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HomeMy WebLinkAboutDrainage Reports - 03/23/2006 (2)f.. J1. A City of Ft. Collins Appr ';anS Approved By _Joe - is VORT COLLINS UTM== 0 �� Drainage Control Study for PVHS Doctors Lane Parking Lot Rantec Fort Collins, Colorado December 28, 2005 December 28, 2005 Mr. Basil Hamden City of Fort Collins Water Utilities -Storm Water 700 Wood Street Fort Collins, Colorado 80521 RE: Drainage Control Study for PVHS Doctors Lane Parking Lot Dear Basil: We are pleased to submit to you, for your review and approval, this Drainage Control Study for PVHS Doctors Lane Parking Lot. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. We appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Respectfully, Stantec Consulting, Ltd. Prepared by: Josh Ziliak Design Engineer Reviewed by: Jim Allen -Morley Project Manager TABLE OF CONTENTS DESCRIPTION PAGE I. GENERAL LOCATION AND DESCRIPTION 1 A. Location 1 B. Description of Property 1 II. DRAINAGE DESIGN CRITERIA 1 A. Regulations 1 B. Development Criteria Reference and Constraints 2 C. Hydrologic Criteria 2 D. Hydraulic Criteria 2 E. Variances from Criteria 2 III. DRAINAGE FACILITY DESIGN. 2 A. General Details 2 IV. STORMWATER QUALITY 3 A. General Concept 3 V. CONCLUSIONS 3 A. Compliance with Standards 3 B. Drainage Concept 3 C. Storm Water Quality Concept 4 VI. REFERENCES 4 APPENDICES VICINITY MAP WATER QUALITY CALCULATIONS DETENTION BASIN SIZING ORIFICE CALCULATIONS 1 2 3 4 I. I u u II. C Cep-�7� /1�iZ�1:11 Y [i]►i:�►1I � � ► A. Location The Poudre Valley Health Systems Doctors Lane Parking Lot is bounded to the east by Lemay Avenue, to the west by Hospital Lane, to the south by Doctors Lane and to the north by a developed lot. The site location can also be described as situated in the southwest quarter of Section 18, Township 7 North, Range 68 West of the 6`h Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado (See Vicinity Map in Appendix 1). B. Description of Property The property consists of approximately 0.35 acres of undeveloped land. The project site is covered in grass in its existing condition and slopes gently towards the three existing roads that bound the site. All runoff flows uncaptured from the site and is conveyed via existing curb and gutter along Hospital Lane, Doctors Lane and Lemay Avenue. The property site, in its proposed condition, will consist of a 27 space parking lot consisting of approximately 0.17 acres of the site. Two small detention ponds and new sidewalk on the south, east and west are also proposed. The rest of the site will remain in its existing condition. DRAINAGE AND DESIGN CRITERIA A. Regulations The Urban Storm Drainage Manual (published by the Urban Drainage and Flood control District — Denver, Colorado) and the City of Fort Collins Storm Drainage Design Criteria have been used to calculate the storm water runoff and design the storm water facilities for the subject site. I 1 1 LJ 1 1 I 1 1 l B. Development Criteria Reference and Constraints The criteria and constraints from the City of Fort Collins will be met. C. Hydrology Criteria The Rational Method was used in determining surface runoff for the project site. The 2-year and 100-year storm event were used in calculating runoff values. The City of Fort Collins intensity duration frequency curves were used to obtain rainfall data for each storm. The FAA method was used for sizing detention ponds. The water quality volumes for the detention ponds were computed using the Water Quality Capture Volume equation from the Urban Storm Drainage Criteria Manual, Volume 3. These calculations and criteria are included in Appendix 2. D. Hydraulic Criteria All hydraulic calculations within this report have been prepared in accordance with the City of Fort Collins Drainage Criteria. E. Variance A variance for the reduction of the freeboard requirement from 1.0' to essentially 0' is requested. This is because there is no convenient adjacent storm sewer that can be accessed for the PVHS Doctors Lane Parking Lot. We have provided the required storm water quality volume as well as the required storm water detention. Because the outlet is to the street and the depth of water is 1.0', one foot of freeboard is impractical for this site. If the storm event exceeds the capacity of the pond, the design allows the pond to overflow to Doctors Lane and does not endanger any structures. III. DRAINAGE FACILITY DESIGN A General Details I 1 L IV. r u 1 u The subject site can be broken down into three main drainage basins in its proposed condition. The first basin consists of the proposed 27-space parking lot that covers approximately 0.17 acres of the site. The parking lot will drain into the proposed detention ponds and be detained to allow for water quality treatment. The detention basins have been designed to detain the 100-year developed conditions (See Appendix 3 for calculations). The runoff will then be released to the existing curb and gutter along Doctors Lane. A minimum time of concentration of 5 minutes was used for the developed site because of its small size (See Appendix 3). The second basin consist of just under 0.01 acres of the proposed parking lot located on Hospital Lane that will be allowed to drain uncaptured from the site. The final drainage basin consist of the remainder of the site that will stay in its existing condition and be allowed to drain uncaptured to existing curb and gutter surrounding the subject site. STORMWATER QUALITY A. General Concept The proposed ponds will provide for the required water quality capture volume. The outlet structure is designed to release the Water Quality Capture Volume over a 40 hour time period. Calculations can be found in Appendix 4. CONCLUSIONS A. Compliance and Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria and the Urban Storm Drainage Manual (published by the Urban Drainage and Flood Control District). B. Drainage Concept n I ' The drainage in proposed concepts presented this report and on the construction plans adequately provide for the conveyance of developed on -site runoff to the proposed drainage facilities of the subject site. The combination of the proposed ' curb and gutter, cross -pan, detention basins and outlet pipe will allow for the 2- year and 100-year developed