Our Views: Chehalis River Dam — What About The Fish?


What exactly would be the impact on the Chehalis River Basin fishery from the flood retention facility proposed above Pe Ell? The recent National Environmental Protection Agency environmental impact study (EIS) found that the impact of the basinwide salmon and steelhead runs is essentially invisible.

That is because only a tiny portion of the salmon and steelhead spawning on the vast Chehalis Basin come all the way to the upper, upper Chehalis Basin mainstream above Pe Ell. Both the state and federal EIS found that impacts to the fishery below the dam site are almost immeasurably small. The only measured impacts on fish numbers are above the dam site. The most important and at risk salmon run in the Chehalis Basin is the spring Chinook. In 2018, the state fishery found that exactly one spring Chinook spawned above the dam site. 

The fact is that any impact on salmon habitat raises alarm bells among environmental and tribal interests. The history of dams and the harm done to the salmon stocks in the Northwest is clear. Anyone wishing to organize opposition and even to raise significant funding doesn’t have to do much more than to say “I oppose a new dam proposed on the Chehalis River.” 

So, how is it that this proposed project has gone so far as to receive EIS analysis from the state and federal governments with wide support from virtually all the local governments in the basin?

The reason is two parts. 

First, the Chehalis Basin strategy has two parts mandated by law — restoring aquatic species and addressing catastrophic flooding. Plans and actions to address both problems have gone forward together. The governor describes this as a “win-win” outcome. They will either continue going forward together or the process will stop. 

The second reason the process has gone this far is that the proposed facility above Pe Ell would not dam up the Chehalis River. The facility would only operate for a few weeks, a forecast average of once every seven years when a catastrophic storm hits the basin. The rest of the time, the gates at the bottom of the facility would remain open, without creating a reservoir and allowing fish to pass up or down unimpeded.

Both state and federal environmental reviews showed that the contribution above the proposed facility to the basinwide spawning salmon is between 0 and 2%. The proponent, the Lewis County Flood Zone District, believes that these impacts can be mitigated so that the facility will result in zero net loss of salmon habitat.

On the other side, the proposed basin-wide salmon recovery habitat recovery plan — the Aquatic Species Restoration Plan (ASRP) — forecasts to turn around the decline in salmon stocks. Several fisheries experts say this is the first basinwide aquatic species plan of its kind and could become a national model. 

The impact of the flood retention facility compared to the positive impact of the ASRP makes the worst-case impacts on the fishery from the facility barely a rounding error.


This is the first installment of a new series focusing on the proposed dam on the Chehalis River. Moving forward, the ongoing series will be published in the Saturday edition of The Chronicle.