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HomeMy WebLinkAboutDrainage Reports - 05/05/2009' � City of Ft. C�lins ed Plans Gallm'qwlowav-mopPiannirg, nrecture.=ngineeriry.' i®�`r 'E 9e +d +K � - ' Final Drainage Report for ' King Soopers Fueling Site 1001 South Taft Hill Road Fort Collins, ' Colorado ' June 25, 2008 Prepared for: King Soopers Supermarket Petroleum ' 65 Tejon Street Denver, CO 80223 Attention: John Atwood (303) 778-2735 ' john.atwood@kingsoopers.com 1 11 1 [1 1 1 11 Prepared by: Galloway & Associates 5350 DTC Parkway Greenwood Village, CO 80111 Attn: Matthew Duhaime, P.E.,P.L.S Phone: (303) 770-8884 Fax: (303) 770-3636 cc: File Job# KS112gra KS112-mfd-Drainage cover.doc Galloway & Company, Inc. 9 Phone 303.770.8884 • 5350 DTC Parkway, Greenwood Village, CO 80111 • www.gallowayUS.com ' Table of Contents ' A. Introduction.................................................................................I Location.............................................................................. I ' Description....................................................................... I Proposed Development..........................................................I ' Floodplain........................................................................1 Variances......................................................................... I ' B. Historic Drainage.........................................................................2 Drainage Patterns.................................................................2 ' Outfalls Downstream of Property.............................................2 C. Design Criteria............................................................................2 References........................................................................2 Hydrologic Criteria..............................................................2 ' Hydraulic Criteria................................................................3 D. Drainage Plan .............................................................................3 Drainage Basins.................................................................3 E. Water Quality .............................................................................4 F. Conclusions................................................................................4 ' Compliance with Standards ....................... :............................ 4 Summary of Concept............................................................4 tF. References..................................................................................5 Appendices. VicinityMap........................................................................................Appendix A ' Runoff Coefficients and Drainage Calculations ...........................................Appendix B Rainfall Depth -Duration -Frequency Charts...............................................Appendix C ' FEMA Map.............................................................................. ...Appendix D Back Pocket — Historical Drainage Plan 1 of 2 ' Developed Drainage Plan 2 of 2 1 1 i ' A. Introduction Location The proposed King Soopers fueling station at 1001 South Taft Hill Road is a redevelopment of the existing Conoco Gas station on a 16,564 square foot (0.38 acres) parcel, located at the southwest corner of Taft Hill ' Road and Elizabeth Avenue City of Fort Collins, Colorado. The legal description for this property is the parcel of land being a portion of Lot A, Replat of Miller Brothers Foothills Subdivision, 6"' Filing located in the SE'/a of Section 16, Township 7N, Range 69W, of the 61' P.M., City of FortCollins, County of Larimer, State of ' Colorado. (See Appendix A for the vicinity map). This site bounded by commercial development on the west and south side, Taft Hill Road on the east, West Elizabeth Street on the North. Description ' The site is currently zoned NC neighborhood commercial and consists