A draft version of the environmental impact statement about juvenile salmon migration on the Lower Snake river has been released by the US Army Corps of Engineers (USACE). But it still does not answer the central question — will dam breaching recover northwest salmon? ‘In a word — it is unclear,’ says Corps spokesman, Greg Graham. Tom Flint of the Save Our Dams Campaign says: ‘If there is one thing we should have learned by now, it is not to expect what we expect. We expected the USACE to release a preferred alternative and they did not.’

The study which began in June 1995, is a response to the National Marine Fisheries Service (NMFS) 1995 Biological Opinion, and has cost US$20M. It aims to address the migration of juvenile fish through the Lower Snake river, and focuses on the effect of the four Lower Snake dams. The four dams are recognised in the study because they are part of the fish migratory corridor.

Owned by the USACE, the dams (Ice Harbor, Lower Monumental, Little Goose and Lower Granite) are all run-of-river, multi-purpose facilities that provide navigation, hydro power, irrigation, recreation and fish and wildlife benefits. The dams, built in the 1960s and early 1970s, had been designed with features to aid both juvenile and adult fish migration but the Columbia Basin salmon and steelhead populations have continued to decline.

The study explores four alternatives for improving salmon migration through the dams within a 140 mile stretch of the Lower Snake river. These are:

•Existing conditions (currently planned fish programmes).

•Maximising transportation of juvenile salmon.

•Major system improvements, focusing on surface bypass collection facilities in conjunction with submersible bar screens and behavioural guidance systems.

•Dam breaching.

The draft includes the best available information on the biological, economic and environmental effects associated with the four specific alternatives. It does not, however, include a recommendation or identify a preferred alternative.

The cumulative risk initiative extinction analysis suggests that dam breaching is likely to be sufficient for recovery of fall chinook and steelhead only if survival rates below Bonneville dam, as a result of this action, increase by at least 20%.

Dam breaching may still be inadequate by itself to reduce the risk of extinction of spring/summer chinook stocks to what NMFS proposes as suitable levels.

There is much uncertainty in predicting future adult passage conditions with dam breaching. The movement of sediment may reduce the quality of spawning habitats in the Lower Snake river for many years following dam removal and reduced river depths would concentrate any contaminants in the river. Water temperatures would also be higher — factors which could cause more harm than good.

Dam breaching will also have major impacts on irrigation, water supplies and power generation. There would be a 3033MW loss of hydro power generation leading to an increase in electricity rates of US$1.20-6.50 per month. A loss of navigational capacity would also lead to higher transportation costs. Other net economic costs of dam breaching would total US$246M annually. The loss of navigation, irrigation, hydro power and cost of implementing drawdowns could amount to US$359M per year.

A report in The Oregonian claims that USACE wants to keep the four Lower Snake river dams in place and find other ways to help salmon. Brigadier General Carl Strock said that the Corps would only recommend breaching if no other measures were found to save threatened and endangered Snake river salmon and steelhead. He said that his agency would first explore modifying the dams and other approaches in an effort to avoid breaching, adding: ‘we are hopeful that we’ll be able to do that.’

The draft will give the public and other agencies an opportunity to review and understand the information, and provide input before a preferred alternative is selected. Following its release on 17 December 1999, the draft has been distributed for a 90-day public review until 31 March 2000.

Comments will be addressed in the final feasibility report which will identify and recommend a plan of action, but as yet a date for this has not been decided.