Fish ladder


  • A fish ladder is a fish pass provide along the divider wall to enable migrating fishes to move from U/S to D/S and D/S to U/S direction, in different seasons.
  • Fish ladders are provide on all such works which hinder their movements.
  • The fish ladder is always locat along the divider wall as some water always remains here.
  • The fish ladder consists of a rectangular trough having a sloping floor joining water levels on D/S and U/S of the weir.
  • The difference in water level on the U/S and D/S sides of the weir is divide into several water steps with the help of a baffleLog chute


  • walls, constructed across the inclined floor.
  • The slope of the fish ladder should not be steeper than 1: 10 so that velocity of flow in it does not exceed 2 m/sec.
  • To exercise effective control on the flow through the fish ladder, grooved gates should be provided on U/S and D/S ends.
  • All the baffle walls are provided with adequate sized holes so that water and fishes can smoothly move through them.


  • It is an incline platform joining U/S and D/S waters.
  • It is provid to pass the wooden logs from U/S to D/S of the weir. Log chutes are locate on diversion
  • works of those rivers only which are being used to transport the timber from jungles.
  • Cut timber is float into the river, which carries them along with the flow.
  • Diversion works constructe across the river obstruct the flow of logs and as such to utilize
  • The transportation capacity of the river all the diversion works constructed across them are provid with log chutes.
  • All the floating logs are assemble at the mouth of the log chute.
  • When sufficient timber logs have accumulate, the gate of the log chute is opened and all the logs are floated to D/S side one by one.
  • In the case of log chute, some minimum depth of water on D /S side is very essential, as otherwise logs may hit the D/S floor and damage it. See Fig. 15.15.
  • Log chutes may also have sidewalls so that logs slipping over the inclined floor may not fall at the sides.


1 thought on “Fish ladder”

  1. You mentioned many reasons for the civil engineering. Yes! Civil Engineer has constructed scientifically and practically. Normally a project plan and drawing are decided how to start work in a project field but some time, as a Civil Site Engineer can change and remodify work and drawing and plan.

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