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Home My WebLink AboutFORT COLLINS MUFFLER - PDP/FDP - 24-97 - REPORTS - DRAINAGE REPORTfill aaaaaa. 1 f 1►�` f •. .. r. yio c■o c.o rtJ ca r. Sri • r FYI/ . - 1 C Yf A u l� 7jo rr Inrs ra0"I: ::_ ;.ME r: ll' t11:11e11'_ .r....op i�rm- ee.• i 0, ■t11 ie./ :IIIIIil:llllll:r��! �'.,t�l�■� 1 I :' k •�FF Y' -•®'i low sae ., i�s,.,a,CON ,. ■ ■ mosm anlr.� u '�d R11^ 'n n'Iftii� [L!L or ;Li o no n �.- v "o, rNtA' W a `von. - L� ) The developed site was divided into Sub -Basin "A" and Sub -Basin `B". The runoff from the two Sub -Basins includes the area of half of Spring Court and the area of half of Johnson Drive. EROSION CONTROL: The site is in the high rainfall erodibility zone and in the moderate wind erodibility zone. There is 0..12 acres of existing asphalt and walk that will not be disturbed and 0.14 acres of bare soil. The foundation will be constructed as the first task on the site and it will contain 0.11 acres. The required effectiveness is 74.6%. The effectiveness that is attained is 84.7%. A silt fence will be placed along the West and.North property lines. A 20 foot wide opening will have to be left open for access to the site for construction. If any silt fence is disturbed it must be replaced daily. A gravel filter shall be constructed at the existing curb inlet. Any mud that is tracked onto Spring Court or Johnson Drive must be removed daily. The runoff calculations, erosion control calculations and the grading and drainage plan are included as a part of this report. This drainage report and the design of the drainage system were made in substantial compliance with the City of Fort Collins Storm Drainage Design Criteria and Construction Standards. If you have any questions during your review of this report, please call. Sincerely, G- a C2'7QLVa Richard A. Rutherford, P.E. & L.S. 5028 A 1.• •' x STEWARr&ASSOCATES Consulting Engineers and Surveyors A■ November 4, 1997 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 Lots 9 and 10, Spring Court Subdivision. The site contains 0.2870 acres and is in the Spring Creek Major Drainage Basin. The site is bounded on the North by Johnson Drive, on the West by a commercial building that faces South College Avenue, on the South by an existing duplex that faces Spring Court and on the West by Spring Court. Lot 9 has an existing house and Lot 10 has an existing duplex. The West half of the lots historically drain to Spring Court and then North in Spring Court and East in Johnson Drive to an existing curb inlet on the South side of Johnson Drive. The East half of the lots have a gravel surface and do not drain off the site. The front yards of the house and duplex are turf It is proposed to remove the two existing structures which were severely damaged in the July 28th major storm An automotive muffler shop will be constructed on the two lots. As in the historic condition the West half of the site will continue to drain West to the East gutter of Spring Court and then North to Johnson Drive and East to a relocated curb inlet. The East half of the lot will drain North thru the paved parking lot to the two relocated curb inlets. There is a low area near the Southeast comer of the site that will not drain out to Johnson Drive and cannot be raised in order to drain Northerly. Therefore an area inlet will be constructed at the low point which is offsite and a 12 inch diameter storm drain will be constructed to a new manhole which will replace the one existing curb inlet. The existing curb inlet is being relocated to two curb inlets because it falls in the driveway into the site. The two inlets will flow to the new manhole and then Northerly across Johnson Drive in the existing storm drain to Spring Creek. The two year runoff from the site historically is 0.31 c.f s. and when developed becomes 0.84 c.f.s.. The 100-year runoff historically is 1.19 c.£s. and when developed would be 2.07 c.fs.. Due to the close proximity to Spring Creek, there will not be onsite storm water detention provided. 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 4-8 Storm Water Runoff Calculations . 9 - 12 Erosion Control .Pocket Grading, Drainage and Erosion Control Plan FINAL DRAINAGE REPORT FOR LOTS 9 & 10, SPRING COURT SUBDIVISION SPRING CREEK DRAINAGE BASIN PREPARED FOR JIM DWYER NOVEMBER 4,1997 PREPARED BY STEWART & ASSOCIATES, INC. 103 SOUTH MELDRUM STREET FORT COLLINS, COLORADO 80521 970/482-9331