Situational Awareness (Tuesday, 2024-11-19)
Today, CO-OP is suspending its daily drought monitoring and reporting. This phase of CO-OP’s drought response is triggered when daily Potomac River flow at the USGS’s Point of Rocks gage falls below 2000 cubic feet per second (cfs). Yesterday’s flow rose above that threshold. According to the Middle Atlantic River Forecast Center predictions, the average basin rainfall may be up to 0.5 inches over the next 3 days. We will continue to monitor conditions closely and we will resume daily drought monitoring if needed.
Thank you to all of the people who provide the data we use in our reports: Washington metropolitan area water suppliers at Fairfax Water, Washington Aqueduct, WSSC Water, and Loudoun Water, and also our partner organizations, the US Geological Survey and the Middle Atlantic River Forecast Center.
Special Conditions
None
Daily flows:
Little Falls gage flow 2024-11-18: 1325 MGD (2050 cfs)
Little Falls gage flow 2024-11-19: 1280 MGD (est., based on recently available real-time data) (1980 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2024-11-18: 1299 MGD (2010 cfs)
Point of Rocks flow 2024-11-19: 1474 MGD (est., based on recently available real-time data) (2280 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2024-11-18: 1376 MGD (2129 cfs)
Note: Estimated flow below Great Falls intake is flow at Little Falls plus Little Falls water supply withdrawal.
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2024-11-18):
Fairfax Water Corbalis withdrawal - Potomac: 88 MGD
WSSC Water Potomac withdrawal: 167 MGD
Washington Aqueduct withdrawal - Great Falls: 67 MGD
Washington Aqueduct withdrawal - Little Falls: 51 MGD
Loudoun Water withdrawal: 10 MGD
Loudoun Water Broad Run discharge: 8 MGD
Total Potomac withdrawal: 384 MGD
Total net Potomac withdrawal: 376 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 2010 cfs
QPR, obs: 2010 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 – https://www.weather.gov/erh/mmefs_marfc?id=PORM2&model=NAEFS. See US Army Corps of Engineers Potomac River Basin page for observed releases from Savage and Jennings Randolph reservoirs - https://www.nab-wc.usace.army.mil/nab/poto.html; See US Army Corps of Engineers North Branch Potomac River and Savage River page for scheduled releases - https://www.nab-wc.usace.army.mil/nab/northBranch.html.
Note: Potomac River flow at Point of Rocks has dropped below the low-flow threshold of 2,000 cfs. When this occurs, per the Water Supply Coordination Agreement of 1982, CO-OP begins daily monitoring and reporting of Potomac flows and withdrawals on behalf of the CO-OP suppliers, Fairfax Water, Washington Aqueduct, and WSSC Water. Suppliers can review data at CO-OP's Data Portal at www.icprbcoop.org. Reports formatted in approved templates should be submitted by email to coop@icprb.org by 8:00 am for automated processing. Published monitoring reports are at http://icprbcoop.org/products/monitoring-reports.