The URL can be used to link to this page

Home My WebLink About2020-02-25 Stormwater Review � I Horsley When Group Sustainable rEnvirontnenfal Solutions 54 IV Water Street 61,Floor •Boston,MA02109 ' 657-263.81M•horsleywltten.com - ti December 6, 2021 Ms. Jean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 01845 Ref: Stormwater Peer Review Modifications to 505 Sutton Street North Andover, Massachusetts Dear Ms. Enright and Board Members: The Horsley Witten Group, Inc. (HW) is pleased to provide the North Andover Planning Board with this letter report summarizing our peer review of the modifications to the Stormwater Management Report and Site Plans for the proposed development at 505 Sutton Street, North Andover, MA. The plans were prepared for Sutton Street redevelopment, LLC (Applicant) by The Morin-Cameron Group, Inc. HW understands that the Applicant is proposing to construct three multifamily residential buildings and associated surface and underground parking, landscaping improvements, a stormwater management system and new utility infrastructure on a 5.10-acre parcel. The south and eastern portions of the site are currently undeveloped. There are no wetlands on-site, however at the south side of the site there is a buffer zone that is associated with an isolated wetland that is located off-site. j The following documents and plans associated with the modified stormwater system and prepared by The Morin-Cameron Group, Inc were received electronically by HW: • Letter to North Andover Planning Department, regarding Summary of Site Plan Updates, dated November 10, 2021 (5 pages). • Stormwater Management Summary, 505 Sutton Street— Multi-Family Site Development, dated November 10, 2021 (2 pages). • HydroCAD Model —505 Sutton Proposed Conditions Hydrologic Analysis Final, Printed 10/12/2021 (72 pages). • Proposed Watershed Plan at 505 Sutton Street, North Andover, Massachusetts (1 Sheet). • Redlined Permit Plans, Dated May 16, 2019, revised through January 31, 2020 (13 sheets), • Multifamily Site Development Plans, 505 Sutton Street, North Andover, Massachusetts, prepared by The Morin-Cameron Group, Inc., dated May 28, 2021, revised October 27, 2021, which include: o Cover Sheet C.1 o Existing Conditions Plan C.2 o Demolition Plan C.3.A Erosion & Sediment Control Plan C.3.B (r+)Hors IeyWittenCroup Horsley Witten Group, Inc. Town of North Andover December 6, 2021 Page 2 of 2 o Site Layout Plan CA o Overall Grading Plan C.5.A o Grading & Drainage Plan C.5.13 o Utility Plan C.6 o Construction Details I C.8 o Construction Details 11 C.9 o Construction Details III C.10 o Construction Details IV CA I o Construction Details V C.12 o Construction Details V1 C.13 Modified Stormwater Design Peer Review The Applicant has made several changes to the site plans for various reasons detailed in its Summary of Site Plan Updates letter. HW has reviewed the changes to the stormwater design and has the following comments: 1. The Applicant has illustrated the perimeter drains that are capturing and directing the roof runoff to the subsurface Retain It systems. The roof drain piping is located around each building, HW recommends that clean outs are proposed at the northeast corner of Building 1, the southeast corner of Building 2, and the southwest corner of Building 3. 2. The Applicant has eliminated the originally proposed CDS units and replaced catch basin 2 and 3 with Stormceptor 450i units. HW recommends that the CDS units be returned to the design and that the Applicant eliminate the catch basin to catch basin configuration where feasible. Conclusions With the minor adjustments suggested, HW agrees that the proposed stormwater design is equivalent to the approved design. Please contact Janet Bernardo at 508-833-6600 or at jbernardo@horsleywitten.com if you have any questions regarding these comments. Sincerely, HORSLEY WITTEN GROUP, INC. Janet Carter Bernardo, P.E. Associate Principal K:1Projects12013U8065 N Andover On-Cal M806511 505 Sutton S4-cet\Reports1211205 I'eerReview nwdirccalions 505 Sutton Yreet,docx The M6rin-Cameron . ............. I H r December 14, 2021 Ms, Jean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, MA 01845 RE: Response to Peer Review„Comments Modifications to 505 Sutton Street North Andover, Massachusetts Dear Ms. Enright: On behalf of Sutton Street Redevelopment, LLC (Owner), The Morin-Cameron Group, Inc. (MCG) prepared this response letter to the peer review comments provided by the Horsley Witten Group, Inc. (HW) in their letter dated December 6, 2021.The original HW comments are included below, with the MCG responses following each comment. Modified Stormwater Design Peer Review: 3 1. HW Comment: The Applicant has illustrated the perimeter drains that are capturing and directing the roof runoff to the subsurface Retain It systems The roof drain piping is located around each building. HW recommends that clean outs are proposed at the northeast corner of Building 1, the southeast corner of Building 2, and the southwest corner of Building 3. MCG Response:The clean-outs described above will be added to the roof drain pipe network in the locations suggested. 