Pacificorp and Cowlitz Public Utility District have reached a settlement on the relicensing of four dams on the Lewis river in southwest Washington state, US, in a move that will see as much as 280km of salmon and bull trout habitat reopened over the next 50 years.

Negotiations had been ongoing for five years between the owners of the dams and native American tribes, federal and state resources agencies, three counties and environmental groups. Pacificorp, which owns the Merwin, Yale and Swift no. 1 dams – that together generate 510MW – is investing US$290M and Cowlitz, which owns the 70MW Swift no. 2, are investing US$19M towards future improvements.

The settlement includes plans for fish passage systems that would transport fish around the dams while surface collectors guide juvenile fish for transport downstream. Hatchery fish would initially be used to kick-start the reintroducion programme. Over time, as naturally produced fish increase in numbers, hatchery supplementation would be tapered off.

Up to US$12M is to be spent protecting and enhancing wildlife habitats for a broad range of big game and other species in the Lewis river watershed. Recreation along the river is to receive a US$20M boost, with improvements planned for parks and day-use facilities. There will also be a focus on flood management, with PacifiCorp agreeing to pay US$25,000 for a new automated notification system for residents.

‘Each of the Lewis river settlement parties can be proud of this agreement,’ Washington Governor Gary Loke said in a statement issued by Pacificorp. ‘This will ensure long-term, substantial benefits for the natural resources of the Lewis river, while preserving a much needed source of electricity.’