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HomeMy WebLinkAbout2024-12-03 Stormwater Review Horsley W*itten Grolup �'f�'i/ IIIIIIIIIIIIIIIIIIIIIIIII' 112 water Street .611 Floor-Boston,MA 02109 op Or 77 November 25, 2024 GIs. Jean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 011845 Re: Second Stormwater Peer Review Proposed Swimming Peel--318 Salem Street North Andover, Massachusetts Dear I ,. Enright and Board Members. The Horsley Witten Group,, Inc. (NW) is pleased to provide the North Andover Planning Board with this, letter report summarizing our second review of the Watershed Special Permit Application for the proposed swimming pool project at 318 Salem Street in North Andover, MA. The plans were prepared by PFS Land Surveying, Inc. on behalf of Jamie-Lyn Pickles (Applicant). The project proposes the installation of a 15-foot by 3,2-foot in-ground swimming pool, with a 4-foot concrete apron, and a 8-foot privacy fence. The s,tormwater management for the proposed improvements includes a -foot wide, 2- folot-d'eep infiltration trench along the edges of the concrete apron to allow stormwater from the concrete apron to infiltrate into the ground during a storm event. In addition, the swimming pool will be equipped with a non-backwash filtration system. The proposed pool is a 480 square foot (sf), permanent structure. The footprint of the existing house is approximately 1,852, sf. A total of approximately 920 sf of additional impervious area including the pool and concrete apron is proposed within the 25,000 sf parcel. The residential lot is located within the watershed Protection District and was created in 191801, pre-dating the October 24, 1994 implementation of the bylaw., Awetland resource area exists at the west corner of the parcel, northwest of the proposed work, and existing flagging was confirmed by the North Andover Conservation Commission. The proposed pool location is within the 325-foot Non-Discharge Buffer to a. wetland resource within the watershed Protection District, and the proposed limit of disturbance is greater than 100,feet from the edge of the bordering vegetated wetland `W). In accordance with §1 g 5-4.1 g B. (2) of the North AndoverZoning Bylaws, any surface or subsurface discharge of stormwater within the Non-Discharge Buffer Zone is only allowed after a special permit has been granted by the North Andover Planning Board. The following documents and plans were received, by Nw in response to our initial review dated November 18,, 2024: Memorandum, Peer Review Comments, 318 Salem Street, North Andover, Massachusetts, prepared by PFS Land Surveying Inc., dated November 20, 2024 1 page); Watershed Special Permit, Project.Description and Supporting Documentation, 318 Salem Street, North Andover, Massachusetts, prepared by PFS Land Surveying, Inc., dated October 14, 2024, revised November 22, �0�4� (7pages); National Flood Hazard sayer FIRMette, dated June 18,, 2024 1 page), and Stormwater Remediation Plan in North Andover, 318 Salem Street, North Andover, Massachusetts, prepared by PFS Land Surveying, Inc., dated October 14, 2024, revised November 20, 2024, (sheets 1 and 2 of 2). rsley%tf .c orn [--lo l l e n G i re IM F ors ley i tl w Inc. Town of North Andover November 25, 2024 Page 2 of 3 Stormwater Management Design Peer Review In accordance with §195-4.19. B. (4)All construction in the Watershed Protection District shall comply with best management practices for erosion, siltation, and stormwater control in order to preserve the purity of the groundwater and the lake;to maintain the groundwater table;and to maintain the filtration and purification functions of the land. The following comments correspond to our initial peer review letter dated November 18, 2024. Follow up comments are provided in bold font. I. In the Watershed Special Permit Application, the Applicant states that the section of Zoning Bylaw that the Special Permit is being requested for is §195-4.19 C. (2)(a) and §195-4.19 C. (2)(c). However, the Drainage Report states that the pool construction is outside of the 250-foot Non-Disturbance buffer from the mean annual high water of Lake Cochichewick. HW recommends that the Applicant clarify whether the proposed work is located within the 250-foot Non-Disturbance Buffer Zone or within the 325-foot Non-Discharge Buffer Zone. HW recommends that the Applicant include a locus map depicting the applicable buffer zone(s) and the watershed protection district area. November 25, 2024: The Applicant provided clarification in the Memorandum dated November 20, 2024 that the Watershed Special Permit Application should reference §195- 4.19. B (2). No further action is requested. 2. The Applicant is subject to the requirements of§1 95-4.1 9 B., "Non-Discharge Buffer Zone"for work between 100 feet and 325 feet horizontally from the edge of all wetland resource areas located within the watershed. §195-4.19 B refers to§195-4.19 A (3)for Prohibited Uses. It is HW's understanding that the proposed pool is not considered a prohibited use per 195-4.19 A(3) and is considered an allowed use in Residence 3 District per§195-4.2 C. November 25, 2024: No action requested. 3. In the watershed Special Permit Application, the Applicant states that the proposed project entails "installation of an in-ground swimming pool, patio, and perimeter fence within the watershed of Lake Cochichewick." The Stormwater Remediation Plan indicates a patio adjacent to the existing structure. The proposed impervious area indicated in the Drainage Report includes the proposed pool and the concrete apron surrounding the pool. HW recommends the Applicant clarify if the patio is an existing structure or is included in the proposed construction work. November 25, 2024: The patio has been labeled as an existing structure on Sheet 2 of the Stormwater Remediation Plan. No further action is requested. 4. The Applicant has included a silt sock surrounding the proposed pool construction area. The silt sock appears to end at the edge of the patio. HW recommends that the Applicant clarify if the patio has a raised edge to prevent stormwater from flowing towards the western side of the existing house. HW recommends that the Applicant include additional erosion control measures on the Plan, including the location of stockpiles and additional mulch sock or silt fence surrounding the stockpiling area for erosion protection. November 25, 2024: The Applicant has revised the Stormwater Remediation Plan to extend the silt sock to a stabilized construction entrance. The Applicant has included the proposed location for stockpiles. HW recommends that the Applicant includes additional mulch sock or silt fence surrounding the stockpiling area for erosion protection. 5. The Applicant has not included a proposed construction entrance/exit. HW recommends that the Applicant include the location of the proposed construction access area and any erosion control measures, such as construction matting to limit the tracking of sediment offsite or onto the driveway, on the Site Plan. K:1Projects12024124018 Town of North Andover124418F 318 Salem Street\Report1241125_2ndSWPeerReview 318SalemStf-eet.docx Town of North Andover November 25, 2024 Page 3 of 3 November 25, 2,024: The Applicant has included a stabilized construction entrance and associated detail on Sheet 2 of the Stormwater Remediation Plan. No further action is, requested. 6. In the Drainage Report, the Applicant stated that a copy of the Flood Insurance Rate Map is, attached. HW did not receive a Flood Insurance Rate Map for review.: HW recommends that the Applicant provide this map to the Planning Board. November 251, 2024: The Applicant has provided the National Flood Hazard Layer FIRMette. No further,action is requested. T. The Applicant provided''an Operation & Maintenance (O&M), Plan as part of the Drainage Report. HW recommends that the Applicant provide a signed O&M Plan prior to land disturbance. November 25, 2024: Suggested Condition of Approval. 81. HW recommends that the Applicant include an inspection and maintenance log as part of the O&M Plan for use by the homeowner. November 25, 2024- The Applicant has included an inspection and maintenance log in the O&M Plan. No further action is requested. 9. The Stormwater Remediation Plan indicates that Salem, Street is north of the property, but,Salem Street is located southwest of the property. The d:istances,from the edge of the property to the existing structure are inconsistent with the scale of 114=40' as listed on the Plan. HW recommends that the Applicant review the north arrow and scale bar and revise the Plan accordingly. November 25, 2024: The scale has been updated accordingly to 1" =201'. The north arrow on the locus map of the Stormwater Remediation Plan is shown correctly; however, the assumed north arrow on Sheet 1 of 2 is illustrated incorrectly by almost 180 degrees, causing confusion. 