All Rock Island Reservoir irrigators are urged to attend an informational meeting on Thursday, March 13 about the implications of the reservoir drawdown resulting from the discovery of a 65’ crack in a Wanapum Dam spillway on February 24.
According to a press release from the Washington State Horticultural Association, a drawdown of water levels upstream from Wanapum Dam in the Rock Island reservoir was initiated by Chelan County PUD to protect the power generating equipment at Rock Island Dam from catastrophic damage. Power generation ceased at Rock Island on March 3 until river levels could stabilize at 609 feet above sea level at the Rock Island Dam headwater. Under normal conditions, river levels in the Rock Island reservoir are between 612-613 feet. On March 8, Chelan PUD was able to restart power generation at Rock Island.
The extent and cause of the damage at Wanapum Dam is not known, the press release said. As a result, it is uncertain how long it will take to restore the river levels above Wanapum Dam to more normal conditions. There are three significant factors coming together that need to be considered:
- Agricultural interests will need water to commence crop protection applications, frost protection and irrigation
- Adult and juvenile salmon runs both upstream and down will require adequate river flows
- Power generation and dam safety will need to be addressed
It is estimated that about 150 individual irrigators and three irrigation districts are drawing from the Rock Island reservoir. Grant PUD will be working with irrigators impacted by the drawdown to the Wanapum reservoir.
The March 13 meeting will be held from 5:30PM – 7:00PM at the Confluence Technology Center, 285 Technology Center Way, Wenatchee. For more information, contact Bruce Grim at firstname.lastname@example.org.