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Home My WebLink AboutDrainage Reports - 08/18/20041 1 1 1 1 1 1 1 1 Final Drainage Study For Raising Cane's Chicken Fingers Fort Collins, Colorado March 23, 2004 R Prepared For: Raising Cane's Chicken Fingers 1212 S. Acadian Parkway Baton Rouge, LA 70806 Prepared By: NORTHERN ENGINEERING SERVICES, INC. 420 S. Howes, Suite 202 Fort Collins, Colorado 80521 Phone: (970) 2214158 Fax: (970) 2214159 Project Number: CHX 03-113.00 NORTHERN NE ENGINEERING ' SERVICES, INC. ' March 23, 2004 Mr. Basil Harridan ' City of Fort Collins Stormwater Utility P.O. Box 580 Ft. Collins, CO 80522 ' Re: Raising Cane's Chicken Fingers Final Stormwater Drainage Report ' Fort Collins, CO Northern No. CHX 03-113.01 FIN ' Dear Mr. Hamdan: Please find enclosed a final stormwater drainage report for the proposed development of Raising Cane's Chicken Fingers on South College Avenue in Fort Collins. The intent of this report is to document the effect of this flow on the adjacent, downstream properties, the effect on the quality of stormwater runoff leaving the site, and what measures are to be taken to minimize or negate these effects. ' Project Description ' The proposed development is the construction of a 3,244 square foot drive-thru restaurant along South College Avenue in Fort Collins, Colorado. Associated parking, driving lanes, utilities, and drainage improvements will be constructed along with the ' proposed structure. Existing Conditions & Historic Drainage Patterns ' The existing site consists of mainly concrete and asphalt paved surfaces, along with an existing building slab in the center of the site. The majority of stormwater falling on the site drains to the northeast through a minor existing swale, discharging into Dartmouth ' Road at the northeast corner of the site. A small portion of the site (approximately 10%) flows to the west, discharging into the easternmost northbound travel lane of South College Avenue. ' Proposed Conditions & Drainage Patterns ' The proposed impervious surfaces for the existing site will be less than or equal to those on the existing site according to the proposed site plan, thereby not increasing the amount of stormwater runoff leaving the site, provided the site is constructed according to the proposed site plan. Similarly, the proposed site will contain approximately the same flow patterns as the existing site. The majority of the site will flow to the east to a proposed water quality pond along the east property line. A small portion of the site, mainly the area immediately west of the proposed building and the area within the College Avenue right-of-way, will continue to flow to the west, discharging into South College Avenue. This area is slightly larger in size than the existing drainage basin in ' this location; however, the existing condition is a fully -paved asphalt surface. The 1 420 SOUTH HOWES, SUITE 202 / FORT COLLINS, COLORADO 80521 / 970.221.4158 / FAX 970.221.4159 Mr. Basil Hamdan Page.............2 Raising Cane's Chicken Fingers March 23, 2004 proposed condition will be a largely pervious surface consisting of lawn, landscaping, with only a small portion of the area being impervious to stormwater runoff. With a lower runoff coefficient, it is anticipated the amount of stormwater runoff leaving the site in this basin will be lower under the proposed conditions than under the existing conditions. The proposed stormwater quality pond will discharge into Dartmouth Road, thereby maintaining the existing stormwater discharge point for the majority of the site. The Rational method was used to calculate stormwater flows leaving the site for the existing and proposed conditions. For modeling purposes, a Rational runoff coefficient of 0.90 was assigned to the site for the existing conditions. A Rational runoff coefficient of 0.90 was assigned to the site for the proposed conditions. These calculations, along with a drainage basin area map, are enclosed in Appendix A for use during review of this report. Stormwater Detention Due to the amount of