10. HW agrees that the infiltration trench surrounding the concrete apron will provide adequate stormwater management for the additional impervious surface. No further action is required. November 25, 2024: No action requested. Conclusions HW recommends that the North Andover Planning, Board require the Applicant to address the two outstanding recommendations as part of its review process. We appreciate the opportunity to assist the Town of North Andover with this project review, Please contact Janet Bernardo at 508-833-6600 or at Lbe,rnardo@hor,sleyAiLLtg�n.com if you have any questions regarding these comments. Sincerely, ............ Janet Carter Bernardo; P.E. Josephine Gustavesen Principal Environmental Scientist KA""rojects\2024\24018 1-own of Nord"i Andover\24018F 318 Salern Sti-ee,t\Rel)orl\241125-2tidSWPoerReview-318,Salem Sti-eet,(Jo(,,x Horsley Witten Group Sustaillable Environmental Solutions 112 water Street.6,0 door Boston,MA 02109 November 18, 2024, s. dean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 01845 e: Initial Stor�mwater Peer Review Proposed Swimming Pool 318 Salem Street North. Andover, Massachusetts Dear Ids. 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 initial review of the ' "watershed Special Permit Application for the proposed swimming pool project at 318 Salem Street in, North Andover, MA. The plans were prepared by PFS, Land Surveying, Inc. on behalf of Jamie-Lyn Pickles, (Applicant). The project proposes the installation of'a 15-foot by 2-foot in-ground swimming pool, with a 4-foot concrete apron, and a 6-foot privacy fence. The storrnwater management for the proposed improvements includes a 2-foot wide, 2-foot-deep infiltration trench along the edges of the concrete apron to allow storm rater from the concrete apron to infiltrate into the ground during a storm event. In addition, the swimming pool will be eq ipped with a non-backwash filtration system. The proposed pool is a 480 square foot sf permanent structure. The footprint of the existing house is approximately 1,852 sf. A total of approximately 920 sf of additional impervious ,area including the pooll and concrete apron is proposed within the 25,000-sf parcel. The residential lot is located within the Watershed Protection District and was created in 1980, pre- dating the October 24, 1994 implementation of the bylaw. A wetland resource area exists at the west corner of the parcel, northwest of the proposed work, and existing flagqlinq was confirmed by the North Andover Conservation Commission. The proposed pool location is within the 325-foot Non- Discharge Buffer r to a wetland resource within the Watershed Protection District, and the proposed limit of disturbance is greater than 100 feet from the edge of the boirdering vegetated wetland (BVW). In accordance with §195-4.19 B. (2) of the North Andover Zoning Bylaws, any surface or subsurface discharge of storrnwater within the Non-Discharge duffer ?one is only allowed after a special permit has been granted by the North Andover Planning Board. The following documents and plans were received by HW • Watershed Special Permit Application, proposed Swimming P�oo:l —318 Salem Street, North Andover, I" assachusetts,, dated January 31, 2024 3 pages), • watershed Special Permit, Project Description and Supporting Documentation, 318 Salem Street, Noirth Andover, Massachusetts, prepared by PFS Land Surveying, Inc., dated October 14, 2024 7 pages); • Stormwater Analysis, 318 Salem Street, stamped by Richard C . Beati, dated October 14, 2024 1 page); • NOAA Precipitation Frequency data 4 pages); Horsk-s.yWitterixorn 91 @ H o rs,I. i iffe n Group, Inc. Town of North Andover November 18, 2024 Page 2 of 3 • Web Soil Survey with Soils (3 pages); • Soil Map--314 Salem Street, North Andover, MA, dated October 7, 2024 (6 pages); • Map Unit Description, dated October 7, 2024, (6 pages); • Abutter List (3 pages); and • Stormwater Remediation Plan in North Andover, 318 Salem Street, North Andover, Massachusetts, prepared by PFS Land Surveying, Inc., dated October 14, 2024, revised November 2, 2024, (Sheets I and 2 of 2). Stormwater Management Design Peer Review In accordance with §195-4.19. B. (4)All construction in the watershed Protection District shall comply with best management practices for erosion, siltation, and stormwater control in order to preserve the purity of