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 (Sunday, 2025-11-09)

Submitted by hmoltz on Sun, 11/09/2025 - 13:11

Situational Awareness (Sunday, 2025-11-09)
According to the Middle Atlantic River Forecast Center, trace amounts of scattered precipitation fell across the Potomac basin over the past 24 hours. Up to 0.25 inches of rain may fall over the next three days, with the highest amounts expected in the eastern portion of the basin.

Special Conditions
None

Daily Potomac flow and demand update (Saturday, 2025-11-08)

Submitted by admin1 on Sat, 11/08/2025 - 13:44

Situational Awareness (Saturday, 2025-11-08)
According to information from the Middle Atlantic River Forecast Center, 1/10 to 1/4 of an inch of rain fell in most areas of the Potomac watershed over the past day. An average accumulation of approximately 1/4 inch is expected over the next 3 days.

Special Conditions
None

Daily flows:
Little Falls gage flow 2025-11-07: 1293 MGD (2000 cfs)

Daily Potomac flow and demand update (Thursday, 2025-11-06)

Submitted by hmoltz on Thu, 11/06/2025 - 13:19

Situational Awareness (Thursday, 2025-11-06)
According to the Middle Atlantic River Forecast Center, trace amounts of rain fell in the northern portion of the basin over the past 24 hours.  Widespread rain is expected over the next 3 days, with the highest amounts (up to 0.25 inches) likely in the western portion of the basin. 

Special Conditions
None

Daily Potomac flow and demand update (Wednesday, 2025-11-05)

Submitted by snummer on Wed, 11/05/2025 - 13:17

Situational Awareness (Wednesday, 2025-11-05)
According to the Middle Atlantic River Forecast Center, no rain fell in the basin over the past 24 hours. Over the next 3 days, the average basin rainfall may be up to 0.25 inches. With the minimal amount of rain expected over the next few days, Potomac River flows at Point of Rocks are expected to fall back below 2000 cfs, the CO-OP Daily Drought Monitoring threshold. 

Daily Potomac flow and demand update (Tuesday, 2025-11-04)

Submitted by admin1 on Tue, 11/04/2025 - 14:13

Situational Awareness (Tuesday, 2025-11-04)
According to the Middle Atlantic River Forecast Center, only negligible amounts of precipitation fell in the Potomac watershed yesterday and little is expected over the next 3 days. We expect Potomac River flows at Point of Rocks to fall back below 2000 cfs in the coming days. 

Special Conditions

Daily Potomac flow and demand update (Saturday, 2025-11-01)

Submitted by admin1 on Sat, 11/01/2025 - 12:29

Situational Awareness (Saturday, 2025-11-01)
According to the Middle Atlantic River Forecast Center, only trace amounts of rain are expected in the Potomac watershed over the next 3 days and no appreciable accumulations are expected over the next 10 days. River flow at the USGSs Point of Rocks gage is currently above 2000 cfs, CO-OP’s threshold for Daily Drought Monitoring, but flow is predicted to fall below 2000 cfs in a few days. 

Daily Potomac flow and demand update (Friday, 2025-10-31)

Submitted by admin1 on Fri, 10/31/2025 - 12:32

Situational Awareness (Friday, 2025-10-31):
Over the past 24 hours, the basin received rainfall ranging from about 0.10 inch in the south to around 1.25 inches in the northeast, with the heaviest amounts in northeastern Maryland and lighter totals to the south. River and stream flows are currently rising in response to the recent rainfall. According to the Middle Atlantic River Forecast Center, no additional rain is expected in the next 24 hours, and only trace amounts are possible over the coming week.

Special Conditions:
None

Daily Potomac flow and demand update (Thursday, 2025-10-30)

Submitted by snummer on Thu, 10/30/2025 - 12:58

Situational Awareness (Thursday, 2025-10-30)
According to the Middle Atlantic River Forecast Center, between 0.25 and 1.5 inches of rain fell in the basin over the past 24 hours with most of the basin seeing around 1 inch of rain. Over the next 3 days, the average basin rainfall may be between 0.25 and 1.5 inches. 

Special Conditions
None