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HomeMy WebLinkAbout2020-03-10 Correspondence Stormwater "l� M-.0' " rin.-Cameron March 2, 2020 Ms. Jean Enright, Planning Director Town of North Andover Planning Department 120 Main Street North Andover, MA 01845 RE: Site Plan Review 127 Marblehead Street Dear Ms. Enright: On,behalf of the applicant, Cen 1 Realty Trust, and based on comments received at the February 25, 2020 Planning Board hearing, our office has revised the Site Plan for the above-mentioned property. The revisions are as follows: • A 6' privacy fence has been added along the west property line. A detail of the fence has been added to Sheet 2 of the plan set; • The driveway to the rear of the building containing the 6 parking spaces has been changed to porous pavement. The area of this proposed driveway is 1,215 s.f. The driveway will have a gravel base of 9" to provide storage and infiltration of the stormwater runoff. This will allow for 395 c.f. of storage of runoff. As discussed, there will be an increase of 520 s.f. of impervious on the site. Using the MRCS rainfall data for the 100-yr. storm event, this would result in a runoff volume of 388 c.f.; • A 2' wide x 2' deep x 40' long infiltration trench has been proposed along the rear driveway to capture any additional runoff from the porous pavement; and • Details of the infiltration trench and porous pavement have been added to Sheet 2 of the plan set. • An Operation and Maintenance Plan has been provided for the site. We took forward to discussing these items with you at the next public hearing. Very truly yours &es Melvin, P.E. CIVIL_ ENGINEERS - LAND SURVEYORS ® ENVIRONMENTAL CONSULTANTS - LAND USE PLANNERS 160 Summer Street, Haverhill, MA 01830 978.373.0310 Providing Professional Services Since 1978 www rnorinr.arnPmn mm Stormwater Best Management Practices Operation and Maintenance Plan for 127 Marblehead Street North Andover, Massachusetts The following operation and maintenance plan has been prepared as a guidance document for the efficient implementation,operation and maintenance of the on-site stormwater management systems. The following procedures shall be implemented to ensure success of the Stormwater Management Plan: 1. The contractor shall comply with the details of construction of the site as shown on the approved plans. 2. Effective erosion control measurers during and after construction shall be maintained until a stable turf is established on all altered areas. Basic Information Stormwater Management System Owner: Centry one Realty Trust 127 Marblehead street North Andover, MA 01845 North Andover Engineering: Town Engineer Engineering Department 384 Osgood Street North Andover, MA 01845 P: (978) 685-0950 North Andover Planning Board: Town Hall 120 Main Street North Andover, MA 01845 P: (978) 688-9535 General Conditions 1. The developer shalt be responsible for scheduling regular inspections and maintenance of the stormwater BMP's until the project has been completed. The BMP maintenance shall be conducted as detailed in the following long-term pollution prevention plan and illustrated on the approved design plans; 2. All Stormwater BMP's shall be operated and maintained in accordance with the design plans and the following Long-Term Pollution Prevention Plan. 3, The owner shall: a. Maintain an Operation and Maintenance Log (see Attachment A) for the last three years. The Log shall include all BMP inspections, repairs, replacement activities and disposal activities (disposal material and disposal location shall be included in the Log); b. Make the log available to the North Andover Engineering Division and Planning Board upon request; c. Allow members and agents of the North Andover Engineering Division and Planning Board to enter the premises and ensure that the Owner has complied with the Operation and Maintenance Plan requirements for each BMP. 4. A recommended inspection and maintenance schedule is outlined below based on statewide averages. This inspection and maintenance schedule shall be adhered to at a minimum for the first year of service of all BMP's referenced in this document. At the commencement of the first year of service, a more accurate inspection/maintenance schedule shall be determined based on the level of service for this site. Long-Term Pollution Prevention Plan (LTPPP) Paved Areas: Sweepers shall sweep paved areas periodically during dry weather to remove excess sediments and to reduce the amount of sediments that the drainage system shall have to remove from the runoff. The sweeping shall be conducted primarily between March 15xh and November 151'. Special attention should be made to sweeping paved surfaces in March and April before spring rains wash residual sand into the drainage system. The frequency of sweeping shall average: • Monthly if by a high-efficiency vacuum sweeper • Bi-weekly if by a regenerative air sweeper • Weekly if by a mechanical sweeper Cost: $1004150 per sweeping Salt used for de-icing on the roadway during winter months shall be limited as much as possible as this will reduce the need for removal and treatment. Sand containing the minimum amount of calcium chloride (or approved equivalent) needed for handling may be applied as part of the routine winter maintenance activities. Porous Pavement: Porous Pavement shall be monitored to ensure that the paving surface drains properly after storms as needed. Porous asphalts and concretes shall be cleaned as needed using a power washer to dislodge trapped particles and then vacuum swept to remove particles. Inspections of surface deterioration shall be completed annually. Cost: $700 - $1,000 Infiltration Trench Infiltration trenches shall be inspected, and debris removed every six months and after every major storm event. Sediment shall also be removed from pretreatment BMPs every six months or after every major storm event. Cost: $200 Debris& Litter: All debris and litter shall be removed from the roadway and parking lots as necessary to prevent migration into the drainage system. Pesticides, Herbicides. and Fertilizers: Pesticides and herbicides shall be used sparingly. Fertilizers shall be restricted to the use of organic fertilizers only. All fertilizers, herbicides, pesticides, sand and salt for deicing and the like shall be stored in dry area that is protected from weather. Cost: Included in the routine landscaping maintenance schedule. The Owner shall consult local landscaping contractors for details. Public Safety Concerns: Chemicals shall be stored in a secure area to prevent children from obtaining access to them. Any major spills shall be reported to municipal officials. Prevention of Illicit Discharges: Illicit discharges to the stormwater management system are not allowed. Illicit discharges are discharges that are not comprised entirely of stormwater. Pursuant to Mass DEP Stormwater Standards the following activities or facilities are not considered illicit discharges:firefighting,water line flushing, landscape irrigation, uncontaminated groundwater, potable water sources, foundation drains, air conditioning condensation,footing drains,individual resident car washing,flows from riparian habitats and wetlands, water used for street washing and water used to clean residential building without detergents. To prevent illicit discharges to the stormwater management system the following policies should be implemented: 1. Provisions For Storing Materials And Waste Products Inside Or Under Cover 2. Vehicle Maintenance And Washing Controls 3. Requirements for Routine Inspections of the Stormwater Management System (i.e.: catch basins, proprietary treatment unit &subsurface infiltration system.) 4. Spill Prevention and Response Plans. Stormwater System Inspection Report Generafinformation Location: Centry one Realty Trust Date of Inspection StartlEnd Time Inspector's Name(s) Inspector's Title(s) Inspector's Contact Information Purpose of Inspection Site-Specific Stormwater Devices Installed and Date for Corrective Operating Action/Responsible Description Properly? Corrective Action Needed Person I ❑Yes ❑No 2 ❑Yes ❑No 3 ©Yes ❑No 4 ❑Yes ❑No 5 ❑Yes ❑No Certification Statement: "I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system,or those persons directly responsible for gathering the information,the information submitted is,to the best of my knowledge and belief,true,accurate,and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations." Print name: Signature: Date: