Correct Answer - Option 4 : All of these
The laying of the impervious layer which protects the bed and sides of the canal is called canal lining. The lining of the canal is necessary for the following reasons:
(a) to minimise the seepage losses through the bed and sides of the canal.
(b) to prevent scouring and erosion of bed and sides of the canal due to the high velocity of flood water at the time of heavy rainfall.
(c) increase the discharge in the canal section by increasing the velocity.
(d) to prevent the growth of weeds along the bed and sides of the canal.
(e) to increase the command area.