Correct option is C
The important terms related to the cross-section of an irrigation canal are:
Service road:
A service road is provided usually on the left bank of the channel. However, on large canals, it may be provided by both the banks.
Service road level should be 50 cm to 1 in above the F.S.L. depending upon the size of the canal.
1) Dowla
A Dowel or Dowla is provided on the side of a service road between the service road and channel.
The top of the dowel is kept above the FSL in the channel the Dowel is provided as a measure of safety for automobiles driven on the service road.
They act as kerbs on the side of the road way towards the canal
2) Counter berm
It is also known as a back berm.
It is provided on the outer slope of the banks.
It is required only in the case of high banks and very permeable soils.
Its main purpose is not to allow the seepage line expose on the outer slope of the bank.
3) Land Width
The width of the land, required to accommodate the canal cross-section is called the land width for the canal.
During the construction of the canal, some additional land is required for borrow pits and for stacking the materials. Such additional width of land is called temporary land width.