the groundwater and the lake;to maintain the groundwater table; and to maintain the filtration and purification functions of the land. HW has the following comments regarding the proposed stormwater management design. I. In the Watershed Special Permit Application, the Applicant states that the section of Zoning Bylaw that the Special Permit is being requested for is §195-4.19 O. (2)(a) and §195-4.19 O. (2)(c). However, the Drainage Report states that the pool construction is outside of the 250- foot Non-Disturbance buffer from the mean annual high water of Lake cochichewick. HW recommends that the Applicant clarify whether the proposed work is located within the 250-- foot Non-Disturbance Buffer Zone or within the 325-foot Non-Discharge Buffer Zone. HW recommends that the Applicant include a locus map depicting the applicable buffer zone(s) and the watershed protection district area. 2. The Applicant is subject to the requirements of§195-4.19 B., "Non-Discharge Buffer Zone" for work between 100 feet and 325 feet horizontally from the edge of all wetland resource areas located within the watershed. §195-4.19 B refers to §195-4.19 A (3)for Prohibited Uses. It is HW's understanding that the proposed pool is not considered a prohibited use per 195-4.19 A (3) and is considered an allowed use in Residence 3 District per§195-4.2 O. 3. In the Watershed Special Permit Application, the Applicant states that the proposed project entails "installation of an in--ground swimming pool, patio, and perimeter fence within the watershed of Lake cochichewick."The Stormwater Remediation Plan, indicates a patio adjacent to the existing structure. The proposed impervious area indicated in the Drainage Report includes the proposed pool and the concrete apron surrounding the pool. HW recommends the Applicant clarify if the patio is an existing structure or is included in the proposed construction work. 4. The Applicant has included a silt sock surrounding the proposed pool construction area. The silt sock appears to end at the edge of the patio. HW recommends that the Applicant clarify if the patio has a raised edge to prevent stormwater from flowing towards the western side of the existing house. HW recommends that the Applicant include additional erosion control measures on the Plan, including the location of stockpiles and additional mulch sock or silt fence surrounding the stockpiling area for erosion protection. 5. The Applicant has not included a proposed construction entrance/exit. HW recommends that the Applicant include the location of the proposed construction access area and any erosion control measures, such as construction matting to limit the tracking of sediment offsite or onto the driveway, on the Site Plan. K:IProjects12324124018 Town of North Andovei,\24018F 318 Salem Street\Reportl241118-SWPeerReview 318SalemStr•eet.docx Town of North Andover November 18, 2024 Page 3 of 3 6. In the Drainage Report, the Applicant stated that a copy of the Flood Insurance Rate Map is attached. NW did not receive a Flood Insurance Rate Map for review. HW recommends that the Applicant provide this map to the Planning Board. 7. The Applicant provided an Operation & Maintenance (O&M) Plan as part of the Drainage Report. HW recommends that the Applicant, provide a signed O&M Plan prior to land disturbance!. 8. HW recommends that the Applicant include an inspection and maintenance log as part of the O&M Plan for use by the homeowner. 9. The Stormwater Remediation Plan indicates that Salem Street is north of the property, but Salem Street is located southwest of the property. The distances from the edge of the property to the existing structure are inconsistent with the scale of 1"=40' as listed on the Plan. HW recommends that the Applicant review the north arrow and scale bar and revise the Plan accordingly. 10. HW agrees that the infiltration trench surrounding the concrete apron will provide adequate, , stormwater management for the additional impervious surface. No further action is required. Conclusions HW recommends that the North, Andover Planning Board require the Applicant to address these recommendations as part of its review process. We appreciate the opportunity to assist the Town of North Andover with this project review. Please contact Janet Bernardo at 5081-833-6600 or at .com ibe rdo��horsle�itten�� if you have any questions regarding these comments., �rn a� Sincerely, 11's-J Janet Carter Bernardo, R.E. Josephine Gustavesen Principal Environmental Scientist KAProjects\2024\240'18 Town of North Andover\24018F 3,18 Salem Sti-eet\Report\24,1118.