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The Mekong under threat

Milton Osborne

Readinch

South-east Asia’s longest river has been transformed in the past three decades. Now, the food security of the Lower Mekong Basin hangs in the balance, writes Milton Osborne.

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Until the 1980s the Mekong River flowed freely for 4,900 kilometres from its 5,100-metre-high source in Tibet to the coast of Vietnam, where it finally poured into the South China Sea. The Mekong is the world’s twelfth longest river, and the eighth or tenth largest, in terms of the 475 billion cubic metres of water it discharges annually. Then and now it passes through or by China, Burma (Myanmar), Laos, Thailand, Cambodia and Vietnam. It is south-east Asia’s longest river, but 44% of its course is in China, a fact of capital importance for its ecology and the problems associated with its governance.

In 1980 not only were there no dams on its course, but much of the river could not be used for sizeable, long-distance navigation because of the great barrier of the Khone Falls, located just above the border between Cambodia and Laos, and the repeated rapids and obstacles that marked its course in Laos and China. Indeed, no exaggeration is involved in noting that the Mekong’s overall physical configuration in 1980 was remarkably little changed from that existing when it was explored by the French Mekong Expedition that travelled painfully up the river from Vietnam’s Mekong Delta to Jinghong in southern Yunnan in 1866 and 1867. This was the first European expedition to explore the Mekong from southern Vietnam into China and to produce an accurate map of its course to that point.

Since 2003, the most substantial changes to the Mekong’s character below China have related to navigation. Following a major program to clear obstacles from the Mekong begun early in the present decade, a regular navigation service now exists between southern Yunnan and the northern Thai river port of Chiang Saen. It is not clear whether the Chinese, who promoted the concept of these clearances and carried out the work involved, still wish to develop navigation further down the river, as was previously their plan. To date, the environmental effects of the navigation clearances have been of a limited character.

The Mekong plays a vital role in the countries of the Lower Mekong Basin (LMB): Laos, Thailand, Cambodia and Vietnam. (Burma is not within the basin). In all four LMB countries the Mekong is a source of irrigation. In Vietnam’s Mekong Delta the annual pattern of flood and retreat insure that this region contributes over 50% of agriculture’s contribution to the country’s GDP. For all four LMB countries the Mekong and its associated systems, particularly Cambodia’s Great Lake (Tonle Sap), are a bountiful source of fish, with the annual value of the catch conservatively valued at US$2 billion. More than 70% of the Cambodian population’s annual animal protein consumption comes from the river’s fish. Eighty per cent of the Mekong’s fish species are migratory, some travelling many hundreds of kilometres between spawning and reaching adulthood. Overall, eight out of 10 persons living in the LMB depend on the river for sustenance, either in terms of wild fish captured in the river or through both large and small-scale agriculture and horticulture.

Since the 1980s, the character of the river has been steadily transformed by China’s dam-building program in Yunnan province. The important changes that had taken place on the course of the river since 1980 and up to 2004 were outlined in the Lowy Institute Paper, River at Risk: The Mekong and the Water Politics of Southeast Asia. In 2010 three hydroelectric dams are already in operation and two more very large dams are under construction and due for completion in 2012 and 2017. Plans exist for at least two further dams, and by 2030 there could be a “cascade” of seven dams in Yunnan. Even before that date and with five dams commissioned, China will be able to regulate the flow of the river, reducing the floods of the wet season and raising the level of the river during the dry. In building its dams, China has acted without consulting its downstream neighbours. Although until now the effects of the dams so far built have been limited, this is set to change within a decade, as discussed below.

For despite the limited environmental costs of the dams China has so far completed, and of the river clearances to aid navigation, this state of affairs will change once China has five dams in operation. And the costs exacted by the Chinese dams will be magnified if the proposed mainstream dams below China are built.

Even if no dams are built on the mainstream below China, the cascade to which it is committed will ultimately have serious effects on the functioning of the Mekong once the dams are used to control the river’s flow. This will be the case because the cascade will:

* Alter the hydrology of the river and so the current “flood pulse”, the regular rise and fall of the river on an annual basis which plays an essential part in the timing of spawning and the migration pattern. This will be particularly important in relation to the Tonle Sap in Cambodia, but will have an effect throughout the river’s course;

* Block the flow of sediment down the river which plays a vital part both in depositing nutrients on the agricultural regions flooded by the river and also as a trigger for fish migration — at present well over 50% of the river’s sediment comes from China;

* At least initially cause problems by restricting the amount of flooding that takes place most importantly in Cambodia and Vietnam; and

* Lead to the erosion of river banks.

