Scattered locations across the upper Potomac Basin received between 0.1 and 0.5 inches of rain over the past 24 hours. Small portions of the basin near Washington D.C received up to 2 inches of rain. 0.1 to 1.5 inches of rain are expected over the next 3 days.
Adjustments made yesterday to the Little Falls gage’s rating curve resulted in discharge values lower than previously reported.
Daily flows:
Little Falls gage flow 2021-08-09: 970 MGD (1500 cfs)
Little Falls gage flow 2021-08-10: 920 MGD (est., based on recently available real time data) (1420 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2021-08-09: 960 MGD ( 1480 cfs)
Point of Rocks flow 2021-08-10: 970 MGD (est., based on recently available real time data) (1500 cfs)
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2021-08-09):
Fairfax Water Corbalis withdrawal (Potomac): 134 MGD
WSSC Water Potomac withdrawal: 136 MGD
Washington Aqueduct withdrawal: 140 MGD
Loudoun Water withdrawal: 11 MGD
Loudoun Water Broad Run discharge: 5 MGD
Total Potomac withdrawal: 421 MGD
Total net Potomac withdrawal: 416 MGD
Loudoun Water drought operations protocol river flow values (based on yesterday's flows):
QPR: 1480 cfs
QPR, obs: 1480 cfs
QPR, WS: 0 cfs
Note to Loudoun Water: See NWS ensemble flow forecasts (HEFS, GEFS, NAEFS) for Point of Rocks flow for the next 7 days – see https://www.weather.gov/erh/mmefs_marfc?id=PORM2&model=NAEFS.