Situational Awareness (Wednesday, 2023-10-04)
CO-OP is reinitiating daily drought monitoring and reporting today because Potomac River flow at the US Geological Survey’s stream gage at Point of Rocks, Maryland, is below 2000 cubic feet per second (cfs), CO-OP's daily monitoring threshold. According to the Middle Atlantic River Forecast Center predictions, no rainfall is expected in the basin over the next three days. The week-long outlook expects a total of approximately 0.2 inches of rain.
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 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.02 (inches)
Daily flows:
Little Falls gage flow 2023-10-03: 1247 MGD (1930 cfs)
Little Falls gage flow 2023-10-04: 1131 MGD (est., based on recently available real-time data) (1750 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2023-10-03: 1228 MGD (1900 cfs)
Point of Rocks flow 2023-10-04: 1138 MGD (est., based on recently available real-time data) (1760 cfs)
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2023-10-03):
Fairfax Water Corbalis withdrawal - Potomac: 91 MGD
WSSC Water Potomac withdrawal: 137 MGD
Washington Aqueduct withdrawal - Great Falls: 71 MGD
Washington Aqueduct withdrawal - Little Falls: 78 MGD
Loudoun Water withdrawal: 10 MGD
Loudoun Water Broad Run discharge: 6 MGD
Total Potomac withdrawal: 388 MGD
Total net Potomac withdrawal: 382 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1900 cfs
QPR, obs: 1900 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.