Situational Awareness (Monday, 2026-10-12)
Yesterday’s average daily flow at the USGS Point of Rocks gage was 2,140 cubic feet per second (cfs), above the 2,000 cfs threshold for CO-OP daily drought monitoring. Flow has continued to rise, with today’s flow estimated at 2,980 cfs based on recently available real-time data. CO-OP is therefore suspending its daily drought monitoring and reporting.
According to the Middle Atlantic River Forecast Center, widespread rainfall occurred across the Potomac basin during the past 24 hours, with estimated totals generally ranging from 0.75 to 2.5 inches and locally higher amounts of 2.5 to 4 inches. Little additional rainfall is forecast over the next three days. The Weather Prediction Center's seven-day outlook indicates generally less than 0.25 inches of additional precipitation across most of the basin through October 19, with locally higher amounts possible in the upper basin.
We will continue to monitor river conditions and resume daily reporting if needed.
Thank you to the organizations and water suppliers for your continued support and cooperation.
Special Conditions
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 2026-10-11: 2404 MGD (3720 cfs)
Little Falls gage flow 2026-10-12: 5274 MGD (est., based on recently available real-time data) (8160 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2026-10-11: 1383 MGD (2140 cfs)
Point of Rocks flow 2026-10-12: 1926 MGD (est., based on recently available real-time data) (2980 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2026-10-11: 2466 MGD (3815 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 (2026-10-11):
Fairfax Water Corbalis withdrawal - Potomac: 87 MGD
WSSC Water Potomac withdrawal: 127 MGD
Washington Aqueduct withdrawal - Great Falls: 56 MGD
Washington Aqueduct withdrawal - Little Falls: 62 MGD
Loudoun Water withdrawal: 7 MGD
Loudoun Water Broad Run discharge: 8 MGD
Total Potomac withdrawal: 339 MGD
Total net Potomac withdrawal: 330 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 2140 cfs
QPR, obs: 2140 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.