Take note that in part of the article they mention they are moving salmon to colder waters. Why are they doing that? The issue there is the river is running shallow due to the dams, the shallow depth allows the river water to be warmed beyond a point habitable for salmon runs.

You can see pictures of what these elevated river temperatures do here: https://english.alarabiya.net/News/world/2021/08/02/Scorchin...

Why is water depth so important? It's pretty well known how hot concrete can get when sitting in exposed California sun. If you have a water depth of a foot - that water is going to get really toasty.

There's quite a few resources regarding water temperatures and the effect it's having on salmon runs:

- https://www.kiro7.com/news/salmon-threatened-hot-temperature...

- https://www.ucsrb.org/low-water-high-temperatures-drastic-ef...