Loading...
HomeMy WebLinkAbout08/27/2019 - Final Stormwater Report & O&M Plan (Part 1) - 481 Sutton Street ;;v 4, " �W , DeVellis Zrein Inc. PO Box 307 Foxboro, MA 02035 Tel. (508) 473-4114 Fax. 774-215-0631 www.develliszrein.com August 27, 2019 Jean Enright, Planning Director Town of North Andover 120 Main Street North Andover, MA 01845 Re: North Andover Senior Center Response to Review Comments Dear Ms. Enright and Members of the Planning Board, This letter has been prepared in response to all of the review comments received from the second submission of the above referenced project with the Planning Board. The following are our responses with the review comments shown in regular type and our responses in bold type. Accompanying these comments are revised Site Plans, supporting documents and Drainage Report supplements all dated August 27, 2019. COMMENTS RECEIVED FROM NORTH ANDOVER DPW JOHN J BORGESI, PE DATED AUGUST 15,2019 1. The Engineering Department still does not recommend the proposed circulation pattern and recommends allowing the ability to exit the site via either the shared driveway onto Sutton Street or Surrey Drive onto Sutton Street. As previously stated, due to the curve of Sutton Street there is increased site distance when exiting the site via the shared driveway onto Sutton Street. DZI Response: The circulation patterns and exit design continues to be discussed and presented to the Planning Board in consult with the traffic engineer. 2. A call out shall be added to Sheet C-2 indicating that a saddle shall be used for the proposed sewer service connection to the existing sewer main. DZI Response: A note indicating this requirement has been added to Sheet C-2 at the connection location. 3. The callout where the drainage system exits onto Surrey Drive shall be modified to indicate in addition a new proposed drain manhole shall be installed at the final connection point. DZI Response: A new proposed drain manhole has been added to Sheet C-2 as requested. COMMENTS RECEIVED FROM TEC PETER F.ELLISON,PE,DATED AUGUSST 6,2019 1 60. Site Signage - TEC recommends that a 2nd "Do Not Enter" sign be installed on the opposite side of the site driveway. DZI Response: A second "Do Not Enter" sign has been added to Sheet C-1 as suggested. 61. Sewer calculations - TEC recommends that the Board include the sewer calculations as a condition of approval. DZI Response: MA Title V 310 15.203 (System Sewage Flow Design Criteria) has no specific category for a Senior Center. Based on experience on similar projects and reference to other commercial/institutional listed within Title V, it is estimated and agreed to by the project architect and plumbing engineer that the maximum number of users at the biggest event is 200 people X 5 GPD/person would yield 1,OOOGPD based on Title V criteria. 65. Parking calculations - TEC defers to the Town of North Andover Building Inspector to determine if adequate parking is provided for this use. DZI Response: Acknowledged 66. Photometric plan - TEC recommends that a revised Photometric Plan be required as a condition of approval. DZI Response: Two new lights have been added and a revised plan has been prepared. COMMENTS RECEIVED FROM HORSLEY WITTEN GROUP INC. JANET CARTER BERNARDO, PE DATED JULY 30,2019 Stormwater Management Design Peer Review The comments shown below in shaded text have been acknowledged by HWG Inc. as being addressed. 1. Standard 1 states that no new storrnwater conveyances (e.g. otgtf lls) Ino.),discharge untreated stornnnrater directly to or cause erosion in iretla.nds or n,aters of the Cornnonn)ealth. a. The Applicant has analyzed the existing and proposed stormwater discharge rates from the project site at the property boundaries. HW notes that there are some minor discrepancies between the pre- and post-development watershed boundaries of the 1 Surrey Drive application and the 505 Sutton Street application (review recently completed by HW on July 1, 2019). HW recommends that the watershed boundaries under existing and proposed conditions be coordinated between the two projects to the extent possible. The Applicant has adequately responded to this comment and has revised the watershed boundaries. b. The Applicant will also be discharging a majority of the proposed flow towards the municipal drainage system on Surrey Drive. To verify that the outlet of the municipal system will not cause erosion in waters of the Commonwealth, HW recommends that the Applicant show the locations of the municipal drainage system on the plans, provide a narrative describing where the municipal system currently outlets and 2 document that no erosion is currently occurring at the final discharge point. The Applicant has noted that the existing conditions plan will be updated, and a narrative will be provided. HW has not received either of these documents for review. DZI Response: The existing conditions survey plan showing the drain lines is being provided by the Town of North Andover and is in process of being updated with the drain line. The drainage analysis shows that there is not an increase to the system. The drain line within Surrey Drive enters the drainage system on Sutton Street at the intersection. It is understood that the residential project's engineer is providing the analysis of this system within their application and it is respectfully suggested that analysis will provide adequate response to the off-site drainage routes 2. Standard 2 requires that stormwatei-mmzageanerit systems shall he designed so thou post- developn?ent peak discharge rates do aiot exceed pre-development peals discharge rates. a. The Applicant has provided calculations for the 2-year, 10-year and 100-year, 24- hour events for pre-and post-development conditions. However,per the North Andover Stormwater Regulations, the 0.5-inch storm and the 25-year, 24-hour event calculations also need to be included. The Applicant has adequately responded to this comment and revised the Drainage Report to include the 0.5-inch and the 25-year storm events. b. Also, the depths of rainfall used for each event shall be as described in the North Andover Stormwater Regulations under Section 7.2 B.b. Specifically noting that the 100-year rainfall amount is 8.6 inches over 24 hours. The Applicant has adequately responded to this comment and revised the Drainage Report utilizing the depths of precipitation as required by North Andover including the 100-year, 24-hour storm event. c. Per North Andover Stormwater Regulations Section 7.2 B.i, pervious lands onsite "shall be considered to be in good condition regardless of existing conditions existing at the time of computation". HW recommends that the Applicant update pervious cover to be in `Good' condition in the HydroCAD modeling calculations for pre- development conditions. The Applicant has adequately responded to this comment and has revised the pervious surface cover to be in "Good" condition in the Drainage Report. d. The Existing Watershed Map provided by the Applicant does not show topography extending to the south (e.g., into 19 Surrey Drive), HW is not able to confirm if there is any off-site drainage from adjacent properties currently being managed onsite. HW recommends that the Applicant confirm the drainage areas under existing conditions. The Applicant has adequately responded to this comment and has confirmed the watershed boundaries by conducting a site walk and has updated the Watershed Map to include off-site topography extending to the south of the site. e. The time of concentration (Tc) value utilized for the EX-1 drainage area was assumed to be 6 minutes. HW recommends that the Te flow path be shown on the Existing Watershed Map and calculated, it appears that the lawn area may have a Te value longer than 6 minutes. 