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HomeMy WebLinkAbout2013-09-17 Planning Board Supplemental Materials (119) 199 Newbury Street, Suite 115 ● Danvers, MA 01923 ● 978.777.7250 ● fax 978.777.8650 ● www.lynnfieldeng.com August 29, 2013 North Andover Planning Board 1600 Osgood Street Building 20, Suite 2-36 North Andover, MA 01845 Attention: Ms. Judy Tymon, Planner Subject: Peer Review Summary 1077 Osgood Street Application for Site Plan Special Permit LEI Job No. 480-60 Dear Ms. Tymon: This correspondence has been prepared on behalf of Angus Realty Corporation North Andover, MA in response to correspondence received dated August 9, 2013 from Joseph Peznola, P.E. Hancock Associates Marlborough, MA regarding the Pentucket Bank development at Butcher Boy Marketplace 1077 Osgood Street North Andover. A. COMMENTS RECEIVED FROM HANCOCK ASSOCIATES 13. Hancock Associates Response: The applicant has provided the top of wall elevation at the location where the new wall will meet the existing wall. The applicant should provide the bottom of wall elevation where the new wall will meet the existing wall or indicate that bottom elevation will match the bottom elevation of the existing wall. LEI Response : Refer to Drawing C-6, Site Grading, Drainage and Utility Plan. Bottom of wall elevation has been added to the drawing. 16. Hancock Associates Response: The Site Grading, Drainage and Utility Plan, C-6, has been revised so that all proposed catch basins drain to either drain manhole PDMH-2 or PDMH-4. It appears that these two manholes drain to water quality structures, but each manhole also has what looks like an additional pipe draining directly to the detention systems. The applicant should clarify on the plans whether the drain manholes have two outlet pipes. Runoff from all catch basins should drain through the water quality structures. If drain manholes PDMH-2 or PDMH-4 are intended to have overflow weirs for larger storm events, this should be indicated and detailed on the plans. Ms. Judy Tymon August 29, 2013 Town of North Andover Page 2 of 4 K:\480-60\Reports\082913_Hancock Resp\01_Tymon J_082913_let_Hancock Aug resp.doc LEI Response : The CDC units were requested to be “off-line” therefore PDMH-2 and PDMH-4 are diversion manholes. The detail on Drawing C-11 provides information on the diversion pipes and inverts. 17. Hancock Associates Response: Based on the structure chart provided, the following three structures do not appear to have adequate cover: PDMH4, PCB12, and PCB13. With a standard 8" high frame and grate the minimum cover over the crown of the connected HDPE pipes is 2' which accounts for the thickness of the pipe, separation required between the cored hole in the structure and the top slab of the structure, the thickness of the top slab, and the height of the frame and grate. If the applicant proposes to use a low profile frame and grate the minimum cover over the crown could be reduced by as much as 4". The applicant should provide a detail of the catch basin frame and grates and the drain manhole frames and covers. LEI Response : The minimum cover over the crown of a 12-inch HDPE pipe is one foot to the bottom of pavement as specified by ADS, a manufacturer of HDPE pipe. A 12-inch HDPE pipe has a dimension of 1.10’ from invert to crown; therefore the minimum cover is 2.35’ to the top of pavement. We have added a note on Drawing C-9 (catch basin detail) indicating that the contractor shall not use a precast flat top for structures having less than three feet from rim to invert. 18. Hancock Associates Response: It appears that the roof drywells and the proposed detention systems (which receive surface runoff from catch basins) are located within the Zone A. Further, since the system of roof drywells, proposed detention systems, catch basins, and pipe networks is very shallow and all of these components are at similar elevations, flow from the catch basins could back up into the roof drywells during large storm events. As previously stated, Hancock Associates believes that if the infiltration and detention systems are allowed in the Zone A area by the DEP and the North Andover Planning Board and Conservation Commission, they should be designed to meet all of the Massachusetts Stormwater Standards and the applicant should provide documentation of their compliance with the standards. LEI Response : The outlet inverts at the drywells are located above the 100 year flood elevation. Therefore backwater to the drywells, from the detention areas, will only occur for storm events greater than a 100 year storm event. LEI is coordinating the specifics of the stormwater design with Eggleston Environmental. The project has been designed to meet all the MassDEP Stormwater Standards. Ms. Judy Tymon August 29, 2013 Town of North Andover Page 3 of 4 K:\480-60\Reports\082913_Hancock Resp\01_Tymon J_082913_let_Hancock Aug resp.doc 19. Hancock Associates Response: It appears that the detention systems with solid pipes and low flow outlets at bottom of 18" and 24" pipes have been raised from the previous submission. No other revisions are apparent. Hancock Associate's previous comment still applies. LEI Response : The detention areas are a closed system that do not exfiltrate stormwater. Test pit data along with the estimated seasonal high ground water table are depicted on Drawings C-6 and C-11. 