|Long Distance Water Transfer: A Chinese Case Study and International Experiences (UNU, 1983)|
International Food Policy Research Institute, Washington, DC
THE CHANG JIANG DIVERSION ROUTES AND RELATED ENVIRONMENTAL PROBLEMS
THE IDEA OF moving water from the Chang Jiang into the drought-stricken North China Plain or even more arid areas of the northwest has been a dream in China for some time. Areas south of the Chang Jiang constituting one-third of the total area under cultivation receive three-quarters of the total flow of surface water, whereas North China, with half of the nation's cultivated land, receives only 8 per cent (Kao, 1978). Annual precipitation varies in China's growing regions from over 2000 mm in the southeast to 200 mm in the northwest. The relative aridity of the north is exacerbated by the uneven precipitation, especially in Hebei, Beijing, Tianjin, Shandong and in the provinces of the northeast (Liaoning, Jilin and Heilongjiang).
Within the period of the People's Republic of China, studies of interbasin transfer began in 1952 and water conservancy departments reportedly drew up over a dozen diversion plans for consideration (Kao, 1978). The alternatives, which are not mutually exclusive, have tended to fall into three general groupings.
The western routes would bring water from the Jinsha Jiang and other upper Chang Jiang tributaries into the upper reaches of the Huang He basin, and specifically to the northwestern provinces and autonomous regions of Qinghai, Ningxia and Gansu. The Middle Route would divert Chang Jiang water from Danjiangkou Reservoir on the Han Jiang tributary through Henan and Hebei Provinces to Beijing. The East Route would draw water from the lower reaches of the Chang Jiang in Jiangsu Province and extend through Shandong Province to Tianjin.
The western routes have never been surveyed as intensively as the other routes. The terrain is exceedingly mountainous and any of the proposed plans involve numerous complex engineering projects which are expected to be costly in terms of time, financial expense and uncertainty. Extensive construction of high dams, mountain tunnels and elevated canals would be required. The target region is sparsely populated with, to large extent, herdsmen belonging to China's national minorities.
The East Route, which was surveyed extensively in 1978, would draw water from the vicinity of Yangzhou and Jiangdu in Jiangsu Province, along the Grand Canal and through a chain of lakes (Hongze, Gaoyou, Luama, etc.) to Lake Dongping and the Huang He. This would require the construction of 30 large pumping stations to lift the water by stages to the Huang He. The width of the Huang He near Lake Dongping is 280 metres and its high silt content would dictate the advisability of keeping the flows completely separate by constructing several tunnels under the river through which the diversion could pass. Beyond the Huang He, transferred water could flow by gravity. In utilizing the Grand Canal, an estimated 1,150 km would be excavated (Kao, 1978).
The plan for the East Route is to draw water from the Chang Jiang at a rate of 1,000 m³/sec for an annual maximum of 30 km³. The water would be utilized more or less in equal parts north and south of the Huang He over the provinces of Jiangsu, Anhui, Shandong, Hebei and the municipal district of Tianjin (Table 1), primarily for irrigating farmland, but also for alleviating industrial and municipal water shortages and quality problems along the route. A principal attraction is the relative speed with which basic engineering of the project could be accomplished.
The principal difficulties discussed in the context of the East Route are;
1) Limnological deterioration and general problems of water pollution along
the transfer route, especially in the system of shallow lakes in Jiangsu and
southern Shandong Provinces.
2) Impact on aquatic production including benefits from greater habitat availability in the north and cost in quantity and variety of economic fish inhabiting the existing aquatic areas, especially the Jiangsu Lake system and the lower Chang Jiang estuary.
3) The lowering of the Chang Jiang estuary and the possible subsequent increase in salt damage to waters and agricultural lands in the rich delta.
4) Flooding and salinization of soils along the transfer route and in areas to be irrigated by the project.
The Middle Route was the subject of extensive surveys in 1979 and seems to be gaining favour over the East Route. This route would require the construction of a 1,265 km canal to Beijing which would cross the Huang He west of Zhengzhou after passing 500 km along the foot of the Funiu Shan and through the Nanyang Basin in southern Henan. After crossing the Huang He, the northern section of the canal would flow parallel to the Beijing-Guangzhou rail line. The water, diverted from relatively high terrain, could flow by gravity, but the construction of the canal and numerous reservoirs would be expensive and time-consuming in comparison with the East Route which relies upon existing lakes and the Grand Canal. The scheme is proposed to irrigate 5 x 106 hectares, again divided evenly between areas south and north of the Huang He and which would bring an average 10 km³/year to the Hai He basin which covers large parts of Hebei, Henan and Shandong Provinces (Xinhua, 1979; Kao, 1978). This discharge would approximate the entire annual flow of the Hai He system.
One of the problems of the Middle Route will be the reduction in output of the Danjiangkou hydroelectric power station by some 700 to 1,700 x 106 kwh. The Gezhouba power station under construction three gorges further west is expected to make up for the loss (Xinhua, 1979). But electric power availability is one of the principal current bottlenecks across the Chinese economy (Stone, 1980a) although further exploitation of China's rich hydropower potential (1st in the world) and known coal reserves (3rd in the world) suggests that eventual alleviation of this constraint is not out of the question (Beijing Review, 1979c).
Table 1. Farm area to be affected by the water transfer projects: estimates of area which will come under irrigation and of currently irrigated area which will receive supplementary irrigation (thousands of hectares)
|Province or |
Area which will Receive
|Presently Unirrigated |
Area which will be
Irrigated by Project
|Total Area |
|Total Both Routes||3,107||6,340||9,447|
Source:Data provided by Liu Changrong, Senjor Engineer , Deputy Head of the planning Office of the Chang Jiang Basin and Deputy Head of the Office of Water Transfer from South to North; and by Chen Chunhai, Engineer, Planning Officer of Water Transfer from South to North and Ministry of Water Conservancy.
It seems clear that there will be a substantial risk of salinization with the Middle Route, although probably less severe than in the case of the East Route (Zhu, 1980; Zhu, Wang and Hseung, Chapter 28). Similarly, most of the water quality problems of the East Route must also be dealt with in the Middle Route, but may not reach critical levels as quickly. The head region of the Middle Route is certainly less developed economically than southern and central Jiangsu. The Grand Canal has fostered development and concentration of population along the East Route for centuries. The water in Danjiangkou is apt to be substantially cleaner than the East Route intake due to the presence of industrial, agricultural and municipal flocculated pollutants in the Yangzhou area. Finally the Middle Route has no vulnerable resource comparable to the shallow lake system of the East Route which will be jeopardized by the project. Nevertheless, the Middle Route crosses some 168 rivers, canals and streams and is designed to link relatively populous areas. The canal itself will no doubt foster rapid economic development all along its length.
The Middle Route presents the additional problem of population displacement. When Danjiangkou was constructed in the 1960s, several hundred thousand people living in the area had to relocate. A large proportion of them now live on the shores of the reservoir not far from their previous homes. In order to transfer water along the Middle Route, the height must be raised, displacing an additional 200,000 or so people. Resettlement will not only be difficult and costly for the refugees and the Chinese government, but may pose social and economic problems for the present inhabitants of the regions in which they will be resettled.
A number of other environmental problems are currently under research or have been proposed as subjects of investigation. These include the role East Route diversion may play in spreading schistosomiasis and fish diseases or in expanding the habitat of the malaria vector; the effect of reservoir expansion on seismic activity in the Danjiangkou area; and project-induced climatic changes in North China. It seems likely, however, that these considerations may prove less serious than the four general categories previously discussed.
Original studies for diversion of the Chang Jiang into North China began in the 1950s but were halted owing to a variety of difficulties with existing projects, including flooding and salinization on the North China Plain (Kao, 1978; Chi, 1965; Greer, 1979). The project was later selected as a major item in the ten year plan, 1976-85, for the development of the national economy (Kao, 1978) and was eventually included in the overall plan for China's Four Modernizations (FBIS, 1979a). The construction and basic costs of each project have been conservatively estimated at around 10 X 109 yuan, double the present proportion of the entire annual state capital construction budget devoted to agriculture (Stone, 1980a). In view of the immense initial costs and the substantial environmental risks and related costs and expenditures required, why is the project being reconsidered at this time?
THE NEED FOR SOUTHERN WATER AND THE ALTERNATIVES
The expansion of irrigated area is considered to be a fundamental requirement for growth in grain production on the North China Plain. The supply of water on a basis relatively independent of precipitation can make the adoption of high yielding seed varieties or the introduction of multiple cropping more profitable and can dramatically increase the effectiveness of fertilizer and pest control. The Plain has been a region of dynamic agricultural growth in the 1970s, and expansion of the area under irrigation there is seen as crucial to satisfying China's increasing demand for foodgrains over the next few decades as well.
Many of the known water resources of the Plain are already utilized intensively. Dependence on further Huang He diversion or sub-surface development presents difficulties and uncertainty. The attraction of transporting irrigation resources from the water-rich south is therefore compelling. But this decision first requires the analysis of a number of constituent propositions. What are the contours of future Chinese food demand growth and the importance of growth in North Chinese grain supply in satisfying that increased demand? What is an acceptable mix of domestic production and international trade? What are the alternatives to interbasin transfer in expanding irrigated area and their associated and comparative time frames, costs, risks, and external benefits? What are the alternatives (and associated considerations) to expanding the irrigated area in increasing farm output'
All of these questions must be systematically addressed and it is within neither the scope of this article nor the ability of its author to assess each of them meticulously. The following discussion, however, should give a flavour of a number of the outstanding issues.
