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Home My Public Portal AboutConstructionBrochureWhy is stormwater runoff so bad? Runoff from rainstorms and snowmelt picks up pollutants like sediment, oil and grease, nitrogen and phosphorus, and other chemicals and carries them into storm drains or directly into the Charles River. Because most storm drain systems do not provide any treatment to the water they collect, preventing contamination of stormwater is critically important. In addition, construction -related erosion can cause problems for downslope property owners, create nuisance problems on adjacent streets, and clog storm drains. Why is sediment harmful to a waterbody? Too much sediment in a waterbody can cloud the water and make it difficult or impossible for aquatic plants to receive the sunlight they need to grow. Excess sediment also smothers aquatic habitat, clogs fish gills, and impedes navigation in our waterways, which can lead to expensive dredging. What can I do? There are many different ways erosion and stormwater pollution from small construction sites can be reduced. • Divert stormwater away from disturbed or exposed areas of the construction site. • Control erosion and sediment and manage stormwater. • Inspect the site regularly and properly maintain BMPs, especially after rainstorms. • Revise erosion and sediment controls if BMPs are not effectively controlling erosion and sediment. • Minimize exposure of bare soils to precipitation. • Keep the construction site clean by putting trash in trash cans, keeping storage bins covered, and sweeping up excess sediment on roads and other impervious surfaces. Does my project require a Permit? Any construction project that disturbs 5,000 SQFT, increases impervious area by 500 SQFT, creates/modifies a connection to the public drainage system, or may impact the public drainage system requires a Stormwater and Erosion Control permit issued by Watertown DPW. All construction sites disturbing 1 or more acres (with few exceptions) require federal stormwater permit coverage as well! For more information, visit the EPA web site: hftps://www.epa.gov/npdes/stormwater-d ischar_qes-construction- activities Note: Land disturbance includes clearing, grading, excavating, and stockpiling of fill materials. This includes the area of the entire project, even if you are responsible for only a small portion. All projects planned in, or within 100 feet of, a wetland or floodplain or within 200 feet of perennial streams require review by the Conservation Commission for compliance with the State Wetlands Protection Act and Watertown Wetlands Protection Ordinance! For more information, contact DCDP at 617-972-6417. Who is responsible for erosion and sediment measures? The site owner or his designee(s) (i.e. Contractor) are responsible to install and maintain the erosion and sediment control measures. The control measures must be installed and maintained as shown on approved permit application documents. In addition, if there is evidence that the control measures are not effective to prevent erosion and sedimentation, the controls should be modified. Maintenance of erosion and control measures requires regular inspection, including after all rain events. In addition, DPW requires inspection and signoff of erosion and sediment controls at specific project milestones (including after initial installation of control measures). Contact DPW to schedule inspections at 617-972-6420. Construction Site Impacts and Erosion and Sediment Control Requirements Watertow� PUDIR We're all about Watertown Department of Public Works 124 Orchard Street Watertown, MA 02472 Tel.: 617-972-6420 r Construction Entrance • Provide a stable entrance and exit from a construction site to keep mud and sediment off public roads. • Maintain entrance to prevent tracking or flowing of sediment onto public right-of-way. This may require periodic topdressing with additional stone. Storage of Soil, Sand, Salt, and Other Erodible Materials Locate stockpiles as far away from storm drains, wetlands, and waterbodies as possible. Cover and contain stockpiles of raw materials to prevent stormwater from running into the covered piles. The covers should be in place at all times when work with the stockpiles is not occurring. If the stockpiles are so large that they cannot feasibly be covered and contained, you can contain sediments by placing hay bales and silt fence around the perimeter of the stockpile. Sweep paved storage areas monthly for collection and disposal of loose solid materials. Do not hose down the area to a storm drain! Concrete and Asphalt Application • Use drip pans, ground cloths, and perhaps even cardboard or plywood wherever concrete, asphalt, and asphalt emulsion chucks and drips are likely to fall unintentionally, such as beneath extraction points from mixing equipment. • Cover storm drains at the beginning of the work day. All accumulations of runoff, aggregate chunks, and other solids should be collected with a shovel or other mechanism for proper disposal at the end of the work day. Contain and collect the slurry from exposed aggregate washing, where the top layer of unhardened concreted is hosed or scraped off to leave a rough finish. Do not discharge concrete, slurry, or rinse water into street gutters, storm drains, or drainage ditches! Designate a wash -out area on -site where cleaning of application and mixing equipment can take place and where rinse water is controlled. It is also acceptable to dispose of rinse water and slurry in a hole in the ground big enough to contain the materials, as long as it is 100-feet away from wetlands and waterways. Sweep the pouring area at the end of each day to collect loose aggregate chunks and dust. Do not hose down the area to a storm drain! Building Demolition • Use dust control methods and commercial dust suppressants to help control fine materials and dust. The amount of water must be actively controlled to eliminate runoff from the site. Avoid excessive and repeated applications of dust suppressant chemicals. Place filter fabric, inlet control measures or a similarly effective device in or around all nearby drains to prevent particles and solids from entering the storm drainage system. Sweep surrounding street gutters, sidewalks, driveways, and other paved surfaces as needed to collect loose debris and garbage. Properly dispose of collected debris and garbage. Do not hose down the area to a storm drain! Building Repair, Remodeling, and Construction Do not dump any substance, wash water or liquid waste on the pavement, the ground, or toward a storm drain or drainage ditch. Use ground or drop cloths underneath outdoor painting, scraping, and sandblasting work and properly dispose of collected material daily. Use a ground cloth or oversized tub for activities such as paint mixing and tool cleaning. Dispose of all wash water from tool cleaning to the sanitary sewer system. Clean paint brushes and tools covered with water - based paints in sinks connected to sanitary sewers or in portable containers that can be dumped into a sanitary sewer. Never dispose of wash water to on - site yard drains or street drains. Brushes and tools covered with non -water -based paints, finishes, or other materials must be cleaned in a manner that enables collection of used solvents (e.g., paint thinner, turpentine, etc.) for recycling or proper disposal. Use a storm drain cover, filter fabric, or similarly effective runoff control mechanism if dust, grit, wash water, or other pollutants may escape the work area and enter a catch basin. This is particularly necessary on rainy days. If you need to dewater an excavation site, discharge to a location where infiltration can occur. You should filter the water prior to discharge, using sediment filters or traps. Discharge should not be made within 100-feet of a wetland. Discharge to a road gutter, catch basin or drainage ditch is prohibited without consent of the Department of Public Works. Store and maintain appropriate spill cleanup materials in a location known to all. Ensure that employees are familiar with proper spill cleanup procedures. Sweep paved areas as needed and collect loose particles for proper disposal. Wipe up spills with rags and other absorbent material immediately. Do not hose down the area to a storm drain. Store toxic material under cover during precipitation events and when not in use (such as overnight). A cover would include tarps or other temporary cover materials. Sediment Fence and Hay Bales • Sediment fence and hay bales (or silt socks) intercept and detain small amounts of sediment from disturbed areas during construction operations and reduce runoff velocity down a slope. • Locate at downstream property lines and at least 25- feet from wetland resource areas. Install parallel to ground contours. • Hay bales and silt fence should be keyed into the ground at least 8-inches. Additional Controls For additional controls, consult the Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban areas, published by DER