Water and water quality. A hatchery needs a clean, disease free supply that is cold enough too support the fish and in sufficient quantity. Form long experience in searching, there are few good sites left where decent water is available. And The Sammamish slough isn't one of them.

It is rather obvious that you cannot have a large hatchery program and a vibrant wild population on the same stream. IF we want huge hatchery runs of steelhead then we will need to write off specific rivers. Triage. One or the other.