Decades of work to improve the health of the Anacostia River are beginning to pay off, according to a report released Wednesday by the Anacostia Watershed Society.

The Nationals Park baseball stadium, pictured here from the Anacostia River, has become the anchor of several redevelopment projects along the river. A recent report card shows the river's water quality is steadily improving. (Dave Harp)

The river earned a “D-minus” on its annual report card, its first passing grade in the decade since the nonprofit began issuing report cards for the waterway that runs through Maryland and the District of Columbia into the Potomac River. A significant uptick in underwater grasses — from zero acres a few years ago to nearly 25 acres in 2017—pushed it over the threshold from “F” to “D-minus.”

Advocates say the Anacostia’s water quality is likely even better than indicated by the report card, which was compiled mostly with the latest data from 2016. Since then, in March of this year, the first of DC Water’s underground tunnels came online to capture 80 percent of the sewage overflows and polluted stormwater runoff in the Anacostia watershed. Instead of entering the river, the flow is now diverted to the District’s wastewater treatment plant.

“This passing grade didn’t have anything to do with the tunnel yet, which was a huge milestone,” said Jim Foster, president of the Anacostia Watershed Society. “The hard, heavy lifting we’ve been doing is finally paying off in improved water quality.”

When the added improvements from the tunnels are accounted for in future reports, Foster said, “then we’re really expecting a great grade.”

The report card’s grading system is based on the Anacostia’s ability to meet certain markers — levels of dissolved oxygen, water clarity and chlorophyll a — that support aquatic life. It also looks for reductions in bacteria, toxic contamination and trash that prevent the river from being swimmable or fishable, a milestone advocates want the waterway to meet by 2025.

With an overall score of 63 percent in the latest report card, the Anacostia barely entered into passing-grade territory. But that score is much better than the 56 percent it received in 2017 and the string of failing grades from previous years.

Public officials and river advocates said they are finally seeing the fruit of billions of dollars and countless hours invested in its improvement.

“This is not happening by accident,” said Rushern Baker, county executive for Prince George’s County, MD, which has taken steps to reduce polluted overflows to the river. “When we signed an agreement to work together to revitalize the Anacostia River a few years ago, it was more than a ceremony.”

In the latest report, the river scored 100 percent for underwater grasses which, at nearly 25 acres, exceeded a 20-acre goal for the river set by scientists at the Metropolitan Washington Council of Governments. Foster said more accurate data was added to the report card after the District Department of Environment and Energy conducted a survey of underwater grasses in 2017, which boosted their numbers.

Surveys indicate that the Anacostia had healthier populations of underwater grasses in the 1980s and 1990s than in the last decade, and researchers don’t entirely understand why. Though the river was by some measures more polluted during that earlier period than in the 2000s, when the grasses took a turn for the worst, researchers theorize that changes in sediment pollution may have reduced certain types of grasses or that monitoring data had gaps.

The Anacostia Watershed Society and other groups have since deployed volunteers to plant several acres of underwater grasses, such as wild celery, over the years and taken steps to protect them — in one instance culling an outsized number of resident geese in a park along the river. But both native and nonnative grasses appear to be faring well on their own thanks to water quality improvements, Foster said.

Biologists also are tracking the presence of water-filtering freshwater mussels in the Anacostia and are considering propagating them.

The river squeaked into passing grades for having more dissolved oxygen and less fecal bacteria, too. Both measures likely benefitted from DC Water’s ongoing efforts to reduce sewage overflows to the river. Less rainfall than usual in 2016, the year the data was collected, also helped.

Once the sewer system — originally designed to overflow into local rivers to prevent urban flooding — is completely retrofitted, the largest sources of fecal bacteria to the system will be wildlife and pets.

The river still earned failing grades for the amount of toxics and trash that plague its waters.

The Anacostia’s toxic problems — linked to an industrial past with nearly a dozen plants along the river slated for environmental cleanup projects —have been studied at length, but the projects to remediate them have barely begun.

The District and Maryland counties have each passed legislation to rein in the river’s trash problems, but the report indicates more enforcement is needed for littering and illegal dumping.

On water clarity, the river also had a failing grade. Studies indicate that more than 70 percent of the river’s sediment pollution is from erosion along streambanks, scoured by fast-flowing water.

The Anacostia Watershed Society produced the report card using government data and the EcoCheck assessment system developed by the University of Maryland Center for Environmental Science, which is also used to grade the health of the Chesapeake Bay and several of its tributaries.

In 2014, the society switched to using school-system letter grades to make their reports more understandable to the public. Some river reports consider a 40– to 60-percent score a “C” or passing grade, while schools would use the letter grade “F.”

Foster said the Anacostia’s 63-percent passing grade means it’s getting closer to its goals — but not that the river is safe for fishing or swimming.

“The only thing really separating us from swimming is higher bacteria counts in the river,” he said. “We are on the cusp of really being able to say that we’re confident that you can swim on a pretty regular basis in the river.” But not yet.

Read the full report at anacostiaws.org.