Potomac River

The Potomac River has one of the highest areas with degraded benthic community condition in the Chesapeake Bay. Much of the problem in the Potomac River is severe oxygen depletion in the lower deep mainstem. In 2003, the Potomac River had the highest percentage of sites among strata failing the Restoration Goals because of insufficient abundance or biomass. Fifty-nine percent of the bottom dissolved oxygen readings at Water Quality Monitoring Program stations in the lower Potomac were below 1 mg/L in 2003. Note the increased estimate of severely degraded condition in 1996 and 2003, the two years with the highest precipitation and most severe hypoxia (chart below).