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Part I: Introduction

2. Central Eurasian water perspectives and arid land studies
3. Major environmental problems in world lakes

2. Central Eurasian water perspectives and arid land studies

International cooperation for peaceful water management in critical areas

Iwao Kobori

I participated in the Tokyo University Iraq-Iran Archeological Mission in 1956. Since then I have visited many rivers and lakes on the Eurasian landmass. Most of these are geographically located in arid and semi-arid areas where sparse precipitation and high evaporation rates are dominant. Among the world's inland lakes, the Dead Sea, the Caspian Sea, and the Aral Sea are of extraordinary interest from the point of view of arid land studies and for the need for future peaceful and sustainable economic development.

The water level of the Dead Sea, one of the deepest inland lakes and with the highest salinity levels, has dropped in recent years, while the water level of the Caspian Sea has risen. The Aral Sea is drying up, and its surface area has decreased by about half. Although we know these facts, there is not enough information for use in long-range planning. These regional changes are proceeding at different time and space scales and for different reasons. We must rescue and rehabilitate these lake regions if there is to be any hope for sustainable development in and around them in the not-too-distant future.

In the case of the Dead Sea, the problem for the future is how to stop the decrease in sealevel and how to revitalize the Dead Sea region. One solution might be to resort to dramatic mega-engineering efforts, another might to support steady, small-scale development along its coastline. Activities such as these will require careful management.

About 40 years ago, a colleague and I translated a book by Ivanov Omsky, in which there was a lot of praise for state plans concerning the transformation of the natural environment, especially in the arid areas of the Soviet Union. The miracle of the development of the Hungry Steppe near Tashkent (Uzbekistan) and the construction of the Karakum Canal (in Turkmenistan), which enabled large segments of the Karakum Desert to be irrigated and developed for agricultural production, have been well publicized. The development of the cotton culture industry in the Central Asian republics, such as Uzbekistan, has been very well known.

After I attended the Fifth All-Union Soviet Geographical Congress (1970, Leningrad) and the International Geographical Congress (1976, Moscow and Ashchabad), I received many papers on arid lands. However, up to the 1980s there was no mention of the Aral Sea crisis, especially the shrinking of the sea basin and its influence on the inhabitants.

I first visited the Dead Sea (Jordan) in 1956, and since then I have visited the upper branches of the Jordan River and its tributaries in Lebanon and Syria several times. In 1961, I visited the Dead Sea and the Jordan Valley on the Israeli side. Unfortunately, the water problems of that area have been largely a function of political tension between Israel and its neighbouring Arab countries. The construction of a national water pipeline by Israel has diminished the water flow from Lake Tiberias into the Jordan River; as a result, the sealevel of the Dead Sea has fallen. The inequitable distribution of water between Israel and the occupied territories has caused a high level of tension between the inhabitants of both regions.

Israel, the PLO, and Jordan agreed on a peace treaty in 1993, although it is a partial one. This was a milestone on the road to peace, even though many difficulties are likely to lie ahead. However, in reality, the planning of water resources is still under debate on both sides of the Jordan Valley and among outside authorities.

In 1958 I visited Professor Reifenberg, the author of The Desert and the Sown. He spoke of the Med-Dead Sea Canal Project. I met Eng. Batz, Vice-Mayor of Beer-Sheva, who was involved in the planning of the Second Suez Canal. During my interviews in 1961, I never expected the evolution of the Arab-Israeli conflicts that we now see. The time has come to reconsider the canal plan, but as yet no assessment has been made of this theoretical plan, and the consensus of relevant countries has not yet been forthcoming.

For the Caspian Sea, one of the largest lakes in the world, environmental studies suggest that the problem of sealevel change is not so acute in comparison with that of the Aral Sea. None the less, the recent increase in the level of the Caspian Sea, especially along the southern and south-western shorelines, pollution by petroleum industries, and the decline of lucrative fisheries will cause problems for the inhabitants of the Caspian Sea coastal region. The Caspian is now surrounded by five states: Iran, Azerbaijan, Russia, Kazakhstan, and Turkmenistan. Just a few years ago there were only two littoral states - the Soviet Union and Iran. In addition, each former Soviet Central Asian republic has its own national political and socio-economic problems, making it difficult to coordinate these states for the sake of resolving the Caspian Sea problems.

