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HomeMy WebLinkAbout2013-09-03 Planning Board Supplemental Materials (12) 1114 I4. III II 1114 �IIII liii a In e ri t a IIII August 7, 2013 North Andover Planning Board 1600 Osgood Street North Andover, MA 01845 Attn: Judy Tymon, Town Planner RE: Stormwater Review 158 Dale St WSP Dear Ms. Tymon and Board Members: Per your request, I have conducted a technical review of the July 18, 2013 Watershed Special Permit Application packet submitted by Christiansen & Sergi, Inc. for the above- referenced project. Included in the materials I received and reviewed were the following: • Watershed Special Permit Application, 158 Dale Street, Kevin McLellan, Petitioner, prepared by Christiansen & Sergi, Inc. and dated July 18, 2013. • Watershed Special Permit Site Plan, 158 Dale St, (2 Sheets) prepared by Christiansen & Sergi, Inc. and dated July 18, 2013. My primary focus in this technical review is on the overall stormwater management approach and design concepts used in the project and its compliance with the Town of North Andover's zoning requirements for Watershed Protection Districts. The proposed project entails the construction of a patio and extension of a stone driveway to serve an existing single family home on the property. The lot was created after October 24, 1994 and is wholly within North Andover's Watershed Protection District. The proposed patio and a portion of the driveway extension are within the Non-Discharge Zone, and the remainder of the driveway extension is in the Non-Disturbance Zone. No work is proposed within the Conservation Zone. My comments on the proposed plan are outlined below: 1. The proposed 1407 sf patio with polymeric sand infill will be largely impervious, however this is adequately mitigated by the proposed infiltration of 1533 sf of roof area from the existing house. 2. Roof drain overflows should be directed onto pervious areas with minimal slope to promote infiltration and prevent scour. 3. Additional information is needed on the proposed gravel drive extension, specifically what type of stone is to be used. My concern is that the portion of the 32 C 2 II7 �.�1776 toll 508 259.1137 fax 866 820 7840 ...�q6 IC::uITuinliu"� Il� uin IC:�6 ��u"�li� 22 611u.suIT 1155 Dae Strect WY1, Stormwater 1aeva w A August 7, 2013 drive to the rear of the existing structure is fairly steep, hence the driveway could be prone to erosion. Runoff from gravel roads can be a significant source of sediment and nutrients to downgradient water resources, particularly when gullying occurs. I appreciate the opportunity to assist the North Andover Planning Board with the review of this project, and hope that this information is suitable for your needs. Please feel free to contact me if you or the applicants have any questions regarding the issues addressed herein. Sincerely, EGGLESTON ENVIRONMENTAL Lisa D. Eggleston, P.E.