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The Potomac River has earned another B grade, but a decade without overall improvement is raising concerns about the waterway’s health and future.
Potomac Conservancy’s latest report card marks the river’s fifth B in 10 years. That remains an improvement over its D in 2011 and C in 2013, yet the analysis concludes the river is still unsafe for swimming and fishing.
The Potomac watershed covers 14,670 square miles across four states and is home to roughly seven million people, 81% of whom live in urban areas. The river supplies drinking water to five million people and forms the eastern boundary of Alexandria and Arlington, Fairfax, Loudoun and Prince William counties in Northern Virginia.
The report evaluates six areas: pollution, fish, habitat, land, people and climate.
Pollution Drops, but Runoff Rises
Nitrogen, phosphorus and sediment levels have steadily declined, while river-related recreation has increased 10% since 2020. More than one-fifth of the watershed’s land is protected from development.
Polluted stormwater runoff, however, is increasing. It is the only pollution source moving in the wrong direction.
Rain flowing across pavement and other hardened surfaces carries oil, fertilizer, trash and additional contaminants into waterways. Urban development and agriculture are major sources, with forest loss, drought and intense downpours compounding the problem.
At a Nov. 12 press conference, Interstate Commission on the Potomac River Basin Executive Director Michael Nardolilli connected the runoff problem to the widespread impervious surfaces created by dense development. Potomac Conservancy President Hedrick Belin emphasized the need to help rainwater soak naturally into soil instead of washing off hard surfaces.
In a separate report, Belin warned that extreme drought and flooding are becoming increasingly common, harming streams and threatening community safety. He also cited weakened federal protections, conservation funding cuts and unchecked data center growth among the pressures facing the watershed.
Key Fish Populations Are Falling
Striped bass, white perch and smallmouth bass populations have declined steadily over the past 20 years. The report gave striped bass a D-, while white perch and smallmouth bass each received a D+. Shad populations remain unstable.
Invasive blue catfish are displacing native species from established habitats. Chesapeake Channa, also known as invasive northern snakeheads, have become firmly established in the watershed.
The report also says eating fish remains illegal for communities living in and around Washington, D.C.
Habitats Face Development Pressure
Forested buffers received an A after installations increased over the past three years. Even so, every state remains behind its watershed implementation goals, with a combined shortfall of 132,645 acres.
Maryland and Washington, D.C., have made progress in adopting Chesapeake Bay Program measures intended to protect and restore water quality, according to the report. Virginia remains far behind.
Development and fragmented planning continue to threaten wetlands, forests and shorelines that filter pollution, reduce flooding and provide habitat. Stream water quality received a C+, while tidal water quality and underwater grasses each earned a C-.
Climate Risks Add Urgency
Warmer air and water, longer droughts and more severe rainstorms are placing additional stress on the river’s ecosystems. Rising sea levels are also expected to worsen local flooding.
By 2080, water levels in Washington, D.C., could stand 1.3 to 4.3 feet higher than they do today.
Proposed responses include restoring wetlands, reconnecting streams, improving stormwater systems, holding polluters accountable and expanding nature-based projects. The report also calls for reclaiming public spaces for community use.
Belin said the work extends beyond protecting forests or removing trash because more than five million people rely on the river for drinking water and recreation. He expressed hope that community-led conservation can address the watershed’s largest problems.
A River With Deep Roots
The Potomac begins as a trickle near West Virginia’s Backbone Mountain, 3,140 feet above sea level, and travels to the Chesapeake Bay.
The river is 383 miles long and passes through some of the world’s oldest land. Unlike many major American rivers, it escaped extensive channelization. It becomes tidal around Alexandria and Mount Vernon and retains five lighthouses, including the Jones Point lighthouse at Alexandria’s southern end.