Concerns rise over Kok River check dam’s ability to reduce toxic substances

A water resource engineering professor and an environmental advocate have expressed concern over the ability of check dams, to be built across the Kok River in Chiang Rai province, to trap toxic substances discharged from mining operations in Shan state of Myanmar.

Dr. Sitang Pilailar, a professor at the Water Resource Engineering Department of the Faculty of Engineering at Kasetsart University

Dr. Sitang Pilailar, a professor at the Water Resource Engineering Department of the Faculty of Engineering at Kasetsart University, said that sedimentation is a normal process in watercourses and the building of a check dam, to promote sediment settling, may do more harm than good and check dams are usually built in streams, not rivers.

She said, if a check dam is meant to be temporary and easily washed away by strong currents, as envisaged by government officials, the concentrated sediments will spread further downstream. To build a permanent check dam, she said more study must be undertaken, including on the location of the dam(s), she added.

Dr. Sitang also said the government should think about how it will deal with and dispose of the toxic sediments collected from the riverbed.

She cited the case of the contamination of a creek in a village in Kanchanaburi by unregulated discharges from lead mining operations, noting that the Pollution Control Department has been unable to tackle the problem after it was ordered to do so by the court several years ago.

So long as the mines in Shan state continue to discharge toxic waste into the river, she said that there is only a slim chance that the contamination of the Kok River can be resolved.

Somkiat Kuenchiangsa, of the Living River Siam Association



Somkiat Kuenchiangsa, of the Living River Siam Association, warned that building check dams will have impacts on the ecological system of the Kok River and its tributaries and, ultimately, people who rely on the river as a source of water for consumption and agriculture will be affected.

Meanwhile, Deputy Interior Minister Theerarat Samrejvanich said the Thai government is waiting for a response from Myanmar regarding a proposal for bilateral discussions on the contamination of the Kok River.

She noted, however, that China is the key to solving the problem, because most of the mines in Shan state are operated by Chinese investors.

She is supportive of the check dam concept, though, noting that they can be built and repaired easily.