Loading...
HomeMy WebLinkAboutCivil and Stormwater PeerReview_Zero_Prescott - HW - Final - Consultant Review - 0 Prescott Street 12/16/2025 December 16, 2025 Ms. Jean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 01845 Re: InitialTechnical Peer Review–Comprehensive Permit Application Zero PrescottStreet North Andover, Massachusetts Dear Ms. Enright and Board Members: The Horsley Witten Group, Inc. (HW) is pleased to provide the North Andover ZoningBoardof Appeals (ZBA) with this report summarizing ourinitialreview of theComprehensivePermit Applicationfor Zero PrescottStreet.The plans and calculations were prepared by Civil Design Group, LLC, dated October 2025, on behalf of RCG,LLC (Applicant).The project proposes to replace the existing garage at 10 Prescott Street with two new buildings housing 296 rental units and a multi-story parking garage on a 6.13-acre parcel.The Applicant is proposing catch basins, hydrodynamic separators, and a subsurface infiltration system to capture and mitigate the stormwater from the proposedincrease inimpervious areas. The project is located within the Downtown Overlay Historic Mill Area:Subdistrict A with underlying zoning districts Industrial S (IS)and Residential 4(R4).The proposed improvements do not appear to be withinthe 100-foot buffer zone of a wetland resource area therefore arenot within the jurisdiction of the North Andover Conservation Commission. The following documents and plans were reviewed by HW: Application for Comprehensive Permit, Zero Prescott, North Andover, MA, preparedby RCG, LLC, dated October 21, 2025(24pages); Determination of Project Eligibility,regarding Zero Prescott, North Andover, MA, prepared by MassHousing, dated September 16, 2025 (9pages); List of Waivers, Zero Prescott, North Andover, MA (23pages); Stormwater Management Report for East Mill Residential Development, 0 Prescott Street, North Andover, MA, prepared by Civil Design Group, datedOctober2025 (137 pages); Architectural plan set, Zero Prescott, North Andover, MA, prepared by TAT, dated October 21, 2025, (13 Sheets); and Town of North Andover December 16,2025 Page 2of 10 Comprehensive Permit, Site Development Plans, for Zero Prescott, Residential Development,0 Prescott Street, North Andover, MA,prepared by by Civil Design Group, dated October 2025(21sheets), which includes: o Cover Sheet1 o Legend & Notes2 o Site Demolition & Erosion Control Plan3 o Site Plan4 o Grading &Drainage Plan5 o Utility Plan6 o Construction Details7-12 o ALTA/NSPS Title Insurance Survey (1/14/24) Shts1-6 o Preliminary Landscape PlanL1.0 & L2.0 o Photometric Lighting PlanL3.0 Stormwater Management Design Peer Review HW offers the following comments concerning the stormwater management design as per the Massachusetts Stormwater Handbook (MSH) dated February 2008, and the North Andover Chapter 165 Stormwater Management and Erosion Control Bylaw (Bylaw), and the Chapter 250 Stormwater Management and Erosion Control regulations (Stormwater Regulations) adopted June 21, 2022. 1.Standard 1: No new stormwater conveyances (e.g., outfalls) may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Commonwealth. a.The Applicant has analyzed the pre-and post-development stormwater runoff to four pointsof analysis(POA). (1)POA-1 is an existing 18-inch culvert that carries stormwater from the existing garage roof and a portion of the existing parking lot (EX-1) under the western driveway and discharges into the existing municipal drainage system in High Street (POA-2). The culvert will remain under proposed conditions.The proposed catchment area (PR-1) is reduced significantly from the existing catchment area because it does not include the proposed building. (2)POA-2 is the existing municipal drainage system in High Street. The stormwater from a large portion of the existing and proposed site is directed into the municipal system(EX-2).Under proposed conditions a portion of the development is directed towards a subsurface chamber system (SIS-1) and a portion of the building is piped directly towards the closed drainage system.The catchment areas directed towards POA-2 include most of the proposed development.HW notesthat the stormwater from a portion of the southern parking lot within EX-2 and PR-2 appears to flow offsite via the center driveway. It is not obvious how this runoff is directed into the drainage system defined by POA-2. (3)POA-3 is the portion of the project area onthe east side of the site that flows towards the east and the adjacent Meadow View Condominium property(EX-3). Under proposed conditionsthis area is reduced slightly(PR-3). H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 3of 10 (4)POA-4 is the portion of the project area that flows southeast onto the southern parking lot(EX-4).Under proposed conditions this catchment area is reduced slightly (PR-4). HW notes that the narrative and Figure 3 describeEX-4as consisting of 0.24 acres. However, it is approximately 0.39 acres as listedin the HydroCAD model.HW further notes that it appears that the western side of EX-4 and PR-4 flows towards an 18-inch corrugated metal pipe (CMP)that is directed into EX-1 and PR-1. HW recommends that the Applicant revisit the catchment areas to POA-4under existing and proposed conditions. b.Theclosest resource area is Mill Pond to the southeast of the project area. The proposed development is greater than 100 feet from this pond. HW recommends that the Applicant clarify where the closed drainage system modeled as POA-2 discharges to. HW further recommends that the Applicant confirm that the final discharge point is not currently causing erosion in wetlands or waters of the Commonwealth. 