CONTEXT:

The Don Sahong dam is constructed on the Hou Sahong channel of the Lower Mekong River mainstream and blocks the full length of the channel at a height of 32 meters. Prior to the dam’s construction, the Hou Sahong channel was the main Mekong channel through Khone Falls that sustained year-round migratory fish passage between the upper reaches of the Lower Mekong River to the Mekong Delta.

PROJECT IMPACTS:

Khone Falls is a complex ecological system consisting of a “large number of small to large channels separated by many large and small islands.” Siphandone, the area where the project is located, is well known for its biodiversity, including a population of Irrawaddy dolphins. Construction of the dam has altered fish migration patterns, harming the Mekong River’s ecosystems and threatening the livelihoods and food security of hundreds of thousands of people. Local communities near the project site and downstream are most at risk, including ethnic minority and indigenous populations. Many live on a subsistence basis and rely on fish and aquatic resources for income and food.

THREAT TO THE IRRAWADDY DOLPHIN

The Don Sahong dam site is located just one kilometer from a core habitat of the Irrawaddy dolphin that is endangered locally. This group of six dolphins is the last remaining in Lao PDR; they inhabit a transboundary deepwater pool on the border between Laos and Cambodia. There are only 85 Irrawaddy dolphins estimated to remain in the Mekong, many of which are found in downstream sections of the Mekong River in Cambodia

IMPACTS ON MEKONG FISHERY AND BIODIVERSITY

The Mekong River houses the world’s largest freshwater fishery, and rich aquatic biodiversity rivaled only by the Amazon, with over 1300 species. In the Mekong Basin, 87% of known species are migratory. 

FOOD SECURITY AND LIVELIHOODS

Fish catch is a critical component of the diet and livelihoods of Mekong River communities. Between 40 to 70% of the region’s animal meat protein comes from inland fisheries. A decrease in fish supply due to the Don Sahong dam will increase fish prices in the market, leaving poorer communities unable to afford fish. The most significant environmental and socio-economic impacts of the Don Sahong dam would therefore be felt by local and regional inland fisheries, threatening regional livelihoods and food security in the Lower Mekong Basin.

Biodiversity Snapshot

IUCN Red List Species & Status:

ENDANGERED

Mekong Dolphin

Julien’s Golden Carp

NEAR THREATENED

Mekongina erythrospila

PROJECT IMPACTS

LESSONS

DON SAHONG

Lao PDR

Project predicted to destroy local population of endangered Irrawaddy dolphin and blocks a critical passage for year round fish migration in the Lower Mekong Basin

Mekong giant catfish caught prior to Don Sahong Dam construction

Image by Suthep Kritsanavarin

Endangered Irrawaddy dolphin

Image credit unknown, CC

Fish catch in the Siphandone are of the Mekong River where fishing is critical to communities' livlihoods

Image by International Rivers

Biodiversity Snapshot

IUCN Red List Species & Status:

ENDANGERED

Mekong Dolphin

Julien’s Golden Carp

NEAR THREATENED

Mekongina erythrospila

Company: Power China

Subsidiary: Sinohydro

Impact Category

Critical Habitat

Impact Category

Food Security

CAPACITY

290 MW

COST

$500 million​

STATUS

Operational​

Local Community Impact​

Resulted in forced eviction of communities who opposed their relocation.

1.

The dam’s significant impacts on a critical fish migration channel important for scores of fish species in the Mekong River, together with the food security of thousands of local people, should have disqualified the project from consideration.

2.

The project’s likelihood of extirpating locally endangered species, in this case the Mekong dolphin, should have disqualified the project from consideration.

3.

Company should prioritize biodiversity impact considerations in its due diligence procedures, regardless of contract type.

4.

Transboundary impact assessment and consultation process should be required for any projects considered on transboundary rivers.

5.

An adaptive approach to impact mitigation is inappropriate, particularly in the case of migratory fish species that are critical to the diets of communities living along the length of the river.