2. HW Comment: The Applicant has eliminated the originally proposed CDS units and replaced catch basin 2 and 3 with Stormceptor450i units. HW recommends that the CDS units be returned to the design and that the Applicant eliminate the catch basin to catch basin configuration where feasible. MCG Response: Following a detailed review and discussion of this particular closed drainage system, the use of 5tormceptor 450i units was recommended by Contech Engineered Solutions (Contech),who recently added Stormceptor to its product offerings (it was previously owned by a separate company). The drain pipe network in the vicinity of C8- 2 & C13-3 does not allow for separate treatment structures, because of the tight angles, shallow cover depths and various underground utility services in those locations. Considering these project constraints, MCG used its best engineering judgement and CIVIL ENGINEERS • LAND SURVEYORS • ENVIRONMENTAL CONSULTANTS • LAND USE PLANNERS 25 Kenoza Avenue, Haverhill, MA 01830 978.373.0310 Providing Professional Services Since 1978 505 Sutton Street December 14, 2021 Response to Comments simplified the design by specifying treatment structures with a combination of piped and grated inlets, in the interest of improving both constructabiEity and long-term maintenance. Based on the physical characteristics of Contech's treatment structures (e.g. Stormceptor, CDS, Cascade), the TSS removal capacities are not dependent on whether runoff is conveyed via pipe flow or a grated inlet, or a combination of the two, For the CDS units that were originally proposed, It is necessary to use a deflector pan with grated inlets in order to induce the desired vortex flow pattern, These deflector pans are not ideal in a shallow cover Installation such as that required for CB-2, because they need to be attached to the underside of the grates and can Interfere with the CDS internals. In this case, the Stormceptor Is the ideal choice because if offers similar treatment capacities without the need for a deflector pan. MCG understands that MassDEP doesn't have a current approval process for these proprietary stormwater units, which can be a challenge for design engineers. However, Stormceptors have been used throughout the country for decades, and have a proven track record of success. We verified with Contech that the historical testing performed on these structures does not differentiate between piped inlets or grated inlets when rating the performance. Provided they are installed per the design plans and corresponding construction detail, all runoff entering them will be treated equally. As such, MCG remains confident that the Stormceptor is the most appropriate choice for this application. Finally, it is worth noting that both CB-2 and CB-3 convey runoff to subsurface infiltration systems which are rated to provide at least 80% TSS removal on their own, when preceded by adequate pretreatment measures.And there is also a high-capacity CDS unit specified for installation at the very end of this project's closed drainage system, which will provide additional treatment for any runoff that Is discharged from the infiltration system outlet control devices. In conclusion, MCG is confident that the final stormwater management system design is in full compliance with the Massachusetts Stormwater Handbook in addition to all local project approvals. We trust that this supplemental information sufficiently addresses the Horsley-Witten Group comments from their peer review of the modified stormwater design. Please contact the undersigned at (978) 373- 310 should you have any questions or requests for additional information. Sincerely, THE MO -CAMERON GROUP, INC. ott . ameron, P.E. Michael C. Laham, P.E. Vice- resident Project Manager Cc: Sutton Street Redevelopment, LLC Horsley-Witten Group, Inc. Page 2 of 2 12116121,8:04 AM Town of North Andover Mail-505 Sutton Street N0 H.ANROVER PAassaclfusGtts Jean Enright<jenright@northandoverma.gov> T77 505 Sutton Street 2 messages Jean Enright <jonright@northandoverma.gov> Wed, Dec 15, 2021 at 2:37 PM To: Janet Bernardo <jernardo@horsleywitten.com> Cc: Amy Maxner<amaxner@northandoverma.gov>, Michael Laham <Mike@morincameron.com> Hi Janet, I have attached Michael Laham's response to your Dec. 6 peer review letter. Please let us know your thoughts. Thank you Sincerely, Jean Enright Planning Director Town of North Andover 120 Main Street North Andover, MA 01845 Phone 978.688.9533 Fax 978.688,9542 Email: jenright@northandoverma,gov Web: www.NorthAndoverMA.gov L,p. cid:image001.jpg@010EOF52.F68A5980 211214 Resp Ltr to HW,pdf 976K Janet Bernardo <jernardo@horsleywitten.com> Wed, Dec 15, 2021 at 3:49 PM To: Jean Enright<jenright@northandoverma.gov> Cc: Amy Maxner<amaxner@northandoverma.gov>, Michael Laham <Mike@morincameron.com> Hi Jean, The response from Michael Laham is acceptable to HW. We have no further recommendations. Thanks, Janot Janet Carter Bernardo, P.E. 'rsley Witten Group 857-263-8193 nmlinal llu/0/?Ik=7c2eff6265&view=pt&search=all&permthid=th read-a%3Ar8275896189030228798&sim pl=msg-a%3Ar-691969526... 112 12/16121,8:04 AM Town of North Andover Mail-505 Sutton Street From: Jean Enright<jenright@ north andoverma,gov> Sent: Wednesday, December 15, 2021 2:37 PM To: Janet Bernardo <jernardo@horsleywitten,com> Cc: Amy Maxner<amaxner@northandoverma.gov>; Michael Laham <Mi.ke c@morincameron.com> Subject: 505 Sutton Street Hi Janet, have attached Michael Laham's response to your Dec. 6 peer review letter. Please let us know your thoughts. Thank you Sincerely, Jean Enright Planning Director Town of North Andover 120 Main Street North Andover, MA 01845 Phone 978.688.9533 Fax 978,688.9542 Email: jenright@northandoverma,gov Web: www.NorthAndoverMA.gov All email messages and attached content sent from and to this email account are public records unless qualified as an exemption under the Massachusetts Public Records Law. Visit us online at www.northwidoverrna.gov, https:#mail.googio.com/maillu/0/?ik=7c2eff6265&view=pt&search=all&permthid=thread-a°/a3Ar8275896180030228798&simpl=msg-a%3Ar'