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HomeMy WebLinkAboutKMART PLAZA, FULLER'S TEXACO - PDP - 38-97A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT3 VICEN rY Mar requirements. The remainder of the site will be disturbed for the new grading. The foundations for the convenience store and car wash will be constructed soon after the asphalt is removed. The runoff calculations, the erosion control calculations and the erosion control cost estimate are enclosed as a part of the report. The Grading, Drainage and Erosion Control Plan is also enclosed. 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. Sincerely, Richard A. Rutherford, P.E. & L.S. meh Fry. 5028 00 a� STEWAU&ASSOC[ATES Consulting Engineers and Surveyors IFebruary 3, 1998 Mr. Basil Hamdan Storm Water Utility City of Fort Collins P.O. Box 580 Fort Collins, CO 80522 Dear Basil, The following is the Final Drainage Report for Fuller Texaco which is a 0.59 acre site in K- Mart Plaza. The site is located in the existing K-Mart parking lot. The site is being developed for a convenience store with gasoline pumps and a car wash. The site is directly West of the existing Jiffy Lube at the Northwest comer of South College Avenue and Drake Road. There will be cross access between the site and the Jiffy Lube site. The existing site is existing asphalt and landscaped islands. The site drains from South to North to an existing area inlet. The runoff sheet flows to the inlet. There is an area West of the site that also drains to the existing inlet. The historic runoff coefficient for the site is 0.85 and the historic runoff rates are Q 2yr = 1.50 c.f s., Q 10yr = 2.15 c.f s. and Q 100yr. = 4.23 c.f s. The developed runoff coefficient for the site is 0.91 and the developed runoff rates are Q 2yr = 1.71 c.f s., Q 10yr = 3.00 c.f s. and Q 100 yr. = 4.23 c.f. s. The storm drainage specifications require that on site detention of the runoff between the two year historic rate and the 100 year developed rate be provided. The historic and developed 100yr. Rate of runoff are the same. Therefore we are not proposing to have on -site detention. None of the K Mart Plaza has on -site storm water detention. The capacity of the area inlet grate is 6.05 c.f s. The storm drain out of the inlet is a 15 inch diameter corrugated metal pipe with a slope of 0.45%. The capacity of the storm drain is 2.3 c.f s. EROSION CONTROL: The site is in a moderate rainfall and wind zone. A silt fence will be placed along the North, East and South sides of the Fuller Texaco site. A gravel filter will be placed around the existing area inlet just North of the site. 7,500 square feet of gravel base will be retained on the site for a staging area and to meet the erosion control effectiveness James H. Stewart and Associates, Inc. 103 S. Meldrum Street P.O. Box 429 Ft. Collins, CO 80522 970/482-9331 Fnv a7niaA9-a.gA9 Table of Contents 1 - 2 Text of Report 3 Vicinity Map 4 - 6 Runoff Calculations 7 - 10 Erosion Control Calculations Pocket, Grading, Drainage & Erosion Control Plan r ri 1 1 i 11" FINAL DRAINAGE REPORT FOR FULLER TEXACO IN SPRING CREEK BASIN I PREPARED FOR RALPH FULLER FEBRUARY 3, 1998 PREPARED BY STEWART & ASSOCIATES, INC. 103 SOUTH MELDRUM STREET FORT COLLINS, COLORADO 80521 970/482-9331