Dams and Food Security in the Mekong: Visiting the Don Sahong Dam

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This is the second in a two-part series of Spotlights documenting Stimson Research Associate Courtney Weatherby’s travel to the Mekong River basin in Southeast Asia. Weatherby along with Richard Cronin, Director of the Southeast Asia program, were given rare access to dams being built in Laos and examine their potential impact on food security in the region.  

Luang Prabang’s status as one of the most developed areas in Laos became clear once we flew south to Pakse and the Siphandon area. Tourism in the south has been booming in recent years, due partly to the relatively untouched, natural beauty of the Siphandon area. Also known as the Four Thousand Islands, the Mekong river splits into many channels and charges over a fault line to create cascading waterfalls.

Despite the region’s natural beauty and the growth of eco-tourism, southern Laos still lacks many of the basics that we saw in and around Luang Prabang—most of the roads in the area are dirt, and access to electricity was not widespread and often limited to only a couple of lamps despite the darkening skies. We saw smoke from woodstoves or fire pits as families circled around to cook dinner as we bounced past on the rough roads. After reaching the island, we were ushered over to two tuk-tuks—really motorcycles with makeshift side cars—and had a jarring ride through the dark over dirt roads and creaky bamboo bridges, with occasional quick application of brakes to avoid water buffalo that walked into our path. The trip was a reminder of the huge differences in development between the villages on these islands, some of whom only recently gained access to electricity, and those living in cities like Luang Prabang, let alone bustling urbanized areas.

The following day’s visit was the main purpose of our trip to southern Laos: the 6 months of consultation for the 240 MW Don Sahong project, which is located only 10 km north of Laos’ border with Cambodia, finished in January 2015 without clear agreement on how to proceed. Like the Xayaburi project, the Don Sahong is controversial: the project is located on the Hou Sahong, one of few channels available to fish for upstream migration even during the dry season. Don Sahong is also the closest of the Laotian dams to Cambodia’s Tonle Sap, making it potentially more impactful to the river’s fisheries than the many-times larger Xayaburi project.

Our trip verified that site preparations are ongoing for a road that will connect the dam and some nearby islands to the mainland, but construction of the dam itself has not yet begun. We spoke with the fisheries research team for Mega First, the dam developer, and then embarked on a tour around the channels involved in the dam construction and mitigation efforts. First was a visit to Hou Sadam, a smaller channel of the Mekong recently found to be accessible to fish during the dry season. We saw the sites monitored for fish tagging, as well as the areas which had been widened and deepened in an effort to facilitate accessibility for fish. Afterwards, we took a ride past the upper reaches of Hou Sahong, where the dam will be built, and then walked inland to meet some local fishermen who are helping the researchers.

A major challenge in understanding the potential impacts of the project is the serious lack of data about fisheries in the Siphandon area. After meeting with the fisheries research team and getting the tour of the site, we are more hopeful about fisheries impact mitigation: Mega First’s preliminary research reveals that other channels apart from the Don Sahong are already used by migrating fish species during the dry season. Mega First’s current plans include deepening and widening these channels—Hou Sadam and Hou Xang Pheauak—to make them more like Hou Sahong and more available to fish. While this doesn’t guarantee that they are a suitable alternative for all fish species, some fisheries experts feel that they would provide a more natural option than a man-made fish passageway.

Mega First’s fisheries researchers fully recognize the need for long-term attention to address the current lack of data about fisheries in a way that would hold up to scientific analysis. As of December 2014, they have engaged in fish tagging and study, with daily monitoring at sites along 5 different channels to identify the species, size, and age of fish migrating upstream. This has already led to new data about migration habits of some fish, and in early 2015 they plan to start camera and sonar monitoring of the main fish passageways to track the mass of fish during each migration pattern.

These efforts — while welcome — by no means assuage broader concerns about the cumulative impacts of multiple dams on the river, nor can they provide certainty that the mitigation efforts will be as effective as they expect. The Lao government seeks to begin construction of the Don Sahong in late 2015, leaving little time for their additional information to be taken into the dam design. The Xayaburi and Don Sahong developers have made real efforts to improve their projects—but even if they are more successful than environmental and fisheries specialists believe they will be, the fundamental problems of managing cumulative impacts and a lack of adequate baseline data remain.

That said, the changes to both projects are important reminders that engagement between project critics and the government officials and developers can have positive impact. As we prepare for future trips to the region, that will be foremost in our minds when we are discussing challenges with colleagues on both sides of the debate.

Weatherby discusses the trip below, or you can view her video here.


Follow Courtney Weatherby, Stimson’s Southeast Asia program, and Stimson on Twitter.

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