3 The Applicant has adequately responded to this comment by reevaluating and revising the Tc value for EX-1 drainage area. f. It is not clear from the Proposed Watershed Map how the Applicant delineated the subwatersheds or which portions are pervious or impervious. HW recommends that the Proposed Watershed Map include the proposed contours and shading or hatching of areas of impervious cover. Based on the information provided on the Layout and Materials Plan and Planting Plan, it appears that the amount of pervious area is closer to 0.3 acres as compared to the 0.4 acres provided in the HydroCAD modeling calculations. The Applicant has partially addressed this comment, the watershed map has been shaded to indicate pervious areas. HW is not in agreement with the proposed area listed in the HydroCAD calculations by the Applicant. In the proposed conditions HydroCAD model, the Applicant has noted 0.53 acres of pervious cover, HW believes that this area is closer to 0.45 acres. HW recommends that the Applicant revisit the area provided. DZI Response: The area in questions was recalculated and confirmed to be 0.53 acres g. Under proposed conditions, the Applicant has indicated that the stormwater runoff from the proposed building roof will be collected via a pipe and directed to a rain garden system. HW recommends that the Applicant provide a detail of the roof leaders and means to overflow if the rain garden system backs up. The Applicant has partially responded to this comment, a detail of the roof leader overflow method will be provided by the architect. DZI Response: A spot shot at the driveway curb (top 165.3 and bottom 164.8) located near the rain garden has been added to Sheet C-2. This spot is the highest elevation that the rain garden can rise without flowing out and into the curbed gutter of the drive. The FFE elevation of the building and associated grades of the downspout collection system outside the building where the downspout enters into the system.is 167.2 which is almost 2 feet higher than where the basin can rise to. The roof drains cannot back up at the connection points at the roof down spout and underground piping. h. The Applicant is showing the use of three rain gardens onsite: two to collect overland flow from the parking lot and another to manage roof runoff. For those collecting runoff overland, it is not clear how the water is being directed to the curb openings and into the rain garden. Also, there does not appear to be any pretreatment provided. HW recommends that the Applicant provide a plan-view cletail for these rain gardens showing pretreatment as required by Standard 3 and the MSH, Volume 2, Chapter 2. For the rain garden collecting roof runoff, there are no invert elevations provided for the flared end sections, The Applicant has adequately responded to this continent by providing additional notations on the plans, a small forebay to the rain garden at the front of the building and the FES inverts to the eastern rain garden. i. The Applicant is proposing the use of a subsru•face infiltration/detention system to manage a portion of the site. HW recommends that the Applicant clarify the 4 following: i. The Applicant is using an exfiltration rate of 0.27 in/hr, which is consistent with a Hydrologic Soil Group (HSG) C soil. The test pit at the proposed subsurface system indicates that soils are of a sandy loam and sandy loam gravel, which are consistent with HSG B soils. As noted in the MSH, Volume 3, Chapter 1, Page 13, the Applicant should use the HSG group based on test pit data at the actual site in place of the NRCS data provided. The Applicant has adequately responded to this comment by updating the exfiltration rate in the Drainage Report to be consistent with the test pit data. ii. The Applicant has not provided elevations of the 12-inch header pipe or the connecting pipes on the plan or in the detail. The outlet elevations of the subsurface system should be clearly labeled on the plans and details. The Applicant has adequately responded to this comment by adding the outlet elevations of the 12-inch header pipe and the connecting pipes to Sheet C-2. iii. The Applicant has indicated that the outlet invert of the 8-inch pipe (presumably between DMH 6 and DMH 7) is 158 as noted in the HydroCAD model. However, the outlet invert appears to be 157.6 on the site plan. The HydroCAD model should be revised to reflect the elevations proposed in the plans. The Applicant has adequately responded to this comment by increasing the fl- inch pipe (between DMH 6 and DMH 7) to a 12-inch pipe and updating the elevation on Sheet C-2, to be consistent with the HydroCAD model. iv. The subsurface system detail provided on Sheet C-5 does not include information on minimum depth between ground and top of the proposed subsurface system or the proposed elevation at the bottom of the system, both which are required to verify the elevations used in the HydroCAD modeling. The Applicant has adequately responded to this comment and provided the elevations of the bottom and top of the proposed subsurface system to the detail on Sheet C-5. j. The Applicant is proposing the use of Stormceptor STC 450i for four catch basins. However, there are no design calculations provided showing that this model has adequate capacity for the contributing drainage areas, including the water quality flow rate calculations. HW recommends that the Applicant provide these design calculations in its drainage report for each of the four proposed proprietary catch basins. The Applicant has not addressed this comment. The Applicant suggested that the proposed catch basin/water quality units proposed will be determined at a later date after coordinating with the DPW. Sheet C-2 includes notes on catch basin 2, 4, 5, and 6 that the structures will be 80% TSS removal units. HW is not aware of a suitable inlet structure that meets this criteria. HW recommends that the Applicant determine the type of units being proposed prior to approval from the Planning Board. 