The water that runs along the ground or
through pipes after a rainfall
(or during snowmelt) is known as stormwater. Stormwater picks up
sediments, bacteria, nutrients, chemicals, and debris as it runs across
lawns, roofs, driveways, parking lots, and residential, commercial, and
industrial sites. Laden with a variety of pollutants, stormwater then
flows into water bodies and storm sewers that drain into Casco Bay.
Common sources of stormwater runoff in the
Casco Bay watershed such as urban development, residential development,
construction activities, air deposition, roadways, industrial sites,
and agriculture.
There are two primary sources of
contaminated stormwater:
1.) point sources conveys stormwater runoff
into rivers and the bay through direct, identifiable conveyances such
as pipes.
2.) nonpoint sources includes runoff from
land or groundwater see page that enters rivers and the bay from
diffuse locations such as malfunctioning septic systems, paved areas,
feed lots, or manure storage areas. National studies estimate that
nonpoint sources of pollution now contribute up to 60 percent of the
pollutant load.
While sewage treatment plants are designed
to handle a certain amount of flow, as flow increases dramatically
during a storm, it can overload the plant. To avoid damage to the
sewage treatment plant, a portion of the combined sewage (sewage and
stormwater) that would enter the plant is diverted without treatment
through relief points known as combined sewer overflows.
Click
here
or on the Current Projects button to the right for
examples of the stormwater activities that CBEP and our partner
organizations are supporting.