24. Hancock Associates Response: As previously stated, since the plans show the proposed driveway as being used for the proposed bank as well as the Butcher Boy Marketplace, the applicant should provide the number of trips for the entire site to demonstrate the daily traffic on the entrance driveway portion of the project which will be used by the entire site. If the total is over 1,000 trips per day, the entrance driveway portion of the project is considered a Land Use with Higher Pollutant Loads, and stormwater runoff from this area must be designed to accordingly. LEI Response : LEI is coordinating the specifics of the stormwater design with Eggleston Environmental. 25. Hancock Associates Response: Water and sanitary sewer services are now shown on the above referenced plan. The sizes and materials of these services should be shown on the plan. Also, the plan should show sizes and locations of gas services (if applicable) and electric and communications services. LEI Response : The size and materials of the water and sewer services are depicted on the plans. It is not known at this time if a gas service will be need at the bank building. The electric service provider will determine the size and location of the electrical service at such time that a work order is placed. Additional Comment: 28. The Site Grading, Drainage, and Utility Plan, C-6, is very confusing. The drainage configuration that includes structures PDMH6, PDMH9, PDMH7, PDMH8, and the Contech Stormfilter is unclear as to where water is intended to be directed between these structures. The applicant should explain the purpose of R19 if R20 and R11 are intended to convey overflow from Proposed Detention System B. Similarly, the applicant should explain the purpose of PDMH7 and R17 (which appears to flow toward PDMH7). If existing drainage is being rerouted, the Ms. Judy Tymon August 29, 2013 Town of North Andover Page 4 of 4 K:\480-60\Reports\082913_Hancock Resp\01_Tymon J_082913_let_Hancock Aug resp.doc plans should note which pipes will be removed, plugged, or abandoned in place. Flow arrows on pipes would also help to clarify. Again, we defer to Lisa Eggleston for full review of stormwater issues and we offer commentary to aid in this review. LEI Response : LEI is coordinating the specifics of the stormwater design with Eggleston Environmental. If you have any questions or desire any additional information regarding this matter, please do not hesitate to contact me at 978.777.7250 Ext. 12. Respectfully Submitted, Lynnfield Engineering, Inc. Richard Barthelmes, P.E. enclosures c: Joseph Peznola, P.E., Hancock Associates Alan Yameen, Angus Realty Corporation both with enclosures ATTACHMENT NO. 1 Correspondence Hancock Associates Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com August 9, 2013 Ms. Judy Tymon, Planner North Andover Planning Board 1600 Osgood Street – Bldg. 20 Suite 2-36 North Andover, MA 01845 Subject: Peer Review Summary #3 1077 Osgood Street Application for Site Plan Special Permit Dear Ms. Tymon: This letter is in response to Lynnfield Engineering, Inc.'s August 2, 2013 letter addressing Hancock Associate's July 15, 2013 peer review summary. Also included is a review of the following: 1. Proposed Site Plans, "Pentucket Bank at Butcher Boy Marketplace", prepared by Lynnfield Engineering, Inc., dated March 15, 2013 and revised August 1, 2013, containing seventeen (17) sheets. The following was used to assist in our review: 1. Zoning Bylaw of Town of North Andover last amended June 12, 2012 2. General Bylaws of the Town of North Andover, (adopted April 23 1979 as amended). Project Description The project entails development of a portion of the Butcher Boy Market Place site current occupied by a stormwater detention basin and access drive from Osgood Street with the construction of a 3,672 square foot bank with a three lane drive-through window featuring two teller lanes and one automated teller machine (ATM). A twenty-one-space parking lot and connection to on site utilities is also proposed. Access to the site will be provided via the existing one-way entrance and exit driveways that serve the current marketplace from Osgood Street. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com Comments 3. As the proposal is an expansion of the existing retail center, the Applicant must present zoning compliance information for the entire site as well as impact on prior approvals and conditions of approvals for the site. Lynnfield Engineering, Inc. Response: No response provided. Hancock Associates Response: Zoning compliance information for the entire site is included in the response to comment 1. Applicant should provide impact on prior approvals and conditions of approvals for the site. Lynnfield Engineering, Inc. Response: There are no known compliance issues related to prior approvals and/or conditions of the site. Hancock Associates Response: No further response. 