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HomeMy WebLinkAboutNATHAN'S SUBDIVISION, 637 COWAN STREET - PDP/FDP - FDP130030 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFORBES ENGINEERING Full Service Civil & Structural Engineering February 25, 2013 Glen Schlueter City of Fort Collins Stormwater Engineering 700 Wood Street Fort Collins, CO 80521 RE: Grading & Drainage Certification Letter for site improvements at 429 So Whitcomb St. Fort Collins, CO 80521 Mr. Schlueter, This letter and attached exhibits are to serve as a drainage certification for the above referenced single family residential property. The property is located at the Southeast corner of South Whitcomb and West Mulberry. The home was originally built in approximately 1910 and presently has one single family residence and a detached garage/outbuilding on the property (see attached existing grading plan). The surrounding neighborhood is a mix of small business and single family residential lots. Proposed site improvements include an 828 square foot garage addition to the existing home along with a 572 square foot carriage house. Site improvements will also include 1143 square feet of concrete to be used for drives and walks. The spot elevations and contours for both the existing and proposed grading & drainage plans are based on survey data provided by Edmonds Land Surveying, Inc. dated May 18, 2012. Historic storm water runoff presently is directed towards the street gutter systems of both Whitcomb (front yard) and Mulberry (south side yard). This will be maintained with the proposed improvements using roof gutters and downspouts to direct the storm water runoff towards the south and east and into the street gutter system (see attached proposed grading plan). Any necessary erosion control measures will be provided at the time of construction including, but not limited to, 2 the provision of perimeter silt fencing and a vehicle tracking control mat if necessary. Both the garage addition and carriage house will be constructed with a finished floor elevation 18 inches above the corresponding base flood elevation (BFE) as defined by the City of Fort Collins Flood Plain maps. It is my conclusion that with proper construction practice and observance to the set finish floor elevation, no adverse affects to the site or to the surrounding properties are anticipated from the proposed improvement of this site. Sincerely, _______________________ Kevin Forbes, P.E. #35265