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 (Monday 09/06/2010)

Submitted by admin1 on Mon, 09/06/2010 - 09:00

The basin continues to receive no precipitation, except for the small
amount seen yesterday. Both the 48-hour and the five-day National
Weather Service precipitation forecasts indicate no accumulated
rainfall in the basin. Given current conditions, enhanced monitoring
will likely begin tomorrow. Tomorrow we will contact the utilities
directly to confirm procedures.

Daily Potomac flow and demand update (Saturday 09/04/2010)

Submitted by admin1 on Sat, 09/04/2010 - 09:00

Except for scattered amounts of trace rainfall yesterday, the basin has not received any precipitation over the past 7 days. The National
Weather Service predicts no precipitation in the basin over the next 48-hour period. A small amount of rain, up to 1/10 of an inch, is
being forecasted to fall in the North Branch area within the next five days. It appears that the artificially varied flow (AVF) release from
Jennings Randolph has reached Little Falls causing increased flow at the gage. It is expected that flows will drop again once the AVF

Daily Potomac flow and demand update (Friday 09/03/2010)

Submitted by admin1 on Fri, 09/03/2010 - 09:00

Over the last 24 hours, less than a 0.1 of an inch of precipitation fell over the mainstem of the Potomac between Goose Creek and the Monocacy; the remaining areas in the basin received no rain. Over the next 48 hours, the National Weather Service indicates a chance of up to 0.1 of an inch of rain in the North Branch, with a possibility of a 0.25 of an inch in the Washington, D.C. area. Over the next 5 days, there is a chance of up to 0.1 of an inch of rain, with most of the central portion of the basin receiving no rain.

Daily Potomac flow and demand update (Thursday 09/02/2010)

Submitted by admin1 on Thu, 09/02/2010 - 09:00

No precipitation fell in the basin yesterday, except for an isolated amount of trace rainfall over the mainstem between Goose Creek and the Monocacy. The trajectory of Hurricane Earl remains off the coast and it does not appear that the basin will receive any precipitation from this event. The National Weather Service does indicate a chance of up to 0.10 of an inch of rain in the next 48 hours in the North Branch area. The flow at Point of Rocks reflects the artificially varied flow release reaching the gage.

Daily Potomac flow and demand update (Wednesday 09/01/2010)

Submitted by admin1 on Wed, 09/01/2010 - 09:00

Negligible amounts of precipitation have been observed in the Potomac basin over the past couple of days. The National Weather Service (NWS) forecasts show no predicted precipitation over the next 48-hour period. As Hurricane Earl moves up the East Coast, the NWS indicates that the 5-day accumulated precipitation could range from 0.1 and 0.5 inches over most of the basin. The artificially varied flow release is currently passing the Potomac River gage at Hancock, MD.

Daily Potomac flow and demand update (Tuesday 08/31/2010)

Submitted by admin1 on Tue, 08/31/2010 - 09:00

No precipitation fell in the Potomac basin over the past 24 hours. The National Weather Service predicts little rain over its 5-day forecast period, but the trajectory of Hurricane Earl is uncertain, and it could have an impact on the basin. Last weekend's AVF water quality release from Jennings Randolph Reservoir should be arriving at Little Falls on Friday. Note: yesterday's daily mean flow values are not available for many Potomac basin gages, including Point of Rocks and Little Falls, so values given below for 8/30 are estimated from available real-time data.

Daily Potomac flow and demand update (Monday 08/30/2010)

Submitted by admin1 on Mon, 08/30/2010 - 09:00

Flows from the Shenandoah River and last weekend's artificially varied flow release should help to maintain flows at Point of Rocks and Little Falls over the next couple of days. No significant precipitation fell in the basin yesterday, and the National Weather Service predicts no rain over the 48-hour forecast period. There is a possibility of between 0.01 and 0.10 inches of rain over the 5-day forecast period.

Daily Potomac flow and demand update (Sunday 08/29/2010)

Submitted by admin1 on Sun, 08/29/2010 - 09:00

Flows in most Potomac basin tributaries are slowly dropping, but recent rain events have increased flow in the Shenandoah River, and this should help to maintain flows at Point of Rocks and Little Falls over the next several days. No significant precipitation fell in the basin yesterday, and the National Weather Service predicts no rain over its 5-day forecast period. The US Army Corps of Engineers initiated a 24-hr 870 cfs AVF (Artificially Varied Flow) release from Jennings Randolph Reservoir yesterday morning.

Daily Potomac flow and demand update (Saturday 08/28/2010)

Submitted by admin1 on Sat, 08/28/2010 - 09:00

Aqueduct withdrawals at the Little Falls intake caused a drop in flows at the Little Falls gage; flows should recover sometime later today. Flows at the Point of Rocks gage remain steady. An artificially varied flow is scheduled to be released from Jennings Randolph Reservoir today and should temporarily raise flows during the next couple of days.