of an existing Conoco gas station. The site slopes gradually west to east. The site is paved with asphalt and concrete with an existing canopy 4 fuel pump dispensers and a masonry building with two repair bays and a carwash. A geotechnical survey has been ordered for the site. Proposed Development ' The proposed development consists of demolition of the existing structures, pavement and underground fueling system and construction of a new 3,612 square foot canopy, 110 square foot kiosk, and installation of new ' underground fuel storage tanks and fueling delivery system. The entire project is expected to be completed in one single construction phase. The onsite construction will consist of relocation of two access drives and ' removal of one, the existing curb and gutter along Elizabeth Street and Taft Hill Road will be replaced with a new 6' detached sidewalk and handicap ramps. Landscape areas will provide water quality, and pedestrian sidewalk connections to the existing offsite pedestrian sidewalk will be installed. The existing overall imperviousness is approximately 98% (See Historical Drainage Plan); the proposed overall imperviousness ' will be 70% (See Developed Drainage Plan). ' Floodplain The site is in Flood Hazard Area "Zone X outside the 500-year floodplain, as determined by graphic ' interpretation, Floodplain information was obtained from FEMA Flood Insurance rate map for Fort Collins, Colorado, Community Panel Number 080102-0978F, effective date December 19. 1996 ' Variances The project is not requesting any variances from the Storm Drainage and Technical Criteria Manual for this prof ect. B. Historic Drainage ' Drainage Patterns The site slopes west to east and the entire runoff from the site is sheet flow. There is no existing storm sewer system located on or adjacent to the site. All runoff flows into Elizabeth Street and Taft Hill Road and continues in a concrete pan across Taft Hill Road as shallow curb flows continuing in the south flow line of Elizabeth Street to the existing public storm sewer system. No existing drainage reports were available. ' Outfalls Downstream of Property The accumulated flows are discharged into the existing concrete cross -pan crossing Taft Hill Road the flows discharge into inlets along the south flow line of Elizabeth Street approximately '''A mile east of the site. ' C. Design Criteria ' References To generate the hydrologic and hydraulic design for this project, multiple resources were used. The City of Fort Collins Storm Drainage Design & Technical Criteria Manual is referenced for composite runoff coefficients, and rainfall data and water quality design. The information for soils onsite was taken from the ' USDA National Conservation Soil Survey website [1] and it was found that the site consists of Nunn Clay Loam, or Type D. Composite runoff coefficients were calculated for the individual basins using the runoff coefficients generally accepted for landscaped, paving & roof areas for the2-, 5-, 10- and 100-year storm events (see recommended coefficients in the runoff calculations in Appendix D). Water Quality is provided for by discharging into two landscape buffers and an emergency fuel spill containment structure. 1 H droloQic Criteria ' The Rational Method was used for calculating runoff for the 2-, 5-, 10- and 100-year event storms. Due to the small basin size and short lengths of storm sewer pipe, a conservative 5-minute time of concentration (Tc) was ' used in calculating runoff (See Appendix B for developed runoff calculations). The rainfall intensities from ' -2 ' Figure 3-1 Intensity Duration Frequency curves for the City of Fort Collins are used to calculate the storm runoff. Rational Method Using the Rational Formula Q = C*I*A ' Q = Maximum Rate of Runoff (cfs) C = Runoff Coefficient ' I = Rainfall Intensity (in/hr) A = Tributary Basin Area (acres) ' Hydraulic Criteria Because the site is an existing development and the