6. The Landscape Plan must be prepared and stamped by a Landscape Architect not a Sanitary Engineer. The landscape plan refers to relocation of trees and shrubs without itemizing quantities. It appears more trees are proposed than available for relocation. The Applicant should provide a plant list containing new and relocated species and sizes should relocation prove unsuitable. The Applicant must demonstrate compliance with Zoning By-law Section 8.4. Lynnfield Engineering, Inc. Response: Refer to revised Drawing L-1, Landscape Plan. Hancock Associates Response: The note 3 on the Landscape Plan, L-1 should be revised to indicate that plants that are deemed unsuitable before, during, or after relocation will be replaced with the same size and species. Lynnfield Engineering, Inc. Response: Refer to revised Drawing L-1, Landscape Plan. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com Hancock Associates Response: No further response. 7. The landscape island modified by the reconfigured entrance is only three (3) feet wide. This is far too narrow for effective landscaping. The Applicant should comment on the impact to the overall Butcher Boy Market Place compliance with Zoning By-law Section 8.4 given the proposed modifications. Lynnfield Engineering, Inc. Response: Refer to revised Drawing L-1, Landscape Plan. Hancock Associates Response: The width of the landscaped aisle has been revised so that it is 5 feet wide in most areas and 4' wide at the narrowest location. The aisle should be 6' wide or greater to comply with Zoning By-Law Section 8.4. Since the aisle is located on the perimeter of the parking lot, at least one tree shall be planted for every thirty linear feet. The trees shall be planted to be in compliance with Zoning By-Law Section 8.4. The applicant must revise the existing plan. Lynnfield Engineering, Inc. Response: Refer to revised Drawing C-5, Site Layout Plan, and L-1, Landscape Plan. The proposed landscape island is 6.5’ wide with one tree planted for every thirty feet. Hancock Associates Response: No further response. 10. The location of the proposed stabilized construction entrance should be added to sheet C-3. Lynnfield Engineering, Inc. Response: The stabilized construction entrance has been added to Drawing C-3, Erosion and Sedimentation Control Plan. Hancock Associates Response: The construction entrance should be oriented so that the edge perpendicular to the direction of travel connects directly with existing pavement. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com Lynnfield Engineering, Inc. Response: Refer to revised Drawing C-3, Erosion and Sedimentation Control Plan. Hancock Associates Response: No further response. 11. The plans should clarify if the proposed entrance is one or two-way and provide appropriate signage on sheet C-4. Lynnfield Engineering, Inc. Response: The site entrance is one way. Proposed signage is presented on Drawing C-5, Site Layout Plan. Hancock Associates Response: Signage and flow arrows are shown on the Site Layout Plan, C-5. The plans should indicate if the entrance is one lane or two. The entrance is shown as tapering from 25' wide to 16' wide. For a two lane driveway, a 20' minimum aisle is required per Zoning Section 8.1(5). If the driveway is one lane, the 16' width is acceptable. Lynnfield Engineering, Inc. Response: The entrance road tapers to 16’ wide and is a single lane one-way site access drive. Hancock Associates Response: No further response. 13. Provide top and bottom of retaining wall elevations on sheet C-5. It appears the wall will be as much as seven (7) feet high along Pond Road. The applicant must provide design plans for the wall stamped by a structural engineer. Lynnfield Engineering, Inc. Response: The top and bottom of wall elevations have been added to the plans. The plans are for permitting purposes only. The wall will be designed by a structural engineer prior to application for a building permit. Hancock Associates Response: Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com The applicant should provide existing and proposed top and bottom of retaining wall elevations at the location where the new wall will meet the existing wall. Although preliminary, the applicant should verify that geogrid required for the proposed wall will not be in conflict with Proposed Extended Dry Detention System B. Lynnfield Engineering, Inc. Response: Refer to revised Drawing C-6, Site Grading, Drainage and Utility Plan, depicting top and bottom elevations of the retaining wall where they meet. The retaining wall will be designed so as not to interfere with the proposed detention system. Hancock Associates Response: The applicant has provided the top of wall elevation at the location where the new wall will meet the existing wall. The applicant should provide the bottom of wall elevation where the new wall will meet the existing wall or indicate that bottom elevation will match the bottom elevation of the existing wall. 14. The proposed retaining wall is directly over the