According to current National Weather Service forecasts, precipitation related to hurricanes Idalia and Franklin seem to be mostly by-passing the Potomac basin.
Note that at this time, we do not see a need for a Washington Aqueduct load shift from Great Falls to Little Falls.
Note that there is a correction in yesterday’s Reservoirs - Usable Storage for the Patuxent reservoirs. The correct values are given in the table below.
Daily flows:
Little Falls gage flow 2023-08-28: 498 MGD (770 cfs)
Little Falls gage flow 2023-08-29: 424 MGD (est., based on recently available real-time data) (656 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2023-08-28: 743 MGD (1150 cfs)
Point of Rocks flow 2023-08-29: 666 MGD (est., based on recently available real-time data) (1030 cfs)
Recommended operations for today (2023-08-29 P.M.):
Per operational preference.
Reservoirs - Usable storage (2023-08-28, BG):
Facility, %Full, Current, Usable Capacity*
WSSC’s Patuxent reservoirs, 52%, 5.3, 10.2
Fairfax Water’s Occoquan reservoir, 98%, 8.3, 8.5
Little Seneca Reservoir, 97%, 3.8, 3.9
Jennings Randolph Total Reservoir, 80%, 23.44, 29.4
Jennings Randolph water supply**, 100%, 13.1, 13.1
Jennings Randolph water quality**, 63%, 10.3, 16.3
Savage Reservoir, 61%, 3.85, 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.