Corps contractors monitor screw traps downstream of Big Cliff Dam, May 28, 2021. The water flow turns a large screw creating hydraulics, which keeps small fish from escaping the trap. These traps are collecting juvenile salmon after they pass through Lookout Point, Cougar and Big Cliff dams. We’ve changed operations at these dams to help with downstream fish passage – or that’s the goal. These traps will give us insight into how well we’re doing.