existing sewer main that feeds the adjacent pump station. The applicant should provide details on how this wall will be constructed without damaging the existing main, and comment on the ability to repair or replace the sewer main once the wall is constructed on top of it. Lynnfield Engineering, Inc. Response: The proposed Versa Lok retaining wall will extend approximately 12” - 16” below the existing grade, approximately 5 to 6 feet above the existing pipe. The Contractor shall video inspect the sewer line prior to and after construction to document the condition of the sewer line. Hancock Associates Response: The plans should include a note indicating that the contractor is responsible for repairing any damages to the existing sewer main. Lynnfield Engineering, Inc. Response: A note has been added to Drawing C-6, Site Grading, Drainage and Utility Plan. Hancock Associates Response: No further comment. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com 16. Proposed catch basin PCB10 appears to connect directly into the drainage system without treatment and does not meet the 80% TSS removal requirement. Lynnfield Engineering, Inc. Response: Refer to the revised site layout and storm drain system. Hancock Associates Response: The Site Grading, Drainage and Utility Plan, C-6, has been revised so that catch basin PCB10 now drains to drain manhole PDMH1 which drains to water quality inlet PWQI#1 before entering Extended Dry Detention System A. Stormwater flow from PCB10 now appears to receive adequate treatment. The existing site drainage system now appears to connect directly into the drainage system via drain manholes PDMH7 and PDMH6 and does not meet the 80% TSS removal requirement. Lynnfield Engineering, Inc. Response: Refer to the revised site layout and storm drain system. Hancock Associates Response: The Site Grading, Drainage and Utility Plan, C-6, has been revised so that all proposed catch basins drain to either drain manhole PDMH-2 or PDMH-4. It appears that these two manholes drain to water quality structures, but each manhole also has what looks like an additional pipe draining directly to the detention systems. The applicant should clarify on the plans whether the drain manholes have two outlet pipes. Runoff from all catch basins should drain through the water quality structures. If drain manholes PDMH-2 or PDMH-4 are intended to have overflow weirs for larger storm events, this should be indicated and detailed on the plans. 17. The applicant should provide a detail of the catch basin frame and grates, with dimensions demonstrating that they can be constructed with only 1.5± feet of cover over the pipe as they are designed. Lynnfield Engineering, Inc. Response: In order to construct the catch basin structures and install the pipe the minimum cover over the HDPE is 1.7 feet. This would include a frame and cover 8 inches deep and a flat top catch basin which is 12 inches thick. Hancock Associates Response: Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com The applicant's response does not account for the thickness of the HDPE pipe which for 12" pipe is typically 2.5" or the fact that the structure cannot be cored within 6" of the cover seal. The applicant should provide a detail of the catch basin frame and grates and adjust the elevations of the drainage system as necessary so that the structures and pipes can be installed as shown on the plans. Lynnfield Engineering, Inc. Response: Refer to revised catch basin detail on Drawing C-9, Site Details. Hancock Associates Response: Based on the structure chart provided, the following three structures do not appear to have adequate cover: PDMH4, PCB12, and PCB13. With a standard 8" high frame and grate the minimum cover over the crown of the connected HDPE pipes is 2' which accounts for the thickness of the pipe, separation required between the cored hole in the structure and the top slab of the structure, the thickness of the top slab, and the height of the frame and grate. If the applicant proposes to use a low profile frame and grate the minimum cover over the crown could be reduced by as much as 4". The applicant should provide a detail of the catch basin frame and grates and the drain manhole frames and covers. 18. The applicant has not provided infiltration as required by the MADEP SWM Regulations. Lynnfield Engineering, Inc. Response: A substantial portion of the property is located in a Zone A Area. The design provides infiltration of the roof area of the proposed bank. The infiltration system will treat the one inch rainfall event. The overflow from the infiltration system will then discharge to extended dry detention systems. Hancock Associates Response: The Massachusetts stormwater handbook states that "Unless essential to operation of a public water system, stormwater BMP's are prohibited within the Zone A." and "Stormwater Discharges to a Zone I or Zone A are prohibited unless essential to operation of the public water supply." The applicant should provide a figure showing the delineation of Zone A area on the project site and a Hydrocad report of the storage within the proposed infiltration and detention systems which should not be located within the Zone A. If the infiltration and detention systems are allowed in the Zone A area by the DEP and the North Andover Planning Board and Conservation Commission, they should be designed to meet all of the Massachusetts Stormwater Standards and the applicant should provide documentation of their compliance with the standards. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com Lynnfield Engineering, Inc. Response: Refer to revised Stormwater Drawings. Infiltration is being proposed outside the Zone A Area with the exception of the roof infiltration system. Hancock Associates Response: It appears that the roof drywells and the proposed detention systems (which receive surface runoff from catch basins) are located within the Zone A. Further, since the system of roof drywells, proposed detention systems, catch basins, and pipe networks is very shallow and all of these components are at similar elevations, flow from the catch basins could back up into the roof drywells during large storm events. As previously stated, Hancock Associates believes that if the infiltration and detention systems are allowed in the Zone A area by the DEP and the North Andover Planning Board and Conservation Commission, they should be designed to meet all of the Massachusetts Stormwater Standards and the applicant should provide documentation of their compliance with the standards. 19. The applicant has considered the underground detention area an "extended dry detention basin" with a TSS removal rate of 50%, they should provide the appropriate data and calculations including volumes and detention times between the low flow orifice elevation and the first primary outlet to document this assumption or change the design to a "dry detention basin" which has no TSS removal. We note that volumes between the bottom of the stone and the low flow orifice appear to be included in the calculations despite having no way to drain this volume between storms. Lynnfield Engineering, Inc. Response: Refer to the revised extended dry detention basins design. Hancock Associates Response: The Underground Extended Dry Detention System details indicated CMP pipe. If this pipe is intended to be perforated this should be indicated on the details. We also suggest that these systems be wrapped with non-woven filter fabric to prevent clogging of the systems. The applicant should indicate estimated seasonal high groundwater (ESHGW) elevations on the "Underground Extended Dry Detention System" and "Roof Drywell" details. A minimum of 2' separation should be provided between the ESHGW and the bottom of the infiltration and detention systems. If the applicant chooses to use infiltration as a discharge outlet for these systems, the separation needs to be 4'. The extended dry detention basins should be designed to meet the criteria described in the Massachusetts Stormwater Handbook in order to provide the TSS removal rate of 50%. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com Lynnfield Engineering, Inc. Response: Refer to revised stormwater design drawings. Hancock Associates Response: It appears that the detention systems with solid pipes and low flow outlets at bottom of 18" and 24" pipes have been raised from the previous submission. No other revisions are apparent. Hancock Associate's previous comment still applies. 21. The "Checklist for Stormwater Report" indicates the site is a mix of new development and redevelopment, as such the project "must improve existing conditions" per the MADEP SWM Regulations. "New stormwater controls (retrofitted or expanded) must be incorporated into the design and result in a reduction in annual stormwater pollutant loads from the site. Proponents of redevelopment projects shall make full use of all opportunities for controlling the sources of pollution and to incorporate environmentally sensitive site design and low impact development techniques." Lynnfield Engineering, Inc. Response: Comment noted. Hancock Associates Response: In order for a project to qualify as a "redevelopment" the project must not result in a net increase in impervious area from the previous developed condition. The portions of this project that do not meet the redevelopment requirements must fully meet all of the Massachusetts Stormwater Standards. Hancock Associates does not believe this project is considered a redevelopment under the Massachusetts Stormwater Handbook. Lynnfield Engineering, Inc. Response: Comment noted. Hancock Associates Response: Hancock Associates would like to re-state our opinion that this project is a "new development" and must fully meet all of the stormwater standards. Hancock Associates defers to further review from Lisa Eggleston. 