Stormwater is water from rain or melting snow that doesn't soak into the ground but runs off into waterways. It flows from rooftops, over paved areas and bare soil, and through sloped lawns while picking up a variety of materials on its way. The quality of runoff is affected by a variety of factors and depends on the season, local meteorology, geography, and land use.
Examples of Pollution in Stormwater
- Nutrients such as phosphorus and nitrogen can promote the overgrowth of algae, deplete oxygen in the waterway, and be harmful to other aquatic life.
- Bacteria from animal wastes and illicit connections to sewerage systems can make nearby lakes and bays unsafe for wading, swimming, and the propagation of edible shellfish.
- Oil and grease from spills during vehicle maintenance activities causes sheen and odor and makes transfer of oxygen difficult for aquatic organisms.
- Sediment from construction activities clouds waterways and interferes with the habitat of living things that depend upon those waters.
- Careless application of pesticides, herbicides, and fertilizers affect the health of living organisms and cause ecosystem imbalances.
- Trash and debris damages aquatic life, introduces chemical pollution, and diminishes the beauty of our waterways.
Regulatory Requirements
The USEPA and New York State Department of Environmental Conservation (NYSDEC) have established general permits and regulations to deal with stormwater. State Pollutant Discharge Elimination System (SPDES) general permits are required for activities associated with stormwater discharges. Two of these are listed below.
- The General Permit for Stormwater Discharges from Municipal Separate Storm Sewer Systems (MS4 GP) requires MS4 Operators (like the Town of Lewisoro) to develop a stormwater management program (SWMP) to reduce the discharge of pollutants to the maximum extent practicable.
- Construction activities disturbing one or more acres of soil must be authorized under the General Permit for Stormwater Discharges from Construction Activities (CGP). Permittees are required to develop a SWPPP to prevent discharges of construction-related pollutants to surface waters. Additional requirements apply to areas within the East of Hudson (EOH) watershed, including much of the Town of Lewisboro.
New York State has a Stormwater Interactive Map that provides information about the areas and waterbodies where these regulations apply.