5 DZI Response: Attached are separate calculations for the STC450i Stormceptor inlets and the CDS1515-3 in line structure showing the flow and water quality analyses. The CDS1513-3 structure has been added to the design to address the 80%TSS water quality effectiveness and the manufacturer's analysis has been included. k. The Applicant has conducted soil evaluations within each of the subsurface systems and has provided the soil logs in Appendix C of the drainage report. HW requests that the surface etevations of the test pits within the infiltration systems be added to the test logs. The Applicant has adequately responded to this comment and has added the surface elevations of the test pits to the test pit logs. I. HW recommends that the Applicant verify that it is providing adequate separation to groundwater from the bottom of the stone. Furthermore, it is not clear why the Applicant has chosen a lower infiltration rate than the rate associated with the soil type documented in the test pits. The Applicant has adequately responded to this comment and has verified that 2 feet of separation has been provided for the system. 3. Standard 3 requires that the annual recharge front post-development shall approximate annual recharge front pre-development conditions. a. In Appendix B of the Drainage Report, the Applicant has provided calculations to address recharge as required by the MSH and Section 7.2 C of the NorthAndover Stormwater Regulations. HW recommends that the Applicant use the total impervious area within the site under post-development conditions, not only the increase in total impervious area. The Applicant has revised the drainage calculations; however, the Applicant has not provided documentation to verify the provided water quality and recharge volume. HW recommends that the Applicant provide a stage storage table illustrating the volume of water that can be stored within the underground detention system up to elevation 161.65 feet. DZI Response: The stage storage table is now attached. The water quality calculations are also now attached per response above. b. The Applicant has not provided the draw down calculations for the subsurface system. IF the subsurface practice is intended for infiltration, the proposed system must be able to drain fully within 72 hours as required by Standard 3. HW recommends that the Applicant provide the required calculations and verify whether the system will be able to drain within 72 hours. The Applicant has adequately responded to this comment and has included the 72- hour drawdown calculations. c. Under the MSH Volume 3, Chapter 1, page 27, the Applicant is required to direct no less than 65% of the site's impervious cover to the practices intended to infiltrate the required recharge volume. Based on the Applicant's HydroCAD modeling reports, it appears that of the 1 acre of impervious area proposed onsite, 0.4 acres is directed to the proposed subsurface infiltration/detention system while the remaining 0.6 acres will drain directly to Surrey Drive and the municipal system. HW recommends that 6 the Applicant adjust the required recharge volume as noted or direct morerunoff to infiltration systems. The Applicant has indicated that the drainage design has been modified, however, the Applicant does not direct at least 65% of the site's impervious area toward a best management practice (BMP). HW recommends that the Applicant further revise the drainage design to comply with Volume 3, Chapter 1,page 27 of the MSH. DZI Response: The Senior Center project within the drainage divide analyzed captures 63% of the total impervious surfaces (or 850 sq ft less than 65%). The actual property lines for the Senior Center extend past the drainage divide and into the residential development area as was decided at the beginning of the project with the town during the masterplanning efforts.According to the residential developments, engineer their drainage divide captures 65.85% of the impervious which provides an additional 870 square feet of impervious area infiltrated.In summary, the residential project slightly over infiltrated and the senior project slightly under infiltrated but collectively the 65% requirement has been met. See correspondence below for verification: From:Annie Rattery/mailto.Annie@morincameron,com] Sent.Friday,August 16, 2019 3:03 PM To.,James J. DeVeRs Cc.,Scott Cameron Subject;505 Sutton Street Hi Jim, I've included our Stormwater Calculations as well, approximately 65.85% of the impervious area in our watershed will be recharged to groundwater(approximately 870 SF more than the 65% requirement) . Please let me know if you need anything else. Thank you, Annie Raftery,ELL Staff Engineer THE MORIN-CAMER ON GROUP, INC 4. Standard 4 requires that the storrnwater system be designed to remove 80% Total Suspended Solids (TSS)and to treat 0.5-inch of volume from the impervious area for water quality. a. TSS removals calculations are provided in Appendix B of the Drainage Report include the use of street sweeping for TSS removal credit. In the MSH, Volume 2, Chapter 1, guidance states that a removal rate of 5% requires quarterly cleaning using one of three types of sweepers. However, in the Applicant's Operation and Maintenance Plan on Page 28 of the Drainage Report, the Applicant suggests cleaning on a semiannual basis. The Applicant has revised the Operation and Maintenance Plan to require quarterly sweeping, however, TSS removal spreadsheets are not included in the Drainage Report. HW recommends that TSS removal spreadsheets be added to the report and that the Applicant ensures that the Town agrees with the proposed street sweeping schedule prior to taking credit for it. DZI Response: The spreadsheets have been added for the town to sweep 4 times per year. b. In addition, the Applicant states that hand sweeping and hand held leaf blowers can be an alternative to street sweeping. HW recommends that the Applicant discuss with the Town the recommended O&M procedures and confirm whether a street 7 sweeping credit is applicable for TSS reductions. The Applicant has adequately responded to this comment by removing the reference to hand sweeping and handheld leaf blowers. c. The TSS calculations provide an assumed TSS reduction for the proposed proprietary devices (Stormceptor STC 450i). HW recommends that the Applicant provide supporting calculations from the manufacturer to ensure that the TSS reduction is adequate to meet Standard 4. Furthermore,MassDEP has provided guidance stating that when the STC450I is utilized as an inlet catch basin only25% TSS removal is accepted practice. HW recommends that the Applicant revisit the proposed stormwater treatment practices. The Applicant has not addressed this comment. The Applicant suggested that the proposed catch basin/water quality units proposed will be determined at a later date after coordinating with the DPW. Sheet C-2 includes notes on catch basin 2, 4, 5, and 6 that the structures will be 80% TSS removal units. HW is not aware of a suitable inlet structure that meets this criteria. HW recommends that the Applicant determine the type of units being proposed prior to approval from the Planning Board DZI Response: As per above, attached are separate calculations for the STC450i Stormceptor inlets and the CDS1515-3 in line structure showing the flow and water quality analyses. The CDS1513-3 structure has been added to the design to address the 80%TSS water quality effectiveness. . The TSS calculations include the 450i units with a 50% reduction as the contributing areas are small as discussed so the revised calculations are between the 80% manufacturer's analysis and the recognizing that the DEP does not fully accept the 80% so the 50% is in the middle for the analysis. Also noted is that although the larger water quality unit addresses the 80% TSS removal without the need for the 450i individual units, the 450i units have been left in the design for an added measure of cleansing and consistency for the DPW. d. The Applicant has provided TSS reduction for one treatment train (for subwatershed PR-1B) but has not provided a calculation for subwatershed PR-IA. HW recommends that the Applicant provide the TSS calculations for the catchment areas which include driveways and parking areas. The Applicant has indicated that subcatchment area PR-lA has been analyzed for TSS removal and added to the report, however, it does not appear that the Applicant has included any additional TSS removal calculations for subcatchment PR-IA. HW recommends that the Applicant revisit the original comment and revise the report as necessary. DZI Response: Catchment areas 1A and 1B are now included in the TSS worksheets separately. e. As noted above in comment 2a, HW recommends that the Applicant provide the analysis for the 0.5-inch storm as required under the North Andover Stormwater Regulations under Section 7.2B,b, The Applicant has adequately responded to this comment and has included the 0.5-inch analysis in the revised Drainage Report. 5. Stondord 5 is related to projects with a Land Use of Higher Potential Pollutant Loads (LUHPPL). 8 a. The proposed development is not considered a LUHPPL therefore, Standard 5 is not applicable to this project. No further comment is necessary. 6. Standard 6 is related to projects with stormwoter discharging into a critical area, a Zone H or an Interim Wellhead Protection Area of a.public iva.tersuppl�),. a. The proposed development is not within a critical area, Zone II or an IWPA area and therefore Standard 6 is not applicable to this project. No further comment is necessary. 7. Standard 7 is related to projects cori side red Redevelopment. a. The proposed development is considered a new development with an increase of impervious area, therefore Standard 7 is not applicable. No further comment is necessary. 8. Standard 8 requires a plan to control construction related impacts including erosion, sedimentation or other pollutant sources. a. On Sheet C-1, the Applicant appears to be showing silt soxx placed at the limit of work on the north west and a majority of the south side of the limit of work, with the exception of the limit of work located within the 505 Sutton Street Development. A detail is provided on Sheet C-4. HW recommends that the Applicant clarify in the legend the different line types shown for limit of work and limit of work with siltsoxx. The Applicant has included the limit of disturbance and silt soxx line on Sheet C-2. The construction sequencing has not been coordinated at this time but will need to be completed prior to any land disturbance. HW recommends that an orange snow/ construction fence be placed at the southern property boundary as a visual indicator to the construction operators. DZI Response: The orange snow/construction fence has been added to Sheet C-lalong the southern boundary as suggested. b. The Applicant mentions tree protection and silt fence in the O&M plan on page 30; however, these sediment and erosion control measures are not shown on the plans. HW recommends that the Applicant confirm the location of these items on the plans. The Applicant has changed the silt fence to silt soxx on the plan. The Applicant has not included a tree protection detail in the plan set, HW recommends that a tree protection detail be added. DZI Response: A tree protection detail has been added to Sheet C-4 as suggested. c. In the Drainage Report, under Section 5, the Applicant states that in regard to Standard 8, additional coordination is necessary to determine the sediment and erosion control measures with the adjacent development, 505 Sutton Street. Also, in the O&M plan on page 30 the Applicant states that during construction the contractor shall present a plan for vehicle entrances and washout areas. HW recommends that the Applicant provide an erosion and sediment control plan as outlined in the North Andover Stormwater Regulations under Section 8.1. The plan should include, if 9 applicable,phasing of work with the 505 Sutton Street development,particularly at the shared limit of work area. HW recommends that the plan address: materials and methods for protecting the municipal drainage system on Surrey Drive,protecting trees to remain in the right-of-way on Surrey Drive and Sutton Street, locations and details for construction entrances and washout areas, locations and details for sediment/material stockpiles, dust control and other items as required by this standard. The Applicant has not provided the erosion and sediment control plan as outlined in the North Andover Regulations and coordinated with the development at 505 Sutton Street. A condition that includes the coordination,phasing, construction entrances, and responsibilities may be acceptable to the Planning Board. DZI Response: At this time, the construction schedule and responsibilities are in flux related to the demolition of the houses, the filling of the foundations and the general earthwork of the project with a masterplanning effort. It is respectfully recommended that rather than assume responsibilities, schedules, entrances and contractors, this phase of the project associated with construction be conditioned with a plan to be prepared after it has been decided and BEFORE construction which is acceptable to the town to provide the best outcome for the town during the public bidding and construction process. As discussed and requested, a note on Sheet Cl has been added expressing this on plan. 9. Standard 9 requires a long-term operation and maintenance plan shall be developed and implemented to ensure that stormwater inanagement systems function,, as designed. a. In the O&M Plan provided on page 28 of the Drainage Report, the Applicant refers to the manufacturer's specifications for cleaning, but does not reference the attachment. The Applicant has indicated that when the TSS removal structure is determined by the DPW, the manufacture's data sheets will be provided with maintenance requirements. flW recommends that the Applicant provide the requested information as soon as it is determined. DZI Response: The water quality structure data is now provided within the O&M plan. b. Further, the Applicant states that the `water quality units will be cleaned during the same schedule as the catch basins'. HW recommends that the Applicant clearly state the frequency of cleaning as required by the manufacturer's specifications or recommendations. Also, the Applicant should specify what equipment is required for cleaning these units. The manufacturer states that maintenance is performed with a standard vacuum truck, whereas typical catch basin cleaning can be done with clamshell buckets. The Applicant has indicated that when the TSS removal structure is determined by the DPW, the manufacture's data sheets will be provided with maintenance requirements. HW recommends that the Applicant provide the requested