An analysis conducted by the U.S. Geological Survey (USGS) indicates that the 27-year-old restoration effort to improve the overall health of the Chesapeake Bay is seeing varying results. While investments in sewage plant upgrades appear to have helped decrease polluted runoff in some areas, farm runoff on the Eastern Shore continues to pour high levels of nutrients into the bay. The Baltimore Sun reports that nitrogen and phosphorus are the nutrients that have been largely detrimental to the health of the bay. When high levels occur, it creates an environment conducive to algae growth, in turn eliminating large levels of oxygen from the bay.
The USGS analysis shows significant improvements in water quality in rivers where sewage plants were a major source of pollution. But little or no progress is apparent in rivers where nutrients more likely washed off the land or seeped into ground water from fertilized farm fields or household septic systems.
On the Choptank, the Shore’s largest bay tributary, farming remains the dominant land use, and many homes are on septic systems. USGS sampling indicates much of the increase there is seeping into the river from ground water.
Ground water is so slow-moving that nitrogen that seeps into it from the land’s surface can take years or even decades to find its way into the river. Some have suggested that pollution-control efforts won’t show results there right away. But Hirsch said the lack of any easing of the increase in nitrogen levels measured up through 2008 suggests that whatever’s been done to try to limit the loss of fertilizer from farm fields hasn’t been particularly effective.
Richard Batiuk, associate director for the U.S. Environmental Protection Agency‘s Chesapeake Bay office, said the USGS study would help regulators as they move forward with establishing a pollution “diet’ for the bay and requiring reductions in nutrients across the six-state watershed. It also may guide them in reevaluating the effectiveness of some widely prescribed measures for controlling polluted runoff, he said.
Some of those facing likely orders to reduce their pollution have complained that EPA is relying on a computer “model” of the bay to determine where and how much to clamp down. Farmers, in particular, contend that the model has failed to account for everything they’ve done to keep fertilizer and manure from getting into the water.