Dams and Landslides

Chapter 23

(May 31, 1994)


by Lu Qinkan

Opinions differ both at home and abroad over whether to construct the Three Gorges project. The main points of view in support of and in opposition to the project will now be summarized.

I. Construction

Pro: The location and environment of the dam site are very favorable. The project will help solve, in an efficient manner, the problems of flood control, electricity generation, and navigation. Therefore, this grand project should be carried out as soon as possible so that the dream of “A Smooth Lake Over the High Gorges” can be realized in our generation. Some have even vowed that they will not rest until they see the completion of the project.

Con: The immediate start-up of the project is not advisable, considering the scale of certain problems, mainly: excessive investment requirements, a long construction period, extensive population relocation, sedimentation that will hinder navigation, increased chances of flooding in the upper reaches and destruction of the natural environment. The priority at present should be given to work on the tributaries in order to meet the energy requirements for the second phase of the national economic plan, which is to double the gross national product by the end of this century. In other words, plans that can bring immediate results should be carried out first, such as flood-control projects in the plains, establishment of hydro-electric power stations on the tributaries, and dredging of the main waterways. Some in the Expert’s Group on Flood Control are totally opposed to the Three Gorges project, arguing that a disaster of unprecedented scale would result if the dam became a military target.

II. Flood Control

Pro: The Three Gorges project will play a key role in flood control at the lower and middle reaches of the Yangtze, and no alternatives exist that could have the same or nearly the same result. The dam will have a capacity for storage and flood diversion of 9.5 to 22 billion m3 for the areas around the middle reaches. If a flood as serious as the one in 1870 occurred, the Jingjiang River dikes might burst, and hundreds of thousands, even millions, of lives might be lost.

Con: All along the Yangtze River, there are sources of floods from both the upper reaches and the lower and middle reaches. The Three Gorges project can only control flooding from the Chuanjiang River2 in the upper reaches, but is helpless against floods coming from the Xiangjiang, Zishui, Yuanshui, Lishui, Hanjiang, and Ganjiang rivers and many other tributaries in the lower and middle reaches.

If a flood as serious as that which occurred in 1954 is to be avoided, 50 billion m3 of water will need to be diverted at the middle and lower reaches. Yet the dam will only work for the area above Chenglingji, which means there will still be 30 to 40 billion m3 of water left to be controlled.3 Wuhan is a key city to protect from floods. Yet the Three Gorges dam will neither lower Wuhan’s water level, nor divert water from the nearby areas, leaving it helpless in the face of flooding from Jiangxi and Anhui provinces in the lower reaches. Therefore, the flood-control ability of the project is very limited.

The weak Jingjiang River dikes did stand up to the big flood in 1870, which had flowed southward towards Songzikou and then into Dongting Lake.4 This was quite a rare case. Today, Songzikou has its own diversion channels and the Jingjiang River dikes have been strengthened, greatly reducing the possibility of an incident resulting in the death of millions. So, using the flood protection argument to hasten the project is a bit far-fetched. Moreover, the flood level in Chongqing in 1870 was 4.7 meters higher than that of the serious flood in Sichuan in 1981.5 If the Three Gorges reservoir is used to store flood waters along with increased sedimentation, this will raise the water level at Chongqing and consequently increase the chances of a flood in Sichuan province. Since there is a chance of a big flood along the Yangtze River occurring every five or 10 years, there is now an urgent need to strengthen and heighten the river bank, to set up more safety facilities in the risky areas, to continue with the construction of reservoirs on the tributaries, and do more work on water and soil conservation, so that the flood-control capacity of the Yangtze River can be gradually increased.

III. Electrical Power

Pro: Most of the waterpower resources along the Yangtze are concentrated in the southwest. But they are quite scarce in the east where there are also limited coal resources. The location of the dam will make it an important source of electrical power to the areas of central and eastern China. Based on a normal pool level of 175 meters, the dam would generate 17,680 MW with the annual production of 84 Twh of electric power. Thus, the dam can share some of the work of the thermal power plants, because hydro-electric power will replace 40 million tonnes of coal burned annually, reducing the pressure for the production and transportation of coal.6

Con: It will be 12 years before the Three Gorges project generates power and 20 years before it goes into full operation. Such a long delay can hardly help solve the immediate problems of serious energy shortage in nearby areas.7 At this time, priority should be given to building more water-power stations and thermal plants in the tributary areas, which have the advantages of being small in scale, requiring less construction time, and achieving faster economic results. But, if these small projects were canceled in favor of the Three Gorges project, the rate of development of the power industry in the near term would certainly be slowed, delaying the whole process of national economic development.

