The methods proposed to reduce the impact on regional fisheries of a mainstream Mekong dam in Laos are untested and unproven, making the Lao government’s decision to move ahead with the Don Sahong dam a dangerous one, critics of the project said Thursday.
An environmental impact assessment carried out by Laos and released this week lists several possible measures that the developers of the 240-MW dam should take to prevent any negative effects to fisheries.
Experts have said that because it will block one of 17 channels in the Mekong River, the project could seriously hurt downriver fisheries, a danger the Laos government has sought to play down.
“If the [river] were blocked with no mitigation measures, there would undoubtedly be a severe impact on the fish population and those that depend on the fishery,” the environmental impact assessment [EIA] report released this week states.
“However, the [EIA] includes measures…so that there will be no significant adverse effect on the resources.”
The measures include physically transporting large fish species that are trapped at the dam site further upstream so that they will be protected. It also recommends the use of “fish-friendly” turbines so that the fish will be able to migrate freely.
“Any large fish caught alive… will be purchased on site by the Project’s fisheries monitoring team and physically transported…and released upstream,” the report states, adding that these measures will allow for 95 percent of migratory fish species to travel unhindered.
Ian Baird, assistant professor of geography at the University of Wisconsin-Madison—and one of the foremost researchers on Laos’ Khone Falls fisheries—took issue with untested approaches laid out in the report.
“The idea is to build the dam and conduct research during construction and afterwards as well, but if things don’t turn out as they hope, it will be impossible to turn back,” Mr. Baird said in an email Wednesday. “At that point, the public in all the countries, including those who rely on the fish will pay the price.”
He also criticized the report’s assumption that losing 5 percent of the region’s fish stocks is a negligible amount.
“Nothing like this has ever been done in the region, so the whole idea is unproven,” Mr. Baird said.
The Mekong River Basin is known for having the highest diversity of fish species of any river in Asia, and the Khone Falls area alone supports more than 200 fish species.
Due to the Mekong River’s robust ecosystem, there is no adequate technology proven to mitigate a dam’s impact to the fisheries, Pianporn Deetes, Thailand coordinator for environmental group International Rivers, said Thursday.
“There have been a lot of studies available talking about the absence of technology to mitigate the fisheries impact on the Mekong because the fish of the Mekong are very diverse in terms of size, migration routes and times as well,” she said.
Construction of the dam is scheduled to start this month.