-,9WPeerReview--318 paler-nsti-e et.(Jocx ?morandum To: Ms. Jean Enright, Planning Director Date: November 20, 2024 Town of North!,Andover Planning Department 120 Main Street North Andover, Massachusetts 01845 Project 318 Salem Street No.: From: David Beati, P.F. Re: Peer Review Comments PFS Land Surveying, Inc. 318 Salem Street North Andover, Massachusetts 01845 PIFS Land Surveying has prepared this memo, in response to Peer Review Comments by the Horsley Witten Group dated' Nolvember 18, 20,24 and offer the following: 1. Noted, The application should' have reference bylaw section 4.19.13(2) as the proposed work is within the Non-Dis,charge Buffer Zone. The proposed work location lies 161-feet from a tributary to Lake Cochichewick, cats well outside the 250-foot buffer zone of Lake Cochichewick itself We agree that this location warrants Special Permit Review, and have designed the Storm water BMP to mitigate 15-times the required volume from our analysis. 2. Agreed, the proposed polo] is an allowed use within the Residential 3 zoning district and not prohibited within the Non-Discharge Buffer :one. 3. The patio is existing and is "at-grade 4. Proposed silt sock has been revised to extend to the stabilized construction entrance. A stockpiling area has been added to the site plan. 5. A stabilized construction entrance has been proposed and added to the site plan. 6. Flood Insurance Map has been submitted with the application. 7. The O&M Plan has: been signed by the applicant. 8. Noted, an O&M log has been suggested to the applicant, and added to the application package. 9. The North arrow is listed as assumed and is properly shown on the locus map. The Plan If you have any questions or need any additional information, please do not hesitate to contact me. Sincerely, David Beati, P.E. F20,Balch Aven�ue Groveland,MA 01834 (978)8191-,51203 LAND SURVEYING, INC. (800)220-6214 fax www.pfsland.com National Flood Hazard Layer FIRMette FEMA Legend 7106'11"11 42"40'57"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT Without Base Flood Elevation(BFE) Zone A,V,A99 6w i"@-m---, SPECIAL FLOOD With BFE or Depth Zone AZ AO,AH,Vi�,AR HAZARD AREAS Regulatory Floodway 0.2%Annual Chance Flood Hazard,Area of 1%annual chance flood with average depth less than one foot or with drainagi 0 row" areas of less than one square mile zone) Future Conditions 1%Annual Chance Flood Hazard zone X s. Area with Reduced Flood Risk due to OTHER AREAS OF Levee.See Notes.zone Ax Area with Flood Risk due to Leveezone D FLOOD HAZARD NO SCREEN Area of Minimal Flood Hazard zone X Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard Zeno BE—PP 177 7 R, GENERAL Channel,Culvert,or Storm Sewer STRUCTURES Levee,Dike,or Floodwall 202 Cross Sections with 1%Annual Chance Water Surface Elevation 'MINIDUH a— — — Coastal Transact MA w— Base Flood Elevation Line(BFE) Limit of Study �7 Jurisdiction Boundary Coastal Transect Baseline OTHER Profile Baseline FEATURES Hydrographic Feature Digital Data Available N No Digital Data Available MAP PANELS Unmapped Q The pin displayed on the map is an approximatf point selected by the user and does not represe an authoritative property location. This map complies with FEIVIA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEIVIA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA.This map was exported on 6/18/2024 at 10:225 PM and does not reflect changes or amendments subsequent to this date and time.The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear:basemap imagery,flood zone labels, legend,scale bar,map creation date,community identifiers, FIRM panel number,and FIRM effective date.Map images for 7105'34"W 42040'31"N Feet 1:67000 unmapped and unmodernized areas cannot be used for 0 250 500 1:000 11500 2:000 regulatory purposes. VV\ A TE----,RSffE---.,D SPECIAL PERM'j IT PRO JECT DESCRIPTION & SUPPORTI N, Ei DOCUME N'TATION FOR THE PR�OPE RT)(A T 31 SAIX—Mi S--TRE----JE----T NOR�TH A NilfDO!(E----,R'. Mi A S—,-)S—,-)ACHUSE=," S--) PRE-PAR E---D FOR, J A L M E-- L--sY N J P I C K�L-EE S 31 —8) SALEM/ S---)TRE--.E----.T NORTH A NKDO!(E----,R,) MA 0 164 5—� B jY DAV, ID R,,, B---)EATI PtE PFS, LA ND SURVE—E.Y1 NN Eiv lNj Ct 20 BALCH AVE Nij UE EiROVE----..LA ND, MA 0 CL)TOBER l4p 2024 RE---,,lVlSED NOlVE MV B--jE--.R 22tv 2024 9VERVIEW The proposed pool project is located at 318 Salem Street and is depicted on North Andover Assessors Map 37.B Lot 45. The parcel consists of 25,000± square feet of land and is located on the northerly side of Salem Street at the Intersection of Appleton Street. The pool construction is over 400 feet from Lake Cochichewick, but Within the Watershed Protection District. The lot was created In 1980, pre-dating the October 24, 1994 implementation of the by-law. The pool construction is outside of the 250 foot Non-Disturbance buffer and the 325 foot Non-Discharge buffer from the mean annual high Water of Lake Cochichewick. A wetland resource area exists at the west corner of the parcel, northwest of the proposed work, and existing flagging was confirmed by North Andover conservation Commission, and located by this firm. The proposed pool location is within 325 foot Non-Discharge buffer to a wetland resource within the Watershed protection District, and 161+ feet from the edge of the bordering vegetated wetland (BVW), as located by this firm. The project Involves the construction of a 15'x32' in-ground swimming pool with a 4-foot concrete apron, located in the rear yard of the existing house. The lot is served by a municipal sewerage system so nitrogen and phosphorus contributions to the groundwater will be minimal and typical of surrounding residential uses. It is anticipated that permit approval will require that fertilizers to be organic and slow release, free of phosphorus further minimizing chemical impact to the groundwater. No perennial streams are shown on or near the lot according to the USCS Massachusetts StreamStats program and the North Andover Riverfront Map. No wetland area will be disturbed as part of the proposed work. A copy of the Estimated Habitat Map is not attached as there are no estimated habitats of rare wetlands wildlife or certified vernal pools on or near the lot according to the Natural Heritage and Endangered Species Program Web site dated August 1. 2021. A copy of the Flood Insurance Rate Map is attached. The parcel is not in the floodplain per Flood Insurance Rate Map 25009CO236F, dated July 3, 2012. Soils on the lot were mapped by the USDA Natural Resources conservation Services (MRCS) as predominately Sutton Fine Sandy Loam, 0% to 3% slopes, and are moderately well-draining. OW.KWATER MANAGEMENT Existing conditions present a gently sloping side yard, northwesterly towards the wetlands and brook, and is presently without stormwater measures. Since the project consists of work on a single family house, the project is exempt from the MA DEP Stormwater Management Standards. Stormwater remediation for the site is proposed by the conveyance of all runoff from the proposed pool area into a 2'wide stone infiltration trench, at a depth of 2-feet. The trench will circumvent the pool and deck, and will be encased in polyethylene filter fabric. During construction, the perimeter of the work will be protected with staked erosion barrier products to prevent migration of sediment from the site until final stabilization. This BMP has been proposed to manage 214.4 cubic feet of stormwater runoff and to mitigate upwards of the too-year, 24-hour intensity storm. L"DSCAPING All downgrade disturbed areas are proposed to be stabilized with loam and seed. UPPOR NQ DoGUMEWA ION 1. Encourage the most appropriate use of land The proposed use of a pool at a single family dwelling is appropriate as the site is located within the R3 zoning district and swimming pools are common appurtenances on single family properties. 2. Preventing overcrowding of land The proposed work complies with the required zoning setbacks and is a ground level pool. The pool shall be located in the backyard and enclosed with a new fence. 3. Conserving the value of land and buildings The proposed project should enhance the value of the properly and provide additional recreational value for the residents. 4. Lessening congestion of traffic The proposed project will not increase the average daily traffic from the lot and the existing driveway is sufficient to accommodate friends or relatives as may visit the site occasionally to enjoy the pool with family or friends. 5. Preventing undue concentration of population The proposed pool is an enhancement to a developed lot with an existing single family home which will not typically concentrate population. occasional visits from family or friends arc generally not considered un undue concentration of people. 