The latest data available on nitrogen and phosphorus loads in the Chesapeake Bay’s tributaries has given the estuary’s stewards hope that their restoration strategy is on target.

“We’ve got a long way to go,” said Bruce Michael, Maryland Department of Natural Resources (DNR) director of Resource Assessment Services.  “We would anticipate seeing these improvements continue.

The water quality survey, which was conducted between October 2009 and September 2010 in streams and rivers throughout the Chesapeake Bay’s vast watershed, indicated nutrient pollution has decreased during the last 25 years.  The survey’s results were released Monday, May, 9.

Scientists affiliated with the Chesapeake Bay Program reported nearly 70 percent of the monitoring stations in six states showed decreasing nitrogen and phosphorus levels. Decreasing trends for sediment pollution were found at approximately 40 percent of the sites.

Peter Tango, the Chesapeake Watershed coordinator for the U.S. Geological Survey (USGS), indicated some of the previous water quality data was collected from “bugs found in the streams.” Insects, snails and mussels provided scientists with a great deal of evidence regarding the health of the tributaries.

“They don’t move very fast and are stressed by environmental changes,” Tango explained.

Both the Patuxent River and Potomac River areas fared well in the most recent study.

Scott Phillips, the Chesapeake Bay coordinator for the USGS, said the data showed “a 57 percent improvement” in the Patuxent related to phosphorus loads. Phillips said the biggest factor driving the improvement was an upgrade in the river region’s wastewater treatment plants.

Not all the news from the Chesapeake Bay Program regarding the watershed’s streams and rivers was good. Despite its significant improvement, the Patuxent River region was still rated overall “poor to fair” with the rating improving in the river’s southern-most area. The Patuxent begins as a small stream in the Mt. Airy area and gradually but dramatically widens as it reaches its confluence with the Chesapeake Bay.

The Potomac River region scored “good to fair” based on the collected data.

According to the Chesapeake Bay Program, the daily river flow into the Chesapeake yielded: approximately 278 million pounds of nitrogen in 2010, 43 million pounds more than in 2009; approximately 16 million pounds of phosphorus, approximately 7 million pounds more than in 2009; approximately 9 million tons of sediment from non-tidal rivers in 2010, an increase