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 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)

Daily Potomac flow and demand update (Friday 09/18/2015)

Submitted by admin1 on Fri, 09/18/2015 - 09:00

No rain fell in the basin yesterday. MARFC indicates a chance of between 0.01 and 0.10 inches on Saturday in the far western portion of the basin.

Daily Flows:
Little Falls gage flow 09/17: 1220 MGD (1880 cfs)
Little Falls gage flow 09/18: 1090 MGD (est., based on recently available real time data) (1680 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 09/17: 1230 MGD (1910 cfs)
Point of Rocks flow 09/18: 1200 MGD (est., based on recently available real time data) (1860 cfs)

DROUGHT EXERCISE - Afternoon Potomac flow and demand update (Friday 09/16/2015)

Submitted by admin1 on Wed, 09/16/2015 - 14:00

(SIMULATED) Daily Flows:
Little Falls gage flow 09/15/15: 210 MGD (320 cfs)
Little Falls gage flow 09/16/15: 310 MGD (est., based on most
recently available real time data) (473 cfs)
Note: Gage flow at Little Falls is measured after water
supply withdrawals.
Point of Rocks flow 09/15/15: 610 MGD (940 cfs)
Point of Rocks flow 09/16/15: 570 MGD (est., based on recently
available real time data) (880 cfs)

Daily Potomac flow and demand update (Tuesday 09/15/2015)

Submitted by admin1 on Tue, 09/15/2015 - 09:00

According to the Middle Atlantic River Forecast Center (MARFC), no rain fell in the Potomac basin over the past 24 hours and no rain is forecast over the next three days. Though flow at Point of Rocks is currently above CO-OP's low-flow monitoring threshold of 2000 cfs, flow is expected to fall back below this level sometime in the next couple of days.