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.

2022 WMA Drought Exercise - Day 1: Morning Potomac flow and demand update (Tuesday, 2022-11-15)

Submitted by admin1 on Tue, 11/15/2022 - 14:26

Welcome to the first day of the 2022 WMA Drought Exercise. The simulation day is Thursday, August 25, 2022, and the basin conditions have reached the threshold of the "Warning" stage of the MWCOG drought regional plan. An actual practice Drought Coordination Technical Committee (DCTC) MS Teams meeting is scheduled for today (Tuesday, November 15, 2022) from 4:00 PM to 5:00 PM, in response to simulated combined storage in Jennings Randolph and Little Seneca reservoirs dropping to 9.9 billion gallons (BG), or 60 percent of the combined capacity.

DISCONTINUATION of Daily Potomac flow and demand updates (Friday, 2022-11-11)

Submitted by admin1 on Fri, 11/11/2022 - 14:10

Today we are ending daily flow and demand updates due to the arrival of rainfall from tropical storm Nicole. According to the Middle Atlantic River Forecast Center, an inch of rain has already fallen in the southern portion of the basin with more on the way, and 1 to 2 inches are expected throughout the basin upstream of the Little Falls gage over the next 24 hours.

Daily Potomac flow and demand update (Wednesday, 2022-11-09)

Submitted by admin1 on Wed, 11/09/2022 - 13:58

Potomac River flow has remained relatively steady over the past week. According to National Weather Service forecasts, we can expect about 2 inches of rain during the next three days, mainly on Friday, as the remnants of tropical storm Nicole pass over 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)

Daily Potomac flow and demand update (Tuesday, 2022-11-08)

Submitted by admin1 on Tue, 11/08/2022 - 13:08

There was no precipitation in the Potomac basin yesterday and none is forecast for the next three days. However, it looks like relief is on the way - there is a good chance of heavy rain late this week from subtropical storm Nicole.

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 (Monday, 2022-11-07)

Submitted by admin1 on Mon, 11/07/2022 - 12:42

According to MARFC and CO-OP's Low Flow Forecast System, precipitation totals between 0 and 0.28 inches occurred yesterday. The next 72-hour forecast predicts a precipitation total of up to 0.1 inches for basin locations above the USGS gage at Point of Rocks. Longer-range forecasts (5- and 7-days) indicate heavier rain with accumulations of about an inch in the North Branch area of the basin.

Daily Potomac flow and demand update (Sunday, 2022-11-06)

Submitted by admin1 on Sun, 11/06/2022 - 13:46

Light rain is forecast in the Potomac basin over the next three days, with accumulations of up to 0.25 inches predicted for some areas. Longer range forecasts indicate heavier rain – with accumulations of about an inch - 6 and 7 days in the future. 

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)