Myth and realities about dams and droughts

Much has been written about the building of hydropower dams in the upper reaches of the Mekong River, especially Lancang River in China, and their role in causing droughts in the Mekong delta region in Vietnam. Many environmental and social activists claim Chinese dams have reduced the water flowing in the delta, seriously harming rice cultivation and allowing saltwater to flow into the delta.

Let us objectively consider the facts and validity of such claims.

Drought indeed dealt a serious blow to Vietnam's agriculture and forestry sector, and seafood industry in the delta region last year. Official data show the growth rate in these sectors was only 1.36 percent last year, the lowest since 2011. The drought also had major economic, social and environmental impacts as it severely affected Vietnam's coffee, rice and shrimp production and exports.

There are many reasons why Vietnam is facing serious water scarcity. First is climate change. According to the World Bank, Vietnam is likely to be one of the five most affected countries by climate change. Last year's El Niño-induced drought seriously reduced robusta coffee production in the central highlands and rice yields in the delta region. Vietnam is the world's largest robusta producer and the third-largest rice exporter.

There is little Vietnam can do alone to reduce the frequency of El Niño-induced droughts. But, of course, it can take steps to make agricultural practices more water-efficient. It could consider changing cropping patterns, using a mix of crops, to improve management and technological practices, in order to reduce water requirements without curbing farmers' incomes.

As for the construction of hydropower dams by China, which many claim has been solely responsible for reduced water availability in the Mekong delta region, we must realize that the demands for electricity and water in the riparian countries－China, Myanmar, Laos, Thailand, Cambodia and Vietnam－are increasing steadily, especially because hydropower does not contribute to carbon dioxide emissions, which accelerate climate change. And since more and more electricity is needed for industrialization, the six countries see rivers such as the Mekong and its tributaries as major sources of energy.

The 132-meter-high Manwan Dam, the first built by China on the Lancang River, became functional in 1995 and can generate up to 1,750 megawatts. Since then 11 hydropower dams have been built on the Mekong river system, six of them in China－and more are likely to be built to meet the demands of an electricity-hungry Asia.

But will hydropower dams cause more droughts in Vietnam? To begin with, such dams do not consume any water. After electricity is generated, water is discharged into the river. Since the dams store the floodwaters during the rainy season and discharge them into the river system over the entire year, they should increase the water flowing in the rivers during dry seasons. This is to say, if dams are built only to generate electricity in the upper reaches of the Mekong and its tributaries in China, Laos and Thailand, they are unlikely to reduce the flow of water in the delta in the dry season.

Institutional arrangements to manage the Mekong River basin leave much to be desired. In 1957, the UN Economic Commission for Asia and the Far East set up a Committee for Coordination of Investigations of the Lower Mekong Basin as an autonomous body, popularly known as Mekong Committee, with four member states. Sixty years on ECAFE has become the UN Economic and Social Commission for Asia and the Pacific, and the Mekong Committee has changed into the Mekong River Commission. China and Myanmar are not members of the MRC, which, along with the MC, has spent hundreds of millions of dollars over the past six decades but not undertaken even one single significant regional scale project. As a result, the Mekong's full potential has not been realized in the riparian countries.

In other words, the effectiveness of the MC and MRC has been disappointing.

Given these conditions, there is an urgent need to develop an effective institutional mechanism in which all riparian countries can jointly develop the Mekong region, in order to improve the lives and livelihoods of the people living there. But there are no signs of that happening in the foreseeable future. Rather, there appears to be a weakening of political will to cooperate, at least through the aegis of the MRC. So the riparian countries should urgently work on a coordinated and sustainable development plan for the Mekong region so as to realize the full potential of the river's system.

Asit K. Biswas is distinguished visiting professor at Lee Kuan Yew School of Public Policy, National University of Singapore, and Cecilia Tortajada is a senior research fellow at Institute of Water Policy at the same School, National University of Singapore, and editor-in-chief of the International Journal of Water Resources Development.