Situational Awareness (Saturday, 2025-12-27)
According to information from the Middle Atlantic River Forecast Center (MARFC), Potomac River flow at the USGS’s Point of Rocks gage will likely remain about CO-OP’s daily drought reporting threshold of 2000 cfs for the next week. Therefore, we are suspending daily drought monitoring and reporting for the time being.
MARFC maps indicate that up to 1/4 inch of rain fell in the northern-most portion of the Potomac watershed during the past 24 hours. Light rainfall with accumulations of up to 1/10 of an inch is expected in most of the watershed over the next 3 days.
Special Conditions
None
Daily flows:
Little Falls gage flow 2025-12-26: 2004 MGD (3100 cfs)
Little Falls gage flow 2025-12-27: 1810 MGD (est., based on recently available real-time data) (2800 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2025-12-26: 1596 MGD (2470 cfs)
Point of Rocks flow 2025-12-27: 1506 MGD (est., based on recently available real-time data) (2330 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2025-12-26: 2004 MGD (3101 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 (2025-12-26):
Fairfax Water Corbalis withdrawal - Potomac: 78 MGD
WSSC Water Potomac withdrawal: 143 MGD
Washington Aqueduct withdrawal - Great Falls: 102 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 9 MGD
Loudoun Water Broad Run discharge: 8 MGD
Total Potomac withdrawal: 333 MGD
Total net Potomac withdrawal: 325 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 2470 cfs
QPR, obs: 2470 cfs
QPR, WS: 0 cfs