS OF LOOSE MATERIAL IN EACH DYER SMALL HOT EXCEED 91 I COMPACTION OF BSM MATERIAL IS HOT REG RTIOD CALL UTILITY NOTIFICATION CENTER OF COLORADO 811 LALL 2-BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, MADE. OR EXCAVATE FOR THE MARKING 01 UNDERGROUND MEMBER UTILITIES. APPROVED BY THE NEW MERCER DITCH COMPANY RANDY GUSTAFSON. PRESIDENT DATE APPROVED: CITY ENGINEER CHECKED BY: WATER a WASTEWATER UTLITY CHECKED BY: STWMWATER UTUTY CHECKED BY: PARKS a RECREATION CHECKED BY: TRAFFIC ENGINEER CHECKED BY: ENNRCNMENTAL PLANER Hn za ZF)o 0 N W W W W O N IN Cr = Z z 6< u 0 ED ¢ <U'QW a ? z U Z S CIF 0 (0 U. N N W U LL Z H J Z W W = U F N— I.. N O� (n < W 0 z U U Z = LU W U 0 0 W I �. Wp 0: W _Z Z Cm a G D -J Q 0� U OW PROD. NO. 127"6500 21 APPENDIX F SOILS INFORMATION, FEMA FIRMETTE, FIGURES, TABLES ' AND EXCERPTS FROM REPORTS 1 L 11 II IJ 11 11 11 II 11 11 F 11 z gM 3 00669r M 1T 5 .507 M.aS s50[ �La8:n' OZL69VV 0896Rtt OV96R" 00969tt z e 0.� S 09S68V6 M1I5 eSOT z z n f0 V N 2 m O � Z d Rf O m 0 U O l0 Z �n E S ¢i X iy v 8� u y R 'o c O y d 7 b Z� C m O Z U M.Ef S oSOI C. �6 z 0 r « � � 0 z CL � a z w 0 w -j IL � ko ® \ § |\22 � CL $ 7rtk 2 {ff0 o E k\aw £ EC \ E f 'm J ui \RZ/ ƒ °� ` §j ) - §(I ƒf// : ca p _ § \mE k �k { §\ \ km r \ < r \;) Co 0j2 ;0 a)Z \§ ���t a4e 2 /§ !$ k §_§ : f 2 § CL ; 4£Ek (Da ('0 {) /c £ m «! §) } CL a 7 f \§\{� 0-0 )k( k2<0C �_ �' / - �a 4f);3 k �a 7 _ ® C� o !0 - - {| I2\ Z'\£6 \\ }) §e;Cr [ƒ { CL M k2 �§ !)B|) �� )� \/ /- }}(} �2 /kJ ƒ{k2) /f )3 A� 3k &S=o \ / m k \ \ ! ƒ ) - e o= z 2 2_ m! O o Q ❑ } / ! J & � { \ \ �! 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(D aL.. Q a) H .� C No Text W F �m W �`a �c r Cry W i CLLS �A W r p. am =im roE C ppj _' m CO O X °O g C S ° Y g SN 00 W«ri r WZZO a b O F? [Q7 a yy yp Z ¢F� E$c$ IIG J Q Q fIg/O�� �P N LL pp� V r o E E LL rLO Z ��+ W I� wy �x 9°`d W w C �y.Qa W i 5 CO) Q W 0p �r �cc�tW Q f� Z OG O Z 8 2 C E 9 w N Qli w W KO 2- UiEm0 IL < {JL dN 9� °c°m� a«m C aVE�m� L G 3 U U m 0, �OE ep ®®®® ® m EvM FE L a ••• i i � l •.1151.:.j. ' co cm ir N ;:.. ,M.,c>.:�s..�y. '��%�� may,• G �p '1005 �b 3 0 s p F- O z z Qp2 r=- 0 � J O LO J n = co I? L G a I~i o o p v In u 10.00 9.00 8.00 t 7.00 m r rc 6.00 t 2 5.00 f x 4.00 J J Q LL Z 3.00 2.00 1.00 0.00 4- 0.00 RAINFALL INTENSITY -DURATION -FREQUENCY CURVE. 10.00 20.00 30.00 40.00 50.00 STORM DURATION (minutes) —2-Year Storm - - - 10-Year Storm 100-Year Storm Figure RA-16 - City of Fort Collins Rainfall Intensity -Duration -Frequency Curves 60.00 t (C) Volume 1, Chapter S - Runoff: (1) Section 1.0 is deleted in its entirety. (2) A new Section 1.1 is added, to read as follows: t 1.1 Runoff Methodologies (a) There are two runoff determination methodologies that are approved by the City, the Rational Method and the Stormwater Management Model (SWMM). The City is the determining authority with respect to the appropriate ' methodology to use under different circumstances. Early contact with the City is encouraged for the timely determi- nation of the appropriate runoff methodology to use. (b) The Rational Method may only be used to determine the runoff from drainage basins that are less than ninety (90) ' acres in size. The Stormwater Management Model (SWMM) must be used to model drainage basin areas of ninety (90) acres or more. (c) All runoff calculations made in the design of both 2-year and 100-year drainage systems must be included with the Storm Drainage Report and all storm drainage facilities designed must be shown on Storm Drainage Plans. (3) A new Section 2.8 is added, to read as follows: ' 2.8 Rational Method Runoff Coefficients (a) The runoff coefficients to be used in the Rational Method can be determined based on either zoning classifica- tions or the types of surfaces on the drainage area. Zoning classifications may be used to estimate flow rates and vol- umes for an Overall Drainage Plan (ODP) submittal, if the types of surfaces are not known. Table RO-10 lists the runoff coefficients for common types of zoning classifications in the city of Fort Collins. 27 DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF Table RO-3—Recommended Percentage Imperviousness Values Land Use or Surface Characteristics Percentage Imperviousness Business: Commercial areas 95 Neighborhood areas 85 Residential: Single-family Multi -unit (detached) 60 Multi -unit (attached) 75 Half -acre lot or larger ' Apartments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools 50 Railroad yard areas 15 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off -site flow analysis (when land use not defined) 45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 0 Lawns, clayey soil 0 ' See Figures RO-3 through RO-5 for percentage imperviousness. C,, = K, + (1.31i3-1.44i2 + 1.135i - 0.12) for CA >: 0, otherwise CA = 0 CCD = KCD + (0.858i3 - 0.786i2 + 0.774i + 0.04) CB = (CA + CCD )12 (RO-6) (RO-7) 2007-01 Urban Drainage and Flood Control District I. . (b) For a Project Plan or Final Plan submittal, runoff coefficients based on the proposed land surface types must be used. Since the actual runoff coefficients may be different from those specified in Table RO-10, Table RO-11 lists coefficients for the different types of land surfaces. The runoff coefficient used for design must be based on the actual conditions of the proposed site. Table RO-10 Rational Method Minor Storm Runoff Coefficients for Zoning Classifications Description ofArea 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 1 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. Table RO-I1 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: 28 2.9 Composite Runoff Coefficient Drainage sub -basins are frequently composed of land that has multiple surfaces or zoning classifications. In such cas- es a composite runoff coefficient must be calculated for any given drainage sub -basin. The composite runoff coefficient is obtained using the following formula: n t i * Ai C = � ( (RO-8) A$ Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (A) Ai = Area of Surface with Runoff Coefficient of Ci, acres or feet? n = Number of different surfaces to be considered A, = Total Area over which C is applicable, acres or feet? (5) Anew Section 2.10 is added, to read as follows: 2.10 Runoff Coefficient Adjustment for Infreauent 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 infil- tration, 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 Stone Return Period (years) Frequency Factor Cf 2 to 10 1.00 11 to25 1.10 26 to 50 1.20 51 to 100 1.25 Note: The product of C times Cf cannot exceed the value of l; 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 Modeline 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 SWAM Users' Manual for appropriate modeling methodology, practices and development. The Us- ers' Manual can be found on the Environmental Protection Agency (EPA) website (http://www.MeQN /ednnnmUmodels/swmmlindex.hUn). ' (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. 29