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 (Tuesday, 2025-09-16)

Submitted by admin1 on Tue, 09/16/2025 - 12:53

Situational Awareness (Tuesday, 2025-09-16)
Minimal precipitation fell in the past 24 hours, and flows continue to decline. The Middle Atlantic River Forecast Center projects little additional rainfall over the next 24 hours. In the 3- to 7-day outlook, basin totals are expected to range from 0.1 to 0.75 inches, with heavier amounts in the lower Potomac and lower overall averages across the basin.

Special Conditions
None

Daily Potomac flow and demand update (Monday, 2025-09-15)

Submitted by snummer on Mon, 09/15/2025 - 12:38

Situational Awareness (Monday, 2025-09-15)
Potomac Rive flow continues to gradually decline. According to the Middle Atlantic River Forecast Center predictions, no rainfall is expected in the next 24 hours. Over the next 3 days, average basin rainfall may be between 0.1 and 0.75 inches, with more rainfall expected in downstream portions of the basin. 

Special Conditions
None

Daily Potomac flow and demand update (Saturday, 2025-09-13)

Submitted by snummer on Sat, 09/13/2025 - 12:43

Situational Awareness (Saturday, 2025-09-13)
According to the Middle Atlantic River Forecast Center, no rain fell in the basin over the past 24 hours. Additionally, no rain is expected to fall in the basin over the next 3 days. The week-long outlook expects a total of approximately 0.1 inches of rain in the basin.

Special Conditions
None

Daily Potomac flow and demand update (Thursday, 2025-09-11)

Submitted by admin1 on Thu, 09/11/2025 - 14:18

Situational Awareness (Thursday, 2025-09-11)
In the past 24 hours, 0–0.25 inches of rain fell in the lower basin near Washington, DC. Forecasts indicate less than 0.1 inches of precipitation, limited to the metro area, over the next day, and approximately 0 inches expected across the basin for the week.

Special Conditions
None

Daily Potomac flow and demand update (Wednesday, 2025-09-10)

Submitted by snummer on Wed, 09/10/2025 - 12:56

Situational Awareness (Wednesday, 2025-09-10)
No appreciable rainfall fell in the basin yesterday, according to the Middle Atlantic River Forecast Center. Over the next three days no rainfall is anticipated in the western portions of the basin. At the same time, eastern portions of the basin are expected to see less than 0.1 inches of total precipitation.

Special Conditions
None

Daily Potomac flow and demand update (Tuesday, 2025-09-09)

Submitted by snummer on Tue, 09/09/2025 - 13:09

Situational Awareness (Tuesday, 2025-09-09)
According to the Middle Atlantic River Forecast Center predictions, no precipitation was observed in the basin over the past 24 hours. Over the next 24 to 48 hours, eastern portions of the basin may experience less than 0.1 inches of total rainfall. 

Special Conditions
None

Daily Potomac flow and demand update (Monday, 2025-09-08)

Submitted by admin1 on Mon, 09/08/2025 - 14:15

Situational Awareness (Monday, 2025-09-08):
Potomac River flow has shown a slight decrease since yesterday. The Middle Atlantic River Forecast Center predicts no appreciable precipitation in the Potomac watershed above Little Falls over the next 7 days, with total accumulation expected to be 0.10 inch or less.

Special Conditions:
None.

Daily Potomac flow and demand update (Sunday, 2025-09-07)

Submitted by admin1 on Sun, 09/07/2025 - 12:29

Situational Awareness (Sunday, 2025-09-07)
Potomac River flows are holding steady due to recent light rainfall. Though more rain is expected in the DC metro region today, the Middle Atlantic River Forecast Center predicts no appreciable precipitation in the Potomac watershed above Little Falls over the next 3 days. 

Special Conditions
None

Daily flows: