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HomeMy WebLinkAboutDrain Narrative 2024-0306 WENTWORTH CIVIL ENGINEERS LLC 177 West Town Street Lebanon, Connecticut 06249 Tel. (860) 642-7255 Fax. (860) 642-4794 Email: Wes@WentworthCivil.com March 6, 2024 Sara Lundy, Chair Montville Planning & Zoning Commission 310 Norwich-New London Tpke Uncasville, CT 06382 Re: Black Ash Estates Re- Subdivision Black Ash Rd. and Old Colchester Rd. Montville, CT Dear Sara: I am writing to you in regards to your above referenced 13 lot subdivision. The subdivision layout has been designed to minimize potential onsite and offsite drainage impacts due to development. The lot design encourages overland sheet flow in three major directions (see attached Overall Drainage Map for reference). The western portion of the site slopes to a large onsite wetland system that drains southerly via culverts under Black Ash Road. Similarly, the central portion of the site also drains to a large onsite wetland that also discharges southerly via culverts under Black Ash Road. The eastern portion of the site slopes southeasterly towards abutting properties that front on the north side of Black Ash Road. Design elements included in the creation of this development include minimizing impervious areas, maximizing wooded areas, keeping wetlands and upland review areas undisturbed and in their existing vegetated state. Other low impact design elements include and encouraging runoff via overland sheet flow and maximizing infiltration within these areas. All proposed roof downspouts are to discharge into underground infiltration drywells. All storm runoff from driveway areas are to be treated in infiltration trenches or rain gardens. These Low Impact Development design features will treat pollutants, maximize infiltration and discourage point discharges of storm water runoff. The re-subdivision design plans include a site specific erosion and sedimentation control plan, design calculations for rain gardens and infiltration trenches, and a long term operation and maintenance plan for these design elements. It is my professional opinion that the development of this project as designed will not result in any significant impacts to drainage flows onsite or offsite. If you have any comments or questions, please do not hesitate to contact me. Sincerely, Wesley J. Wentworth P.E. , Soil Scientist WENTWORTH CIVIL ENGINEERS LLC TEL. (860) 642-7255 FAX (860) 642-4794 web: wentworthcivil.com 177 WEST TOWN ST. LEBANON, CT 06249W