The Lower Mekong

Despite significant changes to the Upper Mekong, or the Lancang as it is known in China, the middle and lower Mekong have remained ecological treasures. Whilst these ecosystems have faced other pressures, from irrigation demands, pollution, fishing pressures and invasive species, the river system still hosts an incredible diversity of freshwater species and supports the lives and livelihoods of more people than any other river on Earth.

For example, excluding estuarine species, the Mekong river basin is known to hold 877 fish species, as well as enigmatic and charismatic species such as the Irrawaddy dolphin and the giant softshell turtle. The wider river basin is also recognised as a biodiversity hotspot, between 2012 and 2014, 367 new species were discovered in the Greater Mekong river basin. Meanwhile the Mekong watershed is also home to approximately 65 million people, about two thirds of which live in rural areas relying on subsistence fisheries for their diet and income.

Planned (red dots) and existing dams or dams under construction (white dots) in the Congo and Mekong basins (Winemiller et al., 2016).

The main threat to the Mekong comes from the planned construction of 88 new dams on the mainstream and its tributaries between 2015 and 2030 (Winemiller et al., 2016). There has been a particular focus on the construction of mainstream dams on the middle and lower Mekong, which had to date remained free-flowing. There are currently 11 planned dams, nine of which will be in Lao PDR. The plan is for power generated by dams in Lao and Cambodia to be exported predominately to Thailand and Vietnam. Lao PDR supposedly hopes to become “the battery of southeast Asia”, financing its development on the basis of exported energy. However, in this vision the incredible value of the naturally flowing Mekong is discounted. Furthermore, whilst the vision is justified on the benefits of an entire network of hydropower dams, the social, ecological, cultural and economic costs of each dam are considered in isolation, if at all. The one independent SEA conducted by the MRC is a robust scientific document, yet it almost reads like a plea against pressing ahead with the construction of the mainstream dams, particularly without any pause for breath and analysis of the impact of the first dams to come ‘on-stream’. For example, it points to the impacts on fisheries productivity (87% of fish species in the river are migratory), the likelihood of increasing poverty in rural and urban riparian communities, exacerbating inequality and driving species extinctions. As Giv et al., (2015) show, it is also not only mainstream dams, but the 78 planned tributary dams which will have strong and non-linear social and ecological trade-offs.

When other threats to the Mekong are considered, such as plans to blast its rapids to make it navigable for freight barges; its sensitivity to climate change impacts; growing human development pressures; pollution, and invasive species, it seems unfeasible that we can protect the rivers ecological integrity. However, across the region there are many grassroots organisations working to conserve the free-flowing Mekong. Despite political regimes making it a challenging context for civil society to operate, there are a growing number of groups now working across the region to advocate for the rights of river-dependent communities and for the river’s protection from industrial development and failing that, mitigation and restoration that will help restore some of the losses.