And a correct conclusion by the tribe, in my opinion.

The upper Chehalis spring chinook are the result of long-term historic annual temporal isolation resulting from naturally occurring summer low flow and thermal barriers in the mid-river reaches during the mid-summer low discharge periods. They ascend the Chehalis early each year before those low flow and high temperature conditions restrict chinook access to the headwaters until later in the year when rainfall and lower temperatures eliminate the mid-basin migration obstacles for fall chinook run timing. The early spring chinook were historically abundant- and still occur- above Pe Ell in the canyons below Fisk Falls and and in other upper chehalis headwater streams including Stillman Creek, S Fk Chehalis, and Newaukum drainages. Currently, the importance of those upper watersheds and the mid-summer chinook migration separation has been under-appreciated in the dam discussions. The dam has a high potential to disrupt this natural separation of chinook timing. This I know from my 40 years as a professional fish biologist very familiar with the Chehalis watershed.

Good decision by the Quinaults.