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Repeating the Truth about Salmon and Dams

by Donovan Bramwell, candidate for U.S. Congress
A Position Paper - October 2000

Slade Gorton, U.S. senator from Washington State, has publicly declared that there is not enough scientific evidence to prove that breaching the four dams on the lower Snake River (in eastern Washington) will benefit the endangered salmon runs. The same old refrain. Propaganda. Repeat a lie often enough, and people will believe it.

As noted by one well-informed and astute participant in the debate, it's tobacco science. Remember? Spokesmen for the big, rich tobacco companies got on their soapboxes and said the same thing about smoking and cancer: "Nobody knows for certain that smoking causes cancer. Lot's of things besides smoking might be causing these people to die of lung cancer. There isn't any scientific proof that tobacco is the culprit." Yeah, right.

So here we are, hearing the same pitch from politicians and bureaucrats: "Nobody knows for certain that the dams are destroying Idaho's salmon runs. Lots of other factors are involved--predators, ocean conditions, urban and rural development, over fishing. There isn't any scientific proof that the dams are causing the problem."

Are these people serious, or are they just playing with words? Drawing delicate distinctions between proof and sufficient evidence? Drawing delicate distinctions between dams causing the problem and removing the dams to solve the problem? Or do they really believe that the dams are innocent? Are these people uninformed? Misinformed? Are they lying?

In 1998 the Idaho Department of Fish and Game (IDFG) published their conclusion that the best way to restore Idaho's salmon runs was to return the river to more natural flows by removing the earthen portions of the four lower Snake River dams. That conclusion was supported by plenty of proof that the dams are causing the decline. The main problem is that the slackwater behind the dams moves too slowly to carry the migrating juvenile salmon downstream to their destination in a short enough time.

There are eight dams on the waterway between Lewiston and Portland, four on the lower Snake River, and four on the lower Columbia. Three of the Columbia River dams were installed in 1937, 1954, and 1960, with the result of a modest decline in the salmon runs. However, the Snake River salmon runs were still reasonably healthy in the 1950s and early 1960s. The fourth Columbia dam, John Day, came on line in 1968. The four Snake River dams (Ice Harbor, Lower Monumental, Little Goose, and Lower Granite) came on line from 1962 to 1975. A drastic decline in the Snake River salmon runs corresponds with the installation of those dams.

The adjacent graph (developed from IDFG data) illustrates the severity of the decline. These are redd counts from a specific drainage, the Lemhi River. Redds are the nests that mated adult salmon build in the gravel, where they deposit and cover their eggs. A redd count is the number of such nests counted in the river at the end of the spawning season. The number of redds is a good indication of the health of a salmon run. These data from the Lemhi River serve here as an example of a natural salmon run (not supplemented by hatchery fish) in a developed valley in Idaho. The Lemhi River converges with the Salmon River at the city of Salmon. The Salmon River joins the Snake River upstream from Lewiston.

The dam's most detrimental effect is on the downstream migration of the juvenile fish, so there is a lag time of a few years between installation of a dam and the effect on the redd count (fewer juveniles survive the trip downstream, so fewer adults return a few years later). Then the effect compounds with succeeding generations. Other factors cause transitory highs and lows from year to year. These transitory fluctuations are superimposed upon the long-term decline caused by the dams.

The jagged solid line shows the actual counts from one year to the next. The stepwise dashed line shows averages for blocks of years roughly defined by the effects of the dams. The average Lemhi River redd count from 1957 to 1964 (as indicated by the dashed line) was 714. After Ice Harbor was installed in 1962, the average dropped to 500. When the fourth dam, Lower Granite, was finished, the average Lemhi River redd count dropped to 110. The average dropped to 34 in the following decade, probably a long-term cumulative effect.

Other wild and natural runs in the Salmon River drainage have fared about the same. Runs supported by large numbers of hatchery fish have fared only a little better.

The declines in the Lemhi River salmon runs are not caused by habitat/development problems in the upper watershed. The Lemhi Valley has been ranched, farmed, logged, mined, and diverted for irrigation since the 1890s, and the salmon runs were still healthy in the 1950s. The declines in the Lemhi River occurred despite significant improvements in habitat (modification of irrigation diversion dams, installation of screens on diversions, etc). The Lemhi River declines that occurred since 1964 almost exactly match the declines in Big Creek, an undeveloped wilderness tributary on the Middle Fork of the Salmon River (1998 IDFG report).

The declines in the Lemhi River salmon runs are not caused by harvesting or habitat problems on the Columbia River or in the ocean. While Lemhi River salmon runs declined after 1964, runs in the Yakima River in Washington and the John Day River in Oregon actually increased (1998 IDFG report and other IDFG sources). The difference? The Yakima and John Day Rivers converge with the Columbia downstream from the Snake River's confluence. Snake River salmon have to negotiate the four notorious dams on the lower Snake, in addition to the four dams on the lower Columbia. The Yakima salmon have only to negotiate the four dams on the Columbia, and the John Day salmon, only three of the four.

The four dams on the lower Snake River have caused the precipitous declines in the Snake River salmon runs. The slackwater behind the dams is the main problem. After decades of experience with it, we know that barging the juvenile fish through the slackwater does not work. Flow augmentation (attempting to flush the juveniles through the slackwater with water pulled from upstream storage) will not work. Any realistic salmon recovery effort that leaves the four dams in place will fail.

Washington Senator Slade Gorton has promised to block any proposal in Congress to breach the four dams, vowing that as long as he is a U.S. senator, no such proposal will pass. May his future career in the U.S. Senate be a brief one.

Related Links:
Donovan Bramwell Campaign Page

Donovan Bramwell, candidate for U.S. Congress
Repeating the Truth about Salmon and Dams
A Position Paper October 2000

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