CONCLUSION OF 2020 ANNUAL WMA DROUGHT EXERCISE - Afternoon Potomac flow and demand update (Wednesday 2020-11-18)

This concludes the 2020 Washington Metropolitan Area (WMA) drought exercise. A report describing exercise assumptions, activities, and tools will be prepared and made available on ICPRB's website in the coming weeks.

Thank you for your help in maintaining the reliability of the regional water supply system! Special thanks to WSSC Water staff for providing a tour of the Little Seneca Dam and to the Black Hill Regional Park for posting signs prior to the release.

We hope that the webinar on Forecast Informed Reservoir Operations by Hazen and Sawyer was informative.

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RECENT CONDITIONS – ACTUAL

Potomac River Flows:

Little Falls gage flow 2020-11-17: 6722 MGD (10400 cfs)

Little Falls gage flow 2020-11-18: 5584 MGD (est., based on recently available real time data) (8640 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2020-11-17: 5552 MGD (8590 cfs)

Point of Rocks flow 2020-11-18: 4518 MGD (est., based on recently available real time data) (6990 cfs)

Today's estimated production* (2020-11-18):

FW estimated production: 150 MGD

WSSC Water 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* (2020-11-19):

FW estimated production:153 MGD

WSSC estimated production:146 MGD

Washington Aqueduct estimated production:116 MGD

Total estimated production:415 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 (2020-11-18):

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):

Maintain a 22 MGD (SIMULATED) water supply release from Little Seneca Reservoir.

Washington Aqueduct:

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

Loudoun Water:

QPR, obs = 473 MGD (732 cfs) (SIMULATED)

QPR, WS = 50 MGD (SIMULATED)

QPR = 423 MGD (SIMULATED))

North Branch Reservoirs Summary:

Maintain (SIMULATED) water supply release with a Luke target of 152 cfs. This is equivalent to 98 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)

"# Net Potomac Withdrawals Actual and Forecast" "# FW_POT = Fairfax Water Corbalis Plant withdrawal from the Potomac, no Loudoun Water purchase water" "# WSSC_POT = Washington Subburban Sanitary Commission withdrawal from the Potomac" "# WA_GF = Washington Aqueduct withdrawal from Great Falls on the Potomac" "# WA_LF = Washington Aqueduct withdrawal from Little Falls on the Potomac" "# LW_POT = Loudoun Water Trap Rock Plant withdrawal from the Potomac" "# FW_OC = Occoquan off-Potomac withdrawal by Fairfax Water" "# WSSC_PA = Patuxent off-Potomac withdrawal by WSSC" "# LW_FW = Loudoun Water purchase water to add to Fairfax Water Potomac withdrawal" "# LW_BR = Loudoun Water Broad Run wastewater return flow" "# Total Annual Average Assumptions: FW = 138.82; WSSC = 158.43; WA = 120.72; LW = 23.86" "# Start Date = 2021-02-04" "# Stop Date = 2021-05-15" "# Time Zone = Eastern Standard Ttime (EST)" "# Units = million gallons per day (mgd)" DateTime,FW_POT,WSSC_POT,WA_GF,WA_LF,LW_POT,LW_FW,FW_OC,WSSC_PA,LW_BR 2021-02-03,73.36,95.49,107.17,0,5.97,12.42,69.41,72.85, 2021-02-04,77.64,98.36,101.29,0,6.56,12.42,70.21,72.78, 2021-02-05,69.42,93.04,95.63,0,5.32,12.42,70.21,72.58, 2021-02-06,74.14,92.97,100.46,0,4.89,13.07,70.19,72.39, 2021-02-07,74.58,92.93,107.67,0,6.04,13.07,70.36,72.21, 2021-02-08,70.39,92.53,111.21,0,5.08,13.07,71.55,72.36, 2021-02-09,67.96,103.65,113,0,5.28,13.07,70.07,64.68, 2021-02-10,78.45,92.59,105.71,0,4.98,13.07,69.53,62.36, 2021-02-11,64.26,92.05,101.38,0,4.48,13.07,71.27,65.24, 2021-02-12,64.53,92.29,97.29,0,4.86,13.07,70.5,60.63, 2021-02-13,64.91,93.55,101.79,0,5.11,13.07,70.39,68.2, 2021-02-14,74.4,93.3,104.13,0,5.14,13.07,71.55,64.23, 2021-02-15,65.04,93.21,100.96,0,5.07,13.07,71.92,62.93, 2021-02-16,82.84,91.08,112.83,0,4.78,13.07,71.57,71.88, 2021-02-17,49.97,91.45,107.29,0,4.84,13.07,70.21,71.84, 2021-02-18,55.38,91.54,62.47,0,5.61,13.07,70.75,66.39, 2021-02-19,59.16,92.32,103.49,0,5.33,13.07,64.61,57.61, 2021-02-20,57.43,92.57,101.64,0,4.35,13.07,68.35,65.64, 2021-02-21,69.89,101.42,109.73,0,5.88,13.07,69.99,70.53, 2021-02-22,63.37,96.59,125,0,12.42,8.19,70.21,64.89,6.78 2021-02-23,58.8,92.07,123.38,0,6.32,13.07,76.42,64.6, 2021-02-24,57.59,92.04,117.83,0,13.07,8.14,71.86,66.53,6.14 2021-02-25,57.34,91.43,132.67,0,4.81,13.07,71.99,63.88, 2021-02-26,57.72,92.12,126.92,0,4.25,13.07,72.3,63.79, 2021-02-27,54.28,91.5,119.88,0,4.19,13.07,72.8,66.57, 2021-02-28,52,90.98,107.92,0,6.87,13.07,72.09,63.37, 2021-03-01,61.96,130.56,116.38,0,6.62,13.07,72.24,18.4, 2021-03-02,61.98,154.71,110.92,0,7.05,13.07,71.55,0, 2021-03-03,79.93,159.92,120.71,0,6.94,13.07,72.15,0, 2021-03-04,80.18,157.2,107.52,0,6.79,13.07,72.2,0, 2021-03-05,81.26,140.33,104.12,0,6.02,13.07,72.15,15.6, 2021-03-06,85.04,93.54,100.1,0,6.25,13.07,72.13,64.15, 2021-03-07,94.21,99.37,105.87,0,7.66,13.07,66.16,58.79, 2021-03-08,82.36,94.17,109.08,0,7.56,13.07,75.44,58.88, 2021-03-09,89.09,94.08,109.41,0,7.7,13.07,72.07,63.49, 2021-03-10,87.66,93.94,109.64,0,7.57,13.07,71.98,57.06, 2021-03-11,88.77,93.9,109.48,0,7.55,13.07,71.98,57.48, 2021-03-12,85.83,94.02,105.06,0,6.39,13.07,71.6,63.66, 2021-03-13,86.66,93.6,100.09,0,6.33,13.07,71.52,64, 2021-03-14,55.19,91.94,113.29,0,7.48,13.07,72.27,60.22, 2021-03-15,82.59,91.98,62,0,7.2,13.07,71.73,60.21, 2021-03-16,83.52,92.76,108.9,0,6.61,13.07,72.43,57.95, 