Situational Awareness (Monday, 2026-02-02):
According to information from the Middle Atlantic River Forecast Center, no precipitation fell in the Potomac basin during the past 24 hours. Small amounts - 0.01 to 0.10 inches - are predicted for the basin over the next 3 days.
Special Conditions:
Flow data at Point of Rocks is currently unavailable due to the presence of ice. For more information about ice effects on streams, see Water-Supply Paper 2175: Measurement and Computation of Streamflow: Volume 2. Computation of Discharge pages 360-376 (WSP 2175). Potomac River flow values for Loudoun Water’s drought operations protocol were estimated based on information from the MARFC’s River Observations and Forecasts webpages.
Daily flows:
Little Falls gage flow 2026-02-01: 1357 MGD (2100 cfs)
Little Falls gage flow 2026-02-02: 1254 MGD (est., based on recently available real-time data) (1940 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2026-02-01: Not available due to ice
Point of Rocks flow 2026-02-02: Not available due to ice
Yesterday's estimated daily flows:
Great Falls estimated flow 2026-02-01: 1357 MGD (2100 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 (2026-02-01):
Fairfax Water Corbalis withdrawal - Potomac: 93 MGD
WSSC Water Potomac withdrawal: 149 MGD
Washington Aqueduct withdrawal - Great Falls: 128 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 8 MGD
Loudoun Water Broad Run discharge: 10 MGD
Total Potomac withdrawal: 378 MGD
Total net Potomac withdrawal: 368 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: > 1400 cfs*
QPR, obs: > 1400 cfs*
QPR, WS: 0 cfs
* Estimated from the MARFC’s River Observations and Forecasts webpages.
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.