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.

2019 Annual WMA Drought Exercise, Morning Potomac flow and demand update (Wednesday 2019-11-20)

Submitted by admin1 on Wed, 11/20/2019 - 09:00

This is Day 1 of the annual Washington metropolitan area (WMA) drought exercise, which will be conducted on Wednesday, Nov 20 and Thursday, Nov 21. The exercise scenario appears below. During the exercise, WMA water suppliers are sending data on withdrawals and reservoir levels twice daily, and ICPRB CO-OP staff are communicating via phone with supplier operations staff regarding requested operational changes.

EXERCISE SCENARIO

Daily Potomac flow and demand update (Wednesday 2019-10-23)

Submitted by admin1 on Wed, 10/23/2019 - 09:00

River flow at Point of Rocks has been above our drought monitoring trigger of 2000 cfs for the past two days, and the Middle Atlantic River Forecast Center's streamflow forecasts indicate that flows will remain above this level for the next week. Therefore, daily monitoring will be discontinued until further notice. Thank you all for your contributions to the monitoring effort!

Daily Potomac flow and demand update (Tuesday 2019-10-22)

Submitted by admin1 on Tue, 10/22/2019 - 09:00

No rain fell in the basin over the past 24 hours according to the Middle Atlantic River Forecast Center. Over the next 7 days, between 1 and 1.75 inches of rain are expected in the basin.

Flows have been fluctuating around 2000 cfs, the threshold for daily monitoring. Daily monitoring will be continued until flows are consistently above the 2000 cfs threshold.

Daily Potomac flow and demand update (Monday 2019-10-21)

Submitted by admin1 on Mon, 10/21/2019 - 09:00

On average, the basin received less than half an inch of rainfall yesterday, with rainfall totals increasing from west to east. Far western areas of the basin received trace amounts of rain while rainfall totals exceeded 1.5 inches in parts of the DC metro area. Between 0.5 and 1.5 inches of additional rainfall is expected over the next 7 days.

Daily Potomac flow and demand update (Sunday 2019-10-20)

Submitted by admin1 on Sun, 10/20/2019 - 09:00

According to the Middle Atlantic River Forecast Center (MARFC), 0.01 to 0.75 inches of precipitation fell in the basin over the last 24 hours (ending at 7:00 AM Sunday). It is currently raining and MARFC forecasts that 0.75 to 2.00 inches of precipitation will fall over the next 72 hours. The National Weather Service expects 1.25 to 3.00 inches of precipitation over the next 7 days.

Daily Potomac flow and demand update (Saturday 2019-10-19)

Submitted by admin1 on Sat, 10/19/2019 - 09:00

According to the Middle Atlantic River Forecast Center, no rain fell in the basin over the past 24 hours. The National Weather Service expects up to an inch of rain in the basin over the next 7 days.

Flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring. Please note, however, that the USGS has been working on some recent issues with the stage sensor at the Point of Rocks gage. Daily monitoring will be continued at this time to confirm that flows remain above the 2000 cfs threshold for a few days given recent gage corrections.

Daily Potomac flow and demand update (Friday 2019-10-18)

Submitted by admin1 on Fri, 10/18/2019 - 09:00

In the last 24 hours, trace amounts of precipitation fell in Washington County, Maryland. According to MARFC's precipitation departure calculations, last Wednesday's precipitation improved basin precipitation totals, which are now near normal for the month of October. Precipitation amounts between 0.5 and 0.75 are expected over the next 5 to 7 days.

Flow at the USGS gage at Point of Rocks is currently below 2000 cfs, the trigger for daily monitoring. Daily monitoring will be continued at this time. *

Recent basin-wide average precipitation (above Little Falls):

​Daily Potomac flow and demand update (Wednesday 2019-10-16)

Submitted by admin1 on Wed, 10/16/2019 - 09:00

No significant amount of rain has fallen in the Potomac basin over the past 3 days. Around midnight last night, flow in the Potomac River at Point of Rocks temporarily dropped below CO-OP's threshold for drought monitoring of 2,000 cfs. We will reassess the need for daily monitoring after today's expected rainfall. According to Middle Atlantic River Forecast Center estimates, 1.25 to 2.5 inches is expected throughout the basin in the next 7 days. Slightly smaller amounts of 0.5 to 1.25 inches is expected in the next 5 days.