Monitoring Reports

No appreciable amount of rain fell in the basin in the past 24 hours. River flows at Little Falls have slowly decreased and are currently at around 600 cfs. Whitewater releases from Jennings Randolph Reservoir were held on August 26 and 27 and may temporarily improve flow levels.

According to Middle Atlantic River Forecast Center predictions, no rain is expected in the next 72 hours.

The proactive voluntary load shift from Great Falls to Little Falls by Washington Aqueduct is still ongoing.  

Current river flow at Little Falls is about 728 cfs (471 MGD) and has remained above 700 cfs for the past 12 hours.

Daily flows:

Little Falls gage flow 2023-08-29: 408 MGD (632 cfs)

Little Falls gage flow 2023-08-30: 471 MGD (est., based on recently available real-time data) (728 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

According to National Weather Service predictions, no rainfall is expected over the next 7 days.

At 3 P.M. yesterday, Washington Aqueduct initiated a proactive load shift of 65 MGD to the Little Falls intake to increase Potomac flow between Great Falls and Little Falls. The recently observed, significant flow fluctuations at Point of Rocks related to hydroelectric dam operations have stabilized. We believe that hydro-dam impacts on flow at Little Flows will not be significant over the next few days.

Current river flow at Little Falls is about 728 cfs (471 MGD) and has remained above 700 cfs for the past 12 hours.

According to National Weather Service predictions, no rainfall is expected over the next 7 days.

At 3 P.M. yesterday, Washington Aqueduct initiated a proactive load shift of 65 MGD to the Little Falls intake to increase Potomac flow between Great Falls and Little Falls. The recently observed, significant flow fluctuations at Point of Rocks related to hydroelectric dam operations have stabilized. We believe that hydro-dam impacts on flow at Little Flows will not be significant over the next few days.

According to current National Weather Service forecasts, precipitation related to hurricanes Idalia and Franklin seem to be mostly by-passing the Potomac basin.

Note that at this time, we do not see a need for a Washington Aqueduct load shift from Great Falls to Little Falls.

Flows at Little Falls are declining, and a Washington Aqueduct load shift to the Little Falls pumps may be needed today. Based on Middle Atlantic River Forecast Center forecasts, we expect ¼ to 1 inch of rainfall in the basin over the next 72 hours, with a basin-wide average of perhaps ½. The longer term forecast is not promising.

River flow at Little Falls has not decreased as drastically as projected over the past 24 hours. Current river flow at Little Falls is about 778 cfs (503 MGD) and predicted to decrease over the next 24 hours. Operations at Dams 4 and 5 are still affecting flows at Little Falls and we are closely watching whether flows will drop below 500 cfs.

Daily flows:

Little Falls gage flow 2023-08-27: 550 MGD (851 cfs)

Minimal rain fell in the basin over the past 24 hours. Expected rainfall over the next three days ranges from 0.25 to 1 inch according to the Middle Atlantic River Forecast Center. Hydropower operations continue to affect river flows. Large fluctuations in river flows are observed at the Shepherdstown and Point of Rocks gages and are expected to affect river flows at Great Falls and Little Falls. 

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

River flow at Little Falls continues to steadily decline. Both our internal tools and the Middle Atlantic River Forecast Center’s flow forecast (based on the NAEFS) predict river flow at Little Falls to reach a minimum of about 500 cfs within the next 24 hours.