Degradation of water-quality conditions due to excessive nutrients and sediment, and loss of habitat, continues to be the primary issue impacting the Bay ecosystem. In spite of 20 years of restoration efforts, there has been only modest improvement of water-quality conditions in some tidal tributaries of the Bay and the streams in the watershed. The USGS science theme to address the “factors affecting water quality and quantity” is focused on nutrients and sediment in the watershed to provide science for improved implementation and assessment of the tributary strategies to improve water quality. Addressing contaminants is focused on providing data to help access the factors affecting the health of fish and bird populations. The primary objectives are:

• Improve monitoring and simulation of, and further define the processes affecting, the occurrence, transport, residence time, and change of nutrients and sediment in the watershed;
• Better define the function of key habitats (forests, wetlands, stream corridors) to adsorb and store nutrients and sediment;
• Relate the delivery of nutrients and sediment from the watershed to water quality in the estuary; and
• Synthesize information and conduct forecasts to provide implications and tools for improved targeting and assessment of water-quality management activities.