Intake

 Intake 

           An Intake is a hydraulic structure that is located at the head-works for diverting desired amount of water to the canals or tunnels or pipes for power generation or any other required purposes. It is the structure containing an opening(orifice) or a pipe for pressure flow.The weir and the intake compose a unit structure which has to meet the following requirements.

1. Safe release of floods
2. Low-loss entrance of the power flow
3. Preventing bedload intrusion into the canal
4. Deflecting and flushing of bedload accumulated in front of the weir
5. Protecting the canal from floating debris and ice, if any, carried by the watercourse. 

The purposes of the intake structures are:

1. To prevent , or at least to reduce, the silting of the canal, in other words, to provide for protection                 against sedimentation in the canal bed.
2. To secure with small head losses the entrance of water to the power canal.
3.  To keep ice and other floating matter off the canal.

Major Appurtenances of the intake structures have the following functions:

a) Inlet sill protects against bed load at bottom.

b) The skimmer wall with splitter piersin the inlet section checks the passage of floating debris and                    sheet ice into the canal. Coarse rack withholds subsurface trash and frazik ice from the canal.

d) The settling basin followed after intake section collects silt carried into the canal.

e) Desilting (or flushing) canal serves the purposes of removing silt deposited in the settling basin at                 the  canal sill.

f) Desilting (or flushing) sluice is used for closing the silting canal.

g) Intake gate (or canal headgate) controls inflow into the canal.

Higher sill height reduce the quantity of water drawn into the canal and also diminish the bed load entering the canal.