Environmental Engineering Reference
In-Depth Information
factors, such as the water availability, management of the water supply,
scheduling of water delivery, control of water levels and discharges, water
measurement, qualification of the operation personal, institutional limi-
tations, field water requirements, water rights, evaluation and monitoring
and maintenance activities. This large range of the numerous options and
constraints makes it difficult to develop a general selection procedure for
the most effective operation (Walker, 1993). Formulation of an operation
plan for a specific irrigation system requires the evaluation of several sce-
narios in view of the reliability of the water delivery. One of the aspects
related to the reliability is the risk of sediment deposition in the canal
system. The simulation of several operation scenarios will support the
evaluation of various effects of the operation on the sediment deposition
in a canal network. In order to present a first assessment of these effects
a canal network will be schematized and the main data will include the
irrigation requirements, the geometrical and hydraulic data and incoming
sediment characteristics.
The network consists of a 16-km long main canal that delivers water to
a command area of 10 000 ha by 6 offtakes along and at the downstream
end of the canal. The canal has six reaches, namely AB, BC, CD, DE,
EF and FG. The first offtake at the downstream end of AB delivers water
to a command area of 1 800 ha that is 3 km from the head of the main
canal. The second offtake conveys water to a command area of 1 600 ha
and is 6 km downstream of the headworks. The third reach, CD, conveys
water to the offtake 3 that irrigates an area of 1 500 ha and is 10 km from
the headworks. The offtake at 12 km from the headworks will irrigate
1 600 ha. At the end of the canal is a water level regulator where the
water is conveyed to two areas, 1 800 and 1 700 ha in size respectively. All
the offtakes are located upstream of water level regulators. Figure 7.20
shows the schematization of the network and the longitudinal profile of the
main canal.
54
52
A
B
50
C
48
D
46
E
44
F
42
40
0
2000
4000
6000
8000
10000
12000
14000
16000
Distance (m)
Figure 7.20. Longitudinal
profile of the main canal
ABCDEF.
Water level
Bottom
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