6. Providing adequate light and air The completed pool project will not adversely impact the light or air quality of the surrounding areas. 7. Reducing the hazards from fire and other danger The proposed project will not pose any hazards from fire or other danger. S. Assisting in the economical provision of transportation, water, sewerage, schools, parks, and other public facilities The addition or a pool to the lot will not negatively impact the public facilities or utilities noted above. g. Controlling the use of bodies of water, including watercourses The proposed pool project is on a lot that does not directly abut Lake Cochichewick and will not have any impacts on present use of the Lake or its tributaries. 10. Reducing the probability of losses resulting from floods The property is not within a floodplain reducing the probability of the work causing damage and loss. 11. Reserving and increasing the amenities of the Town The proposed project will result in an improvement to the property and increased property tax which will help to increase funds available to the Town for public amenities. PROOF of No REASONABLE ALTERNATIVE-LOCATION The proposed work is proposed in an optimal location for the use as the lot is encompassed entirely by the 325 foot non-discharge buffer. Additionally, the parcel is encumbered by the wetland to the northwest, and a sewer easement along the north and east sides of the lot, minimizing the potential for alternative locations to place the pool on the lot. EVIDENCE of APPROVALL FROM MASS DEP No approval from Mass DEP is required for any industrial wastewater treatment or disposal system or any wastewater treatment for a system of fifteen thousand gallons per day capacity as none arc proposed. EVIDENCE-ON SITE OPERATIONS WILL NOT CREATE CONCENTRATIONS of NITRO QENI IN QR0 UNDWATI R.EiREATER.THAN`f I-E FETE ERALL LEMIT D OWN, EiRADIENT of THE PROPERTY The construction of the proposed pool will employ all the best management practices suitable for a pool concerning erosion and stormwater control. Sediments will be managed by installing an erosion control barrier to keep sediments from entering the downhill wetland. The pool is not a source of nitrogen and phosphorus so there will be no increases in nitrogen concentrations downgradient of it. PR,0JECTIONS of DOWN. QRADIENT CoNCENTRAMON of NITRO PHOSPHORUS, D OTHER RELE-VART CHEMICALS AT PROPERTY B-oUNDARIES3 The proposed pool will not create concentrations of nitrogen or phosphorus, or other relevant chemicals, at the property boundaries. WRITTEN GERMFIC TION I, David R. Beati certify that the work depicted on the Plan titled "Stormwater Remediation Plan N 318 Salem Street North Andover MA, dated October 14, 2024, prepared by PFS Land Surveying, LLC will not result in the significant degradation of the quality or quantity of water entering Lake Cochichewick. David R. Beati, MA P.E. #454 19 OPERATIONS & MI-A MTENANCE FLAN: System owner: Jaime-Lyn Pickles 318 Salem Street North Andover MA 01845 IrCiRD ND SW"I_.N.Q POOL 0 The proposed swimming pool shall be equipped with a non-backwash filtration system. A Pentair System 3@ Modular Media Filter is proposed. 0 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. 0 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. 0 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 0 Pool filtration system to be cleaned and maintained in accordance with manufacturer specifications detailed in the attached owner's manual. 0 once operating pressure reaches 10 PSI above initial operating pressure, inspect and clean filter element. Filter element should be cleaned with hose and drained into stone infiltration trench. 0 on a weekly basis, debris should be removed from 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 system is started. WF LTPvATION TRENCH This operations & Maintenance Plan has been prepared to comply with the provisions set forth in the Massachusetts Department of Environmental Protection (DEF) 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 othelwise 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 scarred and tilled to induce infiltration, and all of the stone aggregate and filter fabric or media must be removed and replaced. Inspection and Maintenance Log. Date Inspector condition Maintenance Performed Jaime-Lyn Pickles OWNER,-IS SIB ATUR