Chesapeake Bay is wide and shallow, so contains a small amount
of water for an estuary of its size. It also has a very large
area of watershed for its volume of water, and thus is quite
susceptible to contamination from activities in the watershed.
Originally almost entirely forested, the watershed now is the
site of coal mining, industry, agriculture and, increasingly,
urbanization. A forest acts like a sponge, evening flows and
filtering nutrients. Without its forests, the watershed is prone
do delivering bursts of freshwater, contaminated with nutrients
and worse into the Bay. To save the bay, it is necessary to
reclaim at least part of the forests function in the watershed.