Untold impact on northern Thailand’s wildlife from Mekong dams

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From Thai Enquirer

This article was originally published on The Third Pole. (Original story can be found here)

About a year ago, the Boon Rueang Wetland Forest Conservation Group began a survey of wildlife in the 483-hectare community forest in northern Thailand. “We have recorded some leopards, otters and other animals,” says Songpol Chanruang, chair of the group.

Though only around 130 kilometres long, the Ing River that feeds the Boon Rueang wetlands is the second most important habitat for the Eurasian otter in Thailand, according to the Living River Association, an NGO that promotes community-based conservation in the Mekong basin. The Eurasian otter – a species listed as globally Near Threatened by the International Union for Conservation of Nature – is known to occur at at least 10 locations along the banks of the Lower Ing River.

The Ing River is a tributary of the Mekong. The stretch where the Ing and other tributaries like it in northern Thailand flow into the Mekong is sandwiched between a huge number of dams. There are 11 hydropower dams upstream on China’s section of the Upper Mekong – known as the Lancang – and 11 more in various stages of planning and completion on the Lower Mekong in Laos and Cambodia, most with some level of Chinese involvement in development or construction. The effects of upstream dams on the ecology of downstream tributaries are largely unknown.

Major dams along the Mekong River, including those which are under construction or in the planning stages (Graphic: The Third Pole)

“The seasonal cycle has changed over the years, and this was noticed after dams were built… especially during the past 10 years,” Chanruang says. “The Mekong hardly floods into the Ing River, or if it floods it no longer lasts for a few months, but a week, or even just a few days.”

“We just hope [the otters] can adjust to the changing environment by using their wild instincts to find a safe place to breed and feed,” says Chanruang, stressing the need for more study and public engagement.

The Mekong floods during the wet season between June and October, filling the Ing and other tributaries. This soaks the wetland forests of Thailand’s north.

The natural flooding of the Mekong provides this region of Thailand with the water, fish and nutrients needed to support the Ing River forests and wetlands. The fish nursery this creates sustains both wildlife, such as otters, and communities downstream.

But in the past decade, a spate of dam projects on the Mekong mainstream have resulted in the flooding process becoming unnaturally intense and rapid.

“The water now comes and goes quickly, not lingering in the forest like it did in the past,” says Chanruang, describing the seasonal floodwaters of the Ing River. “It’s clear that [water levels] have dropped significantly during the rainy season over the past few years. Its colour has also changed, from muddy water to clear.”

Continues with photos

https://www.thaienquirer.com/33444/untold-impact-on-northern-thailands-wildlife-from-mekong-dams/