Situational Awareness (Sunday, 2026-10-11)
According to the Middle Atlantic River Forecast Center, the Potomac basin received approximately 0.25–1.5 inches of rain over the past 24 hours, with locally higher amounts up to 2 inches in the southwestern portions of the basin. Widespread rainfall of 1–1.5 inches is forecast over the next three days, with localized totals reaching 2 inches.
Special Conditions
Intra-daily flow fluctuations at Potomac River gages, including Point of Rocks, are occurring due to upstream dam operations associated with eel passage.
Daily flows:
Little Falls gage flow 2026-10-10: 969 MGD (1500 cfs)
Little Falls gage flow 2026-10-11: 982 MGD (est., based on recently available real-time data) (1520 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2026-10-10: 892 MGD (1380 cfs)
Point of Rocks flow 2026-10-11: 1021 MGD (est., based on recently available real-time data) (1580 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2026-10-10: 1050 MGD (1624 cfs)
Note: Estimated flow below Great Falls intake is flow at Little Falls plus Little Falls water supply withdrawal.
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2026-10-10):
Fairfax Water Corbalis withdrawal - Potomac: 96 MGD
WSSC Water Potomac withdrawal: 136 MGD
Washington Aqueduct withdrawal - Great Falls: 43 MGD
Washington Aqueduct withdrawal - Little Falls: 81 MGD
Loudoun Water withdrawal: 7 MGD
Loudoun Water Broad Run discharge: 8 MGD
Total Potomac withdrawal: 362 MGD
Total net Potomac withdrawal: 355 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1380 cfs
QPR, obs: 1380 cfs
QPR, WS: 0 cfs