24. The traffic report indicates an average weekday daily traffic for the bank of 544 trips. The applicant needs to provide the number of trips for the entire site, and if Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com the total is over 1,000 trips per day the site is considered a Land Use with Higher Pollutant Loads and the drainage design must be updated accordingly. Lynnfield Engineering, Inc. Response: The original Butcher Boy Marketplace was constructed in the early 1990’s, more than 20 years ago. This project is not considered to be a phased project; therefore the entire site should not be reviewed as a whole. In addition the majority of the existing site is located outside of the wetland buffer zone and the stormwater system discharges to the Merrimack River. The bank traffic is estimated to be approximately 544 vehicle trips per day which does not classify as a LUHPPL. However, the Applicant is providing improvements to the existing stormwater system. A hydrodynamic separator is proposed, prior to the existing storm drain system exiting the site. The hydrodynamic separator will provide TSS removal for the entire site in an effort to improve the overall stormwater quality exiting the property. Hancock Associates Response: The applicant should provide the number of trips for the entire site to demonstrate the daily traffic on the entrance driveway portion of the project which will be used by the entire site. If the total is over 1,000 trips per day, the entrance driveway portion of the project is considered a Land Use with Higher Pollutant Loads, and stormwater runoff from this area must be designed to accordingly. Particular consideration should be taken if this area is within the Zone A since Land Uses with Higher Pollutant Loads are not permitted in Zone A areas. Lynnfield Engineering, Inc. Response: This project is not a phased project and the proposed bank does not exceed the 1,000 vehicle trips per day or more criteria. In accordance with the Massachusetts Stormwater Handbook and 310 CMR 22 some land uses are not suitable for Zone A. However, parking lots with high intensity use (1,000 vehicle trips per day) is not prohibited within a Zone A. Hancock Associates Response: As previously stated, since the plans show the proposed driveway as being used for the proposed bank as well as the Butcher Boy Marketplace, the applicant should provide the number of trips for the entire site to demonstrate the daily traffic on the entrance driveway portion of the project which will be used by the entire site. If the total is over 1,000 trips per day, the entrance driveway portion of the project is considered a Land Use with Higher Pollutant Loads, and stormwater runoff from this area must be designed to accordingly. Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com 25. The proposed water, sanitary sewer, and gas services for the proposed building are no longer shown on the Site Grading, Drainage and Utility Plan, C-6. These services, including size and materials of the services should be included on the plans. The applicant should also include electric and communications services for the proposed building. Lynnfield Engineering, Inc. Response: Refer to Drawing C-6, Site Grading, Drainage and Utility Plan. Hancock Associates Response: Water and sanitary sewer services are now shown on the above referenced plan. The sizes and materials of these services should be shown on the plan. Also, the plan should show sizes and locations of gas services (if applicable) and electric and communications services. 26. The applicant should demonstrate how the existing "electric hand hole" and associated conduits and/or duct banks will be relocated so as not to be in conflict with the proposed building and other site utilities. Lynnfield Engineering, Inc. Response: Refer to Note 4 on electrical drawing E-1, Site Lighting Plan. Hancock Associates Response: No further comments. 27. The applicant should demonstrate how traffic will enter the existing Butcher Boy development during construction. Lynnfield Engineering, Inc. Response: Traffic will continue to access the site via the existing site access drive until such time that the proposed access drive is operational. Hancock Associates Response: No further comments. Additional Comment 28. The Site Grading, Drainage, and Utility Plan, C-6, is very confusing. The drainage configuration that includes structures PDMH6, PDMH9, PDMH7, Marlborough, MA Danvers, MA 315 Elm Street 185 Centre Street www.hancockassociates.com PDMH8, and the Contech Stormfilter is unclear as to where water is intended to be directed between these structures. The applicant should explain the purpose of R19 if R20 and R11 are intended to convey overflow from Proposed Detention System B. Similarly, the applicant should explain the purpose of PDMH7 and R17 (which appears to flow toward PDMH7). If existing drainage is being rerouted, the plans should note which pipes will be removed, plugged, or abandoned in place. Flow arrows on pipes would also help to clarify. Again, we defer to Lisa Eggleston for full review of stormwater issues and we offer commentary to aid in this review. We believe the Applicant should address the issues raised prior to the Board finalizing their deliberation of the matter. Should you have any questions or comments, please do not hesitate to contact our office. Sincerely, Hancock Associates Joseph D. Peznola, PE Principal