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 2019-10-11)

Submitted by admin1 on Fri, 10/11/2019 - 09:00

According to the Middle Atlantic River Forecast Center, no rain fell in the basin over the past 24 hours. Between 0.1 and 0.75 inches of rain is expected over the next 7 days.

Although flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring, daily monitoring will be continued at this time due to limited rain in the forecast.

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

Daily Potomac flow and demand update (Thursday 2019-10-10)

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

Potomac River flow at Point of Rocks has increased to a level above 2000 cfs, CO-OP's threshold for daily drought monitoring and reporting. However, little rain is on the horizon and streamflow forecasts indicate that flow will fall back below 2000 cfs within a few days, so we will not discontinue daily drought operations at this time. The Middle Atlantic River Forecast Center predicts up to 1/10 inches of rain in the western portion of the Potomac basin over the next 3 days. Over the next 7 days, accumulations of 1/10 to 1/2 inches are expected in the basin.

Daily Potomac flow and demand update (Wednesday 2019-10-09)

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

According to Middle Atlantic River Forecast Center estimates, 0 to 0.50 inches of rain fell in the basin in the past 24 hours. The CO-OP's Low Flow Forecast System reports that this precipitation amounts to a basin-wide average of 0.37 inches for yesterday. Between 0.10 and 0.50 inches of rain is forecast over the next 7 days.

The USGS gage at Point of Rocks is currently above 2000 cfs, our trigger for daily monitoring. We will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Potomac flow and demand update (Tuesday 2019-10-08)

Submitted by admin1 on Tue, 10/08/2019 - 09:00

According to Middle Atlantic River Forecast Center estimates, 0 to 1.50 inches of rain fell in the basin in the past 24 hours. The CO-OP's Low Flow Forecast System reports that this precipitation amounts to a basin-wide average of 0.55271 inches for yesterday. Between 0 and 0.25 inches of rain is forecast over the next 7 days.

The USGS gage at Point of Rocks temporarily rose above 2000 cfs due to the recent precipitation. However, flows have already begun to drop below 2000 cfs.

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

Daily Potomac flow and demand update (Monday 2019-10-07)

Submitted by admin1 on Mon, 10/07/2019 - 09:00

Modest relief from the dry conditions may be on the way - the Middle Atlantic River Forecast Center predicts accumulations of 0.1 to 1.0 inches of rain in the basin over the next 24 hours.

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

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Daily Potomac flow and demand update (Sunday 2019-10-06)

Submitted by admin1 on Sun, 10/06/2019 - 09:00

According to MARFC's forecasted precipitation, the next 7 days is expected to bring between 0.25 and 1 inch of rain to the basin.

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

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)
Past 3-day cumulative area-weighted average basin precip: 0.04 (inches)
Past 7-day cumulative area-weighted average basin precip: 0.43 (inches)

Daily Potomac flow and demand update (Saturday 2019-10-05)

Submitted by admin1 on Sat, 10/05/2019 - 09:00

According to Middle Atlantic River Forecast Center estimates, no rain fell in the basin over the past 24 hours. Between 0.01 and 1.25 inches of rain is forecast over the next 7 days.

The USACE's recreational release has passed the Point of Rocks gage and flows at that gage have dropped below 2000 cfs again. MARFC's GEFS predictions are suggesting that some of the precipitation forecast may affect the Point of Rocks gage flow between October 7 and 11, causing flows at that gage to increase slightly.

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

Daily Potomac flow and demand update (Friday 2019-10-04)

Submitted by admin1 on Fri, 10/04/2019 - 09:00

Adams County, PA, and nearby areas saw some rain yesterday. According to the Middle Atlantic River Forecast Center, accumulations of up to 1/10 inches are expected in the far northern portion of the Potomac basin over the next 3 days, primarily in Pennsylvania. The 7-day forecast is not as promising as it was a few days ago, but accumulations of 1/4 to 3/4 inches are expected throughout most of the basin, mostly occurring Sunday through Tuesday.

Daily Potomac flow and demand update (Thursday 2019-10-03)

Submitted by admin1 on Thu, 10/03/2019 - 09:00

Trace amounts of rain fell over some northern areas of the basin over the past 24 hours according to the Middle Atlantic River Forecast Center. Forecasts are calling for 0.5 to 1.5 inches of rainfall across much of the basin over the next 7 days.

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

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Daily Potomac flow and demand update (Wednesday 2019-10-02)

Submitted by admin1 on Wed, 10/02/2019 - 09:00

According to Middle Atlantic River Forecast Center estimates, no rain fell in the basin in the past 24 hours. However, streamflows have risen slightly due to Monday's rain, and forecasts call for over an inch and a half of rain throughout most of the basin over the next 7 days.

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

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)