2.Standard 2: Stormwater management systems shall be designed so that post-development peak discharge rates do not exceed pre-development peak discharge rates. a.The Applicant has included a Peak Flow Rate ComparisonTable in Section 7.0of the Stormwater Management Narrative. ThePost-developmentpeak flows do not exceed the pre-developmentvalues. HW recommends that the Applicant update the Table,if applicable,after responding to the other comments in this letter. b.Per §250-22 B. (5)(b) and §250-23 A. (1) of the North Andover Stormwater Regulations, Low-Impact development (LID) site planning and design strategies must be implemented to the maximum extent feasible. The Applicant has incorporated onesubsurface infiltration chambersystemas an LID technique. HW recommends that the Applicant document other LID options it considered withinthe Project Area. c.In accordance with §250-22 B. (5)(c),HW recommends that the Applicant identify the watershed basin and the downgradient water body that stormwater from the project site discharges into. d.In accordance with §250-22 C. (4)(c),HW recommends that the Applicant delineate any existing or proposed slopes between 15% and 25% and over 25%. e.In accordance with §250-22 C. (4)(g),HW recommends that the Applicant call out any significant or unique trees or tree clusters. f.In accordance with §250-22 C. (5)(b),HW recommends that the Applicant includes profiles of the drainage truck lines. g.In accordance with §250-22 D. (1 and 4),the calculations provided should include peak flow rates and volumes. HW has confirmed that the peak volumes have been reduced over existing conditions. However, werecommend that the Applicant includesa table with the pre-and post-peak volumes of stormwater runofffor documentation purposes. h.HW notes that the Applicant has used a direct entry of 6 minutes for the times of concentration (Tc) values for all Pre-development and Post-development catchment areas.HW recommends that the Applicant revisit the Tc values for catchment areas EX- 2 and PR-2in accordance with §250-23 E. (18)and provide the flow paths on Figures 3 and 4. H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 4of 10 i.In accordance with §250-23 E. (19),the Applicant must utilize the 24-hour rainfall data taken from National Oceanic and Atmospheric Administration (NOAA) Atlas 14 for the rainfall precipitation depths. The Applicanthas used theNortheast Regional Climate Center(NRCC)values,which are similar. YearNRCCValuesNOAA Atlas 14 Values 2-year3.15 inches3.15 inches 10-year4.83 inches5.00 inches 25-year6.16 inches6.15 inches 100-year8.94 inches7.93 inches j.In accordance with §250-23 E. (22),HW recommends that the Applicant providespipe sizing calculationsusing Mannings Equation and confirmsthat the drainage pipes can accommodate a 25-year storm event. k.HW notes that the existing pipe configuration at the intersection with High Street and the driveway access drive is confusing. HW requests that the Applicant clarify how the various catch basins and manholes are connected. Furthermore, the Applicant is connecting anew18-inch drainpipeto the existing drainage system at an existing catch basin, it is not clear the size of the existing drainpipes and if the existing system can manage the proposed runoff.HW recommends that the Applicant providesadditional documentation on the existing drainpipes.If feasible,HW recommends that the Applicant tie into the existing system at a manhole. l.In accordance with §250-23 E. (30),all drainpipes are to be reinforced concrete pipe (RCP)with a minimum diameter of 12 inches.HW notes that the Applicant is proposing high-density polyethylene (HDPE) pipes. 3.Standard 3 requires that the annual recharge from post-development shall approximate annual recharge from pre-development conditions. a.The Applicant has provided a Natural Resources Conservation Service (NRCS) Soils map which documented that the soils on site are classified as Urban Land and Woodbridge. The Applicant conductedsoil test pits within the footprint of the infiltration system to confirm the Estimated Seasonal High Ground Water (ESHGW)and the exfiltration rate used in the HydroCAD model.The soil in the test holes was listed as sand and the Applicant has used an exfiltration rate of 2.41 inches per hour (iph) in the HydroCAD model. HW finds the exfiltration rate to be reasonable. b.HW notes that bottom of the infiltration system is set at elevation 95.0 and the ESHGW in test pit T-1indicates thatESHGW is at approximately elevation 91.0 providing the required four feet of separation.No further action is requested. c.The Applicant has provided drawdown calculations in Section 9.0 of the Stormwater Management Narrative.HW notes that the Applicant has stated that the increase in impervious area is approximately 0.03+acres. The HydroCAD calculations indicate the H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 5of 10 increase is 0.041 acres. HW could notconfirm the volume of stormwater being retained in the subsurface infiltration system with the information provided. HW recommends that the Applicant provide the stage storage area printout from the HydroCAD model for confirmation. 