Monitoring Reports

During periods of drought, the Cooperative Water Supply Operations on the Potomac (CO-OP) helps manage the Washington metropolitan area water supply system by coordinating withdrawals from the Potomac River and off-river reservoirs and recommending releases from upstream reservoirs when forecasted flow in the river is not sufficient to meet expected needs. These needs include water demands and an environmental flow-by of 100 million gallons per day (MGD) on the Potomac River at Little Falls dam near Washington, D.C.

Daily Potomac flow and demand update (Saturday, 2025-11-22)

Submitted by admin1 on Sat, 11/22/2025 - 13:32

Situational Awareness (Saturday, 2025-11-22)
Potomac River flows have increased slightly. According to information from the Middle Atlantic River Forecast Center, cumulative precipitation in the watershed ranged from 1/10 to 1/2 inches over the past three days. A 1/10th of an inch or less of rainfall is expected over the next three days.

Special Conditions
None

Daily flows:

Daily Potomac flow and demand update (Sunday, 2025-11-16)

Submitted by admin1 on Sun, 11/16/2025 - 13:39

Situational Awareness (Sunday, 2025-11-16):
The Potomac basin received 0.01 to 0.25 inches of rain yesterday, with a few isolated areas seeing slightly higher amounts. According to the Middle Atlantic River Forecast Center, light rain is expected to return to the area, with totals between 0.01 and 0.10 inches and little to no impact on river flows. Over the next week, up to about 0.5 inches of rain is possible across the basin.

Daily Potomac flow and demand update (Friday, 2025-11-14)

Submitted by hmoltz on Fri, 11/14/2025 - 13:15

Situational Awareness (Friday, 2025-11-14)
According to the Middle Atlantic River Forecast Center records, no precipitation fell in the basin over the past 24 hours. Trace amounts of rain are possible across the basin over the next three days, and totals could reach up to 0.5 inches over the coming week. 

Special Conditions
None

Daily Potomac flow and demand update (Tuesday, 2025-11-11)

Submitted by admin1 on Tue, 11/11/2025 - 13:56

Situational Awareness (Tuesday, 2025-11-11)
According to information from the Middle Atlantic River Forecast Center, no appreciable rainfall fell in the Potomac watershed yesterday and little is expected during the next ten days. 

Special Conditions
None

Daily flows:
Little Falls gage flow 2025-11-10: 1150 MGD (1780 cfs)