IV. Navigation

Pro: When the backwater of the reservoir reaches Chongqing, a series of rapids will be covered, thus making it possible to control the slope of the descent and speed of the water. This will make it possible to sail 10,000-tonne ships rather than the current 3,000-tonne vessels. As a result, the carrying capacity and transportation efficiency will be increased and shipping costs reduced. In this way, the demand for 50 million tonnes of freight per year in the upper reaches can be met. At the same time, the water level during the low-water season will be increased by reservoir regulation, thus improving navigability from Yichang downstream.

Con: The Three Gorges reservoir will be located below Wanxian County, making it a perpetual backwater area where navigation will certainly be improved. But, in the area near the end of the reservoir, things could be very difficult. When the backwater level is lowered, the natural river channels will be exposed with their huge sediment deposits that could block navigation. When the clean water from the reservoir washes down the river bed, the water level at Yichang may be lowered, in which case the water level in the locks of the Gezhouba dam will also be lowered, thereby hindering navigation. Improving navigation in the Chuanjiang River area can be better achieved by dredging the waterways in stages, which would increase the annual transport capacity from the present five million tonnes to 18 million tonnes by the year 2000 and 30 million tonnes by 2015. All this needs much less investment than installing shiplocks at the Three Gorges. Only when the waterways of both the tributaries and the mainstream are dredged can an overall network of water transportation be established.

V. The Control of Sedimentation

Pro: There is less sediment in the Yangtze than in the Yellow River. In spite of serious soil erosion due first to deforestation and then to wasteland reclamation on the slopes in the upper reaches, there has been little change in the deposition of sediment in the river.8 During the high-water season, the water level at the dam will be lowered to the level required for flood control. When this season is passed, muddy water will be replaced with clean water. This method can clear away most of the sediment. After 100 years, the sediment will be washed away and a balance restored in such a way that the capacity of the reservoir can be kept at between 86 and 92 percent.

Of course, according to models of the backwater area at the end of the reservoir, sedimentation may indeed become serious in the main trough at Chongqing. Sand may pile up, blocking the mouth of the Jialing River, and the flood level in Chongqing will greatly increase. But the sedimentation problem can be solved by improving the regulation system in the reservoir, modifying port facilities, and dredging the river.

Con: The Yangtze River ranks fourth behind the Yellow, Brahmaputra, and Ganges rivers in terms of sedimentation. In recent years, especially in 1981 and 1984, the annual water volume was about average, but sediment deposition was 70 percent and 30 percent higher respectively, and the amount of sediment deposited by the river continues to increase. This problem will become more serious unless water and soil conservation measures are strengthened and soil erosion controlled. Since flood control is the major purpose of the dam, its reservoir water level must be raised when necessary and at the same time, the sand flow must be held back. Sedimentation at the end of the reservoir will inevitably increase and ultimately endanger navigation.

So far, there is no satisfactory solution to the sedimentation problem. Moreover, the relatively clean water from the reservoir will cause erosion of the embankments at the area below Yichang, which might endanger the Jingjiang River dikes. After the wash-down sediment is deposited in the river section between Chenglingji and Wuhan, it will harm flood control in the areas around Dongting Lake and Wuhan.9

VI. Population Relocation

According to the plan, the normal pool level in the reservoir would be 175 meters, below which, according to the 1985 census, there is a population of 725,500. When national population growth and the resettlement of entire cities, towns, and factories, are taken into account, the number of people involved could reach 1.13 million by 2008. The rising water level caused by sedimentation might bring the figure to 1.3 million.

Pro: If a spirit of self-reliance and hard work is encouraged, plus compensation of Y11.1 billion, the population relocation can be completed in 20 years. After the reservoir starts generating power, revenue retained at the rate of Y0.003 per kWh produced should be used to pay for population relocation and for construction around the reservoir area. The counties and towns in the area concerned have shown their willingness to be relocated. And they are anxious for an early decision, so they can start developing a new economy in a relocated area and achieve prosperity in the near future.

Con: Massive population relocation like this is rare both at home and abroad. Outside China, the biggest resettlement of this kind involved only 100,000 people, and some projects have had to be abandoned because the population involved was too large.

China’s largest resettlement project took place during construction of the reservoirs at the Sanmenxia Gorge, the Xin’anjiang River and the mouth of the Danjiang River. Each case involves more than 300,000 people.

The land around the future Three Gorges reservoir is already overworked and its food production is insufficient. To bring more than one million additional people into the area exceeds the environmental capacity of the land. At present, those who have been promised compensation for migration will be happy, and there are even others outside the reservoir area who are eager to be included, just to get “extra” compensation. But things might become quite different when relocation actually takes place. If the compensation falls short of expectations, social and even political problems could arise.

