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.

Reinitiating CO-OP Daily Drought Monitoring and Reporting (Friday, 2023-08-18)

Submitted by admin1 on Fri, 08/18/2023 - 08:56

CO-OP is reinitiating daily drought monitoring and reporting today because Potomac River flow at the US Geological Survey’s stream gage at Point of Rocks, Maryland, is approaching the 2000 cubic feet per second (cfs), CO-OP's daily monitoring threshold. According to the Middle Atlantic River Forecast Center, no rainfall is expected in the basin over the next three days.

Suspending daily monitoring-Daily Potomac flow and demand update (Tuesday, 2023-08-08)

Submitted by admin1 on Tue, 08/08/2023 - 12:58

CO-OP is suspending daily drought monitoring emails because flow at the US Geological Survey’s gage at Point of Rocks, Maryland, has risen above the 2000 cfs monitoring threshold. Yesterday, a tornado watch lasted until 9 p.m., but there were no confirmed tornadoes in the region. Some parts of the basin observed up to 1.75 to 2 inches of precipitation during this time. The Middle Atlantic River Forecast Center predicts an additional 0.1 to 1.25 inches of rainfall over the next 72 hours, possibly arriving by this Thursday.

Daily Potomac flow and demand update (Monday, 2023-08-07)

Submitted by admin1 on Mon, 08/07/2023 - 13:13

Precipitation amounts over the past 24 hours varied from trace amounts in the middle of the basin to over an inch in some locations in far western areas and in some parts of the DC metro area.  Given the locations of the heaviest rainfall amounts, only a modest increase in flows at the USGS gage at Point of Rocks has occurred at this time.  Flows remain below the threshold for daily monitoring.

Daily Potomac flow and demand update (Thursday, 2023-08-03)

Submitted by admin1 on Thu, 08/03/2023 - 13:06

Yesterday, there was no recorded rainfall. In the next 72 hours, 0.1 to 0.5 inches of rain are expected in 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 precipitation: 0 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0.14 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.63 (inches)

Daily Potomac flow and demand update (Tuesday, 2023-08-01)

Submitted by admin1 on Tue, 08/01/2023 - 12:59

Potomac River flows continue to hold relatively steady. Less than an inch of precipitation is in the cumulative forecast for the basin over the next ten days.

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 precipitation: 0.14 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0.23 (inches)

Daily Potomac flow and demand update (Monday, 2023-07-31)

Submitted by admin1 on Mon, 07/31/2023 - 12:27

In the past 24 hours, up to 0.5 inches of rain fell in localized areas of the Potomac Basin, mainly in the northwestern portions and around the Washington D.C area. According to the Middle Atlantic River Forecast Center’s cumulative forecast, no substantial rain is expected in the next 72 hours. River flow at Point of Rocks increased slightly but is still close to the 2000 cfs daily monitoring threshold.