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Home My WebLink About2013-04-16 Planning Board Supplemental Materials (44) Project No. NAND-0020 April 10,2013 •..� WILLIAMS North Andover Planning Board . SPARAGES North Andover Conservation CommissionENGINE&RS PLANNERS SURVEYORS 1600 Osgood Street North Andover,MA 01845 Subject: Response to Stormwater Review by Eggleston Environments } 250 Clark Street(Flight Landata,Inc.) DEP File No. 242-1584 Dear Members of the Planning Board and Conservation Commission, The purpose of this letter is to respond the few remaining comments that we received yesterday afternoon from Eggleston Environmental (EE) regarding the proposed expansion of the Flight Landata facility located at 250 Clark Street. The comments provided by Eggleston Environmental are shown in italics below, and, our responses are in the bold text that follows. 1. The proposed plan callsfr a siltation fence erosion control barrier. Additional measures (e.g. ha bales or silt socks) may also b y e needed. In the Erosion &Sediment Control Plan included in our original Notice of Intent package dated February 7, eonDevice, lease see the following 2013,under Erosion and Sediment Control Dice p g statement startingin the middle " d e of the second line... I .. tis im octan 1 importantfor the owner, builder, p f r an or site contractor to have access to a supply u 1 o ha bales should the need arse or pp y f y f additional erosion and sediment control measures. We have added this text to the notes (Note 8) found on the revised site plan to ensure that this is emphasized during construction activities. 2. It appears that the proposed project may entail the disturbance of an acre or more of land. If so, it will also be subject to the EPA Construction General Permit and require a Notice o Intent under that program, q f pg and implementation of a Construction Stormzvater Pollution Prevention Plan (SVVPPP) in accordance zvith the EPA guidelines. The amount of proposed disturbance is approximately 37,000 square feet,which is less than the minimum required land disturbance of 1 acre required for a filing with the EPA. 3. The Pollution Prevention Plan included zvith the NOI addresses short-term construction related measures aimed at the site contractors. Per DEP requirements,a Long-Term Pollution Prevention Plan is still needed. As with the O&M Plan, this zvould be aimed at the parties responsible for maintaining the site in order to minimize the pollutant exposure to stormzvater. Given the nature of the p erations on the site, the o storage and use of potentially hazardous materials as zvell as any vehicle (or airplane) washing, deicing, etc. should be addressed. 191 South Main Street, Suite 103 Middleton, MA 01949 Tel: (978) 539-8088 Fax: (978) 767-8579 Response to Stormwater Review 250 Clark Street North Andover, MA April 10, 2013 We have attached a revised Operation&Maintenance Plan that is to be used for thep ost construction period naming Flight Landata,Inc.as the party responsible for the operation and maintenance of the stormwater management system. We have also noted that if Flight Landata,Inc.were no longer the tenant the responsibility would revert back to the Leasehold Owner,Michael Florence. We have also attached a revised Inspection and Maintenance form to be used in the Long-Term which requires inspections twice year, . per y sprang and fall, or within a 24 hours of a storm event with 2 year storm intensity or greater,i.e. 3.1 inches of rainfall within a 24 hour period. We have also shown designated snow storage areas that are currently being utilized by the property which are all up-gradient of the wetlands. We have spoken with Mr. Scott Stetson of KEYW Corporation(the parent company of Flight Landata,Inc.) and they do have an aircraft spill-kit located in their hanger,in the unlikely event of an aircraft leak. As resented b Attorney Jill Mann a t the Apri12,2013 Planning Board hearing,the aircraft rcraf are not fueled at this location. In addition,they do not wash or de-ice thep lanes at this location according to Mr. Stetson. Therefore there is no danger of contaminating the wetland resource areas with wash water runoff. We trust that you will find the responses above adequately address these last few comments made by the technical review agent and will allowg or p ou to close the hearing fthe proposed expansion of Y p pa the Flight Landata,Inc.facility. If you have any questions,please do not hesitate to contact me directly. Very truly yours, Peter M. Blaisdell,Jr.,P.E.,P.L.S. Project Engineer PMB: CPS Enclosures cc: Attorney Jill Mann Scott Stetson/KEYW Corporation Lisa Eggleston,P.E. Operation & Maintenance Plan "250 Clark Street" 250 Clark Street, North Andover, MA 01845 February 7,2013 Revised: March 26, 2013 Revised: April 9, 2013 This Operation&Maintenance Plan has been prepared to comply with the provisions set forth in the Massachusetts Department of Environmental Protection(DEP)Stormwater Management Standards. Structural Best Management Practices (BMPs) require periodic maintenance to insure proper function and efficiency in pollutant removal from stormwater discharges that would otherwise reach wetland resource areas untreated. Maintenance schedules found below are as recommended in Department of Environmental Protections Massachusetts Stormwater Handbook and as recommended in the manufacturer's specifications. The following BMPs shall be utilized for project at 250 Clark Street for pollutant removal from stormwater discharge as well as providing additional groundwater recharge on site: • Parking Lot Sweeping • Biof filters with stone diaphragms • Stone Trench for roof runoff The responsible party for following the Operation&Maintenance Plan long-term after construction has been completed will be Flight Landata,Inc. Should Flight Landata,Inc.not be the tenant of the facility in the future,the responsibility will revert back to the Leasehold Owner,Michael Florence. See attached Inspection Log. Parking Lot Sweeping: • We recommend that the parking lot be swept at a minimum of once per year in the spring. Biofilters: • Inspect and remove trash year monthly throughout the year. • Remove and replace dead vegetation annually in the spring. • Prune the shrubs annually in the spring. • Remove any sediment from the top of the stone diaphragms and from the pretreatment sideslope annually in the spring. • Mow the pretreatment sideslopes once a month during the growing season. • When areas of erosion are identified,repair areas of erosion and revegetate as needed as soon as possible. • Inspections shall be performed at least twice a year,or after a major storm event which is defined as a storm that is equal to or greater than the 2-year storm event. Operation &Maintenance Plan 250 Clark Street, North Andover, MA 01845 Revised: April 9, 2013 • During these inspections,record and map the following information: -The presence of accumulated trash and/or debris, -The presence of dead vegetation and/ or invasive species (invasives must be removed), -Stability of the sideslopes and berms, -Accumulation of sediment, -Survival rate of plantings (dead plantings must be replaced) Stone Trench for roof recharge: • Leaf screens shall be installed in the gutters to prevent debris from reaching the trench. • Install three (3) inspection ports to be located at the beginning,middle and end of trench. • Should standing water be present in bottom of system during a routine inspection or more than twenty-four (24)hours after the end of a rainfall event,it may be as a result of the stone bed layer being clogged. The amount of elapsed time required for the water to infiltrate completely should be recorded. If after seventy-two (72) hours from the end of a rainfall event there is still standing water in the bottom of the trench,the affected area should be excavated and the stone replaced with clean stone. • We recommend the following schedule for system maintenance Monthly in first year of service: -Check inlets for clogging and remove any debris as necessary -Check for depressions in areas over and surrounding the system Spring and fall in the second year service: -Check inlets for clogging and remove any debris as necessary -Check for depressions in areas over and surrounding the system One year after commissioning and every year following -Check inlets for clogging and remove any debris as necessary -Inspect the interior of the trench via inspection ports and measure sediment or depth of standing water -Check for depressions in areas over and surrounding the system -Confirm that no unauthorized modifications have been performed to the site • It should be noted that most failures that occur in subsurface systems are due to inadequate pre-treatment which leads to clogging. However,this system shall only receive roof runoff from the roof,which is considered clean by DEP and does not require pre-treatment. Therefore,we do not expect there to be any adverse impacts to the system due to debris accumulation. 2 250 CLARK STREET, NORTH ANDOVER, MA I TO BE COMPLETED TWICE PER YEAR (SPRING & FALL) OR WITHIN 24 HOURS OFA 2 YEAR STORM EVENT (3.1 INCH OR GREATER WITHIN A 24 HOUR PERIOD) Name of Inspector: Inspector's Company/Affiliation: Days Since Last Rainfall: Maintenance Required: Date: Amount of Last Rainfall: minor / moderate / major minor moderate / major minor moderate / major minor moderate / major minor moderate / major To Be Performed By: On of Before: