In their graphic story “Starving the Mekong”, Reