Potomac scores a hard-earned B-

Sometimes progress comes incrementally.

That’s the case with the Potomac River, the waterway steeped in history that marks most of our state’s western boundary. Five years ago, the river was judged to be quite sick, given a grade of D by the Potomac Conservancy, a watchdog agency. In 2013, the group’s grade improved to a C. And in its most recent State of the Nation’s River Report released last week, the Potomac has rallied to a B-.

Not bad, but there’s obviously still room for improvement.

Hedrick Belin, the president of the Potomac Conservancy, said the progress made on the river is “tremendous,” and the group’s stated goal of making it a swimmable, fishable river again by 2025 can be attained.

The group’s report highlighted that the top three pollutants in the river — nitrogen, phosphorus and sediment — have been on a steady decline. Some key indigenous species of fish are on the rise, including white perch. The rebound of shad in the Potomac has been particularly encouraging to the group, rallying well past federal restoration goals. But he also warns, “the Potomac is not in the clear yet.”

Jim Long, the president of the Mattawoman Watershed Society, said while the grade is a big positive for the Potomac, there is still much to be accounted for – like the dip in the largemouth bass population, particularly off Charles County. The Potomac Conservancy’s study did not address that, but Long praised the group’s overall effort, saying, “This report card says … if you apply yourself and you try, you can have an effect and improve things. That’s one of the big take-home messages.”

The biggest difference between the Potomac of today and the clean, wildlife-laden river the English settlers sailed up in 1634 is that there are so many more people on both sides, directly and indirectly seeping their lives’ leftovers into it. Urban runoff remains a growing source of pollution in both the Potomac and the Chesapeake Bay watershed as a whole, the report said. Invasive blue catfish and snakehead fish are also still living in the waters and putting other fish at risk while underwater habitats are trying to recover.

Robert T. Brown, the president of the Maryland Waterman’s Association, agreed last week that the Potomac is on the upswing.

“The population in the lower part of the river has picked up. We’re not seeing the type of grasses we’d like to have, but hopefully they come back,” Brown said, noting that the health of underwater grasses and water clarity are indicators of ample oxygen content.

The hard truth is that the river, once so loaded with crabs, oysters and fish, will likely never return to what it once was because of all the development around it. But we can do our part by reducing pollution whenever we can. The state has already banned lawn fertilizers with phosphorus, for example. More can and should be done to keep the grade improving. Who knows? Maybe the Potomac can even inch up to a solid B next time.