Proposed dams below China

So China’s dam-building plans are worrying enough, but the proposed new mainstream dams would pose even more serious concerns. In contrast to what has occurred in China, and until very recently, there have been no firm plans for the construction of dams on the mainstream of the Mekong below China. This situation has changed over the past three years. Memoranda of Understanding have been signed for 11 proposed dams: seven in Laos; two between Laos and Thailand; and two in Cambodia. The proposed dams are being backed by foreign private capital or Chinese state-backed firms. Government secrecy in both Cambodia and Laos means that it is difficult to judge which, if any, of these proposed dams will actually come into being. Attention and concern have focused on two sites: Don Sahong at the Khone Falls in southern Laos and Sambor in north-eastern Cambodia. The reason for this attention is that if built these dams would block the fish migrations that are essential to insure the food supplies of Laos and Cambodia.

Those built at sites higher upstream would cause the least damage to fish stocks, but if, as currently seems possible, the most likely dams to be built would be at Don Sahong and Sambor, the costs to fish stocks could be very serious. This is because unanimous expert opinion judges that there are no ways to mitigate the blocking of fish migration that would occur if these dams are constructed. None of the suggested possible forms of mitigation — fish ladders, fish lifts, and alternative fish-passages — are feasible for the species of fish in the Mekong and the very large biomass that is involved in their migratory pattern. Fish ladders were tried and failed at the Pak Mun dam on one of the Mekong’s tributaries in Thailand in the 1990s.

Why are the governments of Laos and Cambodia contemplating the construction of dams that seem certain to have a devastating effect on their populations’ food security? The answers are complex and include some of the following:

* A lack of knowledge at some levels of government;

* A readiness to disregard available information on the basis that it may be inaccurate; and

* A belief or conviction that fishing is “old-fashioned”, whereas the production of hydroelectricity is “modern”.

In Cambodia’s case, and in particular in relation to the proposed dam at Sambor, the fact that a Chinese firm is seeking to construct the dam raises the possibility that prime minister Hun Sen is unready to offend the country that has become Cambodia’s largest aid donor and Cambodia’s “most trusted friend”. In Laos, the proposal for a dam at Don Sahong is very much linked to the interests of the Siphandone family for whom southern Laos is a virtual fief. Of all the proposed dam sites, Don Sahong is the most studied in terms of knowledge of fisheries so that it can be safely said that the planned dam would wreak havoc on a migratory system that involves fish moving through the Hou Sahong channel throughout the year, movement that takes place in both directions, upstream and downstream.

In the face of the threats posed by both the Chinese dams and those proposed for the downstream stretches of the river, there is no existing body able to mandate or control what individual countries choose to do on their sections of the Mekong. The agreement establishing the Mekong River Commission (MRC) in 1995 does not include China or Burma, and though the latter’s absence is not important, the fact that China is not an MRC member underlines the body’s weakness. In any event, the MRC members’ commitment to maintaining the Mekong’s sustainability has not overcome their basic commitment to national self-interest. A prime example of this is the manner in which the Lao government has proceeded in relation to the proposed Don Sahong dam. For at least two years while the dam was under consideration there was no consultation with Cambodia. Similarly, so far as can be judged, Cambodia’s consideration of a possible dam at Sambor has taken place without consultation with the governments of either Laos or Vietnam.

At the moment the best hope is that both the Cambodian and Lao governments will abandon their plans for Sambor and Don Sahong. If they do not, the future of the Mekong as a great source of food, both through fish and agriculture, is in serious jeopardy. At the time of writing the intentions of the Lao and Cambodian governments remain uncertain.

Concern about dams in China and the LMB is given added importance in the light of worries associated with the likely effects of climate change in the region through which the river flows. Research suggests there will be a series of challenges to the Mekong’s future ecological health. Until recently concerns about the likely impact of climate change tended to focus on the ongoing reduction in the size of the glaciers from which its springs in the Himalayas and which feed it as the result of snow melt. But while there is no doubt that a diminishment in size of the glaciers feeding the Mekong is taking place, recent research has suggested that a more immediate serious threat to the river’s health will come from sea-level changes, particularly as rising levels could begin to inundate large sections of Vietnam’s Mekong Delta. To what extent the threat posed by rising sea levels will be affected by another predicted development linked to climate change — greatly increased precipitation leading to more flooding during the wet season — is not yet clearly established. But research is pointing to a greatly increased precipitation that is likely to cause major increases in flooding in the future, possibly as early as 2030.

