Utility uses tagged fish to check migration systems’ efficiency
WENATCHEE – See any helicopters dipping baskets into the Columbia River below Rock Island Dam lately? It’s not what you may be thinking.
The Grant County Public Utility District is using a helicopter to release tagged juvenile salmon into the river to track their movements through Wanapum and Priest Rapids dams.
The two dams are both south of the Interstate 90 bridge at Vantage. The Wanapum Dam reservoir backs up to the Chelan County Public Utility District’s Rock Island Dam.
The helicopter should be in the vicinity of Rock Island Dam, possibly the Tarpiscan area, between 9:30 a.m. and 10 a.m. daily for the next two weeks to release the fish, Grant County PUD spokesman Chuck Allen said.
As the released fish approach the dams, crews can study their mortality in different areas to determine if the deaths are caused by predators, dam operations or other hazards that could be mitigated.
Crews are using a helicopter to reduce the time it takes to transport the fish and to release them in the center of the river, Allen said.
The releases are a requirement of the agreements that contributed to the PUD’s license to operate Wanapum and Priest Rapids dams.
Fish are loaded into the helicopter, transported and then lowered in baskets for release into the river, Allen said. The operation resembles a helicopter’s water-dipping duty when working on a wildfire.
Grant PUD recently completed a $28 million juvenile fish bypass system at Priest Rapids Dam.
The bypass allows the utility to get the same number of ocean-bound juveniles past the dam with about one-quarter the water, a PUD news release said.
This leaves more water in the reservoir for hydropower generation, officials say.
Juvenile migrants are on their way downriver now, officials have said.