Potomac River flows at Little Falls have been relatively steady for the past few days. The USGS conducted two field discharge measurements at Point of Rocks over the course of the past few days and adjusted flow values accordingly. No rainfall is expected in the basin over the next three days.
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)
Yesterday's area-weighted average basin precipitation: 0.04 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0.04 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.06 (inches)
Daily flows:
Little Falls gage flow 2023-08-18: 840 MGD (1300 cfs)
Little Falls gage flow 2023-08-19: 801 MGD (est., based on recently available real-time data) (1240 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2023-08-18: 1047 MGD (1620 cfs)
Point of Rocks flow 2023-08-19: 982 MGD (est., based on recently available real-time data) (1520 cfs)
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2023-08-18):
Fairfax Water Corbalis withdrawal (Potomac): 0 MGD
WSSC Water Potomac withdrawal: 145 MGD
Washington Aqueduct withdrawal: 101 MGD
Loudoun Water withdrawal: 13 MGD
Loudoun Water Broad Run discharge: 5 MGD
Total Potomac withdrawal: 259 MGD
Total net Potomac withdrawal: 253 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1620 cfs
QPR, obs: 1620 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.