Situational Awareness (Friday, 2026-01-23)
Potomac River flow at the USGS’s Point of Rocks gage has again fallen below 2000 cfs, CO-OP threshold for daily drought monitoring and reporting. According to information from the Middle Atlantic River Forecast Center, no precipitation fell in the portion of the watershed above the USGS’s Little Falls gage during the past 24 hours. This weekend’s storm event is predicted to bring an average of approximately 1 1/2 inches to the watershed in the form of snow and ice.
Special Conditions
Icy conditions have been present at many USGS streamflow gages in the Potomac watershed at times during the past week, including at Point of Rocks, Maryland. When ice is present at a stream gage, mean daily flow values are often not made available by the USGS because stream stage values can no longer be used to accurately and automatically compute streamflow. Yesterday's Point of Rocks mean daily flow value in today’s drought report, below, were computed by CO-OP staff from available real-time data and are only provisional estimates.
Daily flows:
Little Falls gage flow 2026-01-22: 1422 MGD (2200 cfs)
Little Falls gage flow 2026-01-23: 1370 MGD (est., based on recently available real-time data) (2120 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2026-01-22*: 1117 MGD (1727 cfs)
Point of Rocks flow 2026-01-23: 1099 MGD (est., based on recently available real-time data) (1700 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2026-01-22: 1422 MGD (2200 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 (2026-01-22):
Fairfax Water Corbalis withdrawal - Potomac: 84 MGD
WSSC Water Potomac withdrawal: 148 MGD
Washington Aqueduct withdrawal - Great Falls: 115 MGD
Washington Aqueduct withdrawal - Little Falls: 0 MGD
Loudoun Water withdrawal: 7 MGD
Loudoun Water Broad Run discharge: 8 MGD
Total Potomac withdrawal: 354 MGD
Total net Potomac withdrawal: 345 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR*: 1727 cfs
QPR, obs*: 1727 cfs
QPR, WS: 0 cfs
*Daily flow values unavailable from the USGS, likely due to the presence of ice; provisional estimates of average daily flow were computed from available real-time data by ICPRB staff.
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.