| What is a Watershed? |
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| A watershed is the area of
land for which water drains into a common body of water. This includes
water
that flows across the land as streams and rivers as well as water that
moves
through the land as groundwater. A watershed is often also referred to
as a
"river basin," a "river valley," or a "drainage
basin." In a more meaningful sense, watersheds are "communities connected by water." Activities that occur on the land or in the waterway of one town will affect the land and waterways of other towns within that watershed. To locate your watershed, visit EPA's website, "Surf Your Watershed," which allows you to enter your zip code and find out the watershed in which you live. To locate your watershed, go to http://epa.gov/surf/ |
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| Why are Watersheds Important? | |
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Many water
quality problems
are best solved at the watershed level rather than at the level of an
individual
waterbody or discharger. It is important that a watershed approach be
used to
address water quality concerns because land-use decisions made in one
area of a
watershed will inevitably affect those living in another part of the
watershed.
Since watersheds can encompass several towns, states or even counties,
this
approach often requires cooperative efforts among a variety of
entities. |
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| How Land Use Within a Watershed
Affects Water Quality |
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Water quality is impacted by both point and nonpoint source pollution. Point sources are those discharges that come directly from pipes such as industrial and sewage treatment plants. Nonpoint source pollution, however, comes from many diffuse sources in which pollutants are transported by runoff from rainfall and snowmelt as makes its way to a waterbody. These nonpoint sources are a direct result of land use decisions. For example, common nonpoint sources of pollution include excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas; oil, grease, and toxic chemicals from urban runoff; sediment from improperly managed construction sites and eroding streambanks; salt from irrigation practices and roads; and bacteria and nutrients from livestock, pet wastes, and faulty septic systems. As the amount of impervious surface increases in a watershed, the amount of runoff increases which in turn amplifies the effects of these nonpoint sources of pollution. (http://www.okcc.state.ok.us/WQ/WQ_FAQ.htm |
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