Trends in China's Supply and Demand for Foodgrains
The rate of natural increase of China's population has reportedly slowed to less than 12 per thousand (Stone, 1980b) but almost 40 per cent of the total are 15 years or younger. The increased requirements for the chronologically maturing population together with the net increase in people may require as much as 40 x 106 metric tons of foodgrains by 1985 over the 1978 level just to maintain the current level of age-specific per capita consumption (Stone, 1980a).
It has been reported that between 100 and 200 x 106 Chinese had inadequate food intake in 1977 (or 1978), consuming less than 150 kg of foodgrains per capita annually (Stone, 1980b). A rough estimate would suggest that 20 to 30 million tons of additional grain might be required to raise the standard of the bottom two quintiles to the current national average (Stone, 1980a).
Diet quality is a serious problem in China with foodgrains supplying close to 90 per cent of the per capita caloric intake (Stone, 1980b), but the substitution of meats and oils as calorie sources will require respectively 3.3 and 10 times the cultivated land devoted to direct foodgrains production (Ishikawa, 1967; 1977). A modest increase of 3 x 106 head of cattle and the targeted 30 per cent increase in hogs by 1985 would necessitate an absolute minimum additional supply of grain of 5 x 106 tons. If the annual per capita meat supply is to meet the 1985 target of double the 1977 level of 7.5 kg per capita, increments on the order of 10 to 25 x 106 tons will be required depending on the means by which the meat production increase is to be achieved. Current trends have moved somewhat away from the most grain conserving methods in animal husbandry (Stone, 1980a). Additional requirements for grain stockpiling, food processing, brewing and other industrial uses could easily add an extra 5 x 106 tons to the requirement, despite leaving some apparently unsatisfied demand for foodgrains in the second and third consumption quintiles (Stone, 1980a). Together these components sum to an incremental demand of 75 to 100 x 106 tons by 1985.
Grain production in 1979, an excellent weather year, was up a remarkable 9% (a rise of 27 x 106 to 332 x 106 tons) despite a fall in foodgrain sown area of some 2 x 106 hectares (Stone, 1980b). Even discounting for the fortuitous weather of 1979,* the grain supply prospects for the immediate future look very good. Supplies of industrial inputs to agriculture are expanding at rates often exceeding those of the rapid foodgrain growth years of the early 1970s (and of substantially greater base values) and much higher than during the stagnant 1976-77 period. China also seems to be taking advantage of opportunities to increase productive efficiency. Suboptimal cropping patterns are being revised, as is the rural pricing system which has contributed to misallocation of productive resources and substantial disincentives to labour and local farm investment (Stone, 1980a and b).
It would hardly be prudent to expect to close completely the gap between actual and potential production, but movement in this direction is not likely to be confined to 1978 and 1979 and will continue to some extent into the 1980s. All in all, growth in foodgrain production can be expected in the range of 3 to 3.5 per cent per year between 1978 and 1985 (or an increment of 70 to 85 x 106 tons) (Stone, 1980a). Thus the difference between projected changes in supply and demand is likely to be within a range which could be handled by adjustments in internationally traded quantities.
But what of the following decade? Would possible failure to complete the Chang Jiang diversion project result in large ex ante gaps between foodgrain supply and demand in the late 1980s and 1990s? Fortunately, the rapidly declining birth rates in the 1970s will mean lower status quo requirements from the chronologically maturing population in the later periods, although indirect incremental demand for foodgrains via diet quality improvements will continue to be high. Over the past two to three decades, wheat and maize have been the fastest growing grain components, not only due to areal displacement of less highly valued and lower yielding coarse grains, but through yield and cropping intensity increases per se, especially due to the development and proliferation of semi-dwarf wheat and single-cross hybrid maize (Stone, 1980a and b; Wiens, 1978).
While the northeast and the northwest registered the fastest average annual growth over the 1957-75 period (Nickum, 1980a), north China as a whole, the central Chinese provinces of Hubei and Hunan, and Zhejiang and Jiangsu in the east were fastest growing in the 1970s (Tuan, 1981). It is not at all clear that grain production in Zhejiang, already with average annual grain yields of 10 t/ha in 1979 (Beijing Review, 1980) and in Jiangsu, with average yields of 6.4 t/ha in 1978 (Stone, 1980b), will be able to grow as quickly in the late 1980s and 1990s as they are currently. Production levels throughout much of the west (notably excepting slow-growing Sichuan) are low so that even high growth rates in most of these regions would have minor impact on aggregate growth. Southern and southeastern provinces have higher production levels but growth rates in these rice-dominant regions have been low and investment requirements for sharply increasing grain production seem costly. Thus the North China Plain (as well as the northeastern and central provinces) will continue to be crucial to the achievement of high aggregate growth in grain production.
A key prerequisite to the successful displacement of coarse grains by high and early yielding wheat and maize strains and the rapid yield increases of the latter in North China, would seem to be the increasing availability and security of irrigation waters. The multiple cropping index was pushed from the 137 to 142 range during most years in the 1955-70periodtoashigh as 151 in 1975 and 1978 (Stone, 1980b) which means an additional rise in crop demands for greater quality and quantity of irrigation. These considerations might suggest that large increments to gross irrigated acreage would continue to be crucial to output growth in North China.
Water Requirement Trends: Emerging Issues
There are a number of issues which suggest that the growth in water requirements in me future need not be so great. Western industrial research has demonstrated immense water conservation potential through design and location of new industry for those purposes. It has also shown that the most economical means of increasing output in technically transforming agriculture is often to concentrate resources in relatively limited areas.
In Tianjin Municipality, for example, where the water scarcity problem is most severe and may well worsen, grain production on unirrigated lands (about 20 per cent of the total farmed area) is about 1.5 t/ha. On irrigated lands as a whole (80 per cent of farmed area) it is about 1.8 t/ha. and in high and stable yield areas (about 30 per cent) around 2.3 t/ha. The very highest yields exceed 4 tons/ha. Although probably slower and more organizationally demanding, a low cost and low water-consuming means of increasing aggregate production in Tianjin may be to invest in further attempts to raise yields on the most productive land as well as endeavouring to increase the "high and stable yield area" average to the 4 ton standard, rather than increase the area under irrigation or raise the standard on irrigated lands across the board.
As is clear from Table 1, most of the water to be transferred by the Chang Jiang diversion project will be devoted to the development of irrigation on currently unirrigated lands. Were there no risk of salinization, this would be a fairly quick method of raising aggregate output. But it is also generally a high cost means of increasing farm production in North China and most prone to secondary salinization since localities handling most of the water will have had the least experience with this problem. If salinization can be controlled, a principal advantage of expanding gross area irrigated is that it may be a comparatively efficient means of increasing incomes and consumption in the poorest agricultural areas where the non-farm skill level may be low. Before devoting massive funds to costly irrigation of such lands, however, it would be useful to explore the possibilities of concentrating farm output increases in the more productive areas and devising separate projects to raise incomes among the poorest rural inhabitants.
On the other hand, interbasin transfer also seems likely to be a relatively highcost means of furnishing supplementary water to the extent that it means providing supplies only in the dry years when existing sources are inadequate. The result is substantial and expensive idle capacity in most years. Where possible, supplementary facilities should have low fixed capital cost. At the same time, to the extent that water from the Chang Jiang would be used to increase cropping intensity in all years, conflicts are likely to emerge in agricultural policy. Although a rise in multiple cropping is consistent with densely populated farm areas experiencing a rise in labour availability and greater exposure to chemical fertilizer and mechanical innovations (Narain & Roy, 1980), there has been a general relaxation of official pressure in China to increase cropping intensity. In some areas where multiple cropping has been increased, losses to the principal crop(s) have not been matched by the additional crop. In many cases, greater input costs have not been matched by gains in crop revenue and farm incomes have fallen. Typically the risks of soil depletion and erosion have increased (Ishikawa, 1977 and 1979; Stone, 1980a).
The principal cropping pattern change contemplated by prospective beneficiary regions is to grow more winter wheat either as a substitute for existing coarse grains or as an additional crop. The appropriate irrigation times for winter wheat in the target region are during months for which the climatic risks of salinization are greatest.
Furthermore, increases in wheat-sown area in North China bear an uneasy relationship with the state's general plans for agricultural regionalization. Wheat is a relatively high water-consuming crop and is now considered to be overemphasized given north China's production conditions. Much of north China, especially Shandong, is characterized by tow-lying depressions. To the extent that wheat, corn, or cotton is grown and irrigated in such depressions, salinization is quite likely to occur. Sorghum and soybeans have been generally undervalued by Chinese planners. Both crops are valuable as hog feed; soybeans have a high nutritive content, improve soil fertility and are a source of oil, and sorghum stalks provide fuel and nutrients. These crops are much more suited to cultivation in low-lying depressions than are wheat and especially corn and cotton.
Although the above considerations imply that the growth rate in water requirements may, with careful planning, decline from the rapid acceleration of the 1970s, it would be unrealistic to expect to achieve brisk growth in grain production across north China as a whole without some substantial increase in water delivery. For clearer perspective, however, let us briefly examine north China's recent history of grain production performance in the context of the region's battle against various water control difficulties.
Grain Production Progress in North China in the 1960s: The Simultaneous Battle Against Drought, Flooding and Salinization
The North China Plain includes some 25 X106 hectares of cultivated area or roughly a quarter of China's total. Over 20 X106 hectares of farmland are encompassed by Hebei, Henan and Shandong (CIA, 196.9; Walker, 1977). The population growth rate of these three provinces including the municipalities of Beijing and Tianjin has been only 1.7 per cent per year since 1953 to a total of 209 X106 in 1979 (Jowett, 1980),but the average rate over the last 10 to 15 years has been much higher (FBIS,1973b). Grain production tripled in Hebei between 1949 and 1974 (FBIS, 1975), but a large share of this increase was poet-war recovery. Output doubled between 1949 and 1952 and the 1957-1970 average annual growth rate was only about 2 per cent (Nickum, 1980a). Considerable progress occurred in the late 1960s and early 1970s. Output in 1965 had only just reached the 1957 level, but grain output growth was about 5 per cent per annum in both the 19651969 and the 1969-1974 periods, (despite a loss of land to Tianjin in 1973) falling to 2 per cent per year between 1974 and 1979 (Tuan, 1981).
Hebei's difficulties were to a large extent related to salinization. Two thirds of the 4 x 106 hectares of irrigated land in north China were threatened with salinization in the early 1960s. Improperly constructed drainage and irrigation projects and inappropriate cultivation practices exacerbated the risk of soil deterioration from farming on the plain. That risk was already substantial owing to the North China Plain's high water table and the regular occurrence of alternating droughts and floods (Vermeer, 1977). By 1961, out of a total area cultivated of around 7 million hectares, Hebei's saline-designated farmland had risen from 1 to 1.5 million hectares (Fang, 1980). Remedial plans were formulated and adopted in 1961 and 1962 but large-scale progress seems to have lagged into the latter part of the decade, such that Hebei as well as Henan and Shandong were just on the threshold of grain self sufficiency in 1970 (FBIS, 1971a). By 1970 already some 200,000 tubewells had been constructed in Hebei. By year-end 1973, the figure was over 300,000. Another 90,000 were constructed in 1974 and an additional 120,000 in 1975 (Stone, 1980a and b).
A key turn in the course of progress in Beijing and Hebei was the completion of the Hai He project in 1970. The Hai He basin covers 265,000 km² and over 70 per cent of the province (FBIS, 1971a). 19 trunk waterways were dredged to reduce flooding and 14 large dikes covering 14,000 km² were constructed (FBIS, 1971b). The project was also responsible for freeing a quarter of Beijing's cultivated lands from excess surface water (FBIS, 1971c). By the early 1970s, the drainage capacity of the Hai He basin was 5 times that of a decade earlier (Fang, 1980). Part of the progress was immediate: 1970 and 1971 grain output in many of Hebei's localities was up 30 to 50 per cent over previous peaks. Prior low yields were blamed on locusts in dry years, frogs in wet years, and the general quality of soils which had become quite saline with frequent droughts and floods (FBIS, 197 la). By 1972-75, however, the area of saline farmland in Hebei had been reduced by some 60 per cent (Vermeer, 1977; Fang, 1980) which consisted primarily of around a million hectares in the Hai He basin (Xinhua, 1974a) but total cultivated area in the province had also fallen by around a million hectares between the 1950s and the 1970s. Likewise, the rate of grain production expansion in Beijing Municipality was less than 2 per cent per year in the 1965-69 period but over 7 per cent for 1969-75 (all endpoints average weather years) and for 1970-74 (both good weather years) (Nickum, 1980a; Stone, 1980a).
At the same time Hebei was becoming a centre for the production of irrigation and drainage equipment. From 1969-70 to year-end 1973, Hebei alone produced 10 x 106 horsepower of equipment for 600,000 pumps (FBIS, 1973a) such that by 1974 two-thirds of the province's irrigated area could be mechanized (FBIS,1973c). These fragmentary data suggest that in addition to increased water availability per se, construction work to prevent excess surface water and quality improvements in irrigation and drainage were important to advancement in Hebei and Beijing.
In Shandong, a similar circumstantial case can be made. Grain production in 1965 was below the 1957 level (Nickum, 1980a), but the situation rapidly improved in the late 1960s (prior to Shandong's rapid development of tubewell construction) and throughout the 1970s. From average weather year 1971 when production probably first surpassed the 1957 level adjusted for soybean inclusion (Nickum, 1980a) until poor weather year 1978, output increased by about 50 per cent (FBIS, 1979b). Production relative to 1949 was up 180 per cent despite a decline in arable land in the province from about 8.7 x 106 ha to 6.7 x 106 ha (FBIS,1979c). However, the 1978 level had probably already been reached by 1976 (Tuan, 1981), making the 1971-76 average growth rate over 8 per cent per annum. The province had built 200,000 tubewells by 1971, added 192,000 in 1974 alone, and claimed 540,000 in 1979, although some 40 per cent were not operating (Stone, 1980a and b).
In north Shandong, the Tuhai and Majia He dredging projects transformed some 400,000 hectares of saline land over the 1965-70 period (Xinhua, 1970). In 1962, the average depths of both the rivers and the water table in their basins were only 2 to 3 metres so there was no groundwater drainage in the channels (Turang tongboo, 1962; Vermeer, 1977). In the northwest, irrigation and drainage alike were significantly improved over the same period. In the south, production increases were particularly linked to anti-flooding efforts, especially dike repair along the Yi He and Shu He (FBIS, 1971e).
In Henan, with 7 to 9 x 106 hectares of farmland (CIA, 1969; Walker, 1977), grain production (including soybeans) probably did not regain the 1957 level until about 1969. Even in recovery, the 1965-69 growth rate was only about 2 per cent per year (4 per cent per year 1965-70). By contrast, the average 1969-75 rate was almost 7 per cent. But as with Anhui, the 1976-79 drought years failed to match the 1975 production level. (Nickum, 1980a; Tuan, 1981). Over the 1965-74 period over a half million hectares of Henan's saline soil were improved (Xinhua, 1974b), but cultivated area fell by one to two million hectares between the 1950s and the 1970s (CIA, 1969; Walker, 1977). Henan's tubewell stock rose from 20,000 in 1965 to 460,000 in 1974 and 510,000 in 1979. The major construction thrust occurred in 1969-72 when 420,000 wells were built (Stone, 1980a and b).
The point of this discussion is that expansion of irrigated area, antiflooding efforts, salinized land reclamation and quality improvements in both irrigation and drainage have all been important to grain production progress on the North China Plain. Moreover, salinization (together with flooding), due to rapid and poorly managed irrigation expansion, was not only the principal man-made cause of the largest grain production setback in the People's Republic history during the Great Leap, but has been on the rise again in north China since the mid-1970s.
By 1962 the area of saline farmland in Hebei, Henan and Shandong had risen from 1.9 to 3.2 X 106 hectares, following Great Leap Forward plans to develop the Huai He and Huang He systems. Substantial sections in these provinces had to cease irrigation altogether and farming areas in northern Jiangsu and Anhui were also affected. By the early 1970s, reclamation efforts had reduced salinized farmland to 1.4 x 106 hectares but cultivated area had fallen by some 15 per cent (Walker, 1977) and gross expansion of salinized area (linked to improper irrigation, drainage, water storage and field preparation) soon began to outstrip reclamation progress. In the late 1970s, salinedesignated farmlands in Hebei, Henan, and Shandong occupied 1.9 x 106 hectares (Hseung, 1962; Xu and Hong, this volume; Zhu, 1980) and total cultivated area continued to fall.
Agricultural salinity is estimated to be increasing on 80 per cent of the country's saline area, especially along the Guangdong coast and on the entire North China Plain north of the Huai He (Hseung, 1980), where saline farmland totals 2.7 x 106 hectares with an additional 4.7 x 106 hectares in danger of salinization.
Since salinization presents such a particular risk to the target region and is already a growing problem with current irrigation methods, the introduction of massive additional quantities of water from the Chang Jiang seems a poor choice in this respect. Despite their energy requirements, tubewells have certain advantages over the interbasin transfer project. Capital construction costs are discrete to the benefit locality and highly divisible. Areas not prepared to handle extra water need not deal with it before they are ready, reducing salinization risks. Energy costs alone provide some natural incentive to avoid excessive irrigation. With some closer supervision, development could proceed at a gradual, carefully controlled rate on an economic basis whereas the Chang Jiang diversion project will require immense initial outlays of capital construction funds which will remain unproductive if completion of the project is delayed or utilization is curtailed. Tubewell construction has been a mainstay of irrigation expansion on the North China Plain in the dynamic agricultural growth years of the 1970s. The following section will discuss perceived difficulties with continued development along these lines.
Tubewell Development and the North China Water Table
Tubewell development has been extensive in the north, northeast, and northwest but the overwhelming concentration of well construction has taken place in the north China provinces of Hebei, Henan and Shandong. Although the threat of long term pollution of groundwater that typically accompanies extensive subsurface irrigation (Radosevich and Skogerboe, 1977; Skogerboe, Chapter 3) cannot be discounted, one salutory effect of tubewell construction has often been the slight lowering of the dangerously high water table in some areas (Vermeer, 1979). Unfortunately, extensive irrigation, protracted droughts, a reduction in natural percolation and lack of prompt artificial replenishment have evidently caused a serious fall in the water table in parts of north China (Hongqi, 1974; Xinhua, 1976; Vermeer, 1977).
Little data have appeared outside of China on the extent of the falling water table and the degree to which further rapid development of underground water resources in the region may render existing wells inoperative, cause soil erosion and lead to a fall in agricultural output. If groundwater use is actually exceeding the recharge of the aquifers even in normal years, then the range of alternatives for protecting soil quality as well as maintaining and expanding existing levels of agricultural output in North China may be greatly narrowed. Large-scale interbasin transfer of irrigation water and the replenishment of subsurface resources in the region might then become more indispensable, despite presenting many of the hazards discussed elsewhere in the paper.
It is difficult, however, to accurately assess the current severity of the problem. The range of existing groundwater resource estimates is large, due to methodological disagreement. Even using a single methodology, estimates vary considerably due to existing problems of measurement. The situation may already be critical over extended farming areas. On the other hand, problems may currently be limited to high demand urban areas and a few rural cases where lack of comprehensive regulation has resulted in overpumping. Furthermore, it is difficult to evaluate the separate effect of the unusual succession of dry years in the 197680 period resulting in abnormally low recharge. Finally, measurement problems have introduced confusion due to the proliferation of reports from operating wells while resource and personnel limitations have retarded timely analysis of data from observation wells.
The Ministry of Water Conservancy and the State Statistical Bureau have verified that a significant portion of constructed wells are not actually operating. In Shandong an estimated 320,000 (1980) of the 540,000 "completed wells" (1979) were operating. In 1980,22 per cent of Henan's wells and 228,000 of the 488,000 wells constructed in Hebei between 1973 and 1978 were not operating (Stone, 1982). But the most immediate limitation does not appear to be insufficient groundwater, but a lack of equipment or ancillary facilities for bringing water into the fields. The question remains, why?
In recent years there has been a sharp decline in tubewell construction brought about by closer government scrutiny and tighter control of central financing which has now been placed on a more economic basis, favouring localities with stronger expectations that the full cost of construction and operation will be justified by increased crop income. This is no doubt a very sensible reform. But it has not yet been demonstrated that north China's underground resources are being chronically over-exploited. While research continues to try to more accurately ascertain the potentials and interdependence of these resources a cautious programme of development may continue emphasizing relatively untapped areas under the North China Plain.
Even in cases where construction and pumping is very likely to be locally unprofitable, a carefully planned government programme to subsidize development might be considered before an expensive project such as the Chang Jiang diversion is undertaken. For this it is necessary to gain a better understanding of production and cost relations in local areas. In cases where additional water is desirable and the projected payback period is long, owing to the high price of electricity and fuel relative to agricultural prices, a long-term financing scheme might be considered together with a reduction in the local quota of grain that must be delivered at the low compulsory procurement price. Thus, energy prices may be maintained and water fees may be charged without causing incomes to decline. This approach may be preferable to a generalized increase in farm procurement prices or, certainly, to direct subsidy. Ultimately, however, it may be imperative to develop some major alternatives to tubewell construction in north China.
Alternative Surface Irrigation Schemes in North China
The river systems in north China, for the most part, have already been heavily developed. During the important irrigation months the flow of many rivers is very low (including the mainstream of the Hai He which is completely dry). A limited number of small to medium scale river development efforts are being pursued. Other water control projects continue to increase the storage of flood water for irrigation but there seem to be technical and cost limitations in highland areas while storage on the plains requires farm acreage displacement and risks salinization of adjacent lands (Yu and Wang; and Zhu, Wang and Hseung, Chapters 20 and 28 respectively, this volume). Inexpensive development of the Huang He continues to be hampered by the greatly elevated river bed, rapid alluvial buildup and sedimentation, although discrete projects continue (Sun, 1958; Vermeer, 1977; Greer, 1979).
The Huang He clearly has the greatest untapped potential of any surface source on the plain. Unlike other north China rivers which tend to dry up when most needed, its major watershed is relatively independent of drought on the plain. Some of the technical difficulties with regular irrigation use are gradually being resolved (e.g., Beijing Review, 1979b), although the silting problems suggest it is more suitable as a source of emergency relief. In 1981 it was successfully used to ease Tianjin's water crisis via three hastily constructed canals through Henan and Shandong Provinces (Beijing Review, 1981).
In general, the extensive establishment of wholly new irrigation districts on the North China Plain by any method must be costly, technically problematic or fraught with uncertainty. On a more limited basis, further development of North China's surface and underground resources can open new districts, but food production growth is not wholly dependent on the expansion of the area under irrigation. Equally important may be alternative means of irrigation (briefly discussed below) and considerations relatively independent of irrigation altogether (which will not be addressed owing to space and subject limitations).
Alternative Approaches to Irrigation Development
To a certain extent gradual yield gains are still available in north China through further improvement in security of irrigation via mechanization. To the extent that greater quantities or more timely application of water is required, further construction and more exhaustive use of existing rivers and wells, including flood season and year-to-year storage are still being actively considered by various branches of the Ministry of Water Conservancy. However, one aspect of new construction that has proved difficult in the past is local completion of ancillary facilities.
Fuller Development of Existing Irrigation Projects. Across north China some 55 per cent of cultivated land has irrigation problems (Xinhua, 1977).
