This is the fourth in a series of annual reports that present the most recent estimates (through 2005) about the status of nutrient and sediment reduction efforts aimed at achieving Chesapeake Bay water quality goals.
Most of the information in this report comes from data provided by the states to the Bay Program about their progress in implementing a variety of nutrient control efforts. Those figures are used by a computer model to predict how those actions will affect the amount of nutrients and sediment entering the Bay from each Bay tributary.
The full impact of those actions—although reflected in figures here—will not be reflected in Bay water quality for years. Many runoff control actions—such as planting buffer strips along streams—can take years to become fully effective. Also, it often takes nutrients years to reach the Bay; actions taken today may not have their full impact until sometime in the future.
To better reflect current conditions, this year’s report includes monitoring data collected from nontidal rivers throughout the watershed on pages 14–15. Unlike the model, which predicts how actions today will affect future nutrient levels, the monitoring data reflect current river conditions. But monitoring only covers the nontidal portion of rivers—not the areas influenced by tides, which include much of the watershed’s population.
More complete descriptions of the modeling and monitoring benefits and shortcomings occur later in this section.
The main forms of pollution affecting the Bay are excess nutrients (nitrogen and phosphorus) and sediment. Nutrients cause algae blooms which—along with sediment—reduce water clarity. This prevents sunlight from reaching—and therefore kills—underwater plants that provide important food and habitat for crabs, fish and waterfowl.
When the algae die, they sink to the bottom and decompose in a process that removes oxygen from the water, contributing to low-oxygen conditions and “dead zones” with no oxygen at all.
Excess nutrients and sediment can also affect the types of algae that grow in the Bay, creating conditions favorable to some nuisance species that are not the desired food for fish and small predators near the base of the food web.
In 2003, the Bay Program, using computer models, established nutrient and sediment reduction goals needed to meet new water quality standards [See “The Cleanup Goal,” box.] Overall, those goals required a 48 percent reduction in nitrogen, and a 53 percent reduction in phosphorus, measured from a 1985 baseline.
All of the jurisdictions that drain into the Bay (Virginia, Maryland, Pennsylvania, the District of Columbia, West Virginia, Delaware and New York) have written river-specific plans called tributary strategies that spell out what mix of actions is required to meet the nutrient and sediment goals for each basin: the miles of riparian forest buffers that must be restored, the number of acres of cover crops that must be planted, the number of wastewater treatment plants that must be upgraded and so on.
Jurisdictions in the watershed continued to make nutrient and sediment reduction progress, but there is little evidence in the latest data, released in December, that efforts to reduce pollution have accelerated. In 2005, the seven jurisdictions in the Bay watershed cumulatively took actions that would
- Reduce the amount of nitrogen entering the Bay by 3.8 millions pounds from 2004 levels. The annual average reduction since 1985 has been 3.4 million pounds.
- Reduce the amount of phosphorus by 290,000 pounds. That was less than the annual average reduction of 400,000 pounds since 1985.
- Reduce the amount of sediment by 51,000 tons. That was about the annual average since 1985.
At recent rates, it would take 28 years to implement enough actions to meet the nitrogen goals, and 15 years for the phosphorus and sediment goals.
Some acceleration is expected in the next several years. New discharge limits being set for wastewater treatment plants throughout the watershed will result in sharp nutrient reductions from those facilities.
But nearly four-fifths of the nutrient pollution reaching the Bay comes from “nonpoint sources,” which includes runoff from farms, cities, suburbs and other land uses. Efforts to implement runoff controls, usually called best management practices, lag badly.
For instance, tributary strategies call for planting 571,628 acres of streamside forest buffers. Through 2005, 48,628 acres had been planted. Similarly, the strategies call for 208,526 acres of wetland restoration, but only 15,282 acres had been restored. They also call for planting more than 2.3 million acres of cover crops, which absorb leftover nitrogen in farm fields when planted in the fall, but fewer than 120,000 acres were actually planted.
Under a court agreement reached in 1999, the EPA will have to write a cleanup plan known as a Total Maximum Daily Load after 2010 if cleanup goals are not met. Like the tributary strategies, the TMDLs will establish the maximum amount of pollution the Bay could receive and still meet water quality standards.
But a TMDL may cast a broader regulatory net. The exact implications of a TMDL are yet to be sorted out, but it could result in more strict limits for urban stormwater systems, animal feedlots and other nutrient sources that have discharge permits. Also, because a TMDL requires “reasonable assurance” that the goal will be met, states would probably have to spell out in greater detail exactly how they would implement their programs.
The Cleanup Goal
The ultimate goal of the nutrient and sediment reductions now under way is a clean Bay—one with water quality that allows underwater grasses, fish, shellfish and other aquatic dwellers to thrive.
Those conditions are listed in legally binding water quality standards adopted by states in recent years. Those standards spell out in detail the amount of oxygen that needs to be available to support creatures that live in different parts of the Bay, and the amount of submerged grass beds that should be able to grow in a Bay filled with clearer water.
Using those yardsticks to measure progress, only 24 percent of the Bay in 2005 met its water quality standards for dissolved oxygen, and only 42 percent of the Bay achieved its goal for underwater grass coverage.
River Basin Overviews: