Stormwater Management

Where does stormwater go?

Stormwater flows directly into our rivers, lakes, streams and the ocean or into a stormwater system through a storm drain.

Storm drains are frequently located in parking lots and along the curbs of roadways. The grate that prevents larger objects from flowing into the storm sewer system is called a catch basin. Once below ground, the stormwater flows through pipes, which lead to an outfall where the stormwater usually enters a stream, river or lake.

In some areas, the outfall may lead to a stormwater management basin. These basins control the flow and improve the quality of stormwater, depending on how they are designed. They can also recharge groundwater systems.

In some urban areas of the state, the stormwater and sanitary sewer systems may be combined. Here both stormwater and sewage from households and businesses travel together in the same pipes and are treated at sewage treatment plants except during heavy rains. During these occasions, both the stormwater and untreated sewage exceed the capacity of the treatment plant, and this overflow is directed into local waterways.

What are some simple changes I can make to protect our waters?

Urbanization and increasing commercial and residential development have a great impact on local water resources. More impervious surfaces (roads, rooftops, parking lots and other hard surfaces that do not allow stormwater to soak into the ground) increase the rate of stormwater runoff. This means a greater volume of water carrying pollution into surface waters and less water soaking into the ground. These contaminants include litter; cigarette butts and other debris from sidewalks; motor oil poured into storm sewers; settled air pollutants; pet wastes; yard wastes; and pesticides and fertilizers from lawn care. Less water soaking into the ground also lowers ground water levels, which can dry up streams and hurt stream ecosystems, and can reduce the supply of well water.

Stormwater also erodes stream banks. This in turn degrades habitat for plant and animal life that depend on clear water. Sediment in water clogs the gills of fish and blocks light needed for subsurface plants. The sediment can also fill in stream channels, lakes and reservoirs, covering the bottom and negatively affecting flow, plants and aquatic life.