US-based Avista Corp, formerly known as Washington Water Power, and the Nez Perce tribe have announced an agreement resolving the litigation between the parties on tribal claims for damages relating to anadromous fish losses on the Clearwater river.

In a lawsuit filed in 1991 against Avista Corp, the Nez Perce tribe alleged that anadromous fish runs in locations where the tribe has treaty fishing rights were destroyed or diminished by the maintenance and operation of the Lewiston and Grangeville dams. The tribe sought damages for these losses.

The agreement concludes eight years of litigation by the two parties. Avista will pay the tribe US$2.5M, followed by 44 annual payments of US$835,498. This resolves not only the lawsuit but also settles issues concerning utility taxes, tribal employment rights fees and rights-of-way.

The Grangeville dam was constructed in 1903 by Grangeville Electric Power and Light Company. Avista acquired the dam in 1937 and operated it until it was demolished in 1963. The Inland Power and Light Company constructed the Lewiston dam in 1927. Avista bought this dam ten years later and operated it until it was destroyed in 1973.

The Nez Perce tribe is a federally recognised Indian tribe that originally occupied over 13.5M acres of land including parts of Idaho, Oregan and Washington.