4.Standard 4 requires that the stormwater system be designed to remove 80% Total Suspended Solids (TSS) and to treat 1-inch of volume from the impervious area for water quality. a.The Applicant has provided waterquality calculationsto confirm that the treatment trains exceed the 80% TSS removal requirement per the MSHand §250-23 C. (1) of the North Andover Stormwater Regulations.HW recommends that the Applicant provides documentation confirming the TSS removal provided by the proposed proprietary devices.HW notes that the Applicant has provided a detail of a Hydroworks HS4. However, we could not locate where this device is proposed. b.In accordance with §250-23 B. (1)(b),HW recommends that the Applicant provides calculations to verify that the proposed stormwater chamber systemscan captureand retainthe volume of runoff generated by 1-inch times the increase in impervious area of the site.HW could notconfirm the volume of stormwater retained with the documentation provided. c.HW recommends that the Applicant address the Phosphorous removal calculations in accordance with §250-23 C. (1) of the North Andover Stormwater Regulations. 5.Standard 5 is related to projects with a Land Use of Higher Potential Pollutant Loads (LUHPPL). a.Theproposed projectis not considered a LUHPPL. Standard 5 is not applicable. 6.Standard 6 is related to projects with stormwater discharging into a critical area, a Zone II, or an Interim Wellhead Protection Area of a public water supply. a.The proposed development is not discharging near or into a critical area, Zone II or an IWPA area. Standard 6 is not applicable. 7.Standard 7 is related to projects considered Redevelopment.A redevelopment project is required to meet the following Stormwater Management Standards only to the maximum extent practicable: Standard 2, Standard 3, and the pretreatment and structural best management practice requirements of Standards 4, 5, and 6. Existing stormwater discharges shall comply with Standard 1 only to the maximum extent practicable. A redevelopment project shall also comply with all other requirements of the Stormwater Management Standards and improve existing conditions a.This project is considered a mix of new development and redevelopment. The Applicant is required to comply with the new development standards for the increase in impervious areas as described under Standards 3 and 4 above. The Applicant is required to meet the standards for the remainder of the site to the maximum extent practicable and improve existing conditions.HW recommends that the Applicant describe how it is improving existing conditions. H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 6of 10 8.Standard 8 requires a plan to control construction related impacts including erosion, sedimentation, or other pollutant sources. a.The Applicant has provided a Site Demolition & Erosion Control Plan. HW recommends that the Applicant clarify the type of erosion control barrier proposed. The plans call for a wattle, and the detail references a silt sock with a silt fence. It is HW’s opinion that the silt sock with a silt fenceis the preferred method. b.HW recommends that the Applicant includesa detail of the construction fence that is proposed on the northern limit of work. c.HW recommends that the Applicant includesinlet protectionin allexisting catch basins within 100 feet ofthe construction entrance. d.The limit of disturbance will be greater than 1 acre therefore aConstruction General Permit (CGP) and a Stormwater Pollution Prevention Plan (SWPPP) is required by EPA. TheZBAmay choose to require a final signed SWPPP a minimum of 14 days prior to land disturbance. 9.Standard 9 requires a Long-Term Operation and Maintenance (O & M) Plan to be provided. a.The Applicant has provided anOperation and Maintenance Planwithin the Stormwater Management Report. The plan liststhe property ownerand site engineer. The ZBAmay choose to require receipt of a signed O&M Plan prior to occupancy as a condition of approval. b.The O&M Plan indicates that solid waste materials will be stored in dumpsters provided on site. It is not obvious onthe Site Plan where the dumpsters are located. c.HW notes that the O&M Plan states that Pet Waste is not anticipated based on the proposed use of the site. HW recommends that the Applicant clarify if dogs will be prohibited from the residential units. d.Section 3 of the O&M Plan references yard drains. However,it is not clear how these should be maintained. e.The Applicant has noted that the Hydrodynamic Separator should be cleaned per the manufacturer’s recommendation. HW recommends that the Applicant includes the manufacturer’s recommendations with the O&M Plan. f.The Applicant has included a Quarterly Stormwater Inspection Report. HW recommends that the Applicant include the catch basins,the yard drains, and the deep sump drain manholesas part of this Report. g.HW recommends that the Applicant includesthesnow storage locations on the Figure -1 BMP Location Plan. h.HW recommends that the Applicant providesthe O&M Plan as a standalone document that can be provided to theproperty owner(s). 