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, 2023-09-23)

Submitted by admin1 on Sat, 09/23/2023 - 12:20

Situational Awareness (Saturday, 2023-09-23):
The U.S. Geological Survey gage at Point of Rocks reports current flow at 1600 cfs (1034 MGD) and shows an upward trend. Projections from the Middle Atlantic River Forecast Center (MARFC) predict 0.8 inches of rainfall in the next 24 hours. Over the next three days, an average basin rainfall of 1.7 inches is anticipated, with a weeklong total forecasted to reach approximately 2 inches.

Daily Potomac flow and demand update (Friday, 2023-09-22)

Submitted by snummer on Fri, 09/22/2023 - 12:22

Situational Awareness (Friday, 2023-09-22)
River flows at Point of Rocks have fallen below 2000 cfs over the past 24 hours. According to the Middle Atlantic River Forecast Center predictions, the next 3 days may see 1.6 inches of rain. The week-long outlook expects a total of approximately 2.2 inches of rain in the basin.

Daily Potomac flow and demand update (Thursday, 2023-09-21)

Submitted by snummer on Thu, 09/21/2023 - 12:50

Situational Awareness (Thursday, 2023-09-21)
River flows at Little Falls continue to hold relatively steady after the impacts of last weeks' rainfall have receded. Flows at Point of Rocks have risen to over 2000 cfs over the past 24 hours. We are still making daily morning email updates on conditions and will continue to do so until we see conditions remain stable above that threshold.

Daily Potomac flow and demand update (Tuesday, 2023-09-19)

Submitted by admin1 on Tue, 09/19/2023 - 11:57

Situational Awareness (Tuesday, 2023-09-19)
Potomac River flows are holding relatively steady due to recent rainfall. According to the Middle Atlantic River Forecast Center, no rain is expected in the basin over the next 3 days. The week-long outlook for the basin calls for an average accumulation of approximately 0.9 inches of rain.

Recent basin-wide average precipitation (above Little Falls):

Daily Potomac flow and demand update (Friday, 2023-09-15)

Submitted by admin1 on Fri, 09/15/2023 - 13:00

Potomac River flows at Little Falls are still elevated due to the recent precipitation. According to the Middle Atlantic River Forecast Center predictions, rainfall averaging about ½ inches is expected in the basin over the next 3 days.

Recent basin-wide average precipitation (above Little Falls):
(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)
Yesterday's area-weighted average basin precipitation: 0 (inches)

Daily Potomac flow and demand update (Wednesday, 2023-09-13)

Submitted by admin1 on Wed, 09/13/2023 - 12:24

Situational Awareness (Wednesday, 2023-09-13)
River flows at both the Point of Rocks and Little Falls gages are now above all CO-OP drought monitoring and drought operations thresholds. We are continuing daily drought monitoring because flows are expected to begin falling in the coming week. According to the Middle Atlantic River Forecast Center predictions, only 0.2 inches of rainfall is expected in the basin over the next 7 days.

Recent basin-wide average precipitation (above Little Falls):

Daily Potomac flow and demand update (Tuesday, 2023-09-12)

Submitted by admin1 on Tue, 09/12/2023 - 08:58

Flow at Point of Rocks has reached 2000 cfs. According to the Middle Atlantic River Forecast Center predictions, the next three days may see 0.3 inches of rain.  

The Washington Aqueduct suspended voluntary load shift (withdrawal) at Little Falls yesterday. They are currently withdrawing 100% from the Great Falls intake.