imperviousness is being decreased the City of Fort Collins requirements for detention, have been waived water quality for this development will be provided by landscape swales and an emergency spill containment structure. D. Drainage Plan ' Based on the proposed grading plan, the King Soopers Fueling development has been divided into 2-basins that sheet flow to the existing flow line in Elizabeth Street and Taft Hill Road. See the Developed Drainage Plan in ' the plan pocket at the rear of this report: Drainage Basins A-1 is a 0.38 acre basin consisting perimeter landscaping the canopy/kiosk and asphalt/concrete parking. ' Runoff from basin A-1 is calculated as 0.91 cfs for the 2-year storm, 1.55 cfs for the 10-year storm and 3.18 cfs for the 100-year storm. These flow values based on a Runoff Coefficient (C) value of 0.84, was ' used. Runoff from this basin drains east to 0.5' curb cuts, which then flows through the water quality landscape swale and discharge through 0.5' curb openings into Taft Hill Road and Elizabeth Street. ' A-2 is a 0.08-acre basin consisting of the perimeter landscape swales and the perimeter sidewalk in the ' eastern side of the site. Runoff from basin A-2 is calculated as 0.17 cfs for the 2-year storm, 0.30 cfs for the 10-year storm and 0.60 cfs for the 100-year storm. These flow values are based on Runoff ' Coefficient (C) value of 0.75 was used. Runoff from this basin drains into the water quality landscape swales and then discharges through the 0.5' curb cuts into Taft Hill Road and Elizabeth Street. 1 -3- ' The receiving system for these flows will be the existing curb and gutter along Taft Hill Road and Elizabeth Street. Flows are intercepted by the existing storm sewer system east of the site in Elizabeth Street. ' E. Water Quality ' Two water quality ponds/swales provide water quality by detaining small flows at a maximum depth of 5" flows that exceed this pond depth will discharge through the curb openings into Elizabeth and Taft Hill Road. ' Additional water quality and spill containment is provided by a sand/oil separator structure at the end of a trench drain at the perimeter of the underground fuel storage area, the structure has a fuel spill containment volume of 150 gallons per City criteria. F. Conclusions . Compliance with Standards This report has been prepared using the rainfall data and runoff computation techniques outlined in the Cit of Fort Collins Storm Drainage Criteria and Construction Standards Manual. Soil conditions are only preliminary and a comprehensive geotechnical report will be completed. Summary ofConceptt ' The proposed developed site will reduce the imperviousness of the existing site and provide a Water Quality treatment system with a fuel spill containment structure according to the City of Fort Collins requirements and ' all applicable design practices for this type of development. This proposed development will have minimal effect on the adjacent properties. 1 1 1 -4- 1. . ' G. References ' 1. http://websoilsurvey.nres.usda.gov/app/, Accessed June 25, 2008, United States Department of Agriculture, Natural Resources Conservation Service, Web Soil Survey. ' 2. Urban Storm Drainage Criteria Manual -Volumes 1. 2 & 3. Urban Drainage and Flood Control District, June 2001.Revised August 2006. City of Aurora Approval # 960135 ' 3. City of Fort Collins Storm Drainage Design Criteria and Construction Standards. City of Fort Collins, revised April 1999. -5- W. MULBERRY ST. 0 J J_ 2 U- H N SITE W. EUZABETH ST.. N N 0 � _W 2 N 0 F CLEAR EW AVE. v, N w U J J 2 W. PROSPECT RD. VICINITY MAP NOT TO SCALE PROJECT: King Soopers Fueling LOCATION: 1001 South Taft Hill Rd. Fort Collins, CO PERCENT IMPERVIOUS VALUES LANDSCAPE _ 0 PAVING 100 ROOFING 90 Project No.: KS112 Date: December 10, 2007 Engineer: M. Duhaime 'RUNOFF COEFFICIENTS USED 5•Year 10-Ve8r 100-Year LANDSCAPE 0.15 0.25 0.50 PAVING 0.88 0.90 0.93 ROOFING 0.85 0.90 0.90 Cnnnnneitw Runnff Cnuffir-inntc nnrl Dumunk Im nnevin,lcnn�r• f... n.