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 simulated Potomac flow and demand update (Wednesday 08/21/2013)

Submitted by admin1 on Wed, 08/21/2013 - 14:00

The weather and flow forecasts and operational recommendations remain the same as reported in this morning's email.

Daily Flows:
Little Falls gage flow 08/20: 1820 MGD (2820 cfs)
Little Falls gage flow 08/21: 1680 MGD (est., based on most recently available real time data) (2600 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 08/20: 2080 MGD (3220 cfs)
Point of Rocks flow 08/21: 2040 MGD (est., based on recently available real time data) (3160 cfs)

Daily Potomac flow and demand update (Friday 10/19/2012)

Submitted by admin1 on Fri, 10/19/2012 - 09:00

Due to a combination of the recent rainfall and yesterday's USGS rating curve revision, flow at Point of Rocks is now at 3,270 cfs (2,114 MGD). The Little Falls gage is currently showing 2,900 cfs (1,875 MGD). Over the last 24 hours the majority of the basin received between 0.25 and 1.25 inches of rain. A few isolated areas received up to 1.75 inches of rain. We are, therefore, discontinuing daily monitoring. Thank you for continuing to participate in the basin's cooperative drought operations efforts.

Daily Potomac flow and demand update (Wednesday 10/17/2012)

Submitted by admin1 on Wed, 10/17/2012 - 09:00

Some precipitation fell in the basin yesterday, though still mainly in the eastern portion. These areas received trace amounts to a quarter of an inch of rain. The Middle Atlantic River Forecast Center's 72-hour and five-day forecasts show a chance of 0.5 to 1 inch of rain across most of the Potomac basin is possible.

Daily Potomac flow and demand update (Tuesday 10/16/2012)

Submitted by admin1 on Tue, 10/16/2012 - 09:00

Flow at Point of Rocks has been below 2,000 cfs for a couple of days. Some precipitation fell in the basin yesterday, though mainly in the eastern portion. These areas received trace amounts to one inch of rain. The Middle Atlantic River Forecast Center's 72-hour forecast shows a chance of 0.1 to 0.25 inches of rain. The five-day forecast shows between 0.25 and 0.75 inches is possible.

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Tuesday 10/02/2012)

Submitted by admin1 on Tue, 10/02/2012 - 14:00

This concludes CO-OP's 2012 Drought Exercise. We'd like to thank everyone who contributed their time and effort to make the exercise possible. We especially thank staff from Fairfax Water, Loudoun Water, Washington Aqueduct, and WSSC, who sent us data every day, including weekends, and responded to our frequent telephone calls about simulated changes in operations. We'd like to thank the Corps' Baltimore District Office staff for taking our call each morning on simulated North Branch reservoir releases, and for preparing a table of simulated Jennings Randolph and Savage storages.

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Monday 10/01/2012)

Submitted by admin1 on Mon, 10/01/2012 - 14:00

Drought exercise simulation day: August 26 2022.

Combined water supply storage at Jennings Randolph and Little Seneca reservoirs fell to 59% of capacity this morning. Today's target flow at the Luke USGS gage remains 325 cfs and the Little Seneca release remains at 25 MGD.

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Sunday 09/30/2012)

Submitted by admin1 on Sun, 09/30/2012 - 14:00

Drought exercise simulation day: August 25 2022.

Combined water supply storage at Jennings Randolph and Little Seneca reservoirs fell to 60% of capacity this morning. Today's target flow at the Luke USGS gage remains 325 cfs and the Little Seneca release remains at 25 MGD.

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Friday 09/28/2012)

Submitted by admin1 on Fri, 09/28/2012 - 14:00

Drought exercise simulation day: August 23, 2022.

Water supply releases from the North Branch reservoirs are continuing. Today's target flow at the Luke USGS gage remains at 375 cfs. The Little Seneca release remains at 30 MGD.

Today's estimated demand (08/23/22) P.M.:
ACTUAL WSSC P.M. estimated demand: 170 MGD
ACTUAL FW P.M. estimated demand: 165 MGD
ACTUAL Aqueduct P.M. estimated demand: 155 MGD
SIMULATED LW total estimated demand: 36 MGD
SIMULATED LW WTP estimated demand: 20 MGD