The main stumbling block is apparently not total water availability, but local completion and able local management of ancillary facilities to major irrigation works. Reservoirs and canals without supplementary facilities cannot provide water to the fields. Some reservoirs are not filled to meet their design capacity. Most irrigation canals are unlined with over half the water conveyed lost to seepage. The efficiency of pump-well irrigation is very uneven and auxiliary equipment is often lacking. Sometimes the land is not levelled or is not of scientific design, resulting in flooding and closed drains and ultimately in excessively irrigated lands leading to salinization and alkalization (Renmin Riboo, 1977).
It should be noted that this sort of problem is not at all confined to China or to China of the current period. Careful attention to local projects yielded the largest gains in China during the 1950s (Wiens, 1978), and has been most clearly connected to yield increases in India (Roy and Narain, 1980). Here again the ease and speed with which the gap can be narrowed between the actual and potential level of operation of existing networks should not be exaggerated. On the other hand, the limitation seems far from immutable. The intention here is merely to emphasize that irrigation network management, especially at the local level, may be a more cost-effective source of variation in impact on the level and security of agricultural water supplies. This point is now emphasized generally by international water management specialists who suggest that on a global basis 57 per cent of water withdrawn is lost in the distribution system (Golubev and Biswas, 1979). In addition to construction problems and technical difficulties such as seepage losses, the problem of effective inter-group cooperation is worthy of mention. Finally the importance of efficiency in use of even the minority of withdrawn water which reaches irrigated fields must be emphasized.
Interinstitutional Issues: Water as a Public Good and the Political/ Environmental Problem of External Costs. Acute problems can occur when water resources are not adequately managed by a single body. Even when the distribution of costs and benefits is strictly determined in advance, ex post equity questions can arise which may be politically explosive, particularly with changing developmental circumstances over time.
The quantity and quality of Colorado River water flowing into Mexico has become one of the most difficult issues in US-Mexican relations. The problem of polluted water flowing out of Germany and into the Benelux nations has also been a problem. Negotiations among the American states of California, Arizona and Colorado over the intertemporal distribution of Colorado River water continue to be heated. Inefficient or tardy political resolution of such difficulties can result in unnecessary additional environmental degradation and economic waste.
Nickum has shown that there seems to be poor delineation in China as elsewhere of the distribution of benefits of water conservancy projects (1980b). Costs of inefficiency and the difficulty of reducing them will be increased with a large interprovincial project.
An economical resolution of Chang Jiang basin development and Shanghai area protection against saltwater backup will require a strong, overarching authority and productive machinery for interprovincial cooperation. Water quantity and quality guarantees to Beijing and Tianjin will also necessitate this type of cooperation and authority. It is important to note that examples of successful interprovincial water projects are still rare in China (see Nickum, Chapter 13). Without the explicit development of administrative machinery to resolve difficulties among provinces there can be little confidence in the project among down-stream areas. Preparation in the offtake provinces of Jiangsu and Henan is considerable and sophisticated. Construction of quite a number of physical components is already under way. Even without state financial support, these provinces are likely to pursue diversion within their boundaries. But in the absence of a guarantee that water will ever reach Hebei, Beijing, Shandong and Tianjin, preparations there are far less extensive with no physical construction.
On the local level, management of freshwater resources involves similar problems without strict overarching control. Each individual locality has little incentive to conserve water since the cost of waste is not borne exclusively by that user but is distributed broadly among all user localities. Similarly, there are insufficient disincentives to reduce pollution of water resources.
In the case of a river or irrigation canal, the problem is even more extreme than that of a reservoir or lake. The individual user locality bears none of the costs of pollution but merely passes them downstream and therefore has almost no pecuniary incentive to reduce the impact of pollutants. The locality has no incentive to conserve water resources since the full cost of wasteful use is borne in the form of shortages downstream, not by the locality itself. Likewise, there are no disincentives to maximum channeling downstream during flood season.
On-farm Water Management. Throughout the world, the general tendency on farms with irrigation districts is over-irrigation, resulting in inefficient water use and, more than occasionally, salinization problems. It seems clear that north China's current salinization difficulties are related to over-irrigation as well as to imperfections in water storage facilities and practices, unusually concentrated precipitation and the high water table. With careful local attention to on-farm water management, yields may be increased in irrigation districts while conserving water. Significantly improved water management cannot be left to sloganeering but must be made the focus of a concerted grassroots development programme (see Skogerboe, Chapter 3). The initial steps along these lines are volumetric irrigation measurement and the establishment of appropriate water fee schedules. The logical order of projects suggests that the water management effort, as well as the establishment of effective machinery for resolving intergroup water disputes, be pursued prior to introduction of large quantities of additional water from outside because: 1) the present value of future expenditures on expensive irrigation construction will be greater if machinery for improving performance in these areas is established in current irrigated districts; 2) the battle against salinization will become a more immediate focus; good experience in these areas will be developed and disseminated and future interbasin transfer efforts will be less likely to risk flooding or salinization; 3) the introduction of systems of efficient water use developed elsewhere along with initial water delivery into a region will be easier than reducing inefficiency later, after water-wasting habits have developed.