10.Standard 10 requires an Illicit Discharge Compliance Statement be provided. a.The Applicant has provided a signed Illicit Discharge Compliance statement.No further action is requested. H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 7of 10 Site Plan Review: A multifamily dwelling unit having seven or more units is allowed by Special Permit by the Planning Board in Subdistrict A.TheComprehensive Permit application proposes two new buildings housing 296 rental units connected by a multi-story parking garage.HW has the following comments regarding the site plans. 11.Parking: a.There are 100 surface level parking spaces,in the south side yardof the proposed building. The typical size is 9-feet wide by 18-feet long with a 25-foot-wide aisle. These spaces are in the same location as the existing parking spaces. Two of the proposed surface spaces will be striped as van accessible. b.There are 77 parking spaces on the first floor of the garage, 10 are marked for electric vehicles (EV), and three are marked as accessible. HW notes that the Applicant has listed 79 spaces, we recommend that the Applicant clarify the number of spaces provided on the first floor. c.There are 80 parking spaces on the second, third, fourth and fifth floors of the garage, 22 on each floor are marked for EV for a total of 88 spaces on the four floors, and two spaces are marked as accessible. The Applicant has noted on the Site Plan,Sheet 4, that 9 accessible parking spaces are provided. HW notes that per 521 CMR 23.2.1,497 spaces require a minimum of nineaccessible spaces. We only counted sevenand recommend that the Applicant revisit the number of spaces marked as accessible. d.The Applicant has proposed a total of 497 parking spaces, 7 of which are marked as accessible, and 98 are marked for electric vehicles (19.7%). HW agrees that thetotal number of spaces proposed complies with Section 195-8.4 of the North Andover Zoning Code. HW recommends that the Applicant confirm the sizes of the parking spaces and aisles inside the garage. 12.Grading: a.On the northwest corner of the garage there is a walkway that provides the pedestrian connection from the garage to Prescott Street. The proposed grading in this area directs the runoff from thelargearea on the north side of the site over this walkway and along the north side of the west wing. HW recommends that the Applicant review this corner and confirm that ponding and/or icing in this area will not be an issue. b.The Applicant appears to have graded the walkways to be ADA compliant. Note 5 of the Grading & Drainage Notes on Sheet 1 states the maximum slopes allowed. 13.Retaining Walls: a.Proposed Retaining Wall #1 is approximately 164feet long and is located on the north side of the amenity space for Building 1.Sections of this wall are greater than 10 feet high and the wall will need to be designedby a structural engineer.HW recommends that the Applicant includesRetaining Wall #1 incross section C-C provided on Sheet A5.01. b.Proposed Retaining Wall #2is approximately 114feetlong and is locatedon the northwest side of the proposed building parallel to Prescott Street. The wall appears to H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 8of 10 be less than 4 feet high. Because of the length of the wall,HW recommends that a structural engineer be involved in the final design.HW recommends that the Applicant include Wall #2 on cross section B-B provided on Sheet A5.00. c.Proposed Retaining Wall #3is approximately 45 feet long and is located on the north side of the proposed garage adjacent to the proposed walkway and approximately 5 feet from the property boundary with 39 Prescott Street.The wall appears to be only 2 feet high.HW recommends that the Applicant include Wall #3 on cross section F-F provided on Sheet A5.02. d.Proposed Retaining Wall #4 is approximately265 feet long and is located on the east side of the parcelapproximately 5 feet from the property line. Sections of the wall are between 6 and 10 feet high, though the portion of the wall that runs parallel tothe property line is less than 3 feet high. e.Proposed Retaining Wall #5 is approximately 112 feet long and located to the east of Building 2, across the driveway from Wall #4. The entire wallappears to be only 1 foot high. f.HW recommends that the Applicant confirmsour description of the walls and documents any modifications it makes. 