Under-Sluices or Scouring Sluices
The under-Sluices are the openings which are fully controlled by gates, provided in weir wall with their crest at a low level. They are located on the same side as the off-taking canal.
Under sluices are also called scouring sluices because they help in removing the silt near the head regulators.
Functions of Under-Sluices
i)Preserve a clear and defined river channel approaching the regulator.
ii)Control the silt entry into the canal
iii)Pass the low floods without dropping the shutter of the main weir.
iv)Provide greater water-way for floods, thus lowering the flood level.
v)They scour the silt deposited on the river bed above the approach channel.
Design consideration of Under-Sluices