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HomeMy WebLinkAboutCorrespondence - 41 SECOND STREET 12/18/2012 andover 1 East River Place ns ultants Methuen, Massachusetts 01844 o Tel. (978)687-3828 Fax(978)686-5100 www.aridoverconsultants.com December 18,2012 North Andover Plavirting Board Town Offices 1600 Osgood Street North Andover,MA 01845 RE: Special Permit-Site Plan Review 41 Second Street North Andover,MA Dear Members of the Board: The intent of this letter is to resp6nd to the"steep slope aimed directly at the abutting property" comment initially contained Lisa Eggleston's review letter dated December 6,2012 and reiterated in email messages from Judy Tymon,Town Planner,dated 12-12-12 and 12-17-12. The slope in question is the grading shown on the easterly side of the proposed dwelling. The grading shown is needed to comply with the"Building Height"definition of the Zoning By-Law, Section 2.27 for the structure approved by the Zoning Board of Appeals on September 27,2012,for Petition No. 2012-002. Tile grading shown proposes a two to one slope,only four feet high;with a toe that is 5 feet from the eastern side line of the property. This grading is not atypical for lot grading,and is quite common. We are unaware of any regulation prohibiting the proposed grading shown. Also,the grading does not increase the runoff from the site. As stated in our previous letter,the runoff from the site is approximately the same for pre vs.post construction conditions and there is actually a reduction in the area of the lot tributary to the neighbor on the easterly side of the lot. Should you have any questions,or require anything further,please feel free to contact our office at your convenience. Sincerely, ANDOVER CONSULTANTS,INC. James S. Fairweather 11,P.E. Project Engineer Enclosure cc Gene Espinola Civil Engineers Land Surveyors Land Planners andover 1 East River Place consultants Methuen, Massachusetts 01844 inc. TeL (978) 687-3828 Fax (978) 686-5100 D cember 11, 2012 www.andoverconsultants.com North Andover Planning Board Town Offices 1600 Osgood Street North Andover, MA 01845 RE: Special Permit-Site Plan Review 41 Second Street North Andover, MA Dear Members of the Board: We are in receipt of review comments from Lisa D. Eggleston,P.E. of Eggleston Environmental made in her review of the proposed project and offer the following in response to her comments. Comment 1: The Site Plan Review regulations require that runoff from the site be mitigated to zero for the 2, 10 and 100 yr storm events. Based on the drainage calculations submitted, the proposed plan will reduce the peak rate of runoff toward the property to the north, and will result in an overall decrease in the volume of runoff discharged from the site. I do note, however, that the calculations indicate an approximately 10 to 25 percent increase in the peak rate of runoff toward the property to the east of the site (Colby Commons). I also note that the proposed grading on the east side of the proposed byi/ding calls for a steep slope aimed directly at the abutting property. I recommend that the kr ding in this area be revised to retain more of the runoff onsite. Response: As noted above,the volume of runoff, in the developed condition,has been reduced to be less than the existing condition-volume. The increase in peak rate is minimal and,in our opinion, negligible for the 2 (+0.01 cfs) 16 (+0.03 cfs) and 100 (+0.04cfs)year events. Comment 2: As proposed, only the roof drainage from the front of the building will be directed to the infiltration system. It is not clear from the plan whether the back of the building will have gutters and, if so, where they will discharge. j Response: The rear roof will have gutters and downspouts that discharge onto the lawn at the rear of the building. Comment 3: Based on the soil d(;ta submitted, the proposed infiltration bed has two feet of separation to the estimated high,'p',oundwater elevation and is adequately sized to capture and infiltrate the 100 year storm eve;d, The ongoing functionality and longevity of the system will depend on how well the proposed catchbasin functions to prevent sediment from entering the infiltration bed. Provision should he made for regular inspection and cleaning of the catchbasin and periodic sweeping of the parking lot,particularly in areas of snow stockpiling. Response: We have attached a sug,-gested maintenance program for the drainage system and parking lot for your review. Civil Engineers Land Surveyors Land Planners andover copsultants Mc. Should you have any questions, or require anything further, please feel free to contact our office at your convenience. Sincerely, ANDOVER CONSULTANTS, INC. _M; rN MWACS James S. Fairweather 11, P.E. Project Engineer Enclosure cc Gene Espinola Operation and Maintenance Plan 41 Second Street North Andover, Massachusetts 1. The infiltration structure and the catch basin sediment sump, and vane grates shall be owned and operated by a condominium association created among the unit owners. The association shall be responsible for the operation and maintenance of the drainage facilities. 2. The association, or its designated agent, shall inspect the stoimwater management system 4 times per year, including visual inspection catch basin sediment sump and roof downspouts. The association shall ensure that no portion of the stormwater management system is damaged, blocked or otherwise in a state that prevents its proper operation. 3. The association shall ensure that accumulated silt and debris within the catch basin is removed in a timely manner. The catch basin shall be cleaned when the sediment reaches a depth of 2 feet within the sump (1/2 depth of sump) and cleaned at least annually in the spring following winter sanding. 4. Illicit discharges are to be prohibited. The property Owner shall report any illicit discharges once discovered-to the North Andover Police and Health Departments. 5. The association should have the parking area swept of sand and debris after the winter sanding season. It is recommended that the parking lot be swept more often, as needed, if sediment and debris is visually present.