flows to be safely routed through the property. ' If groundwater is encountered at the time of construction, a Colorado Department of Health Construction Dewatering Permit will be required. C. Storm Water Quality Concept ' The proposed design has addressed the water quality aspect of storm runoff. The ' extended detention basin will provide opportunity for storm water pollutants to filter out of the storm runoff before being discharged from the site. VI. ' 1. Storm Drainage Design Criteria and Construction Standards by the City of Fort Collins, Colorado, May 1984, interim revision January 1997. [J 1 u 1 APPENDIX I No Text I k APPENDIX 2 1 t 1 1 1 1 1 Desfgn Procedure Form.xExtended Detentlon iasm (EDB) SedlmentaUon Faculty, �r Sheet 1 of 3 Designer: Josh Ziliak Company: Date: Project: Location: Stantec December 8, 2005 PVHS PARKING LOT Lemay Ave/Docters Lane 1. Basin Storage Volume la = 100.00 % A) Tributary Area's Imperviousness Ratio (i = 1./ 100) i =Eja�1 AO r;'1 B) Contributing Watershed Area (Area) Area = 0.17 acres C) Water Quality Capture Volume (WQCV) WQCV =FF�-�`-050_'=;?watershed inches (WQCV =1.0 - (0.91 ' 13 - 1.1912 + 0.78' 1)) D) Design Volume: Vol = (WQCV / 12)' Area' 1.2 Vol =f`,10 0085� acre-feet 2. Outlet Works A) Outlet Type (Check One) x Orifice Plate Perforated Riser Pipe Other. B) Depth at Outlet Above Lowest Perforation (H) H = feet C) Recommended Maximum Outlet Area per Row, (A.) square inches D) Perforation Dimensions: i) Circular Perforation Diameter or D =fin inches ii) 2" Height Rectangular Perforation Width W NMI 1: 9 inches E) Number of Columns (nc, See Table 6a-1 For Ma)imum) nc = ,Wi number F) Actual Design Outlet Area per Row (A.) Ao = r-; square inches G) Number of Rows (nr) nr = number H) Total Outlet Area (AoJ A., =€?j2F ;,: _ square inches 3. Trash Rack A) Needed Open Area: 0.5' (Figure 7 Value P A� _ ( 9 ) � Eby A, =� 1=.m~� square inches -x,�_ B) Type of Outlet Opening (Check One) < 2" Diameter Round ? : 12" High Rectangular Other. C) For 2", or Smaller, Round Opening (Ref.: Figure 6a): i) Width of Trash Rack and Concrete Opening (W...) from Table 6a-1 Wwr, inches ii) Height of Trash Rack Screen (HTR) HTR = �,--i�;,_;� inches USDCM Vol 3 BMP-Prelim.xls, EDB 12/8/2005, 2:49 PM I 1 1 1 11 u 1 APPENDIX 3 1 (For catchments less than 160 acres only. For larger catchments, use hydrograph routing methods) (Note: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended) bestan Inf-ormallon linpufF. Oalcvnent Drainage Imperviousness 1,=i:::i£i ';i:: 1)06, percent Catchment Drainage Area A=i'i 2':'0(1A: acres Predevelopment NRCS Soil Dnoup Type=A, B, C, or 0 Reban Period for Detention COMB T =: i ?i' ii!3'i;11N1i year (2, 5, 10, 25, 50. or 100) Tim of ConceMation of watershed To =: 2"i' %2::2.;; ::: :minutes Almmable Unit Release Rate (See Table A) V '%t:00: chfane On>har Precipitabon P7 Design Rainfall IDF Formula I C1•Pt/(C2+Tc)AC3 ................... Coefficient One ................... Cl = 28. o: Coeffldent Two C2 Coefficient Mee C3=:::�::';:?: Determination of AVerade Outflow from the Basin (Calculated): Ruwg Coefident C= Inflow Peak Runoff Op -in =7ii8i oft