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HomeMy WebLinkAboutConsultant Review - 1895 GREAT POND ROAD 2/17/1999 COLANTONIOV ENGINEEQS AND SCIENTISTS February 15, 1999 Planning Board C/o William Scott Town Hall Annex 27 Charles Street North Andover, MA 01845 RE: Supplemental Engineering Review Great fond Road Special Permit for Watershed District Dear Mr. Scott: In response to your request, Coler & Colantonio, Inc., has reviewed the requirements under the Zoning Bylaws relative to the Watershed District Special Permit for the above referenced project. This property was previously reviewed under a different filing for the development of two house lots. The proposal has since been modified to include only one lot. We also visited the site to observe existing conditions. The plan has been reviewed for conformance under these submittal requirements and standard engineering practice. The submittal package included the following information.: Plan Entitled: ® "Proposed Lot Development Great Pond Road in North Andover, Mass" one sheet dated December 2, 1998, Revised February 3, 1999. Prepared by DeVellis Associates Inc. Washington Street Newton Lower Falls, MA Received February 4, 1999. Reports Entitled: Letter of Response including culvert analyses, test pit log, TR-20 output data and recharge calculations Prepared by DeVellis Associates Inc. Received February 4, 1999. Our latest comments are in italics: ZoningBylaw., 1. Section 4.136)4.)c.)ii.) 1.)The Lake Cochichewick high water mark,should be shown on the plan. It should be noted that the lake may flood into Lot A through the reported 6"VC pipe. Based on our site visit we do not agree that the existing pipe is a 6 in.V.C.pipe. No further comment tot Accord Park Drive 781-982-5400 Norwell, MA 02061-1685 Fax: 781-982-5490 2. Section 4.136)4.) c.)ii.)2.)It is unclear if the Conservation Commission has confirmed the wetland limits. No further comment. 3. Section 4.136)4.) g.) The entire lot is located within the designated 325' non- discharge zone. Design calculations and invert elevations for the proposed infiltration systems have not been included, It is not clear that the proposed crushed stone drains are adequate for collection of all pavement runoff. Test pits for the proposed site development were not included, We recommend that test pits,performed by a certified soil evaluator and witnessed by an agent of the town be performed a the location of proposed infiltration structures. These test pits should identify soil type, permeability and maximum seasonal groundwater. The plan states that final design of the leaching dry well is subject to soil testing. It is unclear when testing is proposed and what would be done if testing indicates unsatisfactory material. The submitted test pit data indicates unsuitable infiltration conditions in the proposed leaching pit. It may not be feasible to provide infiltration on this site. This issue should be addressed by the Planning Board. AMtional Co ents: 4, According to the proposed contours, the culvert at the intersection of Great Pond Road and the proposed common driveway would not properly drain. Calculations and analysis of the existing and proposed culvert should be included and address existing and proposed elevations. The capacity of the existing pipe should be calculated. It has not been demonstrated that this project will not increase flooding at the culvert. Calculations indicate a small increase in peak run off rates. We disagree with the assumption of the proposed twin 12"diameter culverts being modeled under inlet control conditions, the culverts appear to be surcharged. The existing 12" R.CA culvert, which crosses under Great Pond Road, would also be surcharged when Lake Cochichewick is at its annual high water elevation_ This condition should be modeled S. We note that Barker Street is listed as an abutter. Satisfactorily addressed. 6. The proposed wetland replication area is not located in proximity of the wetland to be filled. This may impact flood storage volume. No further comment, 7. The crowning of the proposed common driveway should be indicated in the plan view,together with the proposed crushed stone strip. The grading does not appear to reflect the crushed stone area. Based on our review of the grading plan, it appears that most of the runoff from the driveway would concentrate near wetland flag A-6. No further comment, 8. It is possible that the proposed earth cuts for the construction of the northern half of the drive will experience groundwater weeping. This is counter to the intent of the BY-Law. We recommend