2021-03-17,78.64,92.19,106.7,0,6.41,13.07,71.1,55.17, 2021-03-18,81.08,93.29,105.52,0,6.38,13.07,69.21,50.21, 2021-03-19,79.77,92.72,102.76,0,5.65,13.07,71.38,47.65, 2021-03-20,82,93.47,98.47,0,5.85,13.07,73.42,52.84, 2021-03-21,86.27,93.51,105.06,0,7.37,13.07,73.42,60.66, 2021-03-22,79.57,91.41,108.39,0,6.46,13.07,73.81,64.95, 2021-03-23,80.52,92.56,106.82,0,6.71,13.07,73.81,58.74, 2021-03-24,59.99,91.79,115.29,0,6.84,13.07,72.41,50.96, 2021-03-25,57.58,91.53,114.08,0,7.05,13.07,71.91,51.75, 2021-03-26,56.7,91.2,110.96,0,7.3,11.04,71.99,59.1, 2021-03-27,57.72,91.62,111.54,0,7.61,11.04,72.15,58.95, 2021-03-28,54.43,91.77,121.08,0,8.97,11.04,72.2,59.02, 2021-03-29,52.8,92.74,121.42,0,8.14,11.04,72.15,58.71, 2021-03-30,50.85,92.13,117.38,0,8.03,11.04,72.13,58.97, 2021-03-31,57.27,92.46,112,0,11.21,11.04,66.16,52.91, 2021-04-01,52.62,93.51,114.96,0,11.25,11.04,75.44,47.34, 2021-04-02,55.56,92.75,115.17,0,10.63,11.04,72.07,48.25, 2021-04-03,50.66,93.45,105.63,0,10.96,11.04,71.98,57.41, 2021-04-04,56.82,93.33,112.04,0,12.55,11.04,71.98,56.57, 2021-04-05,65.36,90.39,118.71,0,12.53,11.04,71.6,58.92, 2021-04-06,71.1,90.35,106.57,0,12.8,11.04,71.52,62.24, 2021-04-07,72.19,90.22,116.42,0,11.72,11.04,71.55,61.3, 2021-04-08,70.93,89.71,121.67,0,7.77,14.82,71.73,63.49, 2021-04-09,58.63,89.64,127.04,0,6.39,14.82,72.43,56.54, 2021-04-10,52.38,89.4,109.96,0,6.75,14.82,71.1,54.48, 2021-04-11,62.34,103.35,122.43,0,8.36,14.82,69.21,55.63, 2021-04-12,69.89,101.35,109.28,0,7.41,14.82,71.38,54.09, 2021-04-13,70.13,87.63,109.83,0,7.85,14.82,73.42,55.71, 2021-04-14,97,98.57,120.92,0,7.91,14.82,69.67,62.14, 2021-04-15,74.87,91.59,114.46,0,7.92,14.82,73.81,52.16, 2021-04-16,96.42,91.66,108.29,0,7.18,14.82,73.04,58.74, 2021-04-17,75.41,100.08,113.79,0,7.3,14.82,71.82,58.88, 2021-04-18,71.23,95.97,109.46,0,8.82,14.82,75.72,59.1, 2021-04-19,77.56,101.96,125.46,0,8.85,14.82,77.54,52.59, 2021-04-20,72.51,102.15,124.21,0,8.94,14.82,76.79,47.14, 2021-04-21,67.22,99.6,119.5,0,11.04,14.65,74.84,56.21,6.83 2021-04-22,72.71,88.24,125.88,0,8.44,14.82,71.92,66.73, 2021-04-23,69.49,97.33,117.29,0,6.85,14.82,71.69,63.08, 2021-04-24,72.44,92.57,120.67,0,7.6,14.82,74.22,63.47, 2021-04-25,64.07,92.11,96.5,0,9.28,14.82,75.71,61.88, 2021-04-26,71.11,92.52,118.17,0,9.35,14.82,73.99,62.44, 2021-04-27,79.34,98.53,126.25,0,9.7,14.82,72.39,68.52, 2021-04-28,86.6,98.83,127.42,0,9.52,14.82,74.79,68.81, 2021-04-29,80.64,103.15,136,0,9.44,14.82,80.95,66.09, 2021-04-30,74.02,95.83,144.88,0,15.26,11.52,73.76,62.66, 2021-05-01,78.9,90.97,117.63,0,14.82,10.16,74.16,62.57,6.3 2021-05-02,83.9,106.14,121,0,16.21,11.52,74.18,62.36, 2021-05-03,82.24,99.12,125.29,0,15.68,11.52,74.04,56.17, 2021-05-04,72.01,103.78,128.04,0,16.07,11.52,73.42,54.64, 2021-05-05,73.65,98.23,126.63,0,15.22,11.52,74.38,54.08, 2021-05-06,71.24,91.46,92.75,0,15.46,11.52,72.29,57.96, 2021-05-07,76.42,97.65,124.42,0,14.64,11.52,70.87,61.82, 2021-05-08,56.58,96.64,123,0,15.21,11.52,69.67,55.89, 2021-05-09,63.09,90.65,109.33,0,16.85,11.52,69.96,51.45, 2021-05-10,84.6,101.07,123.92,0,16.59,11.52,73.04,51.26, 2021-05-11,69.56,103.42,125.88,0,17.18,11.52,75.42,51.22, 2021-05-12,85.14,105.09,139.96,0,17.21,11.52,73.72,50.84, 2021-05-13,74.5,105.1,137.46,0,17.2,11.52,77.07,55.11, 2021-05-14,89.85,102.18,136.33,0,16.36,11.52,75.98,55.63,