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Potomac Riverwatch: Spring 2026
NEWS
Potomac Named "Most Endangered" River--The Potomac River has dominated regional news this month because it was officially named the most endangered river in the United States for 2026, driven by January’s massive sewage spill, deepening drought, and rapidly expanding data‑center water demands. American Rivers placed the Potomac at the top of its 2026 endangered‑rivers list. The ranking cites two primary threats:mJanuary’s historic sewage spill (200–300+ million gallons of raw sewage); and rapid, water‑intensive data‑center expansion across Northern Virginia and Maryland. DetailsRemediation Continues--At the site of the sewage spill, near the American Legion Bridge in Cabin John, Md., work continued through March and April. A massive effort to remove debris and contaminated soil in the Chesapeake and Ohio Canal involved scraping the canal down to the clay liner that dates back more than 100 years, and rebuilding the locks and other areas affected. Virginia DEQ officials now describe the January 19 Potomac Interceptor rupture as a “temporary insult” but still advise against swimming. E. coli levels have since tested below EPA thresholds, though long‑term concerns remain about algae blooms and sediment contamination. Details
Data‑center water use emerges as a major regional threat--Data centers are highlighted as a fast‑growing strain on Potomac water supplies, especially during summer when cooling demand peaks. Key findings include: Data centers account for 9% of annual consumptive water use, rising to 12% in summer; Loudoun County alone may withdraw 2–3% of basin water, up to 8% in peak months. Water use is often unreported, and cumulative impacts are poorly tracked. Details
Drought Levels Return--The D.C. region is entering summer with severe drought conditions, with 31% of the region in severe drought and the rest in moderate drought. River flow at Little Falls is near the lowest ever recorded for this date, raising the likelihood of backup reservoir releases later this year.Details
New Boathouse for Arlington--Arlington County Va. is developing plans for a new recreational boathouse on the Potomac River near Key Bridge. The county government is partnering with the National Park Service on the proposed boat-storage facility, floating docks and launching site south of Key Bridge, near Roosevelt Island. The federal government owns the majority of the planned riverfront site, which will link to a county-owned parcel of land near Rosslyn.Details