that groundwater depth be determined in these areas. It has been acknowledged that weeping may occur. The Planning Board should address this issue. We appreciate the opportunity to assist the Planning Board on this project and hope that this information is sufficient for your needs. If you have any questions please do not hesitate to contact us. Very truly yours, COLER&COLANTONIO,INC. C CKd-,W John C. Chessia, P.E. XC: DeVellis Associates Jim Rand, DPW COLANTONIOZ F N(jINE-EIS ANO 5UIENT1575 December 21, 1998 Kathleen Colwell Town Hall Annex 27 Charles Street North Andover, MA 01845 RE: Engineering Review Great Pond Road Special Permit for Watershed District Dear Ms. Colwell: In response to your request, Coler & Colantonio, Inc., has reviewed the requirements under the Zoning Bylaws relative to the Watershed District Special Permit for the above referenced project. This property was previously reviewed under a different filing on October 5, 1998. We also visited the site to observe existing conditions. The plan has been reviewed for conformance under these submittal requirements and standard engineering practice. The submittal package included the following information: Plan Entitled: o "Proposed Lot Development Great Pond Road in North Andover, Mass" one sheet dated December 2, 1998. Prepared by DeVellis Associates Inc. Washington Street Newton Lower Falls, MA Received December 10, 1998. Reports Entitled: • Special Permit Application. Prepared by DeVellis Associates Inc. Received December 10, 1998. • Letter of Potential Degradation. Prepared by DeVellis Associates Inc. Received September 24, 1998. We offer the following comments: A complete review of the drainage system was not performed. No calculations or support data was provided regarding the drainage design. 101 Accord Park Drive 781-982-5400 Norwell, MA 02061.1685 Fax: 781-982-5490 Zoning Bylaw: 1. Section 4.136)4.)c.)ii.) 1.) The Lake Cochichewiek high water mark should be shown on the plan. It should be noted that the lake may flood into Lot A through the reported 6"VC pipe. Based on our site visit we do not agree that the existing pipe is a 6 in. V.C.pipe. 2. Section 4.136)4.) c.)ii.)2.) It is unclear if the Conservation Commission has confirmed the wetland limits. 3. Section 4.136)4.) g.)The entire lot is located within the designated 325' non- discharge zone. Design calculations and invert elevations for the proposed infiltration systems have not been included. It is not clear that the proposed crushed stone drains are adequate for collection of all pavement runoff. Test pits for the proposed site development were not included. We recommend that test pits, performed by a certified soil evaluator and witnessed by an agent of the town be performed a the location of proposed infiltration structures. These test pits should identify soil type, permeability and maximum seasonal groundwater. The plan states that final design of the leaching dry well is subject to soil testing. It is unclear when testing is proposed and what would be dome if testing indicates unsatisfactory material. Additional Comments: 4. According to the proposed contours,the culvert at the intersection of Great Pond Road and the proposed common driveway would not properly drain. Calculations and analysis of the existing and proposed culvert should be included and address existing and proposed elevations. The capacity of the existing pipe should be calculated. It has not been demonstrated that this project will not increase flooding at the culvert. 5. We note that Barker Street is listed as an abutter. 6. The proposed wetland replication area is not located in proximity of the wetland to be filled. This may impact flood storage volume. 7. The crowning of the proposed common driveway should be indicated in the plan view,together with the proposed crushed stone strip. The grading does not appear to reflect the crushed stone area. Based on our review of the grading plan, it appears that most of the runoff'from the driveway would concentrate near wetland flag A-6. g. It is possible that the proposed earth cuts for the construction of the northern half of the drive will experience groundwater weeping. This is counter to the intent of the By-Law. We recommend that groundwater depth be determined in these areas. We appreciate the opportunity to assist the Planning Board on this project and hope that this information is sufficient for your needs. If you have any questions please do not hesitate to contact us. Very truly yours, COLER& COLANTONIO, INC. n� , ohn C. Chessia, P.E. XC: DeVellis,Associates Jim Rand,DPW