Allowable Peak Ounow Rate Op -out =z i ::: I::: D;14: cfs Ratio of Op-aOOp-m Ratio=:+ -.;I+ i:-:'6.1A+ Table A Recommended Unt Flow Release Rate in cWam of bibutary catchment wiW n UDFCD boundaries. dw vo IOF Lis 121, Made :.. .1,0 ^L. wn'..uai bo cm.r m are. -.di :e order. Oraation Intensity Volme AFactornt Outflow Volume I Volume et INnutes inchesM cubic fee eft cubic feel cub Stormwater Detention Volume (Cubic Feet) _: Stormwater Detention Volume (Acre Feet) =i 3i`:D10653:: UPOelention v1.00.45, Modified FM 12BI2005, 2:44 PM Inflow and Outflow Volumes vs. Rainfall Duration Intersection of Modified and FAA Outflow Plots Is at maximum detention volume 3,500 3,000 2,500 0 cu u. 2,000 E .2 1,500 0 1,000 500 0 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 Duration (Minutes) I -g— lnflnw VnIllm. UUDetentlon 0.00)ft, Mdftcl FM 1218t2005,2:44 PM I r tmp#7.txt PVHS DOCTORS LANE PARKING BASIN 1 12-09-05 JOZ #units=Elevation,ft,Area,mi2,volume,ft3,volume,ft3 # Elev Area Cumml Avg Cumml Conic # ft mi2 ft3 ft3 4971.0000 0.0000 221.8751 219.6130 4970.9000 0.0000 .174.2000 171.9400 4970.8000 0.0000 128.1974 125.9403 4970.7000 0.0000 84.0137 81.7599 4970.6000 0.0000 42.2248 39.9796 4970.5000 0.0000 11.5024 9.7700 4970.4000 0.0000 0.0000 0.0000 ' BASIN 2 12-09-05 3Oz 1 1 0 H I 1 1 #units=Elevation,ft,Area,mi2,volume,ft3,volume,ft3 # Elev Area Cumml Avg Cumml Conic # ft mi2 ft3 ft3 4971.0000 0.0001 1434.9579 1430.4644 4970.9000 0.0001 1230.9939 1226.5032 4970.8000 0.0001 1031.1918 1026.7055 4970.7000 0.0001 836.0888 831.6075 4970.6000 0.0001 646.3183 641.8445 4970.5000 0.0001 461.7543 457.2852 4970.4000 0.0001 286.9784 282.5631 4970.3000 0.0000 140.0586 136.1152 4970.2000 0.0000 43.2461 40.8651 4970.1000 0.0000 0.0000 0.0000 PARKING STORAGE 12-09-05 ]OZ VOLUME = DEPTH X LENGTH X 0.5 X WIDTH VOLUME = 0.5 x 22 x 0.5 x 127 = 698.5 ft3 TOTAL PROVIDED STORAGE = 221.87 + 1434.96 + 698.5 = 2355.33 cubic Feet TOTAL REQUIRED STORAGE = 2343.53 Cubic Feet Page 1 1 1 1 1 + LO � _ N V n u U t` 00 II J O Z i= E 0 N Q .. W U Q o O�J� `o 00 LL T W O H CL U) Y O Cl)Q 1 W Q ,c N O Z E uj LL J •C " E o Oo J W > W J w O LO 9U) J O F- J W N z °° Q Qa � U, 2 Zco w C co � w z w w w > a O o u- o0 O J � N J Q z CD CO z w J Q I— U M o Q o 0 Z W ciCN N Q @ Q O co — CDO O O Z APPENDIX 4 I 1 1 .1 1 n 1 WATER QUALITY OPENING Worksheet for Generic Orifice 1 Project Description Worksheet Orifice (WQC Type Generic Orifi( Solve For Opening Arei Input Data Discharge .002571 cfs Headwater Elevat 4.5 in Centroid Elevatior 2.5 in Tailwater Elevatio 0.0 in Discharge Coeffic 0.60 Results Opening Area �188436 in' Headwater Height Above - 2.0 in Tailwater Height Above G -2.5 in Velocity 1.96 ft/s Project Engineer: Alicia Forward v:\...\design\drawing\work\jziliak\projectl.fm2 Sear -Brown Group FlowMaster v7.0 (7.00051 02/17/06 08:24:19 AM 0 Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 10 YEAR DISCHARGE OPENING Worksheet for Generic Orifice Project Description Worksheet Orifice (10 YR DISCF Type Generic Orifice Solve For Opening Area Input Data Discharge 240000 cfs Headwater Elevat 10.0 in Centroid Elevatior 7.0 in Tailwater Elevatio 0.0 in Discharge Coeffic 0.60 Results Opening Area .361009 in' Headwater Height Above - 3.0 in Tailwater Height Above G -7.0 in Velocity 2.41 ft/s Project Engineer: Alicia Forward v:\...