�...,t....,,w n...:......., e�..:�-. BASIN DESIG. OVERALL AREA Of) LANDSCAPE AREA Ise PAVED AREA (sn ROOF AREA (Sn 5-YEAR COEFF. 10-YEAR COEFF. 100-YEAR COEFF. PERCENT IMPERVIOUS BASIN A A-1 16,564 5,317 8,190 4.057 0.69 0.75 0.84 71% A-2 3.424 1,338 2,086 0 0.59 0.65 0.76 61% TOTAL A 19,988 8,655 10,276 4,057 0.67 0.73 0.83 70% BASIN HISTORICAL H=1 16,584 30 12.484 4,050 0.87 0.90 0.92 97% H-2 3,424 0 3,424 0 0.88 0.90 0.93 100% TOTAL 19,988 30 15,908 4,060 0.87 0.90 0.92 98% Galloway. Remem 8 Aa9odatee W5 KS112 m1e- Drainage mwatione.ila R0eheee: 0 1 1 1 1 PROJECT: King Soopers Fueling LOCATION: 1001 South Taft Hill Rd. Fort Collins, CO PERCENT IMPERVIOUS VALUES LANDSCAPE 0 PAVING 100 1 ROOFING 90 Timor of Cnneonfmfinn R Vear CnofArlenf Project No.: KS112 Date: December 10, 2007 Engineer. M. Duhalme ' RUNOFF COEFFICIENTS USED ear to-vear ea LANDSCAPE 0.15 0.25 0.50 PAVING 0.88 1 0.90 0.93 ROOFING 0.85 0.80 0.90 Basin Desig Overall Area 5-Year Coeff Initial / Overland Time, ti Travel Time, it ti +tt Tc Check (Urbanized Basins) Result Length Slope ti Length SLOPE Velocity tt tc Total Length tc- (L/180+10) tc (ac) C5 (tt) %) (min) (it) %) (fps) (min) min (it) (min) (min) BASIN A A-1 0.38 0.89 3 2.00 1.01 125 1.00% 2.00 1.0 2.1 128 10.7 5.0 A-2 0.08 0.59 5 2.00 1.61 50 1.00% 2.00 0.4 2.0 55 10.3 5.0 TOTAL A 0.48 BASIN HISTORICAL H-1 0.30 0.87 95 1.50 3.31 64 0.50% 1.41 0.8 4.1 149 10.8 5.0 H-2 0.08 0.88 167 1.50 4.47 57 1.50% 2.45 0.4 4.9 224 11.2 5.0 TOTAL H 0.38 e (LW.wy, R.& Auec®BA Ke112m D4 ebMbu.�4 IWOlde9 Rw W:0 PROJECT: King Soopers Fueling LOCATION: 1001 South Taft Hill Rd. Fort Collins, CO DEVELOPED RUNOFF CALCULATIONS Project No.: KS112 Date: December 10, 2007 Engineer. M. Duhalme RUNOFF COMPUTATIONS RATIONAL METHOD 2-YEAR DEVELOPED RECURRENCE INTERVAL 10-YEAR DEVELOPED RECURRENCE INTERVAL 100-YEAR DEVELOPED RECURRENCEINTERVAL BASIN DESIG. Ta INTENSITY AREA I AREA RUNOFF COEFF. C (no units) INTENSITY 1 (irvhq RUNOFF O (cfs) RUNOFF COEFF. C (no units) INTENSITY I (inlhr) RUNOFF O (crs) RUNOFF COEFF. C(inmq (no units) INTENSITY (inrhr) RUNOFF (cis) 2-year 10-year =ams) LINE A A-1 1 5.00 2.85 4.87 9.95 16,564 0.38 0.69 2.85 0.75 0.75 4.87 1.38 0.84 1 9.95 3.18 A-2 5.00 2.85 4.87 9.95 3,424 0.08 0.59 2.85 0.13 0.65 4.87 0.25 0.76 9.95 0.60 TOTAL A 19,988 0.46 2.65 0.88 4.87 1.83 0.83 9.95 3.78 BASIN HISTORICAL H-1 5.00 2.85 4.87 9.95 16,564 0.30 0.07 2.85 0.74 0.90 4.87 1.31 0.92 9.95 2.75 H-2 5.00 2.85 4.87 9.96 3,424 0.08 0.88 2.85 0.20 0.90 4.87 0.34 0.93 9.96 0.73 TOTAL H 19,988 0.38 2.85 0.94 4.87 1.68 0.92 9.95 3.48 Assumed runoff coefficients Use minimum Time of Concentration = 5 minutes Use composite coefficients - Ration Method: O = CIA fewirr. R. 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NRV T, DOMAIN15 19&. fl[VAIgN 'Ael BI 1¢ $ i l i i 2 Rr 0 Ell 8a8;R x gmfi DRAINAGE LEGEND PROWNDSED CONTOUR NWMEO I EIN.TNM ,2400 SCREW RAW ETEV.RTgN 1R EMSXFD I ED 104, OR CURB n I T+IE R M fNNllf MRRSECIKN TM TM D WN FEE: PoM OF CREW p tip NONE V CG9 hYNT m TD9 TOP OF GATE Games i W INNvn urvnlaN NE WTM ENISTINO Tm TOP Of TANKS o P TORTS ISVHD r ` ANN Vim, I EFFORTS J .ELoa2jY�E SO CWIB GENIxG d a —.Irm— E.wTING M OTTER^ J J O CO" a Y EPTz uawNG a Qi DEEPER Patin U M MIND MANOR EARN eaRSON EINL III SOON WTG A—i NASN AREA IN MRE ^ - -- O.00 PERCENT MPERA+ous 0.00 000 aa vEAFF E11I MARTKIM HISTORICAL DRAINAGE PLAN 1 OF 2 KING SOOPERS FUELING STATION PART OF TRACT 'A' REPLAT OF MILLER BROTHERS FOOTHILLS SUBDIVISION 6TH FILING 1001 SOUTH TAFT HILL ROAD a N �.� rv,F FARE III"w 6 i I E ZAB p i nv.r]'.lo'E A_q LI ETH.BBmT. �>A = GRECCF- ON A mIwETE RARE BRrn BASF AT nE m R INEST ELIEIAR sr..LRD { CIA � H.oaMI, YYm rur wu RE UVATIa-E9Iv ON OF FEET COLLINS MUSICAL CdRa - NET M 6 V p�SV A A A76 mx _ \ \ \ \ \ \ • �• L�B0.00� A-59'11'XI N%INV51 GAMlET BELT ON FREE iM1TRANT WIIX SC[ R E-NAI ERFEI. 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