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.

Afternoon Potomac flow and demand update (Saturday, 2023-08-26)

Submitted by admin1 on Sat, 08/26/2023 - 14:53

River flows are higher at both Point of Rocks and Little Falls due to the presence of two separate flow peaks caused by hydroelectric power generation at upstream dams (Dams 4 and 5). Flows at Little Falls are now expected to fall significantly over the next 24 – 36 hours as a flow trough – again due to hydropower operations – passes by the stream gage station. We will be working with MDE this week to find a strategy to alleviate this problem.

Morning Potomac flow and demand update (Saturday, 2023-08-26)

Submitted by admin1 on Sat, 08/26/2023 - 08:54

The recent rainfall in the Potomac basin, averaging ¼ inch, has not significantly changed streamflows. Operation of hydroelectric dams on the Potomac River, Dams 4 and 5, are resulting in high peaks and low troughs in flow, which are visible at the USGS Potomac River streamflow gages at Shepherdstown, Point of Rocks, and Little Falls. A flow peak is currently at Little Falls, but we expect a trough to arrive at water supply intakes and at Little Falls late tomorrow.

Initiation of CO-OP Drought Monitoring (Friday, 2023-08-25)

Submitted by admin1 on Fri, 08/25/2023 - 13:05

Today we are initiating CO-OP Drought Operations, per the Water Supply Coordination Agreement (WSCA) of 1982. According to the WSCA, Drought Operations is triggered when flow in the Potomac River at Little Falls, plus Washington metropolitan area Potomac withdrawals, “is projected to be less than twice the projected withdrawals for any of the next five days.”

Daily Potomac flow and demand update (Wednesday, 2023-08-23)

Submitted by admin1 on Wed, 08/23/2023 - 08:10

No rain fell in the basin over the past 24 hours.  Rainfall is expected over the next 3 days according to the Middle Atlantic River Forecast Center, ranging from 0.1 to 1 inch.  The National Weather Service’s 7-day forecast predicts additional rainfall over the course of the next week, with 7-day totals up to 1 ¼ inches in some areas.  

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.