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HomeMy WebLinkAboutSite Certifications - 11/09/2006 (2)November 9, 2006 Mr. Basil Hamdan City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 Re: Pond Certification for Cooler Spring Canyon Community Park Dear Basil, We recently received survey for the Spring Canyon Community Park regional detention pond located on Horsetooth Road in Fort Collins. Spot elevations were checked and as-built contours drawn to verify that the pond was constructed with the proposed volume . The attached drawing shows as-built contours. Observations during the site visit in combination with the attached as-built elevations verify the needed volume of 51 acre-feet was provided. Pond volume calculations based upon field survey of the constructed condition are attached to this letter. They indicate a constructed pond volume of 51.8 acre feet. Thus, the constructed pond surpasses the approved pond volume requirement. In addition, a positive slope is maintained to the outlet point of the pond and the grate was set at the design elevation of 5109.5. It is my recommendation that this pond construction is certified. If you have any questions, please call. Sincerely, ric . Lessard, P.E. Project Manager EPL: sp Enclosure Ayres Associates Inc Engineers/Scientists/Surveyors 3665 JFK Parkway, Building 2, Suite 200, P.O . Box 270460, Fort Collins, CO 80527 (970) 223-5556, FAX (970) 223-5578 Printed on recyded paper ELEV. ft. 5109.75 5110 .0 5111.0 5112 .0 5113.0 5114.0 5115 .0 5116 .0 5117.0 5118 .0 5118 .6 4990 .5 4990 4989 .5 4989 ;s:: 4988 .5 -~ 4988 ~ 4987 .5 Cl> w 4987 4986 .5 4986 4985.5 4985 AREA sq.ft. 0 10256 40320 82146 138447 215686 289008 364183 455620 590921 679664 AS-BUil T POND RATING CURVE Description: Pond 838, Pond A SURFACE DELTA DEPTH AREA VOLUME ft . Acres Acre-feet 0.00 0.000 0.020 0.25 0 .235 0 .543 1.25 0.926 1.378 2.25 1.886 2 .504 3.25 3 .178 4 .032 4 .25 4 .951 5.773 5.25 6.635 7.481 6.25 8.360 9.390 7.25 10.460 11.979 8 .25 13.566 8 .743 8 .85 15 .603 Stage Volume Curve CUM. VOLUME Acre-feet 0.000 0.020 0.562 1.940 4.444 8.476 14.249 21 .730 31.120 43.099 51.843 L---------------__.,- / V / I I 0 .0 2.0 4 .0 6 .0 8 .0 Volume, ac-ft 10.0 12.0 14 .0 CUM. VOLUME Cf 0 855 24492 84498 193577 369223 620679 946552 1355603 1877412 2258278 - 16.0