Situational Awareness (Wednesday, 2025-10-01)
Potomac River flows have been hovering around 2000 cfs due to the recent rain, but no significant rainfall is expected over the next 10 days. According to information from the Middle Atlantic River Forecast Center, trace amounts to 1/4 inch of rain fell in the southern half of the Potomac watershed over the past 24 hours and no rain is forecast over the next 3 days.
Special Conditions
The US Geological Survey reported yesterday that they were experiencing a website/server outage, but they were able to provide us with the following estimates of then current flows:
Point of Rocks Flow : 2120 cfs, 09/30/2025 @ 0545 est (provisional)
Little Falls Flow: 1850 cfs, 09/30/2025 @ 0550 est (provisional)
Their systems providing daily average and real-time flow data were back up and running this morning.
Daily flows:
Little Falls gage flow 2025-09-30: 1189 MGD (1840 cfs)
Little Falls gage flow 2025-10-01: 1170 MGD (est., based on recently available real-time data) (1810 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2025-09-30: 1260 MGD (1950 cfs)
Point of Rocks flow 2025-10-01: 1370 MGD (est., based on recently available real-time data) (2120 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2025-09-30: 1189 MGD (1840 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 (2025-09-30):
Fairfax Water Corbalis withdrawal - Potomac: 99 MGD
WSSC Water Potomac withdrawal: 132 MGD
Washington Aqueduct withdrawal - Great Falls: 135 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 11 MGD
Loudoun Water Broad Run discharge: 7 MGD
Total Potomac withdrawal: 378 MGD
Total net Potomac withdrawal: 371 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1950 cfs
QPR, obs: 1950 cfs
QPR, WS: 0 cfs