Delta Dilemma: Environmental Stresses Threaten Mighty Mekong

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By Lien Hoang

Oct. 11 — Ky Quang Vinh recalls his childhood in the 1960s in Vietnam's Mekong Delta as an idyllic time, even under the cloud of war. When choppers weren't roaring overhead, when communists weren't toting arms to their southern strongholds, Vinh took to the waterways to swim and quench his thirst.

These days, Vinh mourns the polluted rivers and the bricks and concrete that have replaced ponds and bamboo. As director of the Climate Change Coordination Office of Can Tho City, he faces a different battle now, a struggle between the environment and the economy in a delta where climate change poses a bigger threat than almost anywhere else in the world.

“I'm sad and pessimistic about both the environmental problems and the response to climate change,” Vinh said. “If these issues are not resolved, then the future of the Mekong Delta will be very bleak.”

‘Biological Treasure Trove.'

The Mekong River starts in the snow-capped mountains of China's Yunnan province and snakes 2,700 miles through Myanmar, Laos, Thailand, Cambodia and Vietnam, where it fans out in a network of distributaries and empties into the South China Sea.

The World Wildlife Fund calls the Mekong Delta a “biological treasure trove” of rare creatures. It documented more than 1,000 animal species between 1997 and 2007, including the pink dragon millipede, in addition to new species of plants, fish, lizards, and mammals such as the Laotian rock rat, thought to be extinct.

This region of Vietnam is dominated by flat flood plains in the south, with a few hills in the north and west. The terrain was largely the product of tectonic uplift and folding brought about by the collision of the Indian and Eurasian tectonic plates about 50 million years ago. The soil of the lower delta consists mainly of sediment from the Mekong and its distributaries, deposited over thousands of years as the transboundary river changed its course due to the flatness of the low-lying terrain.

Across the delta today, however, salt is creeping in, sea level is rising and banks are receding.

The Mekong risks getting crushed by a perfect storm of external triggers—climate change and foreign dams upstream—mixed with Vietnam's own developmental missteps. If they press on with their plans, developers may have to resketch the maps of a region that is slowly disappearing.

Delta Shrinking, Sinking

For thousands of years, the Mekong River, one of the world's longest and most biodiverse, expanded the delta by nourishing it with sediment from what are now six Asian countries.

The relatively modern delta grew to about 15,000 square miles—roughly twice the size it was 6,000 years ago—wrote Joep Janssen in his book, Living With the Mekong. And it became vital to Vietnam's status as a leading exporter of rice and other food.

But in recent decades the delta has begun to shrink, which Janssen attributes partly to the 1980s construction of the Manwan Dam in China. The power station suppressed water flow from the Mekong River and its fluvial deposits to the extent that the WWF now estimates that Vietnam loses enough land each day to occupy a football field. Researchers are unsure how much erosion stems from climate change, upstream activity, or other causes.

Vietnam is a long, dragon-shaped country, where the coast runs for 2,000 miles and the rural-to-urban land ratio is 2:1. For years it has worried about how the activities of neighboring countries could destroy its environment, from the hydropower dams being built by Laos and China to the global-warming pollution of industrialized nations.

The Mighty Mekong

In 1995, Laos, Thailand, Cambodia and Vietnam established the Mekong River Commission to assist in the management and coordinated use of the Mekong's resources. But environmentalists say the delta also suffers from the domestic actions of Vietnamese people, often undertaken with the goal of expanding their $200 billion economy. These actions include over-farming of shrimp, exhausting the rice crop, badly planning dykes and canals, and overpumping wells.

Scholars at Can Tho University, the de facto capital located at the heart of the delta, calculate that the region dips one to four centimeters annually; if that continues, the area would move below sea level by 2050. They believe the main cause is too much extraction of groundwater. A record drought exacerbated the pumping this year, marking Vietnam's worst dry spell in almost a century.

‘Ferocious' Floods

Before completing its journey to the South China Sea, the Mekong River winds through 12 Vietnamese provinces by way of Cambodia. Residents along the river are periodically pummeled by typhoons between May and January and must deal with extensive flooding.

In 2000, provinces along this border built dikes to subdue floods ushered in by the river. But they went too far, according to Andrew Wyatt, Mekong Delta program manager at the International Union for Conservation of Nature (IUCN).

At his office in Ho Chi Minh City, Wyatt pulled up a Google Earth rendering of the delta, which is a few miles away and shaped like a right triangle. On a projector screen, he pointed to dry areas that used to be covered in blue and noted that one province, Dong Thap, lost 60 percent of its flood plains in a decade.

Border provinces that try to wall off floods merely propel the flood waters downstream into other provinces, which suffer more “ferocious” deluges as a result, Wyatt said.

“If you're not letting the water flood,” he told Bloomberg BNA, “all that water has to go somewhere.”

National Rice Identity

The dikes present a nagging conundrum for farmers. Controlling the floods allows farmers to cultivate a third rice crop each year, where traditionally there were only two. Rice has been essential to Vietnam's national identity and turnaround story. Gone are the postwar food shortages and illegal trading of the 1980s. Vietnam today can feed itself and export more rice than any other country except India and Thailand.

But experts widely agree that the third rice crop is ravaging the soil, with marginal benefit to sellers. Yields are lower on the third go-around, according to Nguyen Huu Thien, a consultant for the International Center for Environmental Management. He said farmers persists because Hanoi subsidizes the cost of land and crop failure through a rice-first policy. As he explained, fertilizer isn't enough to cure the depleted soil and overfarming is pushing rice fields closer to the South China Sea, where they're even more exposed to the vagaries of climate change.

So more of the sea is coming to the chartreuse-green fields.

Historically, the oceans delivered salt into the Mekong Delta. Then flood waters, captured in natural reservoirs and released in the dry season, would help wash the salt back out.

But with dikes, sluices and low-lying reclaimed land in place to curb the floods for the extra rice harvest, the water stays brackish, according to Thien. Ironically, this could make it harder to farm in the future.

“The infrastructure is driven by the rice-first policy, and the problem is the whole market is driven by GDP [goals],” Thien told Bloomberg BNA by phone, pausing as his car crossed one of the delta's many distributaries. “It has negative environmental damages and negative impacts on the natural resources.”

Shrimping ‘Like Gambling.’

Some farmers in the delta opt for intensive shrimping, which involves ripping out mangrove trees in order to form ponds where they cram in as many shrimp as possible. All the little crustaceans come with a higher density of antibiotics, waste, bacteria and disease.

In 2012, early mortality syndrome, also known as acute hepatopancreatic necrosis syndrome, infected shrimp in Vietnam. As soon as that pathogen was under control, a 2015 outbreak of a microsporidian parasite called Enterocytozoon hepatopenaei crippled the shrimp, and is still stunting their growth.

“Intensive shrimp farming is like gambling,” Thien said. “You can have a very good income in the short term, but it's very risky.”

He thinks there is a nearly 100 percent risk that the farms will fail eventually, as more shrimp become infected and wastewater spreads.

Advocates prefer the alternative of mangrove shrimping, which produces a smaller yield, but keeps shrimp sustainable alongside more trees.

IUCN's Wyatt said the mangroves act as a coastal fence that traps sediment, blunting the devastation of monsoons, sea level rise and erosion. They are a bulwark against the increasingly unpredictable weather patterns brought on by climate change.

Nature and Prosperity

Yet demanding that locals reduce shrimping or rice farming is “so illusory and impractical,” said Vinh, the Can Tho city official. “People need adequate income for their life and family,” he told Bloomberg BNA.

Vietnam is juggling its environmental quandary with the livelihoods of 92 million people.

Farming is a priority, especially in the Mekong. In centuries past, nine of every 10 Vietnamese were farmers, starting in the 1600s, when Vietnam pushed south to sack the Cham empire and cultivate its newly claimed delta, according to historian William Duiker. The fertile region has been an economic prize for other conquerors: France began its colonial stranglehold on Vietnam by nabbing three delta provinces in 1862.

From the rubber plantations of the French era to the rice paddies of today, the Mekong remains an agrarian engine of the economy. Instead of telling farmers to cut back, Vinh argues that scientists and other specialists must advise them on how to increase value and productivity, while protecting the environment.

With the onslaught of cable bridges, irrigation pipes, dredging and new people, the delta may never again look as it did in Vinh's bucolic childhood. But he hopes Vietnam can strike a new balance between nature and prosperity.

“The Mekong Delta is fast modernizing,” he said. The people, and their policies, need to keep up.

To contact the reporter on this story: Lien Hoang in Ho Chi Minh City at correspondents@bna.com

To contact the editor responsible for this story: Greg Henderson at ghenderson@bna.com

For More Information

An audio slideshow of life on the Mekong Delta is available at http://src.bna.com/jbr.

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