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HomeMy WebLinkAbout2007-08-08 Application Stormwater Mgmnt Report (Excerpt) Professional Land Surveyors &Civil Engineers ESSEX SURVEY SERVICE 1958- 1986 OSBORN PALMER 1911 - 1970 BRADFORD &WEED 1885 - 1972 STORMWATER MANAGEMENT REPORT 1820- .830 TURNPIKE STREET NORTH ANDOVER, MASSACHUSETTS OCTOBER 2006 104 LOWELL STREET PEABODY, MASS. 01960 TELEPHONE: 978-531-8121 FAX: 978-531-5920 PROPOSED STORMWATER MANAGEMENT FACILITIES PROPOSED STORMWATER MANAGEMENT FACILITIES The proposed stormwater management plan for 1820-1830 Turnpike Street in North Andover proposes a variety of structural and non-structural Best Management Practices to ensure compliance with Massachusetts DEP Stormwater Management Policy. The site consists primarily of undeveloped land underlain by rapid draining soils (hydrologic soil Group A and B), and it produces relatively little runoff in the existing condition. Such runoff, as does occur, flows overland to an existing drainage ditch in the easterly portion of the site. That ditch also receives runoff from the adjacent portion of Route 114. In order to avoid any increase of runoff from the property, a series of infiltration beds have been designed to recharge runoff into the ground following collection and, if required,pretreatment. Since groundwater on site is shallow(28 to 46 inches below existing grade) extensive filling of the site is required to maintain a two foot vertical separation between groundwater and the bottom of infiltration beds while providing adequate cover over perforated pipes to allow for vehicular traffic. Pretreatment Best Management Practices are essential for reliable long-term operation of infiltration facilities. The pretreatment BMP's for the Turnpike Street building include deep sump hooded catch basins and Stormceptor water quality systems. A total suspended solids removal rate of 97 percent will result with 87 to 89 percent of TSS removal occurring in the pretreatment BMP's. No pretreatment is proposed for Infiltration Basin D which receives roof runoff only. Non-structural Best Management Practices include the following: + Stabilization of any vegetated buffers temporarily disturbed by construction + Pavement sweeping and cleaning of catch basins and Stormceptors • A spill prevention program (most significant during the construction phase) An Operation and Maintenance Plan for the various stormwater management facilities is provided. SUMMARY OF STORMWATER ANALYSIS SUMMARY OF STORMWATER ANALYSIS The site of the proposed commercial building at 1820-1830 Turnpike Street has been analyzed for 1, 2, 10 and 100 year storm events for both predevelopment and postdevelopment conditions. The analysis has been conducted using U.S.D.A. TR-SS Methodology for simulation of runoff hydrographs and the stage storage indication method for routing of hydrographs through the proposed infiltration beds. The predevelopment watershed boundary is indicated on the accompanying copy of the existing conditions plan and consists of an area of 2.1 acres, Runoff rates are summarized as follows: Storm period Peak Runoff Rate (cubic feet per second) 1 year 0.01 2 year 0.03 10 year .49 100 year 2.33 Postdevelopment watershed boundaries are similarly indicated on the accompanying copy of the proposed grading plan. 1.14 acres of the site are to be routed through the proposed infiltration basins, The remaining 0,96 acres will generate the following runoff rates: Storm Period Peak Runoff Rate (cubic feet per second) 1 year .01 2 year .02 10 year .30 100 year 1.51 * (Includes overflow from Infiltration Bed A in 100 year storm only) No increase in runoff rate for 1, 2, 10 and 100 year storms will result from the proposed activity. i STORMWATER. MANAGEMENT FORM i LlMassachusetts Department of Environmental Protection Bureau of Resource Protection -Wetlands Stormwater Management Form Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 A. Property Information Important: When filling out 1. The proposed project is: forms on the computer, use a, New development ® Yes ❑ No only the tab key to move b. Redevelopment ❑ Yes ® No your cursor- do not use the (If yes, distinguish redevelopment components from return key. c. Combination ❑ Yes ® No new development components on plans). VQ 2. Stormwater runoff to be treated for water quality is based on the following calculations: 110 a. ❑ 1 inch of runoff x total impervious area of post-development site for discharge to critical areas (Outstanding Resource Waters, recharge areas of public water supplies, shellfish growing areas, swimming beaches, cold water fisheries). Note: b, ® 0.6 inches of runoff x total impervious area of post-development site for other resource areas. This November 2000 version of the Stormwater Management B. Stormwater Management Standards Form supersedes earlier versions including those g Y(March 1997 ement DEP's Stormwater Management Policy includes nine standards that are listed on the ) contained in following pages. Check the appropriate boxes for each standard and provide documentation and DEP's additional information when applicable. Stormwater Handbooks. Standard #1: Untreated stormwater a. ® The project is designed so that new stormwater point discharges do not discharge untreated stormwater into, or cause erosion to, wetlands and waters. Standard#2: Post-development peak discharges rates a, ❑ Not applicable—project site contains waters subject to tidal action. Post-development peak discharge does not exceed pre-development rates on the site at the point of discharge or downgradient property boundary for the 2-yr, 10-yr, and 100-yr,.24-hr storm, b. ❑ Without stormwater controls c.® With stormwater controls designed for the 2-yr, and 10-yr storm, 24-hr storm, d. The project as designed will not increase off-site flooding impacts from the 100-yr, 24-hr storm. Wpaformldoc•Storm,valer Management Form-rev.311/05 Page 1 of 5 1 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Stormwater Management Form Massachusetts Wetlands Protection Act M.G.L, c, 131, §40 B. Stormwater Management Standards (cont.) Standard #3: Recharge to groundwater Amount of impervious area (sq. ft.)to be infiltrated: 54,000 a.square feet Volume to be recharged is based on, b} ❑ The following Natural Resources Conservation Service hydrologic soils groups (e.g. A, B, C, D, or UA) or any combination of groups: 53 A 4.%of impervious area 2, Hydrologic soil group 3.%of impervious area 4. Hydrologic soil group 47 B 5.%of impervious area 6. Hydrologic soil group 7.%of Impervious area 8. Hydrologic soil group c. ❑ Site specific pre-development conditions: 4 Recharge rate 2.Volume d. Describe how the calculations were determined: e. List each BMP or nonstructural measure used to meet Standard#3 (e.g. dry well, infiltration trench). Infiltration Beds Does the annual groundwater recharge for the post-development site approximate the annual recharge from existing site conditions? f. ® Yes ❑ No Standard #4: 80% TSS Removal a. ® The proposed stormwater management system will remove 80% of the post-development site's average annual Total Suspended Solids(TSS) load. b. Identify the BMP's proposed for the project and describe how the 80% TSS removal will be achieved. pteksump catch basins, Stormce tar wa#er ual systems, infiltration bed. Wpaform3.doc•Stormwater Management Form•rev.3/1105 Page 2 of 6 1 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Stormwater Management Form { Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 B. Stormwater Management Standards (cost.) c. If the project is redevelopment, explain how much TSS will be removed and briefly explain why 80% removal cannot be achieved, Standard #5: Higher potential pollutant loans See Stormwater Policy Handbook Does the project site contain land uses with higher potential pollutant loads Vol. 1, page 1-23, for land uses of a. ❑ Yes ® No b, If yes, describe land uses: high pollutant loading (see Instructions). c. Identify the BMPs selected to treat stormwater runoff. If infiltration measures are proposed, describe the pretreatment. (Note: If the area of higher potential pollutant loading is upgradient of a critical area, infiltration is not allowed.) Standard #6: Protection of critical areas See Stormwater Will the project discharge to or affect a critical area? Policy Handbook Vol. I, page I-25, for critical areas a. ElYes 0 No b. If yes, describe areas: (see Instructions). c. Identify the BMPs selected for stormwater discharges in these areas and describe how BMPs meet restrictions listed on pages 1-27 and I-28 of the Stormwater Policy Handbook--VoL 1: Wpaform3.don•Stormwater Management Form-rev.311105 Page 3 of 5 Massachusetts Department of Environmental Protection { Bureau of Resource Protection - Wetlands Stormwater Management Form Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 B. Stormwater Management Standards (cont.) Note: components of Standard#7: Redevelopment projects redevelopment projects which Is the proposed activity a redevelopment project? plan to develop previously a. D Yes ® No b. If yes, the following stormwater management standards have been met: undeveloped areas do not fail under the scope of Standard 7. c. The following stormwater standards have not been met for the following reasons: d. ❑ The proposed project will reduce the annual pollutant load on the site with new or improved stormwater control. Standard #8: Erosion/sediment control a. ® Erosion and sediment controls are incorporated into the project design to prevent erosion, control sediments, and stabilize exposed soils during construction or land disturbance. Standard #9: Ope ratio nlmaintenance plan a. ® An operation and maintenance plan for the post-development stormwater controls have been developed. The plan includes ownership of the stormwater sMPs, parties responsible for operation and maintenance, schedule for inspection and maintenance, routine and long-term maintenance responsibilities, and provision for appropriate access and maintenance easements extending from a public right-of-way to the stormwater controls. Operation and Maintenance Plan b.Planfritle C.Date 1820-1830 Turnpike Street N. Andover, MA. October 2006 d.Plan/Title e. Date Wpaform3.doc•Slormwaler managemanl Form-tev.311105 Page 4 of 5 i Massachusetts Department of Environmental Protection �— Bureau of Resource Protection Wetlands Stormwater Management Form Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 C. Submittal Requirements Online Users: DEP recommends that applicants submit this form, as well as, supporting documentation and plans, Include your with the Notice of Intent to provide stormwater management information for Commission review document consistent with the wetland regulations (310 CMR 10.05 (6)(b))and DEP's Stormwater Management transaction Policy (March 1997). If a particular stormwater management standard cannot be met, information number should be provided to demonstrate how equivalent water quality and water quantity protection will be (provided on provided. DEP encourages engineers to use this form to certify that the project meets the stormwater your receipt management standards as well as acceptable engineering standards. For more information, consult page)with all the Stormwater Management Policy. supplementary information you submit to the Department. D. Signatures Gino Fodera, Trustee Applicant Name Date Signature .Attorney,John T. Smolak Representative(if any) gate Signature WpaforW.doc-Stormwatar Management Farm-rev.3/W5 Page 5 of 6 c OPERATION AND MAINTENANCE PLAN OPERATION AND MAINTENANCE PLAN PROPOSED STORMWATER MANAGEMENT FACILITIES 1820-1830 TURNPIKE STREET NORTH ANDOVER,MASSACHUSETTS The following Operations and Maintenance Plan("O&M") has been prepared to ensure that proposed systems function as designed, The O &M plan includes a maintenance schedule to ensure that structural and non-structural components are implemented properly and identifies the responsible patties. A brief summary of the specific BMP's to be implemented at the site are as follows: Non-Structural Methods Site Layout Any naturally and maintained vegetated buffers temporarily disturbed during stormwater structure installation will be stabilized upon completion of project activities. Source Control A comprehensive source control program will be implemented at the site which includes regular pavement sweeping (at least four times per year), catch basin cleaning, and Stormtech cleaning and infiltration bed inspection and cleaning. Spill Prevention A spill prevention plan that includes an emergency notification plan and cleanup program will be developed as part of the National Pollution Discharge Elimination System (NPDES) Construction General Permit, At a minimum the following good housekeeping practices will be followed on-site during construction: 1. An effort will be made to store only enough product required to do the job. 2. All materials stored on-site will be kept in a neat, orderly manner in their appropriate containers and, if possible, under a roof or other enclosure. Structural Methods A. Deep Sump Catch Basins 1. During Construction a. Protect catch basins grates with hay bales, check dams until base paving course is installed and landscaped areas are stabilized and/or vegetated. b. Inspect basins monthly or following rainstorms of greater than one inch in 24 hours and clean when sediment levels are greater than .twelve inches. 3 2. Long Term a. Inspect basins monthly and clean as necessary,but at least twice annually. B. Stormeeptor Unit 1. Maintain in accordance with Manufacturer's recommendations (copy follows). The Stormceptor Units shall be inspected at least four times annually and after any spill event. The units shall be maintained annually and immediately following any spill event. C. Infiltration Beds 1. During Construction a. Before the development site is graded, areas of infiltration beds should be roped off to prevent heavy equipment from compacting the underlying soils. b. Infiltration beds shall not be used as temporary sediment traps during construction. C. During and after excavation, all excavated materials should be placed away from the infiltration beds to prevent redeposition during runoff events. All excavated materials should be properly handled and disposed, during and after construction. d. Light earth-moving equipment should be used to excavate the infiltration basin. The basin floor should be deeply tilled with a rotary tiller or a disc harrow to restore infiltration rates, after final grading. e 2. Long Term a. The infiltration beds shall be inspected following each major storm (more than one inch of rainfall in 24 hours) but at least four times annually, Water levels in the observation wells should be recorded at the beginning, 24 hours and 48 hours following a major storm. The water level should not exceed six inches at 48 hours after the end of the storm. If so, the bed is likely to require cleaning or replacement, The use and maintenance of pretreatment BMP's (catch basins and Stormeeptors) will minimize the likelihood of maintenance of the infiltration beds. D. Snow Removal Snow removal will be conducted in accordance with the DEl?, Bureau of Resource Protection.Snow Disposal Guidance, effective March 8, 2001. Snow will not be stockpiled in or adjacent to wetland resource areas. Snow will be stockpiled in the designated soil stockpile areas shown on the project plans. Snow will not be stockpiled within the 25'No-Disturbance Zone or on top of storm drains. The party responsible for Operation and Maintenance of the Stormwater Management Facilities is: GPM General Contracting Corporation 325 N. Main Street 415B Middleton, MA. 01949 Tel: 617-877-9963 i Or its heirs and assigns.