information as soon as it is determined. DZI Response: The water quality structure data is now provided within the O&M plan. 10 c. The Applicant does not specify the frequency for inspection and/or maintenance for the proposed rain gardens. Further, many of the maintenance activities outlined in the MSH, Volume 2, Chapter 2 for rain gardens and bioretention areas are not discussed here, such as vegetation management or the repair of eroded areas. HW recommends that the Applicant clarify the O&M procedures for rain gardens. The Applicant has noted that the O&M Plan will be coordinated with the Town of North Andover. HW finds this acceptable however we believe that the designer should provide guidance to the Town operating the site. Maintaining rain gardens is not difficult however HW has witnessed many DPWs decide that it is easier to mow grass then to weed a rain garden and the gardens are eliminated. HW supports the installation of the rain gardens as a low impact development green infrastructure practice. HW recommends that the Town confirm that the rain gardens will be installed prior to approval of the project. DZI Response: The maintenance recommendations are now provided within the O&M plan. d. The Applicant has outlined the O&M for the pervious patio pavers. The pavers are not shown on the plans. The O&M states that that a leaf blower be used at least twice a year for cleaning of debris. HW recommends that the Applicant also address the activities and equipment potentially required if there is ponding, weeding or a covering of the paver joints. Similar to the rain gardens, HW recommends that the Town confirm the installation of the permeable pavers prior to approval of the project. DZI Response: The pervious paver detail is now included on Sheet C-4 and referenced within the O&M Plan. e. The Applicant states that the subsurface detention/infiltration system can be accessed by the manholes at the corner of the system. However, these manholes are not within or in-line with the system for proper jetting or vacuuming, HW recommends that clean out ports for the proposed subsurface system should be included, both in the plan and on the detail, with appropriate labels. Also, the Applicant should also outline the tinieframe for inspections and cleatiouts in the O&M Plan. The Applicant has adequately responded to this comment and added additional detail to the plans for the infiltration system. f. The Applicant has provided a long-term O&M Plan in the Drainage Report. The O&M Plan should be a standalone document and include a simple sketch to clearly indicate the location of all stormwater practices to be inspected as well as locations for snow storage. HW recommends that the Applicant include a simple sketch that will be provided to the property owner. HW recommends that the O&M Plan with a simple sketch and maintenance log be provided to the operator of the property for acceptance and signature prior to approval from the Planning Board. DZI Response: A drawing and form has been provided and are attached. g. The Applicant has not provided an inspection and maintenance schedule with routine and non-routine tasks to be performed of the systems as required by Section 9.1A of the North Andover Stormwater Regulations. 11 HW recommends that the inspection and maintenance schedule be provided to the operator of the property for acceptance and signature prior to approval from the Planning Board. h. HW recommends that the property owner sign the O&M Plan in accordance with the North Andover Stormwater Regulations. HW recommends that the final ownership of the property be determined prior to approval from the Planning Board. DZI Response: An inspection and maintenance log has been provided. 10. Standard IO requires that an Illicit Discharge Compliance Statenent be provided. a. The Applicant provided an Illicit Discharge Compliance Statement to be signed by the owner on page 19 of the Drainage Report. HW recommends that the illicit discharge statement be signed by the property owner prior to land disturbance. HW recommends that the final ownership of the property be determined prior to approval from the Planning Board and that a signed illicit discharge compliance DZI Response: Ownership and signoff is in process of being worked out with the town. 11. Miscellaneous Continents: a. HW has noted the following inconsistencies in the Checklist for Stormwater Report in comparing it to the Applicant's Drainage Report: i. The Applicant has not noted the method they are using to size the infiltration BMPs (page 23). DZI Response: Simple Dynamic has been used and is now checked on the checklist box. ii. The Applicant has stated that runoff from all impervious areas at the site are discharging to the infiltration BMP. However, only a portion of the site (subwatershed PR-lA) is draining to the proposed subsurface detention/infiltration system. DZI Response: Correct. PR-113 is discharging through the water quality units only. This has been clarified on the checklist. iii. The Applicant has stated that a TMDL exists and that documentation has been provided to address the TMDL(page 25). However, no such discussion or documentation is provided in the Drainage Report. HW has not received a revised Stormwater Checklist for review. DZI Response: A revised checklist has been attached. b. HW noted that some drainage pipe diameters and materials were not shown on the plan. HW recommends that the Applicant provide a drainpipe schedule and calculations showing that the pipes have adequate capacity to convey the proposed flows. The Applicant has adequately responded to this comment and has provided pipe calculations in the revised Drainage Report. c. The Applicant should clearly identify the locations of seeding and provide callouts 12 for proposed locations of trees, plants and shrubs, verifying that that all plants are native{oEssex [nun\y. The Applicant has adunnahzy to this onnnnont and has revised the � Landscape Plan Lis requested. d. The drainage report and plans refer to 'Surrey Street' in several locations. The � Applicant should revise these documents to note 'Surrey Drive' as shown on the � oximiin� coudidonuplen. The Applicant has adequately responded to this comment and has revised the various documents to note "Surrey I)dve". � Thank you for your continued assistance. � Sincerely, ! JPan , PI� INC. � � Copy: Project Team � � � ! i � � � � � � 13 WATER QUALITY UNIT MANUFACTURES INFORMATION FOR SIZING, TSS REMOVAL AND MAINTENANCE 14 Stormicel--t-or- C ENGINEERED SOLUTIONS A all MMEWCOMPAW Brief o ne r Sizing Report BJ. North Andover Adult Center 627374 I ����� North Andover J� 1 Massachusetts l�l �/1 rlJJll United States of America f 8/19/2019 David Adams Contech 207-894-4374 dadams@conteches.com Stormwater Treatment Recommendation The recommended Stormceptor Model(s)which achieve or exceed the user defined water quality objective for each site within the project are listed in the below Sizing Summary table. CB1 80 ro 96 STC 450i The recommended Stormceptor Model achieves the water quality objectives based on the selected inputs, historical rainfall records and selected particle size distribution. Stormceptor Model %TSS Removal Provided STC 900 98 STC 1200 98 STC 1800 98 STC 2400 99 STC 3600 99 STC 4800 99 STC 6000 99 STC 7200 99 STC 11000 100 STC 13000 100 STC 16000 100 StormceptorMAX Custom Stormceptor Brief Sizing Report—Page 1 of 2 15 Stormceptor CONTECK ENGINEERED SOLUTIONS A[IUIK WW COMPANY W a. 100.0 / 1 � �ON, 011 BOSTON WSFO AP Massachusetts % ,, ✓JIiJ 1 1IJ J1� /// ✓i%' '% / 0770 58 0.000 0.000 71°0'38"W 0,00000 1.0 0.0 2.65 53.0 3.0 2.65 75.0 15.0 2.65 88.0 25.0 2.65 106.0 41.0 2.65 125.0 15.0 2.65 150.0 1.0 2.65 212.0 0.0 2.65 •Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor,which uses the EPA Rainfall and Runoff modules. •Design estimates listed are only representative of specific project requirements based on total suspended solids(TSS)removal defined by the selected PSD,and based on stable site conditions only,after construction is completed. •For submerged applications or sites specific to spill control,please contact your local Stormceptor representative for further design assistance. For Stormceptor Specifications and Drawings Please Visit: https://www.conteches.com/technical-guides/search?filter-1 WBCOO5EYX Stormceptor Brief Sizing Report—Page 2 of 2 16 Stormceptor ' ENGINEERED 50LUTIt7N5 /,A HHUWW''ONPANY North Andover Adult Center 627374 North Andover J 1 Massachusetts United States of America 8/19/2019 dhl lh 11 David Adams lMM Contech 207-894-4374 11 dadams@conteches.com Stormwater Treatment Recommendation The recommended Stormceptor Model(s)which achieve or exceed the user defined water quality objective for each site within the project are listed in the below Sizing Summary table. CB6 ., 80 96 STC 450i The recommended Stormceptor Model achieves the water quality objectives based on the selected inputs, historical rainfall records and selected particle size distribution. Stormceptor Model %TSS Removal Provided STC 900 98 STC 1200 98 STC 1800 98 STC 2400 99 STC 3600 99 STC 4800 99 STC 6000 99 STC 7200 100 STC 11000 100 STC 13000 100 STC 16000 100 StormceptorMAX Custom Stormceptor Brief Sizing Report—Page 1 of 2 17 r ENGINEERED SOLUTIONS A NVOCI EW"' PAP" I It 0.09 �� � 1////� 80.0 BOSTON WSFO AP Massachusetts 0770 r � t i o/m/n/m/l/m// 58 42°21'38"N 0.000 0.000 71°0'38"W a u� 1 1 uuu � 1.0 0.0 2.65 53.0 3.0 2.65 75.0 15.0 2.65 88.0 25.0 2.65 106.0 41.0 2.65 125.0 15.0 2.65 150.0 1.0 2.65 212.0 0.0 2.65 •Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor,which uses the EPA Rainfall and Runoff modules. •Design estimates listed are only representative of specific project requirements based on total suspended solids(TSS)removal defined by the selected PSD,and based on stable site conditions only,after construction is completed. •For submerged applications or sites specific to spill control,please contact your local Stormceptor representative for further design assistance. For Stormceptor Specifications and Drawings Please Visit: hftps://www.conteches.com/technical-guides/search?filter-1 WBC005EYX Stormceptor Brief Sizing Report—Page 2 of 2 18 ENGINEERED SOLUTIONS A a lDOW COMPAI" IN'll 1lJ 1M North Andover Adult Center ' 627374 j . North Andover '� Massachusetts United States of America 8/19/2019 I I II II I1� inl� 1 I El ',I David Adams Contech 207-894-4374 dadams@conteches.com j Stormwater Treatment Recommendation The recommended Stormceptor Model(s)which achieve or exceed the user defined water quality objective for each site within the project are listed in the below Sizing Summary table. CB7 80 y ..� 95 STC 450i The recommended Stormceptor Model achieves the water quality objectives based on the selected inputs, historical rainfall records and selected particle size distribution. y 1, Stormceptor Model %TSS Removal Provided STC 900 97 STC 1200 97 STC 1800 98 STC 2400 98 STC 3600 99 STC 4800 99 STC 6000 99 STC 7200 99 STC 11000 100 STC 13000 100 STC 16000 100 StormceptorMAX Custom Stormceptor Brief Sizing Report—Page 1 of 2 19 Stormceptor- I " ENGINEERED SOLUTIONS A 111/INRETE•COMPANY VN ; gym ea. Te a � aLM 0.14 % � ���� 80.0 100.0 BOSTON WSFO AP 1 / J Massachusetts 0770 ; 58 71°0'38'1N � 1/10 1.0 0.0 2.65 53.0 3.0 2.65 75.0 15.0 2.65 88.0 25.0 2.65 106.0 41.0 2.65 125.0 15.0 2.65 150.0 1.0 2.65 212.0 0.0 2.65 •Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor,which uses the EPA Rainfall and Runoff modules. •Design estimates listed are only representative of specific project requirements based on total suspended solids(TSS)removal defined by the selected PSD,and based on stable site conditions only,after construction is completed. •For submerged applications or sites specific to spill control,please contact your local Stormceptor representative for further design assistance. For Stormceptor Specifications and Drawings Please Visit: https://www.co ntec h es.com/tec h n ica I-guides/search?filter-1 W BC 005 EYX Stormceptor Brief Sizing Report—Page 2 of 2 20 41-- C%porNTECH' ENGINEERED SOLUTIONS CDS ESTIMATED NET ANNUAL SOLIDS LOAD REDUCTION BASED ON THE RATIONAL RAINFALL METHOD NORTH ANDOVER ADULT CENTER NORTH ANDOVER, MA Area 0.40 ac Unit Site Designation DMH 7 Weighted C 0.9 Rainfall Station# 69 t' 5 min CDS Model 1615-3 CDS Treatment Capacity 1.0 cfs; Rainfall Percent Rainfall Cumulative Total Flowrate Treated Flowrate Incremental Intensity' Volume' Rainfall Volume (cf's) WS) Removal (%) fl n/h Ar 0.02 10.2% 10.2% 0.01 0.01 9.8 0.04 9.6% 19.8% 0.01 0.01 9.3 0.06 9.4% 29.3% 0.02 0.02 9.0 0.08 7.7% 37.0% 0.03 0.03 7.4 0.10 8.6% 45.6% 0.04 0.04 8.1 0.12 6.3% 51.9% 0.04 0.04 5.9 0.14 4.7% 56.5% 0.05 0.05 4.4 0.16 4.6% 61.2% 0.06 0.06 4.3 0.18 3.5% 64.7% 0.06 0.06 3.3 0.20 4.3% 69.1% 0,07 0.07 4.0 0.25 8.0% 77.1% 0.09 0.09 7.3 0.30 5.6% 82.7% 0.11 0.11 5.0 0.35 4.4% 87.0% 0.13 0.13 3.9 0.40 2.5% 89.5% 0.14 0.14 2.2 0.45 2.5% 92.1% 0.16 0.16 2.2 0.50 1.4% 93.5% 0.18 0.18 1.2 0.75 5.0% 98.5% 0.27 0.27 4.0 1.00 1.0% 99.5% 0.36 0.36 0.7 1.50 0.0% 99.5% 0.54 0.54 0.0 2.00 0.0% 99.5% 0.72 0.72 0.0 3.00 0.5% 100.0% 1.08 1.00 0.1 92.2 Removal Efficiency Adjustment2 6.5% Predicted %Annual Rainfall Treated = 93.5% Predicted Net Annual Load Removal Efficiency= 85.7% 1 - Based on 10 years of hourly precipitation data from NCDC Station 770, Boston WSFO AP, Suffolk County, MA 12 - Reduction due to use of 60-minute data for a site that has a time of concentration less than 30-minutes. 21 Purpose: To calculate the water quality flow naba (WKQF) over given site area. In this situation 8laVVQF is derived from the first 1"cf runoff from the contributing impervious surface. Reference: Massachusetts Dept. of Environmental Protection Wetlands Program/United States Department of Agriculture Natural Resources Conservation Service TR-55Manual Procedure: Determine unit peak discharge using Figure 1 or2. Figure 2 is in tabular form so is preferred. Using Lhetc. read the unit peak discharge (qu)from Figure 1 or Table in Figure 2. qu is expressed in the following units: CfS/nie/watorehed inches (cam/in). Compute 0 Rate using the following equation: [>= (qu) QQ (WQV) where: Q =flow rate associated with first 1"ofrunoff qu =the unit peak discharge, inoom/in. A= impervious surface drainage area (in square miles) VVQV=water quality volume in watershed inches (1"in this case) 22 TSS CALCULATION SHEETS 23 NORTH ANDOVER ts3 ADULT CENTER NORTH ANDOVER,MA 6% • ♦♦♦♦ Lq®� PERVIOUS .