Daily Potomac flow and demand update (Thursday 09/24/2015)
A negligible amount of rain fell in the basin yesterday. MARFC indicates some chance of 0.01 to 1.00 inch of rain Friday and Saturday. The heavier rain is expected to the southwest.
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 09/21/2015)
Up to 0.75 inches of rain fell in western areas of the basin yesterday. MARFC predits up to an inch of rain across the basin over the next three days.
Daily Flows:
Little Falls gage flow 09/20: 900 MGD (1390 cfs)
Little Falls gage flow 09/21: 810 MGD (est., based on recently available real time data) (1260 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 09/20: 1020 MGD (1580 cfs)
Point of Rocks flow 09/21: 1000 MGD (est., based on recently available real time data) (1540 cfs)
Daily Potomac flow and demand update (Saturday 09/19/2015)
Flow in the Potomac River continues to slowly fall. According to the National Weather Service, there has been no precipitation in the Potomac basin over the past three days. There is a chance of rain on Monday, with accumulations of approximately 1/10 inch expected over much of the basin.
Daily Potomac flow and demand update (Friday 09/18/2015)
No rain fell in the basin yesterday. MARFC indicates a chance of between 0.01 and 0.10 inches on Saturday in the far western portion of the basin.
Daily Flows:
Little Falls gage flow 09/17: 1220 MGD (1880 cfs)
Little Falls gage flow 09/18: 1090 MGD (est., based on recently available real time data) (1680 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 09/17: 1230 MGD (1910 cfs)
Point of Rocks flow 09/18: 1200 MGD (est., based on recently available real time data) (1860 cfs)
Daily Potomac flow and demand update (Thursday 09/17/2015)
According to the Middle Atlantic River Forecast Center (MARFC), no rainfall was recorded in the Potomac basin over the past 24 hours. MARFC does not predict any rainfall over the next 3 days.
DROUGHT EXERCISE - Afternoon Potomac flow and demand update (Friday 09/16/2015)
(SIMULATED) Daily Flows:
Little Falls gage flow 09/15/15: 210 MGD (320 cfs)
Little Falls gage flow 09/16/15: 310 MGD (est., based on most
recently available real time data) (473 cfs)
Note: Gage flow at Little Falls is measured after water
supply withdrawals.
Point of Rocks flow 09/15/15: 610 MGD (940 cfs)
Point of Rocks flow 09/16/15: 570 MGD (est., based on recently
available real time data) (880 cfs)
Daily Potomac flow and demand update (Tuesday 09/15/2015)
According to the Middle Atlantic River Forecast Center (MARFC), no rain fell in the Potomac basin over the past 24 hours and no rain is forecast over the next three days. Though flow at Point of Rocks is currently above CO-OP's low-flow monitoring threshold of 2000 cfs, flow is expected to fall back below this level sometime in the next couple of days.
Daily Potomac flow and demand update (Monday 09/14/2015)
A small area in the southwestern portion of the basin saw between 0.1 and 0.25 inches of rain over the past 24 hours. MARFC is not predicting any rain until this weekend.
Daily Flows:
Little Falls gage flow 09/13: 1410 MGD (2180 cfs)
Little Falls gage flow 09/14: 1460 MGD (est., based on recently available real time data) (2260 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 09/13: 1320 MGD (2040 cfs)
Point of Rocks flow 09/14: 1290 MGD (est., based on recently available real time data) (2000 cfs)
Daily Potomac flow and demand update (Sunday 09/13/2015)
The vast majority of the basin saw some amount of rainfall yesterday, ranging from 0.1 to 1 inch in most areas. Isolated areas received up to 1.5 inches. MARFC's current forecast predicts no rain in the basin over the next three days. Flow at Point of Rocks is expected to drop back below 2,000 cfs in the next day or two.
Daily Potomac flow and demand update (Saturday 09/12/2015)
The Middle Atlantic River Forecast Center reports that areas in the central portion of the basin received up to 1.25 inches of rain in the past 24 hours.The 72-hour forecast calls for accumulation between 0.25 and 1.25 inches, with the greater amounts to the northwest.