Design Criteria for Irrigation Canals - Sediment Transport in Irrigation Canals: A New Approach - page 58

Downstream control

Set point

Top bank

1

Gate

2
3

Gate

Water level

Bottom level

Upstream control

Top bank

3

Set point

2

Gate

1

Water level

Gate

Bottom level

Figure 4.1. Example of a canal
with upstream control and a
canal with downstream control.

1 Q = 0
2 0 < Q < Q design
3 Q = Q design

- Cost : the final result of the design of earthen and lined canals will
include the horizontal and vertical canal alignment and the cross sec-
tions of the canal. Moreover, the canal design should give the best
performance at minimum cost, meaning that the final design should
result in a balanced earthwork (including cut and fill) as far as possible.

4.2 FLOW CONTROL SYSTEMS

An irrigation system can be operated in different modes to supply the
required water to the irrigation fields. Three parameters can be manip-
ulated to adjust the supply of water; namely the amount, duration and
frequency of the supply. The most complex case from a hydraulic and sed-
iment transport perspective is when all three parameters can be changed.
Irrigation canal operations can be broadly divided into:
- continuous flow . The situation is a simple one, in which all the canals
are opened simultaneously. The available water is proportionally
distributed over the whole area;