What is a Watershed? - Iowa Stormwater Education Partnership

What is a Watershed?

We all live in a watershed

The land area that drains or “sheds” to a lowpoint in the landscape such as to a river, lake or wetland is a watershed.  There are different levels of watersheds from basins to subwatersheds. Think about where the rainfall goes in your yard after a rainfall.  It drains to the street, into a storm drain and into a local stream or lake. This, on the smallest scale, is one form of watershed.  The quality of water draining off your land directly impacts your local stream and lake quality.


Watershed Basin Sub-Watersheds Sub-Sub Watershed

There are many activities that impact water quality in watersheds. One of them is directly tied to the amount of impervious surface in a watershed. Urban areas have surfaces that don't absorb water, such as roads, streets, rooftops, parking lots, and even compacted soil. Studies indicate that as the amount of impervious surface increases in urban areas the poorer the stream quality. 

Watershed Resources

U.S. EPA Surf Your Web

Iowa Watershed Atlas

Center for Watershed Protection

Watershed Planning Grants



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