No matter where you are, you're in a watershed. Chester County's land
area consists of portions of 21 watersheds that ultimately drain to the
Delaware Bay or Chesapeake Bay.
A watershed is the area of land (catchment area) that captures rain and
snow, and then stores, filters, seeps or drains this water into a common
water body (marsh, stream, river, or lake). A watershed includes the
network of streams that drains that surface land area, and the
groundwater and aquifers located underground that contribute water to
those streams.
Watersheds are separated from adjacent ones by a continuous ridgeline
that forms the watershed’s boundary. Watersheds come in all shapes and
sizes and can be broken down into subwatersheds (or subbasins). Each
water body has its own watershed; some are millions of square miles in
size; others are just a few acres.