Potomac River’s health rebounding

WASHINGTON – The Potomac River, once so polluted it was labeled a “national disgrace,” is now the cleanest it has been in decades – its comeback signaled by the re-growth of large areas of underwater grasses, according to a new scientific study.

The study, announced Tuesday, details the Potomac’s slow transformation into an environmental success story.

The authors found that improvements at Washington’s Blue Plains sewage plant had cut down on choking, unnatural algae blooms, and that – once the water became cleaner and clearer - native plants rebounded, helping to clean the river further.

Scientists examined the stretch of river in the 50 miles downstream from Washington’s Chain Bridge. Since 1990, they found, the amount of one key pollutant in this area had dropped by half.

In the same time, the amount of grasses doubled, transforming the river bottom from a mud flat into a kind of underwater forest, more suitable for fish and blue crabs.

“These conditions are actually better than they were in the 1950s. The portion of the Potomac that we’re talking about was completely devoid of vegetation in the 1950s,” said Nancy Rybicki, a scientist with the U.S. Geological Survey and an author of the study.