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HomeMy WebLinkAboutDrainage Reports - 02/23/2017y INT¢RW¢8T C O N S U L T I N G G R O U P February 10, 2017 City of Ft. Collins Approved Plans Mr. Wes Lamarque Approved By City of Fort Collins Stormwater Date Q- — 7 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage Report for Harmony Commons Subdivision Minor Amendment Memo #1 Dear Wes, A Minor Amendment was submitted for Harmony Commons in January, 2017. A part of this amendment to the Site Plan was the addition of four (4) small patios on Lots 3 and 4. Your review comments request a memo discussing the impervious area added by these patios. Lots 3 and 4 are a part of Basin G in the approved drainage report for the overall subdivision. Much of the proposed patio area is proposed under roof overhangs, so there is no increase in imperviousness in these areas. The total area of new pavement where there was pervious area is 2,200 SF. Basin G is 51,412 SF, so this 2,200 SF is a 4% increase to the imperviousness of this sub -basin. It is more appropriate to look at the overall project site in this PDP/FCP (Lots 3, 4, and 5). These lots are basins A through H and 5.73 acres. When looking at these patios compared to the overall project area, the 2,200 SF increases the impervious percentage 0.9%, which is negligible. The original approved drainage design for Harmony Commons is not impacted by this small impervious addition. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, ' C�� •.......••• Ply' Michael Oberlander, P.E., LEED AP Colorado Professional Engineer No. 34288 1218 W. ASH, STE. A, WINDSOR, COLORADO 80550 TEL. 970.464.8488 INTGRWISST CONSULTING -GROUP February 10, 2017 Mr. Wes Lamarque City Oft Collins ppr d Plans City of Fort Collins Stormwater Approved By 700 Wood Street {jam@ .• — 6 Fort Collins, CO 80522-0580 RE: Final Drainage Report for Harmony Commons Subdivision Minor Amendment Memo #1 Dear Wes, A Minor Amendment was submitted for Harmony Commons in January, 2017. A part of this amendment to the Site Plan was the addition of four (4) small patios on Lots 3 and 4. Your review comments request a memo discussing the impervious area added by these patios. Lots 3 and 4 are a part of Basin G in the approved drainage report for the overall subdivision. Much of the proposed patio area is proposed under roof overhangs, so there is no increase in imperviousness in these areas. The total area of new pavement where there was pervious area is 2,200 SF. Basin G is 51,412 SF, so this 2,200 SF is a 4% increase to the imperviousness of this sub -basin. It is more appropriate to look at the overall project site in this PDP/FCP (Lots 3, 4, and 5). These lots are basins A through H and 5.73 acres. When looking at these patios compared to the overall project area, the 2,200 SF increases the impervious percentage 0.9%, which is negligible. The original approved drainage design for Harmony Commons is not impacted by this small impervious addition. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, Michael Oberlander, P.E., LEED AP Colorado Professional Engineer No. 34288 1218 W. ASH, STE. A, WINDSOR, COLORADO 80550 TEL. 970.464.8488