VII. Environmental Protection

Pro: According to the 175-meter normal pool level, the storage capacity of the reservoir is 3.93 billion m3, with a flood-control storage capacity of 22.15 billion m3. Compared with the volume of water flowing in the Yangtze River (453 billion m3 annually at Yichang), the storage capacity of the reservoir is relatively small. Shaped like the gorges, the reservoir will not seriously endanger the local climate, water quality, and temperature. The power produced by the reservoir is a clean energy resource, and will reduce the pollution now caused by the burning of coal. The Three Gorges will become a more attractive scenic spot after the reservoir is completed. Historical relics in danger of being submerged can always be moved to other places. In order to maintain the environmental balance and reduce the damage caused by the submergence of land resulting from the reservoir construction, a more satisfactory plan can be worked out to better facilitate the relocation and reestablishment of cities.

Con: The project will seriously endanger the environment and natural resources of the gorges; for example, the land submerged by the dam and reservoir construction cannot be recovered. Following the 175-meter proposal, the project will submerge up to 357,000 mu of arable land and 74,000 mu of orange groves, which make up the richest land in the area. In the 19 counties involved, hilly areas constitute 96 percent of the land while plains account for only 4 percent. After these relatively flat arable areas are submerged, resettlement will have to be in the hills, where the vegetation will inevitably be destroyed and the soil stripped. Furthermore, a large number of relics below the 180-meter mark will be damaged and the natural beauty of the area ruined.

Along the banks of the reservoir area are 214 hidden landslides, which will become active after being soaked by the reservoir. Being more than 100 meters deep, the reservoir could also cause earthquakes. If landslides and earthquakes induce one another, the entire project will be threatened. If the dam is subject to attack, the biggest flood in the history of the Yangtze River would likely occur. Such a disaster could be catastrophic for the lower reaches.

VIII. Technology

Some important technological problems are beyond present domestic and international standards. Consider the following figures:


3 Gorges Probe

Domestic Standards

International Standards

Capacity of hydro-electric generating set /Diameter of rotor wheel in water turbine

680 MW/9.5 m

320 MW/6.0 m

700 MW/9.223 m

Multi-level shiplocks /Width x length

5 levels /34×280 m

2 levels /8×56 m

4 levels /18×100 m

Total lifting height

113 m

43 m

67 m

Level one largest water head

49.5 m

27 m

34.5 m

Total weight of vertical ship lifting

11,500 tonnes

450 tonnes

8,800 tonnes

Lifting height

113 m

50 m

73 m

Length of cofferdam at the upper reaches /Height/water depth

1,070 /84 / 60 m

895 / 50 / 18 m

580 / 90 / 40 m

Fill/largest volume per month

6.33 million / 1.5 million m3

2.74 million / 1.03 million m3

5.75 million / 1.5 million m3

Annual concrete depositing strength

4.1 million m3

2.03 million m3

3.03 million m3

Pro: These technical difficulties can be overcome with Chinese experience and imported technology.
Con: It might be difficult to overcome some of these unprecedented technical difficulties.

IX. Scale of Construction10

The height of the dam and the water level (above sea level) are the major factors to be considered in determining the construction load of the project, the storage capacity of the reservoir, and the installed capacity. This has always been a controversial issue. Needless to say, the higher the level for normal storage conditions, the more efficient the reservoir will be for flood control, power generation, and navigation; at the same time, losses caused by submerging land, relocating so many people and damaging the environment will increase proportionally. As a result, investment will be larger and the construction period longer.

In the early days, Dr. Sun Yat-sen and Yun Zhen put forward proposals to build locks and small-scale cascade projects at the Three Gorges. In the 1940s, J. L. Savage, an American, suggested a hydro-electric station with a normal pool level of more than 200 meters. In the 1950s, the Yangtze Valley Planning Office proposed a project with a 235-meter water level. In 1958, at the Chengdu conference, the Party Central Committee decided that the future dam should not be higher than 200 meters.11 In the 1980s, the proposed water level was lowered to 150 meters. But recently, it was raised to 175 meters by the leading group’s assessment.

The arguments about water level continue. A 160 meter proposal was suggested by some senior hydro-electric experts, as well as by the Canadian feasibility study of the project.12 Others proposed a double project, that is to build a low dam near Peiling in addition to a high one at the Three Gorges, so as to make full use of the resources, and to help navigation around the Chongqing area. Some navigation departments and the Chongqing Municipal Bureau hope that the level can be raised to 180 meters, so that a fleet of large-capacity freight vessels could have a better chance of directly reaching Chongqing. There are still others who favor a level of 200 meters, or even higher, arguing that flood waters and the water level during the low-water season could be better regulated, or that water could be diverted from the reservoir to flow northward.

X. Investment Plans

The investment estimates vary, depending on when the calculations are made and on the scale of construction and the interest rate during the construction period. Based on a 175-meter normal pool level plan, proposed by the Ministry of Water Resources and Electric Power, and on the basis of the price index at the end of 1986, it was estimated that the key construction would cost Y18.5 billion, population relocation would cost Y11.1 billion, and long-distance power transmission would cost Y6.3 billion, totaling Y36 billion. This represents static investment only and does not include interest costs.

Pro: Apart from state-allocated funds, investment funds can be raised in various ways, including: 1) raising foreign capital funds by issuing state bonds abroad; 2) issuing domestic construction bonds; 3) switching from oil to coal and selling the oil to foreign countries; 4) delaying the repayment of loans and credits for the construction of the Gezhouba dam, and using profits generated by the dam; 5) using income from the partially completed Three Gorges power plant.13

Con: Considering that static investment is Y36 billion, the Three Gorges project will be an extraordinarily large program for our national capital construction. Because of the long construction period, interest on the funds should be taken into account. In the next few years, large amounts of capital funds will be needed to develop energy resources, transportation, and raw materials, as well as to conduct research in education and technology.14 It will be extremely difficult for the state to meet these huge financial demands, and, at the same time, provide funds for the Three Gorges project. Once the project is started, many other development programs will have to be sacrificed.

The interest rates for overseas bonds are very high. How can foreign currency be duly returned? Is it really workable to expect the Gezhouba dam and the Three Gorges dam to turn their income into construction funds without repaying their loans and interest? All these problems, and many more, still remain unanswered. Under such circumstances, the implementation of the project should be carefully considered.

Sources and Further Commentary

1 This essay was included in the original Chinese edition of Yangtze! Yangtze!

2 This section of the Yangtze, stretching from Yibin to Yichang, is 1,030 kilometers in length.

3 Because the maximum storage and flood diversion capacity of the Three Gorges dam is only 22 billion m3.

4 “The peak flood level recorded in 1870 was 27.36 meters. It was 2.37 meters lower than the peak flood level of 1954. The total volume of flood flow for a four-month period was far less than in 1954.” See Luk and Whitney, Megaproject, pp. 223-224.

5 Although the water levels in the 1981 flood were higher than those in the 1870 flood, the 1870 event flooded Chongqing whereas the 1981 event did not. This is because the 1981 event was caused by flooding in the tributaries downstream of the proposed dam site whereas the 1870 event was caused by upstream flooding of the Yangtze River mainstream.

6 In all likelihood, the vast majority of China’s coal-fired power is uneconomic due to the inefficiency of coal mining and of coal-fired generation. In liberalized electricity markets, the generation form of choice is high efficiency gas technologies, or cogeneration based on fossil fuels. Cogeneration has an efficiency two to three times that of a conventional coal-fired station.

7 It is estimated that “at the 1982 per capita electricity consumption level of 325 kWh, population growth would absorb the entire output of Three Gorges in 16 years-only one year longer than the projected 15-year-construction period for the dam. This assumes [the continuation of] the current low living standards; the time needed for the power consumption rate from new additions to China’s population to absorb the 57.2 X 109 kWh annual output expected from the 13,000 MW installed capacity generating plant would be even less if living standards were to improve.” See Philip M. Fearnside, “China’s Three Gorges Dam: ‘Fatal’ Project or Step Toward Modernization?,” World Development, Vol. 16, No. 5 (1988), p. 626.

8 In contrast to this optimistic conclusion, data cited by He Bochuan suggests that sedimentation has increased dramatically in the Yangtze over the last several decades. See He, China on the Edge, p. 3

9 For an analysis of sedimentation problems in the Three Gorges project, see Qian Ning et al., “Some Aspects of the Sedimentation at the Three Gorges Project,” in Megaproject, eds. Luk and Whitney, pp. 121-160.

10 The material in this section was not presented in a “pro” and “con” format.

11 For a review of various decisions on the Three Gorges project from its inception until the late 1980s, see Hong Qingyu, “A review of the Work during the Early Stages of the Three Gorges Project,” in Megaproject, eds. Luk and Whitney, pp. 40-63.

12 The $14 million feasibility study was conducted by a Canadian consortium in 1988. For a complete evaluation of that study, see Barber and Ryder, eds., Damming.

13 Electricity can be generated before the entire project is completed.

14 Growing deficiencies in investment in education and other social infrastructure are analyzed in He, China on the Edge, pp. 157-74.

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