Stormwater Management


The Town of Southeast has developed a Stormwater Management Program (SWMP) to reduce the amount of pollutants entering water bodies within the Town during rain events. The Town contributes stormwater flow to 6 waterbodies that have been listed by the New York State Department of Environmental Conservation as impaired. Five (5) of those waterbodies are part of the New York City Watershed, known as the Croton Watershed system.


Stormwater is water from rain or melting snow that does not 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. As it flows, stormwater runoff collects and transports soil, animal waste, salt, pesticides, fertilizers, oil and grease, debris and other potential pollutants. The quality of runoff is affected by a variety of factors and depends on the season, local meteorology, geography and upon land uses that lie in the path of the flow.

Problems With Stormwater

Stormwater gathers sediment and a variety of pollutants that are mobilized during runoff events. Such runoff degrades our lakes, rivers, wetlands and other waterways. Transported soil clouds waterways and can interfere with the habitat of fish and plant life.

  • Nutrients such as phosphorus and nitrogen can promote the overgrowth of algae, deplete oxygen in waterways and be harmful to other aquatic life.
  • Toxic chemicals from automobiles, sediment from construction activities and careless application of pesticides, herbicides and fertilizers threaten the health of the receiving waterway and can kill fish and other aquatic life.
  • Bacteria from animal wastes or failing septic systems can make local lakes unsafe for wading and swimming and the New York City reservoirs unsafe as a source for drinking water.
Water pouring from a drain and down a hill
A storm drain next to a curb

According to an inventory conducted by the United States Environmental Protection Agency (EPA), half of the impaired waterways in the United States are affected by urban/suburban and construction sources of stormwater runoff. In the New York City watershed here in Southeast, each of the five reservoir basins is currently impaired with respect to elevated phosphorus levels.

Stormwater Management Practices

Stormwater management practices are used to delay, collect, store, treat, or infiltrate stormwater runoff. While specific design objectives for stormwater management practices are often unique to each subwatershed, the general goals for stormwater management practices usually include the following:

  • Maintain groundwater recharge and quality
  • Reduce stormwater pollutant loads
  • Protect stream channels
  • Prevent increased overbank flooding
  • Safely convey extreme floods