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HomeMy WebLinkAboutDrainage Reports - 02/11/2019 (2)A0VAN0E0 ENGINEERING, LLC STRUCTURAL DRAINAGE DRAFTING July 23, 2018 Ck of Fo Collins Approv d Plans Ms.. Beth Gulley 726 Laporte Avenue Approved by: _ Ft. Collins, CO 80521 Date: ?�,/yo(q RE: Site Drainage at Parcel #9610400006, Ft. Collins, Colorado Advanced Engineering, LLC Project Number 3185-01-01B.1 Dear Ms. Gulley: We have consulted with you regarding a new custom home that is proposed to be constructed at the above referenced site. The home is to have one story over a crawl space, with an attached garage and shop. Our office has reviewed the existing and proposed drainage conditions at the site.. This review included visual observations at the site, review of a topographic elevation survey of the site, and area calculations. The purpose for this review was to evaluate the impact of the proposed project on existing drainage conditions. The site is 17.9 acres, predominantly native grass, and gently slopes. to the southeast corner (the Fossil Creek drainage)., The home. is proposed to be built in the north central portion of the site, at the high side of the lot. A swale will be constructed around the north side of the home to direct runoff away from the home. Beyond the home site, all flow will travel along existing natural drainage paths across the lot in sheet flow through the native grasses, there will be no new point sources of flow. All off -site flows that enter the lot will continue to flow across the site, as they have historically. Please refer to our Drainage Plan, Project Number3185-01-01B; which shows our recommendations for the swale and specifies an elevation for the top of foundation. Based on our review, the area of the house and concrete parking pads and gravel :driveway is less than 3% of the site. This is far less than the 15% impervious area assumed by the Ft. Collins Master Plan for the Fossil Creek Basin. Given this, it is our opinion the proposed construction will have a negligible impact on existing drainage conditions. We feel the drainage will continue to function as it has historically. We do not feel any mitigation or large scale grading of the site are needed. The recommendations and conclusions presented in this letter are based on a review of the described site, your plans and your directions. Our review was limited to the items described in this letter, and is not intended to cover structural, mechanical, electrical, environmental, mold; or architectural features of the site/buildings. Discrepancies or deficiencies revealed during construction should be brought to the attention of the engineer. If you have any questions, please feel free to call. Sincerely, Advanced / Jason E. Bakerr,, P.E. 229120 Sfi*N(Wj�61e RQt`L�olorado 80537 Telephone 970-278-1909 AE-GP2WV •: kBdC.• 8004 I780