�� PATIO 2 STORY BUILDING • - GARDENS AW s� 8074 A ; •ice'. INI T ' F V41OUTLET 16� DZ 1' ..,n.1: . CA''4 BASIN O T ��� Deveirs zrein Inc. /��) w iv ss Jl�1/Li • cTo o• to' zo' ao biLuJlLulW s 165 OPERATION&roaua p MAINTENANCE MCA BAS O T OVERVIEW 163 FOR SITE 163 162 VEGETATED SWALE o O&M V INSTRUCTIONS: Version 1,Automated:Mar.4,2008 1. In BMP Column, click on Blue Cell to Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3. After BMP is selected,TSS Removal and other Columns are automatically completed. Location:ITreatment Train 1 (PRIATHROUGH INFILTRATION) B C D E F TSS Removal Starting TSS Amount Remaining BMP' Rate' Load* Removed C*D Load D-E PARKING LOT a) SWEEPING 4X /_YEAR 0.05 1.00 0.05 0.95 STORMCEPTOR 4500i 0 95 0.48 0.48 E INFILTRATION BASIN Er O 0.80 0.48 0.38 0.10 :::] to CDS2015-3 tl) :3 0.80 0.10 0.08 0.02 ca 0.00 0.02 0.00 0.02 Separate Form Needs to e Ceieted for Each Total TSS Removal - 98% outlet or BMP Project: North Andover Adult Center Prepared By: DeVellis Zrein,Inc. *Equals remaining load from previous BMP (E) Date: 27-Aug-19 which enters the BMP Non-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed 1.From MassDEP Stormwater Handbook Vol.1 Mass.Dept.of Environmental Protection V INSTRUCTIONS: Version 1,Automated:Mar.4,2008 1. In BMP Column, click on Blue Cell to Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3.After BMP is selected,TSS Removal and other Columns are automatically completed. Location:ITreatment Train 2 (PR1 B) B C D E F TSS Removal Starting TSS Amount Remaining BMP' Rate' Load* Removed C*D Load D-E O Street Sweeping-5% 0.05 1.00 0.05 0.95 O O Grass Channel 0.50 0.95 0.48 0.48 N Em W 0 Gravel Wetland 0.80 0.48 0.38 0.10 C 0.00 0.10 0.00 0.10 V tQ V 0.00 0.10 0.00 0.10 Separate Form Needs to e Completed for Each Total TSS Removal = 91% Outlet or BMP Train Project: North Andover Adult Center Prepared By: DeVellis Zrein,Inc. *Equals remaining load from previous BMP (E) Date: 27-Aug-19 which enters the BMP Non-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed 1.From MassDEP Stormwater Handbook Vol.1 Mass.Dept.of Environmental Protection REVISED STORMWATER CHECKLIST 27 L7Massachusetts Department of Environmental Protection - Bureau of Resource Protection -Wetlands Program Checklist for Stormwater Report A. Introduction Important:When A Stormwater Report must be submitted with the Notice of Intent permit application to document filling out forms compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for on the computer, (which f d i il t d d ti t b id should h h hi Report R t St e Stormwater e wc sou rove more substantive and offered use only the tab the p P ) but is o key to move your here as a tool to help the applicant organize their Stormwater Management documentation for their cursor-do not Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, use the return the Stormwater Report must contain the engineering computations and supporting information set forth in key" Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer(RPE) licensed in the Commonwealth. The Stormwater Report must include: • The Stormwater Checklist completed and stamped by a Registered Professional Engineer(see page 2) that certifies that the Stormwater Report contains all required submittals.' This Checklist is to be used as the cover for the completed Stormwater Report. • Applicant/Project Name • Project Address • Name of Firm and Registered Professional Engineer that prepared the Report • Long-Term Pollution Prevention Plan required by Standards 4-6 • Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82 • Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads(LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 'The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report,the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects,it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event,the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. 04/01/08 Stormwater Report Checklist•Page 1 of 8 28 Massachusetts Department of Environmental Protection L7 _ Bureau OfResource Protection -Wetlands P0gram Checklist � �= ��� � Report ��'���������N��� ���0° �����0~N������N ���0= ���������� � B. Stormwater Checklist and Certification � The following checklist is intended to serve as guide for applicants aobothe elements that ordinarily � need to be addressed in a complete Stormwater Report. The checklist is also intended to provide � conservation commissions and other reviewing authorities with a summary of the components necessary � for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. |fitia determined that specific item does not apply to the project under review, please note that the item is not applicable (N.Aj and provide the reasons for that determination. � A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stnnnwmher Report. � Registered Professional Engineer's Certification � | have reviewed the Stomnwab*rReport, including the soil evaluation, computations, Long-term Pollution � Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement(if � included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as � further elaborated by the Massachusetts GtormwmterHandbook, | have also determined that the i information presented in the Stonnwater Checklist ia accurate and that the information presented in the � Stormwater Report accurately reflects conditions at the site as of the date of this permit application. � � Registered Professional Engineer Block and Signature � 10 WELL CIVI Checklist � Project Type: Is the application for new development, redevelopment, or a mix of new and � redevelopment? � E New development LJ Redevelopment � � LJ Mix of New Development and Redevelopment 040"08 "°""w""" Report Checklist'Page 2"." 29 Massachusetts Department of Environmental Protection �-" Bureau of Resource Protection -Wetlands Program Checklist for Stormwater Report Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: ® No disturbance to any Wetland Resource Areas ❑ Site Design Practices (e.g. clustered development, reduced frontage setbacks) ❑ Reduced Impervious Area (Redevelopment Only) ❑ Minimizing disturbance to existing trees and shrubs ❑ LID Site Design Credit Requested: ❑ Credit 1 ❑ Credit 2 ❑ Credit 3 ❑ Use of"country drainage"versus curb and gutter conveyance and pipe ❑ Bioretention Cells (includes Rain Gardens) ❑ Constructed Stormwater Wetlands(includes Gravel Wetlands designs) ❑ Treebox Filter ❑ Water Quality Swale ❑ Grass Channel ❑ Green Roof ® Other(describe): Rain Garden Standard 1: No New Untreated Discharges ® No new untreated discharges ® Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth ® Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. 04/01/08 Stormwater Report Checklist•Page 3 of 8 30 Massachusetts Department of Environmental Protection {- Bureau of Resource Protection -Wetlands Program ----.... Checklist for Stormwater Report Checklist (continued) Standard 2: Peak Rate Attenuation ❑ Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. ® Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. ® Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge ® Soil Analysis provided. ® Required Recharge Volume calculation provided. ❑ Required Recharge volume reduced through use of the LID site Design Credits. ❑ Sizing the infiltration, BMPs is based on the following method: Check the method used. ❑ Static ® Simple Dynamic ❑ Dynamic Field' ❑ Runoff from all impervious areas at the site discharging to the infiltration BMP. ® Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. ® Recharge BMPs have been sized to infiltrate the Required Recharge Volume. ❑ Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: ❑ Site is comprised solely of C and D soils and/or bedrock at the land surface ❑ M.G.L. c. 21 E sites pursuant to 310 CMR 40.0000 ❑ Solid Waste Landfill pursuant to 310 CMR 19.000 ❑ Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. ® Calculations showing that the infiltration BMPs will drain in 72 hours are provided. ❑ Property includes a M.G.L. c. 21 E site or a solid waste landfill and a mounding analysis is included. '80%TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. 04/01/08 Stormwater Report Checklist•Page 4 of 8 31 Massachusetts Department of Environmental Protection 1 Bureau of Resource Protection -Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 3: Recharge (continued) ❑ The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. ® Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following: • Good housekeeping practices; • Provisions for storing materials and waste products inside or under cover; • Vehicle washing controls; • Requirements for routine inspections and maintenance of stormwater BMPs; • Spill prevention and response plans; • Provisions for maintenance of lawns, gardens, and other landscaped areas; • Requirements for storage and use of fertilizers, herbicides, and pesticides; • Pet waste management provisions; • Provisions for operation and management of septic systems; • Provisions for solid waste management; • Snow disposal and plowing plans relative to Wetland Resource Areas; • Winter Road Salt and/or Sand Use and Storage restrictions; • Street sweeping schedules; • Provisions for prevention of illicit discharges to the stormwater management system; • Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL; • Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan; • List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. ® A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an attachment to the Wetlands Notice of Intent. ❑ Treatment BMPs subject to the 44%TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: ❑ is within the Zone II or Interim Wellhead Protection Area ❑ is near or to other critical areas ❑ is within soils with a rapid infiltration rate(greater than 2.4 inches per hour) ❑ involves runoff from land uses with higher potential pollutant loads. ❑ The Required Water Quality Volume is reduced through use of the LID site Design Credits. ® Calculations documenting that the treatment train meets the 80% TSS removal requirement and, if applicable, the 44% TSS removal pretreatment requirement, are provided. 04/01/08 Stormwater Report Checklist•Page 5 of 8 32 Massachusetts Department of Environmental Protection Bureau of Resource Protection -Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) ® The BMP is sized (and calculations provided) based on: ® The %"or 1"Water Quality Volume or ❑ The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. ® The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. ❑ A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads(LUHPPLs) ❑ The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. ❑ The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. ❑ The NPDES Multi-Sector General Permit does not cover the land use. ❑ LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the long term Pollution Prevention Plan. ❑ All exposure has been eliminated. ❑ All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. ❑ The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease (e.g. all parking lots with >1000 vehicle trips per day) and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas ❑ The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. ❑ Critical areas and BMPs are identified in the Stormwater Report. 04/01/08 Stormwater Report Checklist•Page 6 of 8 33 Massachusetts Department of Environmental Protection T Bureau of Resource Protection -Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable ❑ The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: ❑ Limited Project ❑ Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. ❑ Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area ❑ Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff ❑ Bike Path and/or Foot Path ❑ Redevelopment Project ❑ Redevelopment portion of mix of new and redevelopment. ❑ Certain standards are not fully met(Standard No. 1, 8, 9, and 10 must always be fully met)and an explanation of why these standards are not met is contained in the Stormwater Report. ❑ The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a) complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information: • Narrative; • Construction Period Operation and Maintenance Plan; • Names of Persons or Entity Responsible for Plan Compliance; • Construction Period Pollution Prevention Measures; • Erosion and Sedimentation Control Plan Drawings; • Detail drawings and specifications for erosion control BMPs, including sizing calculations; • Vegetation Planning; • Site Development Plan; • Construction Sequencing Plan; • Sequencing of Erosion and Sedimentation Controls; • Operation and Maintenance of Erosion and Sedimentation Controls; • Inspection Schedule; • Maintenance Schedule; • Inspection and Maintenance Log Form. ❑ A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. 04/01/08 Stormwater Report Checklist-Page 7 of 8 34 Massachusetts Department of Environmental Protection ` Bureau of Resource Protection -Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) ❑ The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. ❑ The project is not covered by a NPDES Construction General Permit. ❑ The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. ® The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan ® The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: ® Name of the stormwater management system owners; ® Party responsible for operation and maintenance; ® Schedule for implementation of routine and non-routine maintenance tasks; ® Plan showing the location of all stormwater BMPs maintenance access areas; ® Description and delineation of public safety features; ® Estimated operation and maintenance budget; and ® Operation and Maintenance Log Form. ® The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: ❑ A copy of the legal instrument(deed, homeowner's association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; ❑ A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges ® The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; ® An Illicit Discharge Compliance Statement is attached; ❑ NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. 04/01/08 Stormwater Report Checklist•Page 8 of 8 35 STAGE STORAGE CALCULATIONS 36