Situational Awareness (Monday, 2026-08-03)
CO-OP is initiating daily drought monitoring and reporting today because Potomac River flow at the US Geological Survey’s gage at Point of Rocks, Maryland, has fallen below 2000 cubic feet per second (cfs), CO-OP's daily monitoring threshold.
The Middle Atlantic River Forecast Center estimates that 0.1 to 1.0 inches of precipitation fell across the Potomac basin yesterday, with locally higher amounts of up to 1.5 inches. The largest accumulations occurred in the eastern portion of the basin. Current MARFC forecasts indicate that flows are expected to increase over the coming day. An additional 0.1 to 0.25 inches of precipitation is forecast over the next three days.
We appreciate your ongoing daily submission of withdrawal, storage, and discharge data. Please continue submitting these data and make sure they are sent by 8:00 am for the duration of this drought monitoring period.
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Special Conditions
None
Daily flows:
Little Falls gage flow 2026-08-02: 1370 MGD (2120 cfs)
Little Falls gage flow 2026-08-03: 1487 MGD (est., based on recently available real-time data) (2300 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2026-08-02: 1157 MGD (1790 cfs)
Point of Rocks flow 2026-08-03: 1125 MGD (est., based on recently available real-time data) (1740 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2026-08-02: 1370 MGD (2120 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 (2026-08-02):
Fairfax Water Corbalis withdrawal - Potomac: 101 MGD
WSSC Water Potomac withdrawal: 161 MGD
Washington Aqueduct withdrawal - Great Falls: 132 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 12 MGD
Loudoun Water Broad Run discharge: 7 MGD
Total Potomac withdrawal: 406 MGD
Total net Potomac withdrawal: 399 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1790 cfs
QPR, obs: 1790 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.