Since the disintegration of the Soviet Union, the Central Asian republics have suffered from severe economic crises, despite the reemergence and importance of commerce and trade in traditional bazaars. The continued exploitation of hydrocarbon resources and the discovery of new ones may eventually serve to vitalize some of these economies. However, to benefit from the export of petrol or natural gas, close cooperation will be required with neighbouring countries, such as Iran and Turkey, as well as support from the world market-place. Under such conditions, Central Asian affairs cannot be viewed as isolated from happenings in other parts of the world.

Consider the role of Central Asia in history. The dry steppe of the Eurasian landmass has always been a crossroads of civilization, trade, commerce, and military conquests. Once flourishing political entities, such as Khorezm, declined after the destruction of their irrigation systems.

International cooperation for peaceful water management in critical areas

A new model of international cooperation is required for those critical areas in need of peaceful inter-state (i.e. trans-boundary) management of water resources. But who should be expected to take the initiative in this activity: international organizations, non-governmental organizations, national or local decision makers, the inhabitants, or some combination of them?

The environmental catastrophe in the Aral Sea basin has already received much attention from the international community. Turning interest and attention into concrete action, however, is no easy task. For example, the headquarters of Aral-related organizations have been busy receiving visitors who have come time and again to assess the crisis situation, but those visits have yielded very few results. The rehabilitation of the Aral Sea and its disaster zone needs very large investments. Given the increasing demands for scarce international funds, the international community must consider to what extent it should get involved. Good data about what is happening in the region require sustained monitoring of the physical aspects of ecological change, as well as the monitoring of socio-economic and cultural change.

As an ideal plan, the international community should consider establishing an international research centre in the region, whose first act should be to stop the exodus of able regional scientists to Moscow or abroad. Scholars outside the region often accept young researchers in their institutions and send bright students to the region. Japan, for example, has sent several missions either through government agencies or through non-governmental organizations, such as universities and the Global Infrastructure Fund.

Japan is very interested in Central Asia, and it now has a small reservoir of good researchers. Depending on those important human resources, Japan is very pleased to cooperate with international groups through the United Nations University (UNU), other international organizations, Japanese government authorities (such as the Japan International Cooperation Agency, the Environment Agency, or the Ministry of Education, Science and Culture), and other concerned ministries or foundations. The international community is now fostering cooperation through ongoing bilateral projects.

As regards the Caspian Sea, the present environmental situation, relatively speaking, does not appear to be acute. The rising sealevel is causing destruction in the low-lying coastal areas, but scientific analyses of the decadal-scale fluctuations of the Caspian Sea level do exist. For this reason, research on rivers flowing into the sea may be necessary. Because of the huge area of the sea and the resources in it, inter-state cooperation may be difficult. Attempts to establish regional cooperation are very recent. Under these conditions, a different approach from the case of the Aral Sea needs to be pursued.

Encouragement of cooperation among riparian countries and international groups involved in the region is very necessary. Cooperative efforts among riparian countries for ground and space surveys using advanced technology will be necessary. Furthermore, macro and micro socio-economic studies on the people in the Caspian Sea region should also be undertaken cooperatively. The exchange of researchers should be expanded and a fellowship for the region would be very welcome.

In the case of the Dead Sea basin, including the Jordan Valley, a multinational framework is already being developed. International organizations such as the United Nations and the European Union, and big powers such as the United States, Japan, and Canada, are keenly interested in the rehabilitation of this contested zone. The improvement of water works, especially for potable water for local inhabitants, is a high priority. Databases on the water resources are well developed. However, it is a very complicated process to coordinate planning in an area of scattered Palestinian territories, the occupied West Bank under Israeli control, and Israeli territory.

As an example, from a public health point of view, Gaza faces an inadequate water network (potable or seepage), because it is under heavy population pressure. A giant engineering scheme could improve the situation in the future, but urgent funding is needed now to address the acute problems that the local inhabitants face today. We cannot wait for a complete regional political settlement. Furthermore, addressing pressing water supply problems today could help the peace process. Better living conditions and improved infrastructure for inhabitants might accelerate a peaceful settlement of inter-state political tension in the region. Action in the future is very obvious: keep the peace permanently. It is time to keep alive and complete the peace process.

The second introductory chapter in this part is by Professor Kira, whose paper on world lakes and their problems provides a framework for the presentation of environmental problems facing inland bodies of water.

