How do fish ladders work?



  1. 0 Votes

    Fish ladder is synonymous with fishway, fish pass, and fish steps.  Basically, these allow for fish to migrate around barriers.  This can be done through five methods:

    1.  Pool and weir:  uses a series of dams to create different water levels and current velocities.

    2.  Baffle fishway:  redirects water through a series of isolated channels and allowing fish to swim around barrier.  

    3.  Fish elevator: consists of an elevator and lifting fish to the other side of a barrier.

    4.  Rock-ramp fish way: uses rock and wood to create a natural series of pools and water falls for fish to swim up.

    5.  Vertical slot fish passage: similar to pool and weir, except fish do not have to hop up to the next pool.

  2. 0 Votes

    Fish ladders are like staircases that water flows down. They are used in conjunction with dams, usually letting water flow over or around them.

    When fish want to swin upstream, dams prove a serious obstacle for them. Fish ladders are designed so that fish can jum up from one “step” to the next, and overtake the dam in small increments.

  3. 0 Votes

    A fish ladder is basically any pathway that allows fish to pass through a dam, which means they can work a variety of ways depending on the flow of the river and the dam and the local species of fish.  Sometimes they’re designed to mimic the river itself, other times they are a system of pools and barriers designed to reduce the pressure of the flow.  As the article in the citations says, “There are five basic designs for fish ladders that are used throughout the world: pool-weir; vertical slot; Denil; steeppass; and natural bypasses or fishways.”  Check out the youtube link to see one in action!

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