There is a mitagation agreement of 300,000 Coho to be released in the Chehalis above the Shookumchuck. If I recall correctly 100,000 go into Eight Creek off Elk Creek off the upper Chehalis & the balance to the Onalaska school for release into Carliyle Lake that dumps into the Newaukum.
Close but no cigar. The mitigation requires that the smolt be released above the Confederation of Chehalis Tribe reservation at Oakville. Short version is WDF&W did not comply & released the Skookumchuck Coho Mitigation at what is now Bingham Hatchery on the East Fork Satsop. In the 90's the guys in the upper basin figured it out all hell broke loose with Friends of the Chehalis leading the charge and were preparing to seek legal relief ( sue em ) when WDF&W Deputy Director Peck worked out the compromise on the three release sights outlined above.
If memory serves, the majority of salmon grown at the mitigation were (and maybe still are) brought back to Puget Sound instead of meeting the in-basin requirements.
CM is correct as there is a lot more to this issue that is not commonly known . The production CM references is not part of the mitigation but normal hatchery production and yes it goes to Puget Sound.