Because new hatcheries are steel and concrete ( mostly ) and cost a lot to build. What was considered a good location for a facility 50 years ago is not necessarily a good location today. Hatcheries are sited around water quality and quantity, harvesters, and politicians desires. A good example is the Skookumchuck and Satsop Springs facilities in he Chehalis. Both were part of the Governor Evans state wide package to expand harvest opportunity. Once Gov Dan was out of office WDF shut the Springs down and went to raising Coho for the South Sound net pens at Skookumchuck.

You really have to know the history in any given area of the state to have any idea on how and why things are what they are now.

Not only were many facilities poorly sited in a location/harvest/wild fish sort of way but many were built poorly, especially water intakes. Maintenance was difficult, disruptive to the water supply (stream). Like other construction, there is no good reason to put a hatchery in the floodplain except to "save money" during construction.

Salman,

Your point is exactly right on and why we need to build the Deschutes hatchery in Tumwater. No "Wild" fish present -wdfw killed the naturally adapted Chinook run. All fish out of this hatchery would disperse throughout Puget Sound and beyond. Could be built with best hatchery practices.