14.Building Setbacks: The Applicant has included a Zoning Information table on the Site Plan, Sheet 4. a.In accordance with Section 195-18.12 of the North Andover Zoning Code, an application for a proposed project located within Subdistrict A may either use the standards in the underlying zoning district in their entirety, or those standards contained within Part 2 in their entirety.The Applicant has listed the three zoning districts it resides in and the zoning waivers requested per district. As a Comprehensive Permit is not required to fully comply with the local zoning requirements the ZBA may choose to consider the intent of Subdistrict A: Historic Mill Area and whether the proposed project is inline with the originalintent. b.Building 1 is located 18.8 feet from the western property boundary along Prescott Street. This appears to be the closest front yard setback. The Applicant has listed the front yard setback as 20.2 feet and has requested a waiverfrom the 30-foot requirement in a Residential 4(R4)zoning district.HW recommendsthat the Applicant confirmsthe minimum provided front yard setback. c.Building 1 is located 16.5 from the southeast corner of 39 Prescott Street.A four-foot- high black metal picket fence is proposed along the property boundary. The existing East MillGarage is located approximately 45 feet from this same corner. This appears to be the closest point to a residential property.It would be beneficial for the Applicant to add the adjacent buildings including the residential garages to the plan set.The Applicant has requesteda waiver from the35-footside yard setbackrequired for anew building in Subdistrict A when the Subdistrict Aline abuts a residential zoning district located outside Subdistrict A.The Applicant is also requesting a waiver from the 30-foot front yardsetback required in a R4district. H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 9of 10 d.Building 2 is located 34.6 feet from the eastern property line adjacent to Meadow View Condominiumwhich is in a residential5 zoning district.This areamay be defined as the rearyardrequiring 30 feet of setback from the R4 and the IS districtsand 35 feet from Subdistrict A. Or it may be considered a sideyardrequiring a 35-foot setback for a new building in Subdistrict A when the Subdistrict A line abuts a residential zoning district located outside Subdistrict A. The Applicant has not requested a waiver from the rear yardsetback line but has requested a waiver from the sideyardsetback line. HW recommends that a determination be made regarding thearea between the building and theeastern property line. e.Thehighest proposed building height is approximately 54 feet 7 inchesfeetfrom the average finish grade. The Applicant is requesting a waiver from the maximum height of 35 feet within an R4 district.The IS district and Subdistrict A appear to allow a maximum height of 55 feet by right. f.The maximum lot coverage calculated by the Applicant is 34%. The maximum allowable lot coverage within the IS district is 35%. The Applicant has requesteda waiver. However,it is not apparent that one is needed. g.The Applicant is requesting a waiver from the Maximum Floor Area Ratio(FAR) and is proposing a FARof 1.70:1. A ratio of 1:1 is allowed by right in Subdistrict A. A ratio of 0.5:1 is allowed by right in an IS district. A FARof up to 2:1 is allowed by Special Permit in Subdistrict A. 15.Design Criteria: a.The Applicant is using the same curb cuts as exists for the existing parking garage with a 25-foot-wide driveway. b.It is not obvious if bike racks are proposed. HW recommends that the Applicant includes an interior storage location for bicycle accommodation in accordance with Section 195- 18.18 C. c.HW recommends that the Applicant consider a solid five-foot-high fence along the property of 39 Prescott Street or additional trees for screening. d.The Applicant has proposed two generators, one for each building that are located near the surface parking spaces. The size of the generators looks small for the size of the building. HW recommends that the Applicant confirm the size and determine if additional screening or enclosureis necessary. e.The Applicant has provided a Photometric Calculation Plan, Sheet L3.0. The light candles appear to spill over onto the Meadow View Condominiums and slightly ontothe property at39 Prescott. HW recommends that the Applicant confirm that the amount of spillover will not be a nuisance for any abutting residents. f.HW recommendsthat the Applicant includesa locus plan showing the names of abutters, land uses, and locations and width of all adjacent streets. g.The Applicant is proposing one new fire hydrant. There is an existing hydrant on Prescott Street near 139 Prescottand an existinghydrant on High Street atthe intersection with Prescott Street. It appears that fire apparatus can reach three sides of the proposed building. HW recommends that the Applicant coordinatewith the fire H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx Town of North Andover December 16,2025 Page 10of 10 department to confirm thatthe hydrant locations are adequate and that they canaccess, circulate, and egressthe site andbuilding safely. h.HW recommends that the Applicant confirmwith the North Andover Department of Public Works that the municipal sewer and water systems have adequate capacity to accommodate an additional296 residential units. i.HW recommends that the Applicant add the depth of gravel subbase tothe Typical Bituminous Pavment Detail, on Sheet 8. j.HW recommend that the Applicant confirmshow trash and recycling operations will be performed by the residents. Conclusions HW recommends that the ZBArequires that the Applicant provide a written response to address these comments as part of the Board’s review process. 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. Principal H:\\Projects\\2024\\24018 Town of North Andover\\24018P Zero Prescott Street\\Reports\\251216_SWPeerReview_Zero_Prescott.docx