I think it is just basically exempted each year. About 15 years ago WDFW was (for the umpteenth time) trying to find a site in deep South Sound to use as base for that production. The Deschutes hatchery, in Pioneer Park, was supposed to do this. It was also supposed to bring the Tumwater Falls Chinook production into Cleanwater Act compliance for hatchery discharges.

It is, i believe, simply easier to keep doing what has been done than it is to get the funding, get the permits, and so onto build a new facility of facilities that would meet current rules.

This worked well so long as the Chehalis basin folks kept quiet.