This is the final day of the three-day 2022 WMA Drought Exercise. Simulated Potomac River flows at Little Falls have fallen to 104 MGD. Forecasts for today indicate that SIMULATED flows are expected to rise. We requested a SIMULATED Jennings Randolph water supply release this morning of approximately 30 MGD with a Luke target of 297 cfs. Little Seneca continues to make a SIMULATED water supply release to augment flows at Little Falls. There is hope for the basin, however, because the National Weather Service indicates the development of a SIMULATED tropical storm off the coast of Florida in the coming week.
ACTUAL 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: trace amount
Past 3-day cumulative area-weighted average basin precipitation: 0.66 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 2.71 (inches)
ACTUAL Daily flows:
Little Falls gage flow 2022-11-16: 8855 MGD (13700 cfs)
Little Falls gage flow 2022-11-17: 6980 MGD (est., based on recently available real-time data) (10800 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2022-11-16: 6366 MGD (9850 cfs)
Point of Rocks flow 2022-11-17: 6528 MGD (est., based on recently available real-time data) (10100 cfs)
ACTUAL Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2022-11-16):
Fairfax Water Corbalis withdrawal (Potomac): 84 MGD
WSSC Water Potomac withdrawal: 112 MGD
Washington Aqueduct withdrawal: 118 MGD
Loudoun Water withdrawal: 8 MGD
Loudoun Water Broad Run discharge: 7 MGD
Total Potomac withdrawal: 322 MGD
Total net Potomac withdrawal: 315 MGD
ACTUAL Yesterday's Patuxent, Occoquan, and Net Total System Withdrawal (2022-11-16):
FW Occoquan withdrawal:60 MGD
WSSC Patuxent withdrawal:40 MGD
ACTUAL Yesterday's total system withdrawal (2022-11-16): 415 MGD
ACTUAL Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 9850 cfs
QPR, obs: 9850 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.
ACTUAL Today's estimated production* (2022-11-17):
FW estimated production:122 MGD
WSSC estimated production:146 MGD
Washington Aqueduct estimated production:121 MGD
Total estimated production:389 MGD
LW total estimated consumption:21 MGD**
*Based on CO-OP daily demand forecasting models. FW includes the LW purchase and excludes Falls Church. Washington Aqueduct includes Falls Church
**LW total estimated consumption includes purchase and production water and is not included in the total production estimate
ACTUAL Tomorrow's estimated production* (2022-11-18):
FW estimated production:125 MGD
WSSC estimated production:147 MGD
Washington Aqueduct estimated production:120 MGD
Total estimated production:392 MGD
LW Total estimated consumption:21 MGD**
*Based on CO-OP daily demand forecasting models. FW includes the LW purchase and excludes Falls Church. Washington Aqueduct includes Falls Church
**LW total estimated consumption includes purchase and production water and is not included in the total production estimate
SIMULATED Recommended operations for today (DREX Day 3, A.M.):
SIMULATED Fairfax Water:
Per operational preference, keep Potomac withdrawals steady. Maintain Griffith WTP at maximum production of 70 MGD.
SIMULATED WSSC Water:
Maintain Patuxent at maximum production of 60 MGD. Potomac withdrawals per operational preference, keeping as steady as possible.
SIMULATED Little Seneca Reservoir (release date, time, amount in MGD):
Reduce Little Seneca release to 118 MGD.
SIMULATED Washington Aqueduct:
Meet all demands from Little Falls in order to maintain the Great Falls flow-by.
SIMULATED North Branch Reservoirs A.M. Summary:
Initiate a North Branch Water Supply release; Luke target = 297 cfs (192 MGD). The assumed Luke flow without water supply releases is 251 cfs (162 MGD) (simulated).
SIMULATED Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 723 cfs
QPR, obs: 748 cfs
QPR, WS: 25 cfs
SIMULATED Reservoirs - Usable storage (DREX Day 3, A.M., BG):
Facility, %Full, Current, Capacity*
WSSC’s Patuxent reservoirs, 61%, 6.21, 10.2
Fairfax Water’s Occoquan reservoir, 70%, 5.6, 8.05
Little Seneca Reservoir, 56%, 2.19, 3.9
Jennings Randolph Total Reservoir, 64%, 18.73, 29.4
Jennings Randolph water supply**, 59%, 7.69, 13.1
Jennings Randolph water quality**, 68%, 11.04, 16.3
Savage Reservoir, 33%, 2.09, 6.3
*Storage and capacities for Occoquan, Patuxent and Little Seneca reservoirs are provided by Washington metropolitan area water utilities, and based on best available information. Storage and capacities for Jennings Randolph and Savage reservoirs are based on observed water levels and available US ACE water level/storage tables from 1998. ICPRB estimates that sedimentation has resulted in a loss of total available storage in Jennings Randolph Reservoir of 1.6 BG in recent years, and this loss is not reflected in the numbers above.
** ICPRB's initial estimate. Final accounting of Jennings Randolph water supply versus water quality storage will be provided at a later date by the US ACE.
Note: Flow levels have dropped to a level that has triggered enhanced monitoring, per the drought operations manual of the Water Supply Coordination Agreement. When adjusted flow at Little Falls (adjusted flow is gage flow plus upstream withdrawals) less the environmental flow is less than twice the Washington metropolitan area withdrawals, the water suppliers will begin reporting yesterday's and today's withdrawals and this morning's reservoir storage volumes. ICPRB asks that communications be sent by 7:30 am and updates sent by 1:00 pm. Reporting can be submitted through www.icprbcoop.org, by email to coop@icprb.org, or by telephone by leaving a message with the CO-OP operations number at 301-274-8132. Monitoring emails can be viewed at http://icprbcoop.org/products/monitoring-reports. Thank you for your contribution to the monitoring efforts.