Part II on the Aral Sea contains a paper discussing creeping environmental problems in the context of the Aral Sea basin, an essay on the socio-economic development prospects of the region in the light of its Soviet history for most of the twentieth century, and a set of satellite images showing changes in the Aral Sea region over time. These papers are supplemented by three voices from the region. These brief papers were drawn from comments during the Forum discussion session.

Part III contains two essays, one from a Russian perspective and the other from an Iranian perspective, on environmental problems in the Caspian Sea region. The Caspian Sea level has risen considerably since 1977, creating havoc in riparian countries whose low-lying areas have been inundated by the relatively rapid increase in sealevel.

Part IV focuses on the Middle East and the Jordan River watershed. There is considerable concern that countries in the Middle East will eventually engage in conflict, not over ideological or religious issues but because of water shortages in the region. The two contributions in this section not only describe some of the regional problems related to water but propose political as well as engineering solutions.

The final chapter addresses the role of international organizations in assisting riparian countries in their attempts to devise ways of equitably and sustainably managing the water resources associated with inland drainage basins and the rivers that feed them.

3. Major environmental problems in world lakes

Declining water levels
Rapid siltation
The progress of eutrophication
Contamination with man-made toxics
The collapse of aquatic ecosystems

Tatsuo Kira

Everywhere in the world, lakes and reservoirs are becoming more and more important as the most dependable sources of water in large amounts. Lakes and reservoirs are more attractive water sources than rivers and underground water for big water consumers such as cities and industrial centres. In terms of size, number, and distribution, man-made lakes today are quite comparable with freshwater natural lakes.

On all the continents, however, the environments in those lakes and reservoirs are deteriorating rapidly and extensively due to various human impacts. Both the quantity and the quality of lakes' water resources are being threatened in that an increasing number of lakes have already lost not only their value as sources of water but also such traditional roles as the space for fisheries and waterborne transportation.

For this very reason, the International Lake Environment Committee (ILEC) was established soon after the First World Lake Conference held in Japan in 1984. Since 1986, ILEC has made efforts to formulate guiding principles and programmes on the environmentally sound management of lakes and their watersheds along the line of sustainable development policies. Its activities have so far included the publication of lake management guideline books (Jørgensen and Vollenweider, 1989; Jørgensen Löffler, 1990; Hashimoto, 1991; Matsui, 1993; Jørgensen, 1993), convening training courses in lake management, symposia, and workshops, promoting environmental education in schools of several countries, supporting a series of World Lake Conferences, and, above all, compiling environmental data on world lakes. Detailed limnological and socio-economic data on some 220 lakes have already been accumulated and are being published by a joint project of ILEC, the United Nations Environment Programme (UNEP), and Lake Biwa Research Institute (LBRI and ILEC, 1988, 1989, 1990, 1991). Descriptive information on more than 500 lakes is also available for reference.

Figure 3.1 shows the range of water volume in relation to mean transparency for 145 lakes whose data had been published before 1990. The range covered is very wide, amounting to the order of 107, though most of the lakes are in a narrower range of 102-104 km3. Transparency appears to depend on lake size, but certain lakes, e.g. shallow lakes on windy plains such as Lake Winnipeg (Canada) and Lake Balaton (Hungary), tend to have exceptionally small Secchi depth values.

A preliminary synthesis of the accumulated data on world lakes and reservoirs revealed the global prevalence of six types of environmental disruption as major problems of urgent concern (fig. 3.2): decline of water level, accelerated siltation, acidification, eutrophication, toxic contamination, and extermination of ecosystems and biota.

Declining water levels

Falling water levels and the resulting shrinkage of lake areas are due to the overuse of water drawn from the lake itself or from inflowing or outflowing rivers.

The extreme case of the Aral Sea is now widely known. Similar situations are also reported for other Central Asian lakes such as the Caspian Sea in the middle decades of the twentieth century (Golubev, 1992), Lake Balkhash in Kazakhstan, Lake Qinghai in China, and some lakes in Iran. Lake Mono in California also lost about 30 per cent of its former area owing to a fall in the water level of 11 m, and suffers from raised salt concentration in the lake water (as does the Aral Sea), owing to the diversion of 85 per cent of its tributary river water to the city of Los Angeles.

