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What is a Watershed? - Site Description - Problems - What can you do?

What is a Watershed?

The U.S. Environmental Protection Agency (EPA) defines a watershed as:

a geographic area in which water, sediments, and dissolved materials drain to a common outlet--a point on a larger, a lake, an underlying, aquifer, an estuary, or an ocean (includes both the surface and ground water drainage basins).

The California State Water Resources Control Board (SWRCB) states that watersheds are delineated by physical features of the landscape and associations of natural resources that rely on the type and quality of water present.

By force of gravity and under topographic limits, water that runs downhill or percolates into aquifers eventually empties into a waterbody at a lower elevation. In smaller subwatersheds, runoff from a few acres of land may drain into a small stream or creek, which in turn flows to larger waterbodies.

The Arana Gulch watershed includes all the land areas that drain to Santa Cruz Harbor.