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HomeMy WebLinkAboutRevised LTPPP and O&M 2022-06-30_SignedWarehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 1 LONG-TERM STORMWATER POLLUTION PREVENTION AND OPERATION & MAINTENANCE PLAN TO COMPLY WITH STORMWATER STANDARDS 4, 6, & 9 APPLICABILITY This document identifies constituents of concern that have the potential to contaminate stormwater from the proposed Warehouse and Distribution Center Alteration project located at 225 White’s Path, Yarmouth, Massachusetts and provides a framework of Best Management Practices (BMPs) for handling stormwater runoff. It also outlines an inspection and maintenance program to ensure continued effectiveness of the proposed stormwater management system. The proposed BMP’s are shown on the plans prepared by CHA, 141 Longwater Drive, Suite 104, Norwell, Massachusetts. PROJECT OVERVIEW: The proposed project located on White’s Path includes alterations to the existing commercial building and incorporates associated site improvements including parking and utilities. The project will not increase the overall footprint of the building. The project has been designed to meet State and Local standards for TSS and pollutant removal through the use of BMPs. Runoff from impervious surfaces will be collected and treated by deep sump hooded catch basin, oil/grit separators, a CDS Water Quality Unit, and conveyed to a stormwater recharge/retention basin that will infiltrate the runoff into the surrounding soils. The existing rooftop runoff is collected and conveyed to an independent underground infiltrration system will not be altered by the Project. Appended to this document is a sample maintenance form and a chart describing the anticipated frequency of tasks. OWNER AND RESPONSIBLE PARTY: Owner: 225 White’s Path Units Two and Three, LLC 231 Willow Street Yarmouthport, MA 02675 Day-to-day Operation and Maintenance: Maintenance Company hired by Owner. ON-GOING MAINTENANCE CONTRACT The non-structural and structural approaches recommended below, as well as the required BMP maintenance, will be completed by an appropriate contractor. Adequate personnel with appropriate training and access to proper equipment will be available to complete the tasks. Future responsible parties must be notified of their responsibility to operate and maintain the system in perpetuity. LIVING DOCUMENT PROVISIONS Due to the difficulty of identifying all sources of potential stormwater contamination and Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 2 maintenance activities, this document should be updated as necessary to reflect new procedures, technologies or requirements. MAINTENANCE LOG The Responsible Party shall develop and maintain a log of inspections, maintenance, repairs, and disposal (including location of disposal) during the life of the project. Records will be maintained for at least 3 years and be made available to the Massachusetts Department of Environmental Protection or the Town of Yarmouth in accordance with the provisions of the Massachusetts Stormwater Handbook and Town of Yarmouth Stormwater Regulations. INSPECTIONS The Responsible Party shall allow the Yarmouth Conservation Commission to inspect each BMP to confirm that the Operations and Maintenance is being implemented. CERTIFICATION The Responsible Party shall submit an annual certification, in accordance with Section 2.07(1)(i) iv, to the Yarmotuh Conservation Commission. MINIMIZING EXPOSURE The Responsible Party shall minimize exposure of potential pollutant sources, including debris from coming into contact with precipitation and being picked up by stormwater and carried into drains and surface waters using the following steps: Storing all containerized materials in a protected, secure location away from drains and plainly labeled. Containing all activities that can generate sources of contaminants from reaching the receiving water or the stormwater management system. Securing any equipment or supplies so that they are not transported during storm events into receiving waters or stormwater management system. BEST MANAGEMENT PRACTICES (BMP) MAINTENANCE The proposed stormwater management system has been designed with appropriate BMPs aimed at reducing the pollutants discharge based upon the intended use of the proposed development. All BMPs require regular maintenance to function as intended. Some management measures have simple maintenance requirements; others are more involved. The Responsible Party must have all BMPs regularly inspected to ensure they are operating properly on a weekly basis during construction. A description of the non-structural and structural approaches to be incorporated is indicated below. The following Best Management Practices are proposed to be incorporated into the stormwater management design to reduce source runoff and improve stormwater runoff discharge quality. The Responsible Party will regularly inspect all BMPs to ensure they are operating properly. If any deficiencies are identified during these inspections, action to resolve it will be initiated and documented on the maintenance log. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 3 NON-STRUCTURAL BEST MANAGEMENT PRACTICES (BMPs) STREET/PARKING LOT SWEEPING This practice, considered by MassDEP to be a non-structural BMP, provides effective removal of Total Suspended Solids (TSS) in a comprehensive stormwater management program. A maintenance program of roadway/driveway sweeping with a High Efficiency Vacuum Sweeper or a Regenerative Air Sweeper to reduce sediment accumulation in the deep sump catch basins and subsurface systems shall be implemented based on the owner discretion. Sweeping can be conducted on a quarterly basis (primarily in the spring and fall) to keep low impact BMPs operating effectively. GRADING The impervious areas of the site shall be graded as gently as possible, generally not more than 6% slopes, to reduce runoff velocities. Steep slopes will be permanently vegetated to dissipate energy and reduce potential erosion. No constructed vegetated slopes shall exceed 3H:1V without providing additional reinforcement. Steep slopes may require soil reinforcement and additional vegetation. SNOW STORAGE AND DEICING Snow storage will be located adjacent to parking area as directed. In the event of a large snow event that exceeds snow storage on the site, snow will be removed and hauled off-site. In the interest of reducing the volume of dissolved salt that enters the watershed, the operator of the development will rely on sand alone where traction on snowy surfaces is the primary objective. However, parking areas, driveways, and sidewalks which require deicing for safety during winter months will typically be treated with calcium magnesium acetate or another alternative as approved by the Yarmouth Conservation Commission. FERTILIZER: Due to the project’s location within an environmentally sensitive area, any use of fertilizers will be limited to those as approved by the Yarmouth Conservation Commission and per the Stormwater Management Regulations of the Yarmouth Conservation Commission, restrictions on the application of fertilizers shall include: i.Fertilizer shall not be applied during or immediately prior to heavy rainfall, such as but not limited to thunderstorms, hurricanes, or northeastern storms, or when the soil is saturated due to intense or extended rainfall; ii.Fertilizer shall not be applied between November 12 and the following March 31; iii.Fertilizer shall not be applied, spilled or deposited on impervious surfaces or in a manner that allows it to enter into storm drains; iv.Fertilizer shall not be applied within 100 feet of any surface water or within the Zone I of a public drinking water well; v.Fertilizer containing phosphorus shall not be applied unless a soil test taken not more than three years before the proposed fertilizer application indicates that additional Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 4 phosphorus is needed for growth of that turf, or unless establishing new turf or reestablishing or repairing turf after substantial damage or land disturbance; vi.A single application of fertilizer that contains nitrogen shall not exceed 1.0 pound of nitrogen per 1,000 square feet, shall consist of at least 20% slow-release nitrogen (SRN) fertilizer (NOTE: This represents the minimum percentage: use of higher SRN content is generally preferable, especially on sandy root zones, during stress and pre-stress periods, and when there are fewer annual applications of nitrogen made to a lawn) and the annual rate shall not exceed 3.2 pounds of actual nitrogen per thousand square feet. Single applications shall be done at intervals of no less than four weeks until the annual maximum is reached; vii.Grass clippings, leaves, or any other vegetative debris shall not be deposited into or within 50 feet of water bodies, retention and detention areas, drainage ditches or stormwater drains, or onto impervious surfaces, such as, but not limited to, roadways and sidewalks, except during scheduled cleanup programs. PESTICIDES/HERBICIDES: Due to the project’s location within an environmentally sensitive area, any use of pesticides/herbicides will be prohibited unless otherwise approved by the Yarmouth Conservation Commission. WASTE MANAGEMENT: Solid waste will be contained within dumpsters. Waste deposition in these receptacles will be consistent with state and local permits. The covers and doors of the dumpsters will be kept closed to limit rainwater/wildlife intrusion. STRUCTURAL BEST MANAGEMENT PRACTICES: Prior to final completion and full occupancy of the development, it is recommended that a representative of the Contractor, Manufacturer, and/or Engineer either designing or building the facility for the Owner properly instruct the Responsible Party as to the maintenance practices required to responsibly maintain the effectiveness of the drainage system. These frequencies and requirements are recommendations to maintain minimum effectiveness in most typical environments. Ultimately, the Responsible Party will implement the procedures and frequencies as they see fit under their current plan and inspect the systems as needed to maintain minimum effectiveness as recommended by the manufacturer. The following maintenance of structural BMPs will be implemented: ROOF DRAIN GUTTERS, DOWNSPOUTS, AND SUBSURFACE INFILTRATION BASIN Roof drain gutters, downspouts, and subsurface infiltration basin should be inspected and cleaned twice a year, once in the fall after leaf drop and in the spring after snow melt. Cleaning will take place at the completion of construction and in early spring after snow melt. Any obstructions, sediment, and debris that could potentially cause clogging shall be removed within the roof drain gutter and downspout system as necessary. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 5 DEEP SUMP CATCH BASINS AND MANHOLE STRUCTURES Catch basins shall be cleaned, in dry weather, when half of the sump capacity is filled or at a minimum quarterly or as required through periodic inspection. Cleaning will take place at the completion of construction and in early spring after sanding of roadways has ceased or as needed depending on the frequency of major storm events (greater than 1-inch of rainfall). All manholes shall be inspected at least once annually. Any obstructions, sediment, and debris that could potentially cause clogging shall be removed within the conveyance system as necessary. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. OIL/GRIT SEPARATORS Oil/Grit separators are used to manage runoff from land uses with higher potential pollutant loads where there is a risk that the stormwater is contaminated with oil or grease. Oil/grit separators require regular maintenance with inspection monthly and cleaning at least twice per year. Cleaning included removal of accumulated oil and grease and sediment using a vacuum truck. Polluted water or sediments removed should be disposed in accordance with CDS- HYDRODYNAMIC SEPARATORS (WATER QUALITY UNITS) The CDS stormwater treatment units are a type of hydrodynamic separator. Hydrodynamic separators are a type of water quality manhole or catch basin inlet that relies on flow through the structures to promote settling and separation within the unit in order to remove sediments and other pollutants that are widely found in storm water. This technology will be used as a part of a treatment train consisting of other structural and non-structural approaches. Each device has been sized using the 1.0” equivalent water quality flow and will be reviewed per manufacturer’s recommendations and checked by the representative. Water quality inlets will be installed throughout the site to remove trash, debris, sediment and a limited amount of oil and grease from stormwater runoff. The hydrodynamic separators shall be inspected four times per year and cleaned, in dry weather, at least once per year or in accordance with the manufacturer’s recommendations. Cleaning will take place at the completion of construction and typically in early spring after sanding of roadways has ceased. Periodic inspections performed by the responsible party may dictate cleaning on a more frequent basis depending on the suspended solids loading. During construction accumulated sediment may need to be removed more frequently. Usually, a vacuum truck removes accumulated sediment and oil most efficiently. See maintenance documentation from the manufacturer for additional maintenance criteria. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. RETENTION/RECHARGE BASIN A retention/recharge basin receives stormwater from the upstream drainage system and retains and infiltrates it into the surrounding soil. The basin shall be inspected on a semi- annual basis in the early spring and fall. Additional inspections shall be performed during the first few months after construction to ensure that adequate vegetation has been established. Regular maintenance shall include mowing, fertilizing, pruning, debris, trash and sediment removal, and weed/pest control. The basin buffer area, side slopes, and basin bottom shall be Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 6 mowed at least twice per year. SPILL CONTROL: The development consists of a warehouse and distribution facility. It is recommended, that if there is no existing contingency plan to address the spillage/release of petroleum products and any hazardous material, one be developed and implemented. The recommendation includes that the Owner have all MassDEP emergency spill response information posted onsite at all times. It is also recommended an emergency spill response kit including absorbent pillows be stored on-site along with instructions for the kit, a copy of applicable regulations regarding spills, and a list of individuals to contact (local and state officials) in the event of a spill. Spills or leaks will be treated properly according to material type, volume of spillage, and location of the spill. Mitigation will include preventing further spillage, containing the spilled material in the smallest practical area, removing spilled material in a safe and environmentally friendly manner, and remediating any damage to the environment. LONG-TERM OPERATION AND MAINTENANCE BUDGET: Consistent with Standard 9 of the Massachusetts Department of Environmental Protection Stormwater Handbook (February 2008) the approximate cost of inspections and maintenance based on the abovementioned post-construction activities and frequencies is as follows: •Pavement Sweeping - $3,000 per year based on annual sweepings. •Deep Sump Catch Basins - inspection/cleaning - $1000 per year/per catch basin based on quarterly inspections and sediment removal of both single and double grate deep sump catch basins. •Oil/Grit Separator - inspection - $1000 per year based on semi-annual inspections. Cleaning/debris removal/maintenance - $1,000 per year for accumulated sediment and trash removal. •Water Quality Unit – inspection - $1000 per year based on quarterly inspections. Cleaning/debris removal/maintenance - $1000 per year for accumulated sediment and trash removal. •Retention/Recharge Basin - inspection - $1,000 per year based on semi-annual inspections. Cleaning/debris removal - $1,000 per year for accumulated sediment and trash removal. Additional costs may be incurred if it is determined during routine inspections of the BMP's that further corrective actions are necessary. Page 7 6/30/2022