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HomeMy WebLinkAboutHARMONY VILLAGE PUD - PRELIMINARY - 65-93C - CORRESPONDENCE - Stormwater Related DocumentsMr. Basil Hamdan October 19, 1998 Page 2 for use as a detention area and a drainage easement was dedicated on the Final Plat for Harmony Crossing P.U.D. We appreciate your time and consideration in reviewing these points. If you have any questions or comments, or need additional information, please do not hesitate to contact us. Thank you. Sincerely, A ENGINEERING, LTD. Reviewed by, David W. Klockeman, .E. Project Manager cc: Ty Fangman, Dial Properties Linda Ripley, VF Ripley Associates Ted Shepard, City of Fort Collins Current Planning Department JREngineering, L 2620 East Prospect Rd. Suite 190 Fort Collins, Colorado 80525 (970) 491-9888 • FAX (970) 491-9984 www.jreng.com October 19, 1998 Mr. Basil Hamdan City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80521 RE: Preliminary Approval for Harmony Village P.U.D. Dear Basil: Sh-� uhao This letter is in response to our meeting on August 28, 1998 regarding approval of preliminary plans for Harmony Village P.U.D. As discussed in this meeting, two items need to be addressed before final construction plans are submitted. The first is the runoff "C" coefficients and percent impervious values that were used in the storm water runoff calculations and the SWMM model. The second was determining if off -site runoff would be blocked by the Harmony Village development, and if any off -site grading was necessary on the west side of the property adjacent to the existing warehouse. We have reevaluated the percent impervious value for the entire site and found that 67 percent impervious is more realistic than the 65 percent impervious that was used in the Preliminary Drainage Report. This value along with a revised basin width and an updated storage -discharge curve for the proposed detention pond was incorporated into the most recent SWMM input file for the McClellands Basin, which was obtained from your office. The results of the SWMM run indicate that there would be no negative downstream impacts from the development of Harmony Village P.U.D. With the final drainage report, runoff "C" coefficients will be calculated for each subbasin based on the relative areas of parking, building, landscape etc. Final design for the storm drainage system including pipes, inlets and swales will reflect these updated "C" values. Runoff from the warehouse property will not be blocked by the Harmony Village P.U.D. Stormwater runoff from the warehouse site will continue to flow to the south and west along the warehouse property line to outfall onto the railroad as it has done historically. A concrete trickle pan and culvert pipe will be installed on the Harmony Village property as these flows currently enter our site in route to the railroad property. No off -site grading is required in this area. Off -site grading will be required in the southeast corner of the Harmony Village property for the proposed detention pond. This area was intended 4935 North 30th Street 6020 Greenwood Plaza Blvd. 704 Fortino Blvd. West Colorado Springs, Colorado 80919 Englewood, Colorado 80111 Pueblo, Colorado 81008 (719) 593-2593 • FAX (719) 528-6613 (303) 740-9393 • FAX (303) 721-9019 (719) 583-2575 • FAX (719) 583-8119