Daily Potomac flow and demand update (Sunday 2019-10-20)

According to the Middle Atlantic River Forecast Center (MARFC), 0.01 to 0.75 inches of precipitation fell in the basin over the last 24 hours (ending at 7:00 AM Sunday). It is currently raining and MARFC forecasts that 0.75 to 2.00 inches of precipitation will fall over the next 72 hours. The National Weather Service expects 1.25 to 3.00 inches of precipitation over the next 7 days.

Flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring. Daily monitoring will be continued at this time to confirm that flows remain above the 2000 cfs threshold for a few days given recent gage corrections.The MARFC GEFS forecasts that flows may improve this week, at which point we may revise this decision.

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 precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.00 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.65 (inches)

Daily Flows:

Little Falls gage flow 2019-10-19: 1461 MGD (2260 cfs)

Little Falls gage flow 2019-10-20: 1396 MGD (est., based on recently available real time data) (2160 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-19: 1409 MGD (2180 cfs)

Point of Rocks flow 2019-10-20: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Yesterday's Net Potomac withdrawal (2019-10-19):

FW Corbalis withdrawal (Potomac): 85 MGD

WSSC Potomac withdrawal: 157 MGD

Aqueduct withdrawal: 130 MGD (estimated)

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 382 MGD