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.

DROUGHT EXERCISE - Afternoon Potomac flow and demand update (Wednesday 8/13/2017) - DROUGHT EXERCISE

Submitted by admin1 on Sun, 08/13/2017 - 14:00

This concludes the 2017 Washington Metropolitan Area (WMA) Drought Exercise - thank you for your support of WMA drought preparedness!
Actual daily drought monitoring continues, so suppliers please continue to submit your withdrawal data every morning.

DROUGHT EXERCISE - Afternoon Potomac flow and demand update (Wednesday 8/13/2017) - DROUGHT EXERCISE
NOTE: In our twice daily reports for the 2017 exercise we will be reporting ACTUAL basin flows and system withdrawals, and SIMULATED recommended operations.

Daily Potomac flow and demand update (Saturday 09/10/2016)

Submitted by admin1 on Sat, 09/10/2016 - 09:00

Over the past 24 hours, accumulations of rain of up to an inch were recorded in scattered areas, in the northwestern portion of the basin. According to the Middle Atlantic River Forecast Center's quantitative precipitation forecasts, between zero and 1/2 of an inch is expected over the next 72 hours, mainly in the northern portion of the basin.

Daily Potomac flow and demand update (Saturday 09/26/2015)

Submitted by admin1 on Sat, 09/26/2015 - 09:00

A limited area in southwestern portion of the basin received a half to one inch of rain over the past 24 hours. Other areas in the southern half of the basin received up to a quarter of an inch. Accumulated rainfall predictions over the next three days remain the greatest to the south. Today's prediction ranges from 0.01 to 0.75 inches.

A white water release has begun from Savage Reservoir. It will conclude early this evening.

Daily Potomac flow and demand update (Friday 09/25/2015)

Submitted by admin1 on Fri, 09/25/2015 - 09:00

A negligible amount of rain fell in the basin yesterday. MARFC continues to show some chance of rain through the weekend. Between 0.01 and 0.50 inches are possible today in the southern portion of the basin. The chance of rain extends north on Saturday and Sunday. Accumulated rainfall may reach 1.50 inches to the south. The northern areas may see a 3-day accumulation between 0.10 and 0.50 inches.

Last weekend's artificially varied flow release is now passing Little Falls.

Daily Potomac flow and demand update (Monday 09/21/2015)

Submitted by admin1 on Mon, 09/21/2015 - 09:00

Up to 0.75 inches of rain fell in western areas of the basin yesterday. MARFC predits up to an inch of rain across the basin over the next three days.

Daily Flows:
Little Falls gage flow 09/20: 900 MGD (1390 cfs)
Little Falls gage flow 09/21: 810 MGD (est., based on recently available real time data) (1260 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 09/20: 1020 MGD (1580 cfs)
Point of Rocks flow 09/21: 1000 MGD (est., based on recently available real time data) (1540 cfs)