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HomeMy WebLinkAboutRAINTREE ANIMAL HOSPITAL - PDP/FDP - 22-98A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTJ) 4�.-1.aaipe.J.v.._: aa' a+ a e I Hobbit St. LLB. 1 th POL ��la9e p} i INC.0 �j , s�-�• �.-..L Qt ' of Ed ew c� — - '- �P�� _ctg 1?i, __..._..... "fci_ I of Q �� l 5i ' �� f in r�( L., CI d w� o and Dr ell ' I-ClEa d {t' Sande in � . Ctr. o+rmer Ct br� at N POLI .ecar or C. c,Br:. o��t novel :.. Gten �u3II_Di.�� Wa oneM I Di. Q �tWischekler�.. ., c sa "Y owl OrII D-43 i st.I MMN Aq —_� ' ILL awl ' . t D 1f a Cp of Froatlei tF ..' N. W Sya1 is rn am' I o>iz@LCE LI t 14L} Oft f ra i d . 'a .�: i� �?'�J.'� • de' t • .�� 't.> c3,•, Ti� � 1, .1.'.:.�/!r.�. .. ..:.� A .•. r P EROSION CONTROL: The site is in the moderate wind erodibility zone and in the high rainfall erodibility zone. A silt fence will be constructed along the North, East and West property lines. Straw bales will be placed at the area inlet after the discharge pipe is constructed for the time interval until the water quality outlet tower and riser pipe are constructed and the gravel filter is placed. The entire site will be disturbed with the grading. The basement foundation will be constructed as soon as the site is graded. A water quality outlet for a dry extended detention basin will be constructed. The storm water runoff calculations, the erosion control calculations, the extended erosion control calculations and the Grading, Drainage and Erosion Control plan are enclosed as a part of this report. This drainage report and the design of the drainage system are in compliance with the City of Fort Collins Storm Drainage Specifications and Criteria. If you have any questions regarding this report, please call. 1 Sincerely, Richard A. Rutherford, P.E. L.S. RAR/meh STEWART$,ASSOCIATES Consulting Engineers and Surveyors November 16, 1999 Mr. Basil Hamdan Fort Collins Utilities City of Fort Collins P.O. Box 580 Fort Collins, CO 80522-0580 1 Dear Basil, The following is the final storm drainage report for the Raintree Village Animal Hospital P.D.P. situate in the Southeast 1/4 of Section 22, Township 7 North, Range 69 West of the 6th P.M., Fort Collins, Colorado. The site is bounded on the North by Evenstar Court, on the East by South Shields Street, on the South by a metes and bounds parcel with a single family residence and on the West by the Fort Collins Senior Center P.U.D. The site is in the Spring Creek Drainage Basin. The site contains 0.36 acres more or less. It slopes from South to North at an approximate slope of 4.3%. The ground cover is existing dryland grass and weeds. The historical drainage condition is to runoff into the South gutter of Evenstar Court and then East to existing curb inlet on the South side of Evenstar Court, 70 feet West of Shields Street. The inlet discharges North and Northwesterly to Spring Creek. The proposed site plan will have the Raintree Village Animal Hospital and its parking lot. The ' parking lot will have an access from Evenstar Court and an access through the Fort Collins Senior Center P.U.D. to Raintree Drive. ' It is proposed to provide onsite detention in the parking lot and in a grass area at the Southwest corner of the site. The extended detention for water quality will be in the grass area. There will be an area inlet box in the extended detention area with an overflow grate at elevation 5051.54, which is the highwater line of the extended detention. The area inlet will have a vertical restriction plate in the bottom of the inlet over the 12 inch R.C.P. storm drain which will discharge ' into the Fort Collins Senior Center existing stoi-mdrain at a new manhole. The existing Senior Center drainage system discharges to Spring Creek, West of the Senior Center. The release rate from the detention area is at the two year historic runoff rate from the site, which was calculated by the ' Rational Method. The detention volume was calculated as the difference between the two year historic runoff rate and the 100 year developed. runoff rate, using a mass diagram. The release rate is 0.17 cubic feet per second and the required volume of detention for the site is 2,838 cubic feet. The amount of detention provided is 3171 cubic feet to a high water line of 5052.75. James H. Stewart and Associates, Inc. 103 S. Meldrum Street P.O. Box 429 Ft. Collins, CO 80522 970/482-9331 Fax 970/482-9382 TABLE OF CONTENTS 1-2 Text of Report 3 Vicinity Map 4-9 Storm Water Runoff and Detention Calculations 10-11 Senior Center Drainage Table 12-15 Erosion Control Calculations 16-19 Extended Detention Calculations Pocket Grading, Drainage & Erosion Control Plan J FINAL DRAINAGE REPORT FOR RAINTREE VILLAGE ANIMAL HOSPITAL P.D.P. SPRING CREEK DRAINAGE BASIN PREPARED FOR RAINTREE VILLAGE ANIMAL HOSPITAL NOVEMBER 16, 1999 PREPARED BY STEWART & ASSOCIATES 103 SOUTH MELDRUM STREET P.O. BOX 429 FORT COLLINS, CO 80522 TEL. 970-482-9331 FAX. 970-482-9382