Chesapeake Bay progress uneven, study shows

Data suggest sewage upgrades working, farm runoff controls aren’t

By Timothy B. Wheeler, The Baltimore Sun
September 15, 2010 A new study shows some Chesapeake Bay rivers have gotten cleaner over the past three decades, while others are getting worse. The analysis, released Wednesday by the U.S. Geological Survey, suggests costly upgrades of sewage plants have helped, scientists say, but it raises questions about the effectiveness of efforts to date to curb polluted runoff, particularly from farms on Maryland’s Eastern Shore. “We’re going in the wrong direction in some places, and the right direction in others,” said William Dennison, vice president for science applications of the University of Maryland Center for Environmental Science. He called the USGS analysis a breakthrough in tracking where the 27-year-old bay restoration effort is making progress — and where it’s falling short.
Using a new statistical technique to factor out weather’s variable impact on water quality, USGS researchers say sampling of the bay’s rivers indicates that nutrient pollution has declined in the Patuxent and Potomac since 1978, and in the Susquehanna as well, though there are signs of backsliding there in the past decade. Pollution levels have either increased or remained unchanged in Virginia’s major rivers, the study says. And in Maryland’s Choptank, levels of nitrogen — one of the two main nutrients fouling the bay — have increased 53 percent, with no sign of letting up. The USGS calculations “confirm the success we’re having with sewage upgrades and the big challenges we’re having with diffuse runoff,” said Dennison, whose UM scientists draw up annual “report cards” on the health of the bay and its tributaries. That’s particularly true in the Patuxent and Potomac, he noted, where municipal sewage treatment plants have been overhauled at great expense in the past three decades to remove more phosphorus and nitrogen from wastewater before it gets discharged into the rivers. Dennison said he was concerned to see levels of phosphorus in the Susquehanna have started to climb again in the past decade. The Susquehanna furnishes half of all the fresh water getting into the bay and a major portion of its nutrient pollution as well. …