Situational Awareness (Friday, 2025-12-05):
According to observations from the Middle Atlantic River Forecast Center, between 0.01 and 0.1 inches of precipitation fell across the basin yesterday. The seven-day outlook indicates a similar basinwide total of about 0.01 to 0.1 inches, with isolated areas in the western part of the basin possibly receiving up to 0.5 inches. Daily average flow in the Potomac River remains slightly above 2,000 cfs, the threshold for daily monitoring.
Special Conditions:
None
Daily flows:
Little Falls gage flow 2025-12-04: 1726 MGD (2670 cfs)
Little Falls gage flow 2025-12-05: 1680 MGD (est., based on recently available real-time data) (2600 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2025-12-04: 1454 MGD (2250 cfs)
Point of Rocks flow 2025-12-05: 1551 MGD (est., based on recently available real-time data) (2400 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2025-12-04: 1726 MGD (2671 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 (2025-12-04):
Fairfax Water Corbalis withdrawal - Potomac: 76 MGD
WSSC Water Potomac withdrawal: 149 MGD
Washington Aqueduct withdrawal - Great Falls: 118 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 10 MGD
Loudoun Water Broad Run discharge: 7 MGD
Total Potomac withdrawal: 353 MGD
Total net Potomac withdrawal: 347 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 2250 cfs
QPR, obs: 2250 cfs
QPR, WS: 0 cfs
Note to Loudoun Water: See NWS ensemble flow forecasts (HEFS, GEFS, NAEFS) for Point of Rocks flow for the next 7 days – https://www.weather.gov/erh/mmefs_marfc?id=PORM2&model=NAEFS. See US Army Corps of Engineers Potomac River Basin page for observed releases from Savage and Jennings Randolph reservoirs - https://water.usace.army.mil/office/nab/; See US Army Corps of Engineers North Branch Potomac River and Savage River page for scheduled releases - https://water.usace.army.mil/office/nab/releases/north-branch.
Note: Potomac River flow at Point of Rocks has dropped below the low-flow threshold of 2,000 cfs. When this occurs, per the Water Supply Coordination Agreement of 1982, CO-OP begins daily monitoring and reporting of Potomac flows and withdrawals on behalf of the CO-OP suppliers, Fairfax Water, Washington Aqueduct, and WSSC Water. Suppliers can review data at CO-OP's Data Portal at www.icprbcoop.org. Reports formatted in approved templates should be submitted by email to coop@icprb.org by 8:00 am for automated processing. Published monitoring reports are at http://icprbcoop.org/products/monitoring-reports.