Virginia recently released tributary strategies outlining nutrient and sediment reductions for the Rappahannock, York and James river watersheds as well as the Eastern Shore Coastal Basins. The plans, like those for other major Bay rivers, serve as guides for future nutrient reduction efforts.
Strategies for the Potomac and rivers in Maryland and Pennsylvania were written years ago to achieve the Bay Program’s overall 40 percent nutrient reduction goal for the Chesapeake. But final strategies were delayed for the lower tributaries because they have less of an impact on Chesapeake water quality than Upper Bay tributaries.
Instead, the strategies set nutrient reduction goals based on improvements to water quality and habitat conditions predicted by the Bay Program’s computer models. The lower Bay rivers provide important habitat for blue crabs and many fish.
“Virginia’s approach, to base reduction goals on the anticipated responses of living resources, was a first for the Bay Program,” said Virginia Secretary of Natural Resources John Paul Woodley, Jr. “These are also the first tributary strategies to include sediment reductions.”
The strategies, developed with input from stakeholder groups in each watershed, are to be implemented by 2010. They set the following nutrient and sediment goals.
- The York River basin calls for annual reductions of nitrogen of about 2.3 million pounds (from about 9 million), a 60,000 pound phosphorus reduction (from about 540,000), and a 9,000 ton reduction in sediment. The reductions are expected to help reduce anoxic conditions (water depleted of oxygen), and increase underwater grass beds. Because much of the tidal river is heavily influenced by the Rappahannock, the strategy notes that water quality improvements from that river are needed as well.
- The Rappahannock strategy calls for reducing by 50 percent the annual volume of anoxic water and increasing by 50 percent the density of underwater grass beds. The strategy calls for reducing nitrogen from about 10 million pounds to 6.9 million pounds a year, reducing phosphorus from about 930,000 pounds to 663,000 pounds a year, and achieving a 20 percent reduction in sediment.
- The James strategy calls for reducing nitrogen by about 13.2 million pounds a year (from about 46 million), reducing phosphorus by more than 2 million pounds a year, (from about 6 million) and reducing sediment by about 180,000 tons per year. As a result, underwater grass beds are expected to return to tidal fresh areas, and the amount of algae in the river should decline substantially.
- The Eastern Shore strategy focuses on increasing the area and density of underwater grass beds in tidal creeks and embayments to historical levels. The strategy calls for additional monitoring and modeling work to better establish water quality issues on which to base nutrient reduction goals. But it does set short-term targets, to be achieved by 2003, of reducing nitrogen by 382,000 pounds (from 2.4 million pounds), reducing phosphorus 55,400 pounds (from 220,000 pounds), and reducing sediment by 9,300 tons.
The strategies are available on the internet at www.deq.state.va.us or at www.state.va.us/~dcr