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 baffle
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.
LOG CHUTE
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.