impervious surface on the site not being increased, thereby not increasing the amount of stormwater runoff leaving the site, stormwater detention is not planned for the site at the current time. An exhibit depicting the amount of existing and proposed impervious surfaces is included in Appendix A for review. Water Quality The quality of stormwater runoff leaving the site will be addressed within a proposed water quality pond that is to be constructed along the east boundary of the site. This water quality pond has been sized in accordance with criteria contained in the Urban Drainage Manual to accommodate stormwater runoff falling within the site, and will discharge into the existing drive at the northeast corner of this site, thereby maintaining the existing discharge point for stormwater runoff leaving the site. Exhibits depicting the proposed stormwater quality pond, sizing of the outlet works, the proposed location of the discharge point, and the associated stage -storage relationship are contained in Appendix B for review. If you have any questions regarding this proposed development, the information included in this report, or require additional information, please contact us at your convenience. Sincerely, Priineering Services, Inc. ORED/S C. Pq, P.E. V :�� 0'. o Project Engineer • '� Z ' 1 AttachmentsA1- I I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Appendix A Existing and Proposed Conditions t rON t I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 soon z vvl I oil 11 oil 11 Aj OR I I NCFRXW[Sr CQiMER:OF M {- FWNO 1 SURLXEBOX uAgHtED 1 LSI: ]{97 ff 111 I fl ItI �� G � I I i I � i a I i I I iI �tt 1 j li I i Il I i I kl I ST CORNER � ' I FOUND KUN. LSJR4Ev BOx NFRNEO — — — LS :I ]a9] 1 ` 20 0 20 {u 60 Fee1 ( IN FEET ) I mcN - 20 D. LEGEND: PROGENY BOUNDUN, EXISTING STORM SEWER I_}=:: .. ..._ .... ..... EXISTING STORM SEWER INIET EXISTING CONTOUR 20 — GRorosED CONTOUR GROF O CUM .0 GUTTER INFLOM (ME DETNL) PROPoSEO CURB M GUTTER (/,1�n.\ OUTFLOW (SEE OETNL) MBER A RUMOR' COEFFICIENTNU BALN SIZE. ACRES PROJECT BENCHMARK 7NCHUH6( C-322 TOM COLLINS BATUM ELEV.-496622 LOCATED 2A MILES MIUTN HANG U.S. 267 FROM ITS JUNCTION WITH STATE HIGHWAY 1{ IN FORD COLLINS. IN THE SOUTNE.LST END OF THE N=R V Cm rnErE MNCWKL OF BRIDGE NUMBER DISH OVER S .0 CREEK. 26.2' WEST OF THE CENTERLINE OF ME SOUTN BOUND VNES OF THE HIGHWAY. A LEVEL MTH THE HIGHWAY. PRELIMINARY NOT FOR CONSTRUCTION MARCH 23, 2004 ARTHUR DITCH CO. APPROVED: a nn a von, res. -_De — i APPRO ED' Gene rLiher. orney. I CALL UTILITY NOTIFICATION CENTER OF COLORADO 1-800-922-1987 OR 303- 232-1991' oEIMn"N' VLL 2 B SNESS MYS W NNNK{ BEFORE YOU DIG. GRADE, OR EX4VATE FOR ME uN6pNG OF UNDERGROUND MEMBER UTILITIES, City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: I Y ngmeer --MEe CHECKED BY: her 66 eWA <r �Hy �— CHECKED BY: ormwa r , y —pT— CHECKED BY: ar a h e<reetlon �z-C— CHECKED BY: m ngmeer �� CHECKED BY: ji Qe+sX�j_(4 fi#j,�yt{�-Ft'4i VZ g1 uccWMI fi W ==v at 'Xi CC a CCa`�r OZm zwu) „l g" F- //�/ W m W ax Z zW Q Q Q U cr Q Q Z Lll Q� Q LL Z Q tr Ifl m F I I I I I I I I I I I I I I I I 1 NORT.W J_ER1OF FOUND 31 ALU4 CAPiIN SURY BOX WALKED I I -St 17497 ALUM. BOX N OWNER XNHR LET I & 2 Sn SuRAJN SUBDIVISION REPLAT 6REC1. 9900iW36II CINDER BRICK P w w... ..... .. ... .. . .... OWNER. EXISTING Z�T z ACL �Hzns BUILDING TING ♦ w PF-1999.78 FEW - - - - - - - - - - - - - - - - - - - - - - - - - I EMSIING.SAn. SLE 4 RETAININWALL 2 00000, RETORT G MAXS AP 11.11 'AMH N S 89L57L*4' E, _222.65' (P" Wl EXTSTI.G OFn NES I ASPHALT w J _j !V WATER 4 VALK to IN Icoi < 10000' _9 PLm-'rER ',al', zl A I '��/I• AWHALI 3.4' DEPRESSION R1 WX IA.IDHKT S v ASPHALT AWHM.T RETALINING WALL HEIGHT VAMES 7' a- RETABPMG WALL C C�c RETE PAU 'COMCRETE PAD WOOD .. . ....... N89-57-54-W 249,65- as 7it ELI WCR R COMPANY EASEME A si9iei.064 I woo:09rtio- t HALL PENCE . ... BOOK 1020, PACE 37T3 30.00' 8.80.• 11}BUILDING ... . __7 SOUTH COLLEGE HEIGHTS STH BUILDING IC I 6' BLOCK RETAJNINC WALI N89"1,930"W 57.00* SOUTH COLLEGE HEIGHTS FF=5010.42 ARTHUR DITCH CO. APPROVED' e_ne a er. Prney--- Ua aEee ,IN =WN I - P11 20 0 20 AD W 1W.t IN FEET ;. . 20 11, LEGEND: PROPER', BOUNDARY EXISTING STORM MWER EXISTING STORM SEWER INUOT EXISTING CONTOUR SECTION CORNER TELEPHONE PEDESTAL 141 CAEI.E PEDEST& Gi SANITARY MANHOLE t)CKT POLE POWER POLE URUFF MANHOLE CAS ..HIER ORB PEDESTAL TELEPHONE PEDESTAL 12 WATER VALVE FIBER OPTIC ENEZILIEN't END METRIC VAULT WATER METER axamc PEEI PROJECT BENCHMARK BERCHMARK C-322 FORT COLLINS DARN ELEN.�49W.22 LOKLA7TO 2.0 MILES !LCUFH ALONG iT& 267 FROM ITS JUNCTION WITH 7 THE SOUTHEAST AREE��AIA�44 F COME. 'H THE .4" CONERET WNCWALL OF SMOGE NUMBER 916H O£ 1PRA, �EEK, AND 26.2 WEST OF THE CENTERLINE OF THE IRKITH BOUND LAMES OF THE MPMAi(. ABOUT LEMEL WITH THE XIGHWA1, PRELIMINARY NOT FOR CONSTRUCTION MARCH 23, 2004 CALL UTILITY NOTIFICATION CENTER OF COLORADO 1- 800- 922-1987 11303-232-'IM'N METRO DER"ER CALL 2 ENSNUZ DAYS IN A"'A"CE BEFORE YOD DG. CRAEE, OR EXCAVATE FOR THE MARKAMG OF UADERGR"D MEMBER UTILITIES. City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: --- — CHECKED Br CHECKED DY. CHECKED CHECKED BY: CHECKED BY 1 1 1 i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Appendix B Water Quality Exhibits ' De5ign of Dry Extended Detention Ba5in5 for Water Quality Reference: Urban Storm Drainage Criteria Manual, Volume 3 - Best Management PraCtICe5, Urban Drainage and Flood Control District, September 1999. ' Project: Raismg Cane'5 Chicken Fmger5 Water Quality Pond Location: Fort Collm5, CO 1) Determine the Required Water Quality Storage Volume: ' I . I) Determine Basin Imperviousness: Basin Parameters 1 [] L 1 t Ba5m Area (acres)= 0.99 Ba5m Imperviou5ne55 (%)= 90 Tributary Area's Imperviou5ne55 Ratio (i = la/ 100) = 0.90 1.2) Use a 40-hour detention time for extended detention ba5m5; 1.3) Determine the Water Quality Capture Volume (WQCV) from Figure ED5-2; WQCV= 0.40 watershed inches 1.4) Determine the Required Storage in ac-ft; Required Storage = (WQCV/ 12)'(Area)' 1 .2 Area = the tributary drainage area upstream of the water quality enhancement facility (ac) Required Storage = 0.04 ac-ft 2) De5tgn the Outlet Works: 2.1) Outlet Type: Water Quality Structure Built Into Wall 2.2) Determine Depth at the Outlet: From the Stage -Storage Table for Water Quality Pond, at 0.04 ac-ft; Elevation= 5002 Invert Elevation of Structure = 5000.50 Depth at the Outlet (Dwo or Hwocv, feet) = 5002-5000.50 = 2.50 ft. 2.3) From Figure ED13-3, Required Area per Row= 0.09 in 2.4) From Figure 5: Use 5/ 1 G" diameter holes drilled into 5/ 1 G" thick steel plate Space holes at 3" on -center vertically, 2" on -center horizontally, two columns wide, ten rows high Total Outlet Area, Aot = 1.50 in 1 L i ARTDITCH NCO. 1 APPRO E0: e .nn O noon, rev �Te APPRO ED ene aer. Mrney i �— (9NORTH 20 0 20 .0 bB FW IN FEET ) I loch . 20 ft. LEGEND: — — PROPERTY Wknl µY EXISTING STERN SEWER EXISTING STORM SEVER INLET PR SED STERN SEWER Fn�ffimmga� IVPa.� PROPOSEO STORM SEWER INLET .-- _,)- -.__. EXISTING CONTQIR 2O — P QSEO COTRdIR PROPOSED NRS AND CUTTER INFWW (SEE DUAL) PRJPOSE0 NRB AMD FITTER EUTFLEV (SEE DETML) Sat u OI 5 ALA SECDON srtn wo. OBt_pS GRAMEL INLET FILTER OL+yty STRN, BHE INLET PROIECTIM OC srRur a ONE O—SF— 4lT FEN(£ 3T 2"o SEGMENT TW RIPrIM gRL[T gpTECDON O (SEE DETML SHEET) pRECTICfV1 ROW ARROW PROJECT BENCHMARK BENCHMARK C-322 FORT COLLINS DATUM EI %I =.22 LOCATE. 2.0 MILES SOUM riOVG UII. 2B) FROM In J NCTIOY WIITI SLATE HIGNWAY IA N FORT COL 1 N THE SOUTNE END OF THE NGRTMWEST CpKIQT[ IINGX, L OF BRIDGE' NUMBER BIW OvER WING CREEK, AND 28.2' WEST OF THE CENTERLINE OF F E SOUIN .DUNG LINES OF THE No... ABDUT IEKL MTH THE HIGHWAY. PRELIMINARY NOT FOR CONSTRUCTION MARCH 23. 2004 CALL UTILITY NOTIFICATION CENTER OF COLORADO 1-800-922-1987 BI1303-232-iM OCM1MgRO - CM.L 2 BUVNESS an IN ADVANCE BEFORE TOJ GO. GRADE. CW EXCAVATE FOR THE MNMING OF UNDERGROUND MEMBER UDI.TES. L City of Fort Collins, Colorado UTILITY PLAN APPROVAL ROVED: I Y nemeer �ele CHECKED BY ,.ter as ewa er I y — CHECKED BY- ormwa CHECKED BY arW enreation ---Da[— CHECKED BY: ra m ngmeer �� CHECKED BY: �a[e L 9