Aside from such lakes in the arid zone, the water level in other lakes has often been significantly lowered by dredging their outlets in order to increase the capacity of hydroelectric power generation in outflowing rivers. This has often caused the temporary advance of eutrophication, as, for instance, was the case in Lake Sevan Armenia (Oganesian, 1991).

Fig. 3.1 The transparency of lake water in relation to lake water volume in 145 lakes and reservoirs of the world

Fig 3.2 Six major environmental problems of world lakes and reservoirs

Rapid siltation

Rapid siltation of lakes is the result of soil erosion accelerated by the overuse of farming and grazing lands, deforestation, the over-harvesting of fuelwood, and other imprudent land uses in lake catchment areas.

This is a very serious problem facing many lakes and reservoirs in China, India, Africa, and other less developed countries. Particularly alarming is the fact that cultivated fields and pastures, which have been sustainably used as more or less stationary semi-natural systems for centuries, are being devastated almost irreversibly by overuse. Overpopulation, as well as the residents' strong desire for more cash income to buy imported industrial products, has encouraged the abandonment of traditional sustainable methods of land use. The same situation is causing desertification in arid regions and forest destruction in the humid tropics.

The silt load of lake water, indicated by the concentration of suspended solids, is significantly correlated with the area of cultivated land per lake water volume in lakes in humid/subhumid climates, as illustrated in figure 3.3. A correlation in the arid zone could not be detected owing to the scarcity of available data.


Acidification of lake water is caused by the input of acid air pollutants such as acid rain and dry fallout, either directly on the lake surface or indirectly via inflowing rivers.

Tens of thousands of small lakes in northern and central Europe and in North America have already become too acid to allow fish to breed there and, in extreme cases, almost any kinds of animals to survive. At present, the acidification of lake water is largely confined to rather limited regions such as Scandinavia, parts of central Europe, the north-eastern United States, and neighbouring parts of Canada, most probably owing to particular geological conditions, though acid precipitation itself occurs more widely over the northern hemisphere.

Fig. 3.3 The relation between the concentration of suspended solids in lake water and the area of farmland in corresponding catchment areas (Note: closed and open circles refer, respectively, to lakes and reservoirs in humid/subhumid regions and those in arid regions)

However, soil scientists have recently tried to predict how long it will take for the buffer capacity of the soil to be exhausted by continued acid precipitation. The predicted value of course depends on soil type, but may range, e.g. in Japanese soils, from several years to several decades. This is an alarming prediction, which suggests that the acidification of lake water may sooner or later become a global issue.

The progress of eutrophication

Eutrophication is spreading, owing to the combined effects of such factors as industrialization, the urban concentration of populations, changing ways of life toward mass consumption and mass dumping, the increased application of fertilizers on cropfields, deforestation and other types of ecosystem disturbance in catchment areas, the submergence of terrestrial biomass caused by reservoir construction, aquaculture within lakes, and so on.

Eutrophication has been, and perhaps will continue to be, the most widespread type of environmental pollution of water bodies. It is expanding rapidly from industrialized or urban areas to rural areas, from small streams to larger rivers, from small lakes to larger lakes, and from inland waters to coastal marine waters. The current situation in some lakes of overpopulated areas is critical, because newly growing large cities have to depend for their water supply on hyper-trophic lake water filled with blooms of blue-green algae. Eco-technological measures are not effective enough to overcome the crisis in the short term, and large-scale environmental technology such as sewage treatment systems is too expensive to be easily adopted.

Contamination with man-made toxics

The post-war epoch of environmental pollution started almost 40 years ago with a series of heavy metal contamination events in coastal and inland waters of Japan and some other countries. The situation has not yet been improved very much. The development of monitoring and warning systems for toxic contamination may prevent the recurrence of such tragedies as Minamata disease (caused by mercury poisoning) in industrialized countries, but many water bodies, including lakes and reservoirs, still remain dangerously contaminated. The kinds of identified toxins have significantly increased, including various kinds of mutagens and carcinogens whose risks have to be managed in a different way from those of heavy metals, agro-chemicals, etc.

There are also indications that contamination is spreading to less developed parts of the world, keeping pace with the advance of industrialization and urbanization. During ILEC's survey of world lake environments, however, it was recognized that information on toxic contamination of lakes in less developed countries, especially reliable numerical data, was disappointingly scarce. Here is one of the most urgent needs for international cooperation.

