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Home My WebLink About250204 Responce to 1.30.2025 Peer Review - - 75 COACHMANS LANE February 4, 2025 North Andover Planning Board Attn: Jean Enright,Planning Director W-100 WILLIAMS North Andover Planning DepartmentSPARAGES 120 Main Street ENGINEERS I SCIENTISTS i SURVEYORS North Andover, MA 01845 Re: 75 Coachman's Lane Peer Review Response S Watershed Special Permit—Proposed Swimming Pool Dear Jean, As you are aware, our office submitted a Watershed Special Permit on behalf of the property owners, Thomas &Amanda Lough, to install an in-ground swimming pool and paver patio at their property at the above referenced address. We are in receipt of the peer review comments provided by Horsley Witten Group, Inc. dated January 30, 2025. The following is a list of their comments and our responses: 1. The Applicant has included erosion controls on the Plan and has shown where the stockpiles will be located during construction. The Applicant has also included a 6- inch mulch sock along the perimeter of the construction access for additional erosion protection. HW notes that the North Andover Conservation Agent has requested that the erosion controls be added to the easterly side of Coachman's Lane to protect the wetland from any transport of dirt or sediment from construction equipment passing back and forth from the site. The Planning Board may choose to include this request as a condition of approval, the suggested location is within the Town's right of way. The plan has been revised to show a 6" mulch sock along the easterly side of Coachman's Lane opposite of the existing driveway. 2. The Applicant has proposed a construction access around the north side of the house. HW recommends that the Applicant consider construction matting to limit the tracking of sediment offsite or onto the driveway. The plan has been revised to show construction matting within the construction entrance. 3. The Applicant proposes that the swimming pool be equipped with a non-backwash filtration system. HW recommends that the Applicant includes a checklist log that specifies the frequencies of inspecting the filtration system as part of the Operations and Maintenance (O&M)Plan. Williams&Sparages I Engineers•Scientists•Surveyors 189 North Main Street I Suite 1011 Middleton, MA (978)539-8088 1 www.wsengineers.com Page l 1 'W__4 C_ T S A checklist log has been included as part of the revised Operations & Maintenance document and attached to this letter. 4. The Applicant has noted in the O&M Plan that during normal dewatering following storm events, the pool water shall first be dechlorinated and then pumped into the infiltration trench. No further action is requested. No comment. 5. HW agrees that the infiltration trench surrounding the patio will provide adequate stormwater management for the additional impervious patio surface,provided that the property owners follow the proper inspection and maintenance protocol as outlined in the O&M Plan. Maintenance of the stormwater management system is the responsibility of the property owners. No further action is requested. No comment. 6. HW notes that the Applicant has illustrated the approximate location of the Zone A Federal Emergency Management Agency (FEMA) flood line. FEMA is in the process of updating the flood maps in North Andover. The line as illustrated is consistent with the 2023 zoning map. No further action is requested. No comment. If you should have any questions regarding this information, or require any additional information,please do not hesitate to contact our office. Sincerely, 444-1�17 Thorsen Akerley, P.W.S., R.S. Project Manager, Williams & Sparages LLC cc: Thomas &Amanda Lough, 75 Coachman's Lane Janet Carter Bernardo, P.E., Horsley Witten Group, Inc. Enclosures Williams&Sparages I Engineers•Scientists•Surveyors 189 North Main Street I Suite 1011 Middleton, MA (978)539-8088 1 www.wsengineers.com Page 12 'W--4 C- T S January 22, 2025 Revised: February 4, 2025 75 Coachman's Lane I North Andover, MA Operations&Maintenance Plan Operations &Maintenance Plan:75 Coachman's Lane,North Andover, MA System Owner: Thomas&Amanda Lough 75 Coachman's Lane North Andover MA 01845 In-Ground Swimming Pool • The proposed swimming pool shall be equipped with a non-backwash filtration system. A Pentair System 30 Modular Media Filter is proposed (see attached filter description and owner's manual). • The property owner shall engage a water hauling company to pump the water and truck the water offsite anytime the pool needs to be drained. Final disposal of the water by the water hauling company shall be in accordance with all federal and state regulations. • Pool water shall be dechlorinated by not adding chemicals and letting the pool water sit for a minimum of 10 days. At that point,the pool water can be pumped into the proposed infiltration trench system during normal dewatering following storm events. • Pool chemicals shall be properly stored according to manufacturers' labels in an enclosed shed or garage to ensure proper containment of any spills or drips. Pool Filtration System &Filter Cleaning Procedure The pool filtration system to be cleaned and maintained in accordance with manufacturer specifications detailed in the attached owner's manual. • Once operating pressure reaches 10 PSI above initial operating pressure, inspect and clean filter element in according with the attached owner's manual. Filter element should be cleaned with a hose and drained into the stone infiltration trench. Weekly Pool Inspections & Checklist Log_ On a weekly basis, the following should be completed as part of ongoing maintenance of the pool filtration system: ❑ Debris should be removed from the skimmer basket. ❑ The pump should be stopped,release all pressure, and remove trap cover and basket to remove any additional debris. ❑ Air filter should be bled each time the system is started. Williams&Sparages I Engineers-Scientists-Surveyors 189 North Main Street I Suite 1011 Middleton, MA (978)539-8088 1 www.wsengineers.com Page 11 'W--4 C- T S January 22, 2025 Revised: February 4, 2025 75 Coachman's Lane I North Andover, MA Operations&Maintenance Plan ❑ Check pump for leaks. If found, see pump owner's manual. ❑ Check the pump strainer lid for tightness. Stone Infiltration Trench This Operations &Maintenance Plan has been prepared to comply with the provisions set forth in the Massachusetts Department of Environmental Protection (DEP) Stormwater Management Standards. Structural Best Management Practices (BMPs) require periodic maintenance to ensure proper function and efficiency in pollutant removal from stormwater discharges that would otherwise reach wetland resource areas untreated. Maintenance schedules found below are recommended in Department of Environmental Protection's Massachusetts Stormwater Handbook and as recommended in the manufacturer's specifications. The stormwater management system owner and the party responsible for maintenance of the stormwater management system shall be the property owner and their designated employees. • Inspect and clean every six months and after every major storm event of 0.5 inches in a 24-hour period. • Remove accumulated sediment,trash, debris, leaves and grass clippings. • Remove tree seedlings before they become firmly established. • Inspect the trench 24 hours or several days after a rain event to look for ponded water. If there is ponded water at the surface of the trench,it is likely that the trench surface is clogged. • To address surface clogging,remove and replace the first layer of stone aggregate and filter fabric. If the water is ponded inside the trench,it may indicate that the bottom of the trench has failed. • To rehabilitate a failed trench, all accumulated sediment must be stripped from the bottom,the bottom of the trench must be scarified and tilled to induce infiltration, and all of the stone aggregate and filter fabric or media must be removed and replaced. Williams&Sparages I Engineers•Scientists•Surveyors 189 North Main Street I Suite 1011 Middleton, MA (978)539-8088 1 www.wsengineers.com Page 12 'W--4 C- T S