Situational Awareness (Thursday, 2026-09-24)
Yesterday’s average daily flow at the USGS Point of Rocks gage was 2570 cubic feet per second (cfs), above the 2000 cfs threshold for CO-OP daily drought monitoring. Flow has continued to rise, with today’s flow estimated at 3600 cfs based on recently available real-time data. CO-OP is therefore suspending its daily drought monitoring and reporting.
According to Middle Atlantic River Forecast Center, scattered rain fell across the Potomac basin during the past 24 hours, with amounts generally ranging from 0.1 to 0.25 inches with up 0.5 inches locally. Little rain is forecast across most of the basin over the next week.
We will continue to watch river conditions and resume daily reporting if needed.
Thank you to the organizations and water suppliers for your continued support and cooperation.
Special Conditions
The U.S. Army Corps of Engineers, Baltimore District, reports that the final scheduled whitewater release from Savage River Dam for 2026 will occur on Saturday, September 26. The 2026 water-quality release schedule for Jennings Randolph and Savage reservoirs is available here: https://water.usace.army.mil/office/nab/releases/north-branch.
Intra-daily flow fluctuations at Potomac River gages, including Point of Rocks, are occurring due to upstream dam operations associated with eel passage.
Daily flows:
Little Falls gage flow 2026-09-23: 2443 MGD (3780 cfs)
Little Falls gage flow 2026-09-24: 2120 MGD (est., based on recently available real-time data) (3280 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2026-09-23: 1661 MGD (2570 cfs)
Point of Rocks flow 2026-09-24: 2327 MGD (est., based on recently available real-time data) (3600 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2026-09-23: 2443 MGD (3780 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 (2026-09-23):
Fairfax Water Corbalis withdrawal - Potomac: 99 MGD
WSSC Water Potomac withdrawal: 145 MGD
Washington Aqueduct withdrawal - Great Falls: 129 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 11 MGD
Loudoun Water Broad Run discharge: 8 MGD
Total Potomac withdrawal: 384 MGD
Total net Potomac withdrawal: 376 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 2570 cfs
QPR, obs: 2570 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: Under the Water Supply Coordination Agreement of 1982, CO-OP begins daily monitoring and reporting of Potomac River flows and withdrawals when the average daily flow at Point of Rocks falls below 2000 cfs. CO-OP provides these reports on behalf of Fairfax Water, Washington Aqueduct, and WSSC Water. Suppliers can review data at CO-OP’s Data Portal at www.icprbcoop.org. Published monitoring reports are available at http://icprbcoop.org/products/monitoring-reports.