The Skokomish Indian tribe in Washington, US, has filed a US$5.7B claim against the US federal government for damage it contends has been done by Tacoma Power’s Cushman hydroelectric project, a dam which supplies power to the city of Tacoma in Washington. The claim is the first step toward getting both the utility and the US government into federal court to decide a contentious case that has been pending for more than a quarter of a century.

The tribe also intends to sue FERC over terms of the operating licence it issued to Tacoma Power in July last year.

Tacoma Power, the city-owned utility, built the two Cushman arch dams in 1926 and 1930, in what was the Olympic National Park. The two dams, 280ft and 24ft high, on the North Fork of the Skokomish river, dried up the river by diverting the water to a powerhouse on the Skokomish reservation.

When FERC issued Tacoma Power a new licence in July, the agency ordered the city utility to draft a plan to release 240ft3 of water per second down the river channel.

Tacoma has objected to the order, saying that such releases would cost it US$2.5M a year and may render the project uneconomical.