Man vs. nature: flooding in the Mekong Delta

30 November 2011 | Article

The recent flooding in the Mekong Delta has forced decision makers to address an important question: does it make sense for the state to support the high levels of investment in large-scale water resource management infrastructure needed to produce a third crop of rice. The answer depends on who you ask and how you define the costs and benefits. Many researchers and farmers representatives argue that the direct and hidden costs of a third crop exceed the benefits in terms of the extra rice produced. But many government officials insist that a third crop of rice makes economic sense.  

 To understand these different positions requires an understanding of the history of rice production in the Mekong Delta. Starting in the 1860s under French colonial rule, canals were built to facilitate transportation, expand commerce, and for military purposes. This initiated a process of “opening up” of the delta that continued until the 1960s. During this period, only one crop of rice was grown: a winter-spring crop using traditional long-stem varieties adapted to the deep floods. In the 1970s, when the International Rice Research Institute introduced high yielding varieties, two crops per year became common practice.

Starting in the 1980s, a dense network of dykes and canals was built in the Plain of Reeds (POR), a vast wetland covering the northern parts of Dong Thap and Long An Provinces, and then in the Long Xuyen Quadrangle (LXQ), to allow two crops of rice to be grown. Starting in the 1990s, with funding from the World Bank and technical assistance from the Dutch government, a third “autumn-winter” crop was made possible in the POR and LXQ by building higher dykes to limit flooding caused by the peak Mekong flow in October-November. The use of higher dykes to “suppress” floods was introduced by irrigation engineers from the Red River Delta. They also introduced the word lu, or destructive floods, which had no meaning in the Mekong Delta where farmers had traditionally relied on the flood pulse as the basis for their livelihoods.

Growing three crops of rice a year in the POR and LXQ initiated a process of “closing off” or “polderization” of the Mekong Delta. Of the delta’s 4 million hectares, 1.8 million hectares are used to grow rice, an area that’s barely changed for 35 years. But thanks to a second and third crop, rice production rose from 4.5 million tons in 1976 to 21 million tons in 2008. Of this, 7 million tons was exported, making Vietnam the world’s second largest rice exporter. In 2011, the total area of the third crop was 644,000 hectares, up from 512,000 hectares in 2010. This increase was driven by high prices for the off-season third crop ($0.38/kg in 2011, a record high) and the absence of high floods since 2000, which encouraged planting in flood-prone areas.

The costs of intensification are increasingly evident, however. The higher dykes needed to grow a third rice crop have resulted in the deposition of sediment on the river bed, thereby causing the river bed to rise relative to the floodplain and increasing the flood risk. And the dykes, by preventing flooding of the rice fields, have displaced flooding to settlements near the dykes, including the cities of Long Xuyen and Can Tho. The risk of severe flooding, even when Mekong flows are only slightly above average, will increase under most climate change scenarios, which predict more intense rainfall during the rainy season.

Reduced flooding has cut off the supply of nutrient-rich sediment, resulting in a big increase in fertilizer use. And the indiscriminate use and improper handling of fertilizers, herbicides, and pesticides (which are required by the new fast-growing rice varieties) have serious public health impacts. A 2005 World Bank study that used explicit medical tests rather than conventional self-reporting of symptoms showed that 25% of the farmers sampled suffered from chronic pesticide poisoning.

Reduced flooding has also reduced groundwater recharge and the surface water storage capacity of the POR and LXQ, which in the past acted as a giant sponges, absorbing flood waters during the rainy season (when the Mekong flow reaches 30,000 m3/second) and releasing them during the dry (when it drops to 3,000 m3/second). These changes have reduced river base flow and may be contributing to increased dry season salt water intrusion and drinking water shortages.

So if rice intensification in the Mekong Delta isn’t necessary for domestic food security and has serious environmental and economic impacts, why is government so keen to grow even more rice? The answer lies in the distribution of the costs and benefits. As with infrastructure projects anywhere in the world, dyke construction involves lucrative contracts and thousands of well paid jobs. The dyke companies and their friends in local government are vocal advocates for dyke construction. At the same time, rice exports from the delta are negotiated by a few state-owned companies that buy low, sell high, and pocket the difference. And after the fees that farmers paid the local irrigation companies were canceled in 2007, they have no say in water use and consequently in what crops to grow.

A series of articles in the Saigon Times Online questioned the value of the third rice crop in wake of this year’s flood damage and loss of life. Professor Vo Tong Xuan, a renowned rice scientist and former rector of An Giang University, questioned whether farmers can ever get rich growing rice. “Vietnam’s rice exports have increased but this has not necessarily improved people’s lives.” “Every year,” he writes “the government spends billions on construction and dredging, but these costs aren’t included in the cost of rice production.” As well as these direct costs, indirect or hidden costs include reduced wild capture fisheries, reduced nutrient replenishment, reduced groundwater infiltration, and increased river bank erosion. And because the poor and landless depend disproportionately on wild capture fisheries and on the flood sediments to maintain fertility, the third rice crop contributes to greater social inequality. In response to a question about the low levels of compensation for flood damage, an official from the Ministry of Agriculture and Rural Development (MARD) replied that compensation was the responsibility of other ministries. MARD argues, predictably, that the solution to the problem is to build higher dykes rather than reconsider the wisdom of the third rice crop.

In Vietnam, the government often blames natural disasters on climate change. It’s a convenient excuse because it diverts attention away from the consequences of poor planning and flawed policy. In the case of recent Mekong flooding, the cause of the damage is almost entirely man-made. Sooner or later, the government has to accept the fundamental trade-off between maintaining high levels of rice production and pushing production beyond its natural limits. The Mekong Development Plan, which is being prepared with Dutch support, is an opportunity to highlights this trade-off and initiate steps to “de-intensify” rice production in ways that maximize the economic, environmental, and social benefits of a more natural hydrology. This process will no doubt be resisted by vested interests and involve short-term political pain. But the long-term advantages are clear, as the Dutch learned when they launched their “room for the river” program after the devastating floods of 1995. Vietnam often talks about learning from international experience. Here’s a chance to put that principle into practice.