The collapse of aquatic ecosystems

The collapse of aquatic ecosystems and loss of biodiversity in natural lakes is the ultimate result of all the above-mentioned five processes.

Freshwater ecosystems are by no means as rich in plant and animal species as terrestrial ecosystems, but they are highly specialized with a high percentage of endemic species. For instance, the current number of fish species is said to amount to 22,000, of which one-third live in freshwater environments. In relation to the very limited area of inland waters, this percentage is surprisingly high and indicates the diversity of freshwater environments and the profound effect of geographical isolation.

Lake ecosystems, with their unique environment and biota, very vulnerable to or intolerant of disturbance from outside. This is shown by the frequent invasion of alien species and their explosive prolification in many lakes. The opportunities for such immigration are ever increasing owing to the development of intercontinental travel and transportation. Waterweeds of New World origin are flourishing and suppressing native species in Old World lakes (e.g. Elodea canadensis, E. nuttallii, Egeria densa) and vice versa (e.g. Myriophyllum spicatum). It is said that Nile perch, a big carnivorous fish introduced into Lake Victoria, have already exterminated some 200 native fish species, a greater part of which are endemic to the lake (Chamberlain, 1993). The recent invasion by zebra mussel (Dreissena polymorpha) from Europe of the Great Lakes of North America offers another very remarkable example (Nalepa and Schlosser, 1993). Similar cases are known from many other lakes.

Lake ecosystems are also vulnerable to environmental changes. The excessive advance of such processes as siltation, water level decline (and resultant salinization), acidification, toxic contamination, and eutrophication may lead to the eradication of high plants and animals in the lake. We are thus losing highly characteristic gene pools in lake ecosystems from time to time.

The exploding world population and developing industries are always thirsty for fresh water. A critical shortage of freshwater resources may possibly arrive sooner than that of food in the near future. As this brief review shows, the critical situation of world lake environments should properly be placed among the important environmental problems of global scale because of its worldwide occurrence and profound influence on human life. In order to halt its further advance, concerted international efforts are indispensable. The International Lake Environment Committee sincerely hopes that the Fifth World Lake Conference (Stresa, 1993), together with the preceding and subsequent conferences, will take significant steps forward in responding to the challenge of this problem.


This paper originally appeared in Memorie dell'lstituto Italiano di Idrobiologia, 52: 1-7, 1993, and is reprinted with permission. The original text has been partially modified and/or abridged by the editors.


Chamberlain, J. 1993. "Lake Victoria: A tropical sea in distress." Our Planet 5 (1), pp. 9-11.

Golubev, G. N. 1992. "Environmental problems of large Central Asian lakes." In: Proc. Symp., Water Resources Management - With Views of Global and Regional Scales. Otsu: UNEP and ILEC, pp. 55-63.

Hashimoto, M. (ed.). 1991. Guidelines of Lake Management, Vol. 2, Socio-economic Aspects of Lake Reservoir Management. Otsu: ILEC and UNEP.

Jørgensen, S. E. (ed.). 1993. Guidelines of Lake Management, Vol. 5, Management of Lake Acidification. Otsu: ILEC and UNEP.

Jørgensen, S. E. and H. Löffler (eds.). 1990. Guidelines of Lake Management, Vol. 3, Lake Shore Management. Otsu: ILEC and UNEP.

Jørgensen, S. E. and R. A. Vollenweider (eds.). 1989. Guidelines of Lake Management, Vol. 1, Principles of Lake Management. Otsu: ILEC and UNEP.

LBRI (Lake Biwa Research Institute) and ILEC (International Lake Environment Committee) (eds.). 1988-1991. Data Book of World Lake Environments: A Survey of the State of World Lakes, 4 vols. Otsu: ILEC and UNEP.

Matsui, S. (ed.). 1993. Guidelines of Lake Management, Vol. 4, Toxic Substances Management in Lakes and Reservoirs. Otsu: ILEC and UNEP.

Nalepa, T. F. and D. W. Schlosser (eds.). 1993. Zebra Mussels - Biology, Impacts and Control. Boca Raton, FL.: Lewis Publishers.

Oganesian, R. O. 1991. "Anthropogenic eutrophication of Lake Sevan and ways of preventing its negative consequences." Lecture at Lake Biwa Research Institute.

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