44
CHIAO-MIN HSIEH
in only two months. Human factors were (1) failure to provide vegetation cover, and (2) inadequate building of levees or dikes. Successive Chinese governments of different dynasties have considered plans for controlling the river but the only technique used was the building of dikes. There are about 1,200 miles of dikes.
Now with the slogan of "Turning China's sorrow into China's joy", the communist regime, using modern techniques for building dams, has set up a comprehensive plan. The plan calls for the building of 46 dams. These dams have the multiple functions of flood prevention, irrigation, power generation, and navigation. During the first phase of the plan, two huge dams will be built; one in Sanmen gorge and the other in Linkia gorge. The Sanmen Gorge is 297 feet high and has a total electricity of 1,100,000 kilowatts—less than the Knibyshev or the Valgagrad power stations in the Soviet, or the Grand Conlee or the Boulder dam in the U.S.A., but more than Beauharmois station in Canada or the Bhakra in India. While the "staircase" plan is being carried out, it will be necessary at the same time to undertake extensive water and soil conservation in loess region, especially for the Sammen Gorge scheme. If soil erosion is not checked, the reservoir will be filled with silt in about 25 years and the whole effect of the dam will be lost. The intention is to make the water conservation and soil conservation work so effective that the reservoir will be good for 70 to 100 years.
The second water control project is the diversion of water from the Yangtze to the Yellow River, which was included in the second Five-year plan, from 1958 to 1962.
The water problem in China is due not to the total amount of water available, but to the lack of balance in the supply. This lack of balance is of two kinds. One is the uneven seasonal distribution of rainfall. For example, in northern China the rainfall is concentrated in July, August, and September. Hence in Spring droughts occur, and in Autumn floods. The solution to this kind of problem is to build reservoirs. The other problem is the lack of balance in water supply between regions. For example, the northwestern part of China includes 51 percent of the cultivated land of the country, but accounts for only 7 per cent of the surface flow; whereas south-eastern China includes only 33 per cent of the cultivated land, but accounts for 76 per cent of the surface flow. In order to balance the water supply between the northwest and southeast part of China,