Situational Awareness (Friday, 2024-11-01)
ICPRB’s CO-OP Section is reinitiating daily drought monitoring and reporting today because yesterday’s Potomac River mean flow at the US Geological Survey’s stream gage at Point of Rocks, Maryland, fell below 2000 cubic feet per second (cfs), CO-OP’s daily monitoring threshold. According to forecasts by the Middle Atlantic River Forecast Center, no appreciable precipitation is expected in the Potomac basin over the next week.
We appreciate your continued successful submission of withdrawal, storage, and discharge data through regular emails. Please continue making those submissions on a daily basis by 8:00 am for the duration of this drought monitoring period.
Please send any questions or comments to coop@icprb.org. Thank you for your continued support!
~CO-OP Drought Team
Special Conditions
None
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 (inches)
Daily flows:
Little Falls gage flow 2024-10-31: 1260 MGD (1950 cfs)
Little Falls gage flow 2024-11-01: 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 2024-10-31: 1280 MGD (1980 cfs)
Point of Rocks flow 2024-11-01: 1293 MGD (est., based on recently available real-time data) (2000 cfs)
Yesterday's estimated daily flows:
Great Falls estimated flow 2024-10-31: 1299 MGD (2011 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 (2024-10-31):
Fairfax Water Corbalis withdrawal - Potomac: 100 MGD
WSSC Water Potomac withdrawal: 128 MGD
Washington Aqueduct withdrawal - Great Falls: 93 MGD
Washington Aqueduct withdrawal - Little Falls: 39 MGD
Loudoun Water withdrawal: 10 MGD
Loudoun Water Broad Run discharge: 7 MGD
Total Potomac withdrawal: 369 MGD
Total net Potomac withdrawal: 362 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1980 cfs
QPR, obs: 1980 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.