Yet another hazard to migratory salmon will disappear soon, when local, state, and federal officials finish building a permanent, fish-friendly weir in the Yolo Bypass.The Wallace Weir Fish Rescue project, located four miles northwest of Woodland and near Knights Landing, will help prevent adult Sacramento River salmon from swimming into a drainage ditch that leads deep into farm fields where spawning is hopeless. By building a permanent barrier across the Knights Landing Ridge Cut, the agencies will be able to better control farm drainage releases to avoid attracting salmon.