Wanapum dam, part of the Priest Rapids hydro project in Washington, US is to be fitted with a new type of turbine which aims to increase generation capacity and to provide the facility with better fish passage.

Partly funded by a grant from the US department of energy (DOE) worth US$2.4M, Grant County Public Utility District, the licensee of the facility, is to spend the next eight years installing and testing a new six-bladed turbine runner and hub, which it is hoped will improve conditions for downstream migrating juvenile salmon and steelhead.

The plan will also see the plant’s total generating capacity increase from 900MW to 1038MW and has just been granted approval by the Federal Energy Regulatory Commission.

The new turbine was developed as part of the DOE’s Advanced Hydroturbine programme, which identified various features of the conventional Kaplan turbine affecting fish survival. As well as installing turbines with the new design at Wanapum, engineers will also carry out modifications to hydraulic shapes in the dam’s concrete structure, and improve the facility’s wicket gates and stay vanes.

Initial turbine replacement work is to be completed this year, with testing expected to follow next spring. If the trials prove to be a success, Wanapum dam’s remaining nine turbines will be replaced between 2006 and 2012.

The new plan was developed in consultation with the Washington Department of Ecology, Washington department of Fish and Wildlife, National Marine Fisheries Service, US Fish and Wildlife Service and the Columbia river Inter-Tribal Fish Commission.