Today is the first day of the 2020 Washington Metropolitan Area Drought Exercise, which will be conducted from Monday, November 16 through Wednesday, November 18.
From the suppliers we need
Every morning by 7:30 AM: most recent (yesterday’s and early morning of today) hourly withdrawals and most recent reservoir storage levels
Every afternoon by 1:00 PM: update of today’s hourly withdrawals
Data can be submitted via your automated email. Data not in your email can be submitted via Data Portal (https://icprbcoop.org). If you need a password or assistance, email sahmed@icprb.org.
The scenario for this week’s exercise is as follows:
The day is Monday, August 16, 2021 and the basin is in moderate drought. During the past winter, the weather was unseasonably warm with very little precipitation, resulting in significantly below average winter recharge to the basin’s fractured bedrock aquifers. On June 1, all system reservoirs were above CO-OP's target of 90% of capacity. But in late June, flow in the Potomac River fell to a level requiring releases from the system’s upstream reservoirs, and since that time, periodic releases have been made from Jennings Randolph and Little Seneca reservoirs to augment river flow. Combined upstream water supply storage in Jennings Randolph and Little Seneca is currently 7.5 BG, or 44% of combined capacity. The drought stage, per the MWCOG regional plan, is “Warning”, and regional voluntary water use restriction are in place.
In our morning and afternoon reports, we will first give ACTUAL flows, withdrawals, and reservoir storage levels, in order to test our data communications and processing procedures. We will then give SIMULATED operations, in order to exercise CO-OP’s operations support tools operational policies. The ability to make SIMULATED operational changes will be verified by phone with the appropriate suppliers.
Daily Potomac flow and demand update (Monday 2020-11-16)
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 precip: 0.19 (inches)
Past 3-day cumulative area-weighted average basin precip: 0.19 (inches)
Past 7-day cumulative area-weighted average basin precip: 1.73 (inches)
Daily Flows:
Little Falls gage flow 2020-11-15: 11052 MGD (17100 cfs)
Little Falls gage flow 2020-11-16: 8855 MGD (est., based on recently available real time data) (13700 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2020-11-15: 9630 MGD (14900 cfs)
Point of Rocks flow 2020-11-16: 7239 MGD (est., based on recently available real time data) (11200 cfs)
Yesterday's Net Potomac withdrawal (2020-11-15):
FW Corbalis withdrawal (Potomac): 79 MGD
WSSC Potomac withdrawal: 90 MGD
Aqueduct withdrawal: 106 MGD
Loudoun withdrawal: 0 MGD
Total Potomac withdrawal: 275 MGD
Yesterday's Patuxent, Occoquan, and Net Total System Withdrawal (2020-11-15):
FW Occoquan withdrawal:57 MGD
WSSC Patuxent withdrawal:48 MGD
Total system withdrawal:380 MGD
Loudoun Water Broad Run discharge:
Yesterday's (2020-11-15):8 MGD
Today's (2020-11-16):0 MGD
Tomorrow's (2020-11-17) :0 MGD
Today's estimated production* (2020-11-16):
FW estimated production:159 MGD
WSSC estimated production:153 MGD
Washington Aqueduct estimated production:113 MGD
Total estimated production:425 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* (2020-11-17):
FW estimated production:152 MGD
WSSC estimated production:148 MGD
Washington Aqueduct estimated production:114 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
Reservoirs - Usable storage (2020-11-16 A.M., BG):
Facility, %Full, Current, Capacity*
WSSC’s Patuxent reservoirs, %81,8.28,10.2
Fairfax Water’s Occoquan reservoir, %95,8.1,8.5
Little Seneca Reservoir, %100,3.91,3.9
Jennings Randolph Total Reservoir, %79,23.1,29.4
Jennings Randolph water supply**, %100,13.1,13.1
Jennings Randolph water quality**, %61,10,16.3
Savage Reservoir, %65,4.1,6.3
*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.