The Bay was listed as an "impaired water body" under the Clean Water Act due to low dissolved oxygen that has killed fish and other organisms. Nutrient sources in the watershed must be further reduced in the tributary strategy basins (see map) to meet new dissolved oxygen, water clarity, and chlorophyll standards by 2010 or a Total Maximum Daily Load (TMDL) for the Bay would be required. Additional science is needed to better assess the types and locations of management actions to most effectively reduce nutrients from reaching streams and the Bay. The USGS will help meet these needs by:

• Better define, map, and simulate process, landscape settings, and habitats controlling nitrogen movement;
• Better quantify the amount and residence times of nitrogen discharging to streams and directly to tidal waters;
• Provide leadership for improved design and implementation of the nontidal water-quality network;
• Continue to enhance techniques for load computations and trends analysis of nutrients and sediment;
• Relate water-quality findings in the watershed with estuary conditions;
• Integrate findings from the impact of human activities on land use with improved water quality and quantity models to forecast potential water-quality changes in the future; and
• Synthesize information to improve environmental indicators, assessments, and identify areas in the watershed that would provide the most immediate benefit for implementing tributary strategies.