SECOND DAY OF WMA DROUGHT EXERCISE: Afternoon Potomac flow and demand update (Tuesday 2020-11-17)

An actual Little Seneca test release was initiated this morning at 10:00 AM. The planned release rate was 400 MGD, but during ramping up the release, it was found that the maximum possible rate is 275 MGD. You can follow the release at the USGS 01645000 SENECA CREEK AT DAWSONVILLE, MD here: https://waterdata.usgs.gov/usa/nwis/uv?01645000.

We look forward to seeing you at this afternoon's webinar at 2:00 PM. You should have received a Teams Meeting invitation, but you can also access the event here. An update was made to the meeting link, please disregard any cancelation messages.

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RECENT CONDITIONS – ACTUAL

Potomac River Flows:
Little Falls gage flow 2020-11-16: 8531 MGD (13200 cfs)
Little Falls gage flow 2020-11-17: 6528 MGD (est., based on recently available real time data) (10100 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2020-11-16: 7109 MGD (11000 cfs)
Point of Rocks flow 2020-11-17: 5306 MGD (est., based on recently available real time data) (8210 cfs)

Today's estimated production* (2020-11-17):
FW estimated production: 150 MGD
WSSC estimated production: 146 MGD
Washington Aqueduct estimated production: 114 MGD
Total estimated production: 410 MGD
*Based on CO-OP daily demand forecasting models. FW includes the LW purchase and excludes Falls Church. Washington Aqueduct includes Falls Church

Tomorrow's estimated production* (2020-11-18):
FW estimated production: 155 MGD
WSSC estimated production: 146 MGD
Washington Aqueduct estimated production: 113 MGD
Total estimated production: 414 MGD
*Based on CO-OP daily demand forecasting models. FW includes the LW purchase and excludes Falls Church. Washington Aqueduct includes Falls Church

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Recommended (SIMULATED) operations for this afternoon (2020-11-17 P.M.):

Fairfax Water:
Maintain the (SIMULATED) load shift of 24 MGD off the Corbalis plant (Potomac) and onto the Griffith plant (Occoquan). Keep Potomac withdrawal rate as steady as possible.

WSSC Water:
Keep Potomac withdrawal rate (SIMULATED) as steady as possible.

Little Seneca (release date, time, amount in MGD):
No (SIMULATED) water supply release.

Washington Aqueduct:
Maintain (SIMULATED) withdrawals at Little Falls of 150 MGD. Great Falls per operational preference.

Loudoun Water:
The following values (SIMULATED) are provided under the protocol developed to satisfy the Virginia Water Protection permit # 10-2020, Part I. 2. f (p. 10), and Part I.J.10
QPR, obs = 514 MGD (695 cfs) (SIMULATED)
QPR, WS = 40 MGD (SIMULATED)
QPR = 474 MGD (SIMULATED)

North Branch Reservoirs Summary:
Maintain (SIMULATED) water supply release with a Luke target of 169 cfs. This is equivalent to 109 MGD.

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. Thank you for your contribution to the monitoring efforts.

ICPRB CO-OP Drought Operations Team (Alimatou, Cherie, Heidi, and Sarah)