Dam calamity a wake-up call for Mekong hazards

Dam calamity a wake-up call for Mekong hazards

Lucky survivors of the Laos dam collapse perch on the roof of a house while waiting for rescue. (FB/THOLAKHONG Khmu)
Lucky survivors of the Laos dam collapse perch on the roof of a house while waiting for rescue. (FB/THOLAKHONG Khmu)

The recent case of the Xe Pian Xe Namnoy dam collapse in Laos is a timely reminder that there are potential hazardous factors associated with the failure of storage dams. These include large mass movements into a reservoir close to the dam such as a sudden influx of water and/or huge falling rocks, design errors, poor construction, faulty operation of reservoirs, sabotage, terrorism, acts of war and seismic risks.

The Mekong River and its tributaries now have some 300 storage dams with more being constructed and planned. On the mainstream, there are already six dams in operation in Yunnan province of China which constitute a cascade of reservoirs in the upper river section with a few more being planned. In the lower part of the river, from the "Golden Triangle" area where Laos, Myanmar and Thailand meet down to the delta region of Vietnam, there are two dams currently under construction in Laos with plans for several others to be built. Laos has a development policy to be the "battery of Southeast Asia" relying on its rich potential of hydropower resources to generate revenue by selling the electricity to neighbouring countries.

It is well-known that some of the places where the dams are or will be located in this river basin are in seismically active areas. A 2014 study indicated that of the 19 dams on the Mekong mainstream examined, either existing, under construction or planned, 11 were found to be in extreme or high earthquake hazard areas. Four of these are existing dams and two are being planned within China while the rest are in northern Laos including the Xayaburi dam currently being built.

We should focus on the possible seismic risks in the areas around dams in the Mekong. Admittedly, the probability is rather small that a strong earthquake will strike one of the large storage dams on the Mekong especially in the upper section of the river in China causing failure and subsequent uncontrolled release of the reservoir water. However, should it occur, a tremendous flood wave will travel down the river and the dams located immediately downstream will likely be overtopped and damaged as well. Concrete dams may be able to better withstand such waves, but heavy erosion along the abutments and in the downstream dam foundations may cause failure and the release of the additional stored water. This may lead to a cascade or domino effect in which dams further downstream will all likely collapse, thus creating a tsunami-like tidal wave which travels down the river system. Such a worst-case scenario would have devastating consequences for the communities located in the path of the destructive flood wave.

With proper safeguards to minimise such catastrophic incidents from happening, coupled with emergency disaster preparedness measures including effective alert systems when such a calamity occurs, the people could be warned and evacuated in time as the formation of such flood waves could take hours to several days depending on the topography and distance from the failed dam. In mountainous regions, and especially in the upper reaches of the Mekong River, the evacuation routes are probably shorter but likely to be more remote and difficult, while in the middle and lower reaches of the river and where the terrain is flatter, large areas may be inundated as experienced during the recent dam failure in Laos. In this case, distances to safe places will likely be further and thus a longer time for the evacuation will be required. Moreover, depending on the topography, volume, velocity and force of the flood wave, it may even change the course and shape of the river in some affected sections and as a result alter the international boundary between the riparian countries which share and use the river as the border demarcation.

As indicated earlier, the likelihood of such an enormous disaster is relatively small and hopefully will never happen. Nonetheless, where the only certainty nowadays is often, ironically, uncertainty, it would therefore seem prudent to err on the side of caution. What is really needed is an effective water alarm system and a related emergency preparedness plan for the entire Mekong basin, along with an open and participatory multi-stakeholder dialogue involving all concerned countries, the relevant sectors and a broad and representative segment of the respective societies on the detailed benefits and cost/risk of such infrastructural schemes in the river basin. The idea is not to dismiss dam building altogether but any decision to proceed should be arrived at only after a careful and comprehensive deliberation of all feasible options, consideration of all potential adverse effects and ensuring that adequate safeguards are incorporated for whatever is being constructed together with having good early warning systems, risk management and contingency measures and compensation schemes in place should mishaps occur. Existing storage dams should also comply with international dam safety standards, which include structural safety, dam safety monitoring, operational safety and emergency planning. Accordingly, the risk classification of dams must be standardised across the different riparian countries in the Mekong basin.

There is also a need to have a broader discussion on the equity issues involved in the various developmental activities in the Mekong basin. The general sense is that the people living outside the basin stand to reap more benefits and bear relatively little if any of the undesirable consequences from such projects whereas those residing in the basin are likely to not only gain much less from such schemes but on the other hand suffer more disproportionately especially when misfortune strikes. Since practically all countries around the world have adopted and are implementing the United Nations Sustainable Development Goals up to the year 2030, which is underpinned by the two basic principles of "putting people first and "leaving no one behind" then it is essential that some of the points made earlier be seriously considered and acted upon.

All the mainland Southeast Asian countries that share the Mekong River also happen to be member states of the Association of Southeast Asian Nations, or Asean. Interestingly, the Asean leaders, at their summit meeting in October 2013, issued a Chairman's Statement which contained a section which states: "We recognised the importance of preserving, managing and sustaining use of water resources and call on Asean Member States to continue effectively implementing the Asean Strategic Action Plan on Water Resources Management, including assessing the impacts that economic development has on the environment and people's livelihoods in major river basins including the Lower Mekong Basin".

If there is any painful yet important lesson that we can draw from the recent Lao dam calamity, it is that the lives, livelihoods and property of many inhabitants in the Mekong Basin may be at stake -- from the standpoint of social equity and justice across boundaries, the long-term sustainability of our planet as well as the greater collective good of all peoples concerned and not simply narrowly-defined economic benefits alone. We have no more time to waste and the moment to act is now. Let us all roll up our sleeves and try to make a difference.

Apichai Sunchindah is a development specialist with an interest in Southeast Asia.

Apichai Sunchindah

An independent development specialist

Apichai Sunchindah is an independent development specialist.

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