William and Mary  Water Quality Primer  Water quality in
different bodies of water in a watershed will tell us "how we're
doing".  Is water quality good?  Is it bad?  Is it variable from
season to season?  Do we need to do anything about it?  When we
sample in the field, we measure water temperature, dissolved
oxygen concentration, salinity, and acidity.  We also bring
water samples back to the Keck Lab to analyze for suspended
sediment load, fecal coliform bacteria, and nutrient levels.
 Sediments, bacteria, and nutrients-specifically nitrogen-are
the major contaminants found in the streams and lakes of local
watersheds. These contaminants also are the pollutants that are
in part responsible for declining fisheries productivity in
Chesapeake Bay.  If we don't want these pollutants in Chesapeake
Bay, then we need to keep them out of the streams and lakes of
our local watersheds (and all of the thousands of little
watersheds that collectively make up the Chesapeake Bay
watershed).