Can a Fish Climb a Ladder?

Can a fish climb a ladder? No, it’s not a bad riddle and the answer is yes — if it’s a fish ladder. Fish ladders are specially designed devices that allow fish to get around dams, and they’re an important environmental feature for many hydropower plants

A hydropower plant has to include a dam, which poses a major obstacle to migrating fish. Unless fish passage* is included in the dam design, the river system is drastically changed. When fish can’t move freely up and down rivers to spawn, fish species are drastically impacted.

Some of the country’s most important hydropower dams are found on the Columbia River, home to many economically and ecologically important fish like Pacific Salmon, steelhead, lampreys, and American Shad. Knowing how important fish were to this river and to the region, the U.S. Army Corps of Engineers (USACE) designed the dams with two completely different ways to move the fish around the obstacle presented by the dam.

* Fish passage includes devices like fish ladders or special locks.