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 (Friday 2017-09-29)

Submitted by admin1 on Fri, 09/29/2017 - 09:00

National Weather Service forecasts indicates that the basin will have no relief from the dry weather over the next week. Potomac River flow at Point of Rocks is now close to its 25th percentile level for this day of the year.

The daily flow and demand update was inadvertently not sent out yesterday. Yesterday's reported demand values appear at the end of today's report.

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Monday 09/28/2017) - DROUGHT EXERCISE

Submitted by admin1 on Thu, 09/28/2017 - 14:00

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Monday 09/28/2017) - DROUGHT EXERCISE

Daily Flows (simulated):
Little Falls gage flow 09/27: 140 MGD (210 cfs)
Point of Rocks gage flow 09/27: 390 MGD (610 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Little Falls gage flow 09/28: 140 MGD (210 cfs)
Point of Rocks gage flow 09/28: 400 MGD (620 cfs)

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Sunday 09/27/2017) - DROUGHT EXERCISE

Submitted by admin1 on Wed, 09/27/2017 - 14:00

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Sunday 09/27/2017) - DROUGHT EXERCISE

Daily Flows (simulated):
Little Falls gage flow 09/26: 190 MGD (300 cfs)
Point of Rocks gage flow 09/26: 420 MGD (650 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Little Falls gage flow 09/27: 120 MGD (180 cfs)
Point of Rocks gage flow 09/27: 400 MGD (630 cfs)

Daily Potomac flow and demand update (Wednesday 2017-09-27)

Submitted by admin1 on Wed, 09/27/2017 - 09:00

Forecasts indicate that dry conditions will continue for at least the next 7 days.

Daily Flows:
Little Falls gage flow 2017-09-26: 969 MGD (1500 cfs)
Little Falls gage flow 2017-09-27: 982 MGD (est., based on recently available real time data) (1520 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-26: 1079 MGD (1670 cfs)
Point of Rocks flow 2017-09-27: 1034 MGD (est., based on recently available real time data) (1600 cfs)

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Saturday 09/26/2017) - DROUGHT EXERCISE

Submitted by admin1 on Tue, 09/26/2017 - 14:00

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Saturday 09/26/2017) - DROUGHT EXERCISE

Daily Flows (simulated):
Little Falls gage flow 09/25: 180 MGD (280 cfs)
Point of Rocks gage flow 09/25: 380 MGD (590 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Little Falls gage flow 09/26: 130 MGD (190 cfs)
Point of Rocks gage flow 09/26: 370 MGD (580 cfs)

Daily Potomac flow and demand update (Tuesday 2017-09-26)

Submitted by admin1 on Tue, 09/26/2017 - 09:00

Dry conditions are expected to continue over the next week.

Daily Flows:
Little Falls gage flow 2017-09-25: 1021 MGD (1580 cfs)
Little Falls gage flow 2017-09-26: 957 MGD (est., based on recently available real time data) (1480 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-25: 1028 MGD (1590 cfs)
Point of Rocks flow 2017-09-26: 1125 MGD (est., based on recently available real time data) (1740 cfs)

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Friday 09/25/2017) - DROUGHT EXERCISE

Submitted by admin1 on Mon, 09/25/2017 - 14:00

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Friday 09/25/2017) - DROUGHT EXERCISE

Daily Flows (simulated):
Little Falls gage flow 09/24: 130 MGD (210 cfs)
Point of Rocks gage flow 09/24: 550 MGD (850 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Little Falls gage flow 09/25: 120 MGD (186 cfs)
Point of Rocks gage flow 09/25: 440 MGD (681 cfs)

Daily Potomac flow and demand update (Monday 2017-09-25)

Submitted by admin1 on Mon, 09/25/2017 - 09:00

Potomac basin stream flows continue to fall. The 7-day forecast indicates that dry conditions will persist.

Daily Flows:
Little Falls gage flow 2017-09-24: 1138 MGD (1760 cfs)
Little Falls gage flow 2017-09-25: 1034 MGD (est., based on recently available real time data) (1600 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-24: 1021 MGD (1580 cfs)
Point of Rocks flow 2017-09-25: 1021 MGD (est., based on recently available real time data) (1580 cfs)

DROUGHT EXERCISE - Afternoon simulated Potomac flow and demand update (Thursday 09/24/2017) - DROUGHT EXERCISE

Submitted by admin1 on Sun, 09/24/2017 - 14:00

Daily Flows (simulated):
Little Falls gage flow 09/23: 230 MGD (360 cfs)
Point of Rocks gage flow 09/23: 590 MGD (920 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Little Falls gage flow 09/24: 250 MGD (380 cfs)
Point of Rocks gage flow 09/24: 730 MGD (1130 cfs)

Today's estimated demand (09/24/17) P.M.:
WSSC P.M. estimated demand: 190 MGD
FW P.M. estimated demand: 185 MGD
Aqueduct P.M. estimated demand: 150 MGD
Total P.M. estimated demand: 525 MGD

Daily Potomac flow and demand update (Sunday, 2017-09-24)

Submitted by admin1 on Sun, 09/24/2017 - 09:00

The Middle Atlantic River Forecast Center (MARFC) predicts no rain in the basin over the next 3 days.

Daily Flows:

Little Falls gage flow 2017-09-23: 1222 MGD (1890 cfs)
Little Falls gage flow 2017-09-24: 1144 MGD (est., based on recently available real time data) (1770 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-23: 1105 MGD (1710 cfs)
Point of Rocks flow 2017-09-24: 1034 MGD (est., based on recently available real time data) (1600 cfs)