HKDSE Geography/E2/Solutions to Droughts

Droughts can be resolved from two directions: Getting more water and wasting less.

Using Existing Rivers
Rivers can be better exploited by setting up dams and reservoirs. They store water collected at wet season to use during dry season. Examples include Liujiaxia, Longyangxia and Sanmenxia dams. Liujiaxia and Longyangxia are in the upper course and Sanmenxia in the middle.

Effectiveness

 * Tourist spots, historical heritage sites, cultivated land and settlements are drowned. Compensation is needed for relocation.
 * The pressure of reservoirs on rocks may trigger earthquakes.

Vertical Expansion: Wells
Wells can be dug under government supervision to tap underground water during droughts.

Effectiveness

 * Land subsidence may occur. Foundations of buildings are weakened.

Horizontal Expansion: South-to-North Water Diversion Project
The South-to-North Water Diversion Project diverts water from the South, which has a water surplus, to the North, which has a water deficit.

The plan has three branches
 * West route: From the source of the Jinsha Jiang to the upper course of the Huang He. It generates little water pollution and benefits the Go West policy.
 * Central route: From the Danjiangkou Reservoir in Han Shui to Beijing and Tianjin. It enhances flood control at the Chang Jiang and is reliable.
 * East Route: From the lower course of Chang Jiang near Yangzhou to Tianjin. It makes use of the existing Grand Canal, so cost is lower.

Effectiveness
It is harmful to Chang Jiang. Its water supply and discharge are reduced, leading to drought in the lower course, reduced river discharge to encourage silting, and a decrease in water supply for navigation and hydro-electric power.


 * West route: It runs through rugged relief, difficult terrain, harsh climate, etc. Altitude sickness is common.

Water Conservation
Industries, agriculturalists and households are encouraged to save water through education and legislation.

Sewage treatment is carried out and sewage charge is imposed.

Water-saving and dry farming techniques like drip irrigation, drought-resistant crops and so on.

Afforestation, grain-for-green, prohibiting agriculture on steep slopes, etc. reduce soil erosion and thus reduce silting in the Huang He.

Effectiveness
Water conservation education takes time. Industry and agriculture are discouraged and water charges increase financial burdens.