Monitoring Reports

We expect Potomac River flows to start slowly declining over the remainder of the holiday weekend. No significant precipitation is predicted to fall in the basin over the next five days.

Daily flows:
Little Falls gage flow 2023-09-01: 457 MGD (707 cfs)
Little Falls gage flow 2023-09-02: 487 MGD (est., based on recently available real-time data) (753 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2023-09-01: 821 MGD (1270 cfs)

Potomac River flows at Little Falls have increased slightly, we believe due to last weekend’s Jennings Randolph Reservoir whitewater recreational releases along with the past week’s modest precipitation in the upper basin. According to National Weather Service, no rainfall is expected in the Potomac basin over the next three days. The week-long outlook points to an approximate total of 0.1 inches across the basin.

River flows at Little Falls continue to decline. The proactive voluntary load shift from Great Falls to Little Falls by Washington Aqueduct is still ongoing.  

According to Middle Atlantic River Forecast Center forecasts, small amounts of rain are expected in the basin tomorrow, and accumulations of approximately ½ inch are expected over the next three days. The longer-term forecasts are currently very promising, with accumulations of 1 to 2 inches expected. Tropical Storm Lee is expected to become a major hurricane, with potential impacts on the eastern US.

According to the real-time USGS gage flow at Little Falls, flows have fallen from 409 MGD (633 cfs) to 365 MGD (565 cfs) since this morning. 

Based on yesterday's daily flow and withdrawals, flows fell below the numerical threshold for the Alert Stage of the Low Flow Allocation Agreement (LFAA). 

According to Middle Atlantic River Forecast Center predictions, no rain is expected for the next 24 hours. Forecasts suggest an average basin rainfall of around 0.15 inches over the next three days and 0.83 inches over the next week.

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

Little precipitation is expected in the Potomac basin over the next several days according to National Weather Service forecasts.
 

According to Middle Atlantic River Forecast Center predictions, a trace of rainfall is expected in the basin over the next 3 days. The week-long outlook points to an approximate total of 0.02 inches across the basin.

River flows at Little Falls have been relatively steady over the past day.

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

No rain fell in the basin in the past 24 hours. According to Middle Atlantic River Forecast Center predictions, no rain is expected in the next 72 hours. The week-long outlook points to an approximate total of 0.1 inches across the basin.

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

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