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HomeMy WebLinkAboutSCARPELLA SUBDIVISION, REPLAT OF LOT 3 - PDP/FDP - 27-00 - REPORTS - DRAINAGE REPORTVICINITY MAP SC4LE - IIt- 1000• Plum Street Plum Street West Sizat etn Street o Aver�e Cleo o g O � G West Lake Street Everg n Ori SITE lb g West Prospect Road �+ oiro� -oo 1 m Q 0 Q 1 water quality control procedures. There should be no erosion control measures required for the construction of the single family residence on a lot with an area of 7553 square feet. The storm drainage calculations and procedures provided and proposed for this project are in compliance with the City of Fort Collins Criteria. Sincerely, �►= 4502 Phillip I. Robinson, P.E. & L.S. ,o PIR/meh a I STEWART&kSSOCIATES Consulting Engineers and Surveyors October 18, 2000 Mr. Basil Hamdan Stormwater Utilities City of Fort Collins P.O. Box 580 Fort Collins, CO 80522-0580 Dear Basil, RE: Replat of Lot 3 of the Scarpella Subdivision Mr. Ivfichael Scarpetla owns Lot 3 of the Scarpella Subdivision which is located at 2400 West Prospect Road. Lot 3 extends from Prospect Road on the South to Evergreen Drive on the North, and there is an existing house and a detached garage located on the South part of the lot. Mr. Scarpella desires to divide the lot so that the vacant North portion of Lot 3 can be made into a separate residential lot which will face North onto Evergreen Drive. The proposed new lot drains Northerly to Evergreen Drive, and also the North portion of the existing residence drains to Evergreen Drive. The South portion of Lot 3 drains Southerly to Prospect Road. The drainage South to Prospect Road will not be changed by the proposed development. The North portion of the South lot, which includes the North half of the roof and the rear yard, will drain across the new North lot to Evergreen Drive. This is the historical drainage pattern. An eight foot drainage and utility easement will be dedicated over the East side of the North lot to provide a path for this offsite flow. The drainage basins and flow patterns are shown on the utility and grading plan included in this report. Lot 3 is located in the Canal Importation Basin, and the developed percent imperviousness used in the calculations for this basin is 45 percent. The calculated developed percent imperviousness of the North basin, which includes the North part of the existing house and garage, the proposed new residential construction and .the pavement to the center of Evergreen drive, is 45 percent, and the percent imperviousness of the South basin, which includes the South part of the existing house and garage and the pavement to the center of Prospect Road, is 41 percent. Since the percent imperviousness of the proposed development is not greater than that used for calculations in the Canal Importation Basin, a variance is hereby requested from the requirement of on -site detention. Also, a variance is requested from the requirement for on -site 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 Cover Letter and Teat 3 Vicinity Map 4 Imperviousness of South Basin 5 Imperviousness of North Basin 6 Runoff Calculations 7 Runoff Calculations 8 Swale Calculations Pocket Utility and Grading Plan M DRAINAGE REPORT FOR THE REPLAT OF LOT 3 OF THE SCARPELLA SUBDIVISION LOCATED IN THE CANAL IMPORTATION BASIN PREPARED FOR MICHAEL SCARPELLA PREPARED BY STEWART & ASSOCIATES 103 SOUTH MELDRUM STREET P.O. BOX 429 FORT COLLINS, CO 80522 TEL. 970-482-9331 FAX. 970-482-9382 OCTOBER 18, 2000