Daily Potomac flow and demand update (Thursday, 2022-10-27)

Submitted by admin1 on Thu, 10/27/2022 - 12:46

According to Middle Atlantic River Forecast Center (MARFC) map products, there was 0.01 to 0.27 inches of rain in the basin over the past 24 hours. The LFFS average basin precipitation is 0.12 inches. MARFC predicts no rainfall over the next three days, although 0.25-0.75 inches of rain is expected in the 5 and 7-day forecasts.

Yesterday, WSSC Water temporarily provided all of the City of Rockville's water. WSSC Water is no longer serving them.

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: 0.12 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0.17 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.19 (inches)

Daily flows:
Little Falls gage flow 2022-10-26: 1293 MGD (2000 cfs)
Little Falls gage flow 2022-10-27: 1293 MGD (est., based on recently available real-time data) (2000 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2022-10-26: 1260 MGD (1950 cfs)
Point of Rocks flow 2022-10-27: 1163 MGD (est., based on recently available real-time data) (1800 cfs)

Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2022-10-26):
Fairfax Water Corbalis withdrawal (Potomac): 78 MGD
WSSC Water Potomac withdrawal: 108 MGD*
Washington Aqueduct withdrawal: 129 MGD
Loudoun Water withdrawal: 11 MGD
Loudoun Water Broad Run discharge: 5 MGD
Total Potomac withdrawal: 325 MGD
Total net Potomac withdrawal: 320 MGD
*WSSC Water temporarily served the City of Rockville yesterday. 

Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1950 cfs
QPR, obs: 1950 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.

AM Report
Daily Monitoring