Fauna & Flora International warns of environmental impacts of Lao dam project

Fauna & Flora International (FFI) are increasingly concerned about the development of plans to go ahead with the building of the first hydroelectric dam on the Mekong River at Xayabouri in northern Lao PDR.

“There will be major impacts on biodiversity, fisheries and food security. The dams will block vital fish migration routes, reduce wetland area and change the habitat necessary for many elements of Mekong fisheries. This is significant as river fish provide a substantial part of the average Cambodian diet,” said Matt Maltby, Projects Officer at FFI Cambodia.

Our concerns are based on the Strategic Environmental Assessment (SEA) prepared for the Mekong River Commission (MRC) and conducted by the International Centre for Environmental Management (ICEM).

The assessment identified a number of far reaching environmental impacts. These impacts include an estimated fishery loss of 26 to 42 percent, which would cost around USD 500 million per year, with Cambodia expected to suffer the most.

The SEA states that the decision to go ahead with the dams must be taken with the knowledge that the loss in biodiversity “would be a permanent and irreplaceable global loss which could not be compensated”.

The proposed dam is also a significant issue as five percent of the land in the area impacted by the proposed dam is composed of National Protected Areas and Wetlands of International Importance (Ramsar) sites.

Iconic and critically endangered species, such as the Irrawaddy dolphin and the giant Mekong catfish are threatened by these developments.

Through changes to the river’s morphology, flow and aquatic habitat, the globally significant biodiversity of the Mekong River will be threatened. More than 100 species would be placed at risk.

Effects of dams on ecosystems

The environmental impacts of dams on ecosystems are widespread– affecting terrestrial as well as river ecosystems, as a result of inundation caused by the dam’s reservoirs and the breaking of natural water flows.

Dammed rivers reduce flood rates, impacting badly on the floodplains that rely on seasonal variations of water. Dams prevent sediments that replenish downstream ecosystems naturally.

A reduction of sediment flow of more than 50% has serious consequences on the transport of critical nutrients, such as phosphorus and nitrogen which fertilize riverbanks and flood plains.

The loss of water-dependent species and habitat loss is common following the construction of dams. This is because dams change the whole environment of a river to which all surrounding ecosystems have adapted.

Need for further consultation

FFI supports the findings of and recommendations of the SEA to defer decisions on building this dam and further mainstream dams for up to ten years.

This will enable a comprehensive suite of feasibility studies to take place and for further distribution of the SEA report within each affected country in national languages. It will also allow for consultation with other agencies, the private sector, the NGO community and other stakeholders in government.