What is a watershed?
How big is the Bay?
A watershed is the land area drained by a multitude of streams that flow downhill into a major river or lake or estuary. Watersheds are also called drainage basins. Depending upon where you are in a network of streams draining the landscape (e.g., near the top in the headwaters or at the bottom on the shore of Chesapeake Bay), a watershed can be small (draining only a few acres), or very large (draining thousands of square miles).
Another way to think about a watershed is to imagine a large funnel open to the sky. The funnel is analogous to a watershed, call it Watershed A. Any rain, sleet or snow that falls inside the rim of this funnel belongs to Watershed A. The rim of the funnel is analogous to a watershed boundary. Hence, any rain or sleet or snow that falls outside the rim of this funnel belongs to adjacent watersheds. On the landscape, boundaries between watersheds are usually determined by elevation.
- Ron Klauda,
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