Environmental Engineering Reference
In-Depth Information
T
able 1.4
Projection
of the development of irrigation areas in riv
e
r basins
High development
Low development
Basins
Irrigation area (million ha)
Irrigation area (million ha)
2010
2030
2050
2010
2030
2050
S
onghua-Liaohe
6.5
7.5
7.7
6.2
6.7
6.7
H
aihe
7.4
7.6
7.7
7.4
7.5
7.5
H
uaihe
10.4
10.7
10.8
10.5
10.6
10.7
Y
ellow
5.4
5.8
6.0
5.4
5.6
5.7
Y
angtze
15.1
15.6
15.8
15.0
15.3
15.2
P
earl
4.5
4.6
4.7
4.4
4.5
4.5
S
E Rivers
1.9
2.0
2.0
1.9
1.9
1.9
S
W Rivers
0.8
0.9
0.9
0.8
0.8
0.9
I
nland Rivers
4.7
4.9
4.9
4.3
4.6
4.6
T
he North
34.5
36.5
37.0
33.7
35.1
35.3
T
he South
22.4
23.1
23.4
22.1
22.5
22.5
Total average
56.9
59.5
60.4
55.8
57.6
57.8
Source: Ministry of Water Resources of China
River training and river uses have resulted in many rivers “dead”. For instance water diversion in the
middle and lower reaches of the Yellow River caused the river dried out in the period of 1972-1998.
Flow cut-offs have occurred in 19 years in the period 1972-1998. Another example is the pollution of the
Yongding River near Beijing since the construction of the Guanting Reservoir and numerous small
reservoirs in the upstream reaches. Figure 1.37 shows the Yanghe River, which is a tributary of the
Guanting Reservoir. Almost all fresh water is diverted for the irrigation and urban use and only sewage
and waste water discharged from urban areas and industries is flowing in the river. The water is so
seriously polluted that all fish and most of the macro-invertebrates have been extinct and only a few very
tolerant species of invertebrates can be found from the river.
Fig. 1.37
Seriously polluted water in the Yanghe River, which is a tributary of the Yongding River and flows into
the Guanting Reservoir
In river management, the decision makers often put the economic benefits before the ecological
protection. For instance, Shanghai has a problem of land shortage and has been reclaiming the wetland in
the East Chongming Shore in the Yangtze River estuary to ease the land shortage. Figure 1.38 shows the
agricultural development from the wetland in the East Chongming Shore in several phases (left) and the
Search WWH ::
Custom Search