Against the pessimistic views outlined in this article perhaps the best that can be hoped for is that once serious consequences begin to become apparent advice can be offered to mitigate the worst effects of the developments taking place. Where once it was appropriate to write of risks, when assessing the Mekong’s future it is now time to write of fundamental threats to the river’s current and vital role in all of the countries of the Lower Mekong Basin.


Milton Osborne is visiting fellow at the Lowy Institute. He has been associated with the south-east Asian region since being posted to the Australian embassy in Phnom Penh in 1959. Osborne is the author of 10 books on the history and politics of south-east Asia, including The Mekong: turbulent past, uncertain future (2006) and Southeast Asia: an introductory history.

An earlier version of this article was published as "
The Mekong River Under Threat," The Asia-Pacific Journal, 2-2-10, January 11, 2010. It is used here with permission.

This article draws on the author’s Lowy Institute Paper 27, 2009. See the complete paper
here. To read the complete paper, it is necessary to type in the current year after entering the site.

Homepage image shows the proposed location of the Sambor Dam, Kratie province, Cambodia. Photograph by Carl Middleton, International Rivers.

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翻译有误

是南中国海,不是中国南海!

Translation mistake

It is 'South China Sea', not 'China South Sea'!


中国的经验

现在在中国已经很难吃到野生的河鱼了,绝大部分都是通过饲料喂养的鱼类,哪怕就是生活在大江大河旁边,也是这样。从生物多样性的角度来看,实在有必要拆除这些水库丑八怪,恢复水道的自然面目。但是,问题是,很多时候木已成舟,就像中国的例子,鱼不鱼的没人关心,反正又不是吃不到鱼。我看这个逻辑也同样适用于老挝和柬埔寨,人们会说,你看呀,中国不是修了那么多水电站,拉动了多少内需,带动了多少就业,提高了多少人民生活水平啊,我们为什么不能走中国的路呢?实在不行,未来我们把这些坝子炸掉不就行了。但愿我的预言是错的。

China's experience

Currently in China it is very difficult to eat wild river fish, most are farm-raised fish, this is the same even with those who live next to large rivers. From the perspective of biodiversity, these ugly dams need to be dismantled and the natural features of the watercourse need to be revived. However, the problem is that what is done is done. As for China's example, people don't care whether or not there are any fish, and people no longer eat fish. I see this logic similarly appropriate to Laos and Cambodia, people said: Look, China is not repairing its many hydropower stations, but is working on its countless domestic issues, which has brought countless jobs, has raised countless people's living standards, why can't we follow China's path? If that doesn't work we will blow up the dams in the future. But I hope that my prediction will be wrong.


大坝破坏生态

大坝的大量建设严重破坏了周边地区的生态平衡,白鳍豚的灭绝和中华鲟的悲剧都是人类这种模式自然的态度造成的

The dam is destroying the ecology

The large-scale construction of the dam is seriously destroying the ecological balance of surrounding areas, the extinction of the Chinese river dolphin and the tragedy of the Chinese sturgeon are a result of the form people's attitude to nature has taken.


用权力补偿

外国私有资本可能来自投资渠道,建立起来帮助中国宣传这些工程和出口信贷机构,因此,这些私有部分很有可能包含了一些既定的利益团体。大型的水电工程,热力发电站,不应该成为出口信贷机构,或者任何官方的援助机构(除非关及社会和环境影响评估,对公众检查来说,也应该是可靠可随时进行的。)这些工程表明,中国长期想不尊重其他人民,他们的邻友,而去追逐他们地缘战略。

Compensating those in power

The "foreign private capital" is probably from investment vehicles set up specifically to assist China in promoting these projects and Export Credit Agencies - so the "private" component is likely include vested interests.

Large hydro-electric projects - thermal power stations - should not be eligible for Export Credits - or any other official aid (except in relation to social and environmental impact assessments - which must be credible and freely available for public scrutiny).

These projects demonstrate China's continued willingness to disrespect other people, their livelihoods and the environment in pursuit of its geo-strategic agenda.


回应评论1

南中国海是国际上普遍的翻译,但跟国内通用的中国南海是一个概念。

Response to comment 1

'South China Sea' is the widespread international translation, The domestically commonly used 'China South Sea' is actually the same thing.


我爱柬埔寨

在柬埔寨工作了一年有余,我深深爱上了这个国家!

可是,今天,我竟然发现,我们国家在云南修建的大坝竟然会对柬埔寨的洞里萨湖产生难以估量的负面作用,我真的感到心情沉重!!

I Love Cambodia

After working in Cambodia for more than a year, I have deeply fallen in love with this country!

However, today, I unexpectedly discovered that the dam, that our country is constructing in Yunan, has negative affects on Cambodia's Tonlé Sap. I really feel gloomy!!


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