Monitoring Reports

Flows at the Little Falls gauge have risen over the past 12 hours, likely in response to the rain that occurred in some parts of the basin yesterday. 

Please remember to begin sending a supplemental email each morning by 7:30 am with predicted total and off Potomac withdrawals (in MGD) for today and tomorrow. Thank you for your continued cooperation.  

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

According to Middle Atlantic River Forecast Center predictions, the next three days may see approximately 1.5 inches of rainfall. 

ICPRB continues to work to improve projected demands and incorporate supplier projections. In an effort to provide the most robust projections possible, we will be contacting suppliers and asking them to begin sending a supplemental email each morning with predicted total and off Potomac withdrawals (in MGD) for today and tomorrow.

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

According to Middle Atlantic River Forecast Center predictions, no precipitation is anticipated over the next 72 hours. The whitewater releases on August 26th and 27th from Jennings Randolph Reservoir are expected to arrive at Little Falls over the weekend. 

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.