\design\drawing\work\jziliak\projectl.fm2 Sear -Brown Group FlowMaster v7.0 [7.00051 02/17/06 08:24:37 AM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 A-� PLAN NEW \ a, � 1 (49710) \ N. g• PVCJ O 0.50% �g"0!3pi I��. SILTY aT IIAS YAW ,roG v / O sIHAWUAL! �_ F<•. _ 3T auv Maa x/comTmmxa lrb 4 INLET FILTER wml W/ wW \ . L _ _ 70. _ E o 63 Y3 V/ g' C Axon - Irac -.. • .. . • .': `�. Fro . 8' O 0.501E : ]• DETAIL 'A• _ -- — __ SEE SHEET C-502 -- - --' -' - o _ _ o FOR RAMP DETAIL \\ 4 ' _ 1 ` f 1 . Gv —__ 1 -- DOCTORSLANE — .-- Iv ,� S 1 - ..amr u2w[� SECTOR A —A NOTE: WHEN THE CURB IS SEPARATED FROM THE SIDEWALK THE STEEL PLATE SHALL BE PLACED ON THE SIDEWALK AND THE CONCRETE CHANNEL (WITH 6• THICK WALLS ON EACH SIDE) CONTINUED INTO THE CURB AND GUTTER. 2' SIDEWALK CHASE W/ 2' A METAL CULVERT � G,>a LEGEND g � M W PROPERTY UNE e .-_ PROPOSED MNVM1E { PROPOSED W RS AND CUTTER Try LL ' PR0i HNOIW RAND $ a /n\ r PROPOSED A`hRRElY£ AC' STET 9 n3 FT 7SAkk PROPOSES SPOT EI£VAMYI GR —70.6— PROPOSED (NACXG CONTOURS NLT FENCE — 4970 — MISSING 001ITWRs - -1Ad- - Easnio SANITARY ROVER SSANCE _ _ _ _ DTSMD RATES UK sEAMCE 0 EPSnRG WATER METER =mmmzPmwzm EXISTING cMB A CUTTER COSnxG RAW OPROTECT TIES NOTES: 1. DETENTION POND TO BE BUILT AT START OF GRADING. 2. EXCAVATE 6• DOWN AND 2' NOE ALONG THE LENGTH OF THE EXISTING CURB ON DOCTORS LANE FOR EROSION CONROL DURING CONSTRUCTION. (FILL IN DURING FINAL GRADING) 3. NO STOCK PILING ONSITE. 4. PROTECT TREES PER BHA LANDSCAPE PLAN. REFER TO PLAN PRIOR TO ANY CONSTRUCTION. U CONOETE CDEWAIK O3 INFLOW PIRG (SEE OCTAL SHIM (5dl) O3 SUNTORY MM (SEE DETAIL SHEEID CSDI OINSTALL WIDCA➢ RAMP (SE£ DMW SHEET (501) OALLOW CURB W I SECTOR FOOTING OB NRUGN MRS TEnnCN-s1RQ1(ACE PETAL DIAL C50M) 1) . ALL DIMENSIONS TO FLONUNE OF AS NOTED. 2) . ALL DISTURBED AREAS TO BE RE -SEEDED 3) . EOP=EDGE OF PAVEMENT, PL=ELOWUNE, ME -MATCH EXISTING, SW -SIDEWALK, W=GRADE BREAK AND TC=TOP OF CURB ® MKIRO ED RETENTION BASIN PROPOSED CCgER I Ii 0 10 A 30 SCALE IN FEET CALL UTILITY NOTIFICATION CENTER OF COLORADO 1-800-922-1987 City of Fort Collins, Colonado UTILITY PLAN APPROVAL THESE PLANS LAVE BEEN REVIEWED BY THE LOCAL ENTRY FOR CONCEFr ONLY. THE APPROVED: RENEW D06 NOT IMPLY RESPONSBIUTY BY City Engimer Date THE RENEWING DEPARTMENT, THE LOCAL CHECKED BY: ENTITY ENGINEER, OR THE LOOSE ENTRY FOR Walu A Westexaler WI"4y Oate ACCURACY AND CORRECTNESS OF THE CALCULATIONS. TURITERMCRE, THE REVIEW CHOCKED dY: WE NOT IMPLY THAT QUANTITIES OF ITEMS S(armvafer Wily Dote ON THE PLANS APE THE FINAL OMNTMES CHECKED BY: REQUIRED. THE REVIEW SHALL NOT BE Parks A Recreation Date CONSTRUED IN PINY REASON AS ACCEPTANCE OF n WCML RESPONSIBILITY BY THE LOI>L CHECKED BY: Date ENTITY FOR "MOW OUNTITIES OF ITEMS Traffic Engineer SHOWN THAT MAY BE REWIRED DURING THE CHECKED HP: CONSTRUCTION PHASE. Date UU W Ao0 z CD 0 Q Y h a w W Z � DL J Z a3 a� D O (90 W Y Z K 1— �o �Z a00 4. JU P(mitSeal _r 18701UQ o 4e NMVNC-170 RevMian Shot 0 4Dt6