Loading...
HomeMy WebLinkAbout2013-06-18 Planning Board Supplemental Materials (25) 1 East River Place er Methuen, Massachusetts 01844 /�7oovd nsultants rel. (978)Massachusetts 01828 In C. Fax(978)686-5100 www.andoverconsultants.com June 10,2013 North Andover Planning Board Town Offices 1600 Osgood Street North Andover,MA 01845 I RE: Watershed Special Permit 1665 Great Pond Road Ladies and Gentlemen: We are in receipt of review comments made by your consultant,Ms. Lisa Eggleston,P.E.,for the project captioned above,contained in her letter to the North Andover Planning Board dated May 20, 2013. Five copies of the revised plan revision dated June 3, 2013 are attached. The plan was revised in response to the review comments are as noted below: I Comment 1. The proposed development activity is located within Non-Disturbance and Non- Discharge Zones of the.Watershed District. It is my understanding that this lot was created before October 24, 1994, hence the limitations of the General Zone of the Watershed Protection District li regulations do not apply.As shown, the project includes clearing, grading and construction of a paved driveway and associated drainage structures within the Non-Disturbance Zone and construction of a new house within the Non-Discharge Zone. Regrading and vegetation removal are allowable in the Non-Disturbance Zone only by Special Permit. Construction of a new permanent structure within the Non-Disturbance Zone is also allowed only by Special Permit and only after a variance has been granted by the Zoning Board of Appeals. I believe that a driveway would be considered a permanent structure under the Town's Zoning Bylaw,, therefore a variance from the ZBA is needed for this project. Response: A Special permit is required for the proposed work; however, a variance is not required for this project. The proposed dwelling is outside of the Non-Disturbance Zone and a driveway is not a structure, see Section 2-Definitions in the North Andover Zoning Bylaw (Section 2.68- Structure). Comment 2. The boundaries of these buffet zones are based on the horizontal setback from the edge of all wetland resource areas as defined by the Wetlands Protection Act and the North Andover Wetland Bylaw. It is not clear whether the wetland boundaries shown on the plan have been confirmed by the Conservation Commission, e.g. through an ANRAD or NOL Response: A Notice of Intent (NOI) was filed with the Conservation Commission in April 2013 (DEP File No 242-1595). As part of the filing Jennifer Hughes, Conservation Administrator, reviewed the wetland boundaries. Two wetland flags,numbers 15 and 30,were moved 5 feet uphill from their original position. The revised locations for these two flags are depicted on the revised plan. Civil Engineers • Land Surveyors • Land Planners 7 �samm consultants inc. Comment 3. The Plan should also show the Zone A for the Lake Cochichewick public water supply, defined by the Massachusetts Drinking Water Regulations (310 CMR 22.02) as including the land area within a 400 foot lateral distance from the upper boundary of the bank of a Class A surface water source and 200 foot lateral distance from the upper boundary of the bank of a tributary or associated surface water body. Response: Although not required by the special permit bylaw, the additional boundaries have been depicted on the revised plan. The entire lot is essentially within 400 feet of Lake Cochichewick and about half(eastem)of the lot is within the 200 foot boundary to the wetland bordering an associated water body, Rae's Pond. We have also added the 325 foot Non-Discharge Zone from Lake Cochichewick. The 325 foot zone from the adjacent wetland is well off the lot. Comment 4. The Plan should show the proposed edge of vegetation clearinglUmit of work. While much of the proposed development area is already cleared, the creation of any new lawn or landscaped area should be limited to that which is absolutely necessary and constructed in such a manner as to minimize the maintenance that is required, e.g. the soil should be well aerated, it should have a minimum of 6-inches of topsoil and, where possible, native vegetation should be planted to minimize the need for fertilizer and watering. The Planning Board may also want to request a planting or landscape plan for the property. Response: The limit of work along the easterly side of the site is defined by the proposed hay bale .line. The remaining limit of the work, along the westerly side, including demolition of the existing garage, has been added to define the work area. The use of native vegetation can be conditioned in the permit. Comment 5.As with similar projects permitted within the Watershed Protection District, both the limits of approved clearing and the Board's standard restriction on lawn care products should be permanently recorded on the deed to the property. Response: Noted,the limits of the work are now depicted for the Board's review. Comment 6. The narrative indicates that roof runoff from the proposed house will be directed onto lawn areas for infiltration; however it is not clear from the plan how this is to be accomplished. Rcsnonse: Runoff from the roof will fall directly on lawn areas in the event that no gutters are installed. If gutters me installed, the leaders can be easily directed to the lawn areas per standard practice. Comment Z The plan calls for driveway runoff to drain to a stone trench along the northern edge of the driveway, which in turn drains to a 60-ft flat swale at the base of the driveway (within the 100-ft buffer zone). The plan also calls for a 8-in overflow pipe from the swale under the driveway, discharging toward Great Pond Road. It is not clear why this overflow pipe is needed, as the trench and swale should be designed to handle all of the runoff from the proposed driveway. Response: There was a drafting error in the initial submittal which improperly indicated east to west flow from the culvert and an overflow diversion. However,the culvert is not intended to be an overflow. The driveway culvert is intended to.slope west to east to drain the west side of the driveway without runoff from this area running over the new driveway. The revised invert data for the culvert is depicted on the revised plan. Andover consultants Inc. Comment 8. Given its nearly 10 percent grade, I recommend adding check dams in the stone trench to slow the rate of flow and promote infiltration. Response: Check dams have been added as recommended. 6 inch wide by 3 inch high washed pea stone check dams have been added to the driveway swale spaced every 40 feet. Comment 9. A design detail for the proposed swale is needed. Given its proximity to wetland resource areas and the town's water supply the swale should be designed to maximize water quality treatment and promote infiltration, e.g. incorporating a bioretention area with an overflow swale. Response: The swale is approximately 64 feet long, 2 feet wide with a flat slope. Additional crushed stone, 2 feet wide by 10"deep has been added to the invert of the swale. Also, washed pea stone check dams spaced every 20 feet have been incorporated to enhance treatment and promote additional infiltrative capacity. Comment 10. Ongoing maintenance and preservation of the proposed stormwater management structures should be addressed Response: Maintenance of the stone trench will generally consist of occasionally sweeping of the driveway, as needed, to remove winter sanding. Leaves, grass clippings and other yard debris will need to be removed by raking, also as needed. Should you have any comments or require any additional information concerning the revisions above, or have any additional questions,feel free to contact us. Sincerely, ANDOVER CONSULTANTS,INC. % ' ' - James S. Fairweather II, P.E. - Project Engineer Enclosures cc Eggleston Environmental Technical Training