Weirs are a pain.

First I think it's more prudent to follow up on Stlhdr1's suggestion and verify how many wild fish there are, as differentiated from unmarked hatchery fish, and then attempt to determine whether any wild fish are actually being harmed by hatchery fish on natural spawning grounds. Might be able to avoid building a lot of weirs, depending on the outcome of that investigation. Don't get me wrong, I think separating hatchery and wild fish is worthwhile. I just want to make sure that an action taken actually contributes to its intended result.