Mekong civil society groups are urging the governments of Thailand and Cambodia to shift their Mekong River policy towards protecting ecosystems and promoting environmental justice.
The environmental campaigners and activists have spoken out ahead of Sunday's election in Thailand and an upcoming poll in Cambodia (July 23).
They want to reverse the current stance towards hydropower investment in favour of protecting the river's rich biological treasures and unique ecosystems, as well as the environmental rights of local communities across the region.
Plea to poll candidates
As a result of hydropower dam development in the Mekong region, the entire stretch of the Mekong River is now facing environmental crises that are damaging the river's ecosystems and rich natural resources, on which over 60 million people across the region depend.
Chanang Umparak, from The Mekong Butterfly, an environmental group based in Thailand, said the projects may well determine the fate of the mighty Mekong. Six nations share this international river, but the matter was barely raised during the election campaign.
According to International Rivers, 11 dams are operating in the upper Mekong River in China, while two hydropower dams -- the Xayaburi Dam and Don Sahong Dam -- are at work on the Mekong mainstream in Laos.
Three more dams are under construction -- Luang Prabang Dam, Pak Beng Dam, and Pak Lay Dam.
"Phenomena such as unseasonal fluctuations in the water level and the 'blue Mekong effect' from sediment loss both result from the dams on the river, but the governments [of the Mekong countries] are silent on this matter," Ms Chanang said.
However, even though the impacts of hydropower dams on Mekong ecosystems are clear, the Electricity Generating Authority of Thailand (Egat) earlier this year signed power deals with Laos, allowing Thailand to buy up to 10,500 megawatts of power from Pak Lay Dam and Luang Prabang Dam.
"The governments of the Mekong region normally view the river merely in terms of economic development and investment opportunity, while overlooking other vital values such as it being an important source of food and income for people, a cradle of diverse Mekong cultures, and the river being one of the major biodiversity hotspots of the world," she said.
She urged the next government to reconsider Thailand's energy strategy by revoking power purchase deals from harmful hydropower dams on the Mekong and stopping new projects.
She also called for a constitutional amendment to protect people's rights to live in a clean and healthy environment, and urged the government to work with other Mekong River Commission (MRC) member states to improve the prior consultation process (PNPCA) to ensure inclusive public participation before construction affects the river.
"A new Transboundary Investment Supervision Act is also needed to make sure all Thai direct investment abroad is carried out appropriately without negative impacts," Ms Chanang added.
Cambodia's Environment Minister Say Sam Al says his government has no concern about hydropower projects on the Mekong, as it sees hydropower development as an opportunity to advance economic prosperity and enhance corporation between Mekong countries to establish an Asean Power Grid.
Sithirith Mak, Senior Research Fellow and Head of the Environmental Unit at the Cambodia Development Resources Institute, insisted the threats from hydropower dams to the environment are real.
Tonle Sap Lake, which is the largest and most significant wetland biosphere of the Mekong River Basin, has been damaged by the impacts of upstream hydropower dams, said Mr Sithirith.
This biodiverse water body sustains more than 200 fish species and contributes to the health and prosperity of over 15 million Cambodians, according to a study by the Inland Fisheries Research and Development Institute under the Fisheries Department of Cambodia.
"However, ecological transformations have been underway at Tonle Sap Lake since 2019. The hydrological pattern of the annual reverse flow from the Mekong River into Tonle Sap Lake has altered drastically, resulting in rapid depletion of fish stocks in the lake," he said.
"According to hydrological data at Tonle Sap Lake, the pattern of annual reverse flows from the river into the lake were relatively consistent every year until 2019, when the surging tide into Tonle Sap Lake came three months late and with a significantly smaller volume of total reverse flow."
He said the annual reverse flow at Tonle Sap Lake still fluctuates unseasonably. This hydrological anomaly coincided with Xayaburi Dam commencing operation the same year. It is the first hydropower dam project to be built on the lower reaches of the Mekong River in Laos.
"As a result of the hydrological impacts, the number of fish caught in Tonle Sap Lake also fell.
"Figures show annual fish production in Tonle Sap Lake in 2020 (144,635 tonnes) has dropped by half since 2018 (291,260 tonnes)," he said.
He said the collapsing fisheries in Tonle Sap Lake will add to social and economic problems for already impoverished local communities, as people will lose their incomes and traditional livelihoods.
"The Cambodian government does not have capacity to efficiently mitigate and respond to these emerging environmental and socioeconomic problems," he said.
"So, we would like to call on the new government to prepare strategies to address these challenges."
He also urged the government to rethink the country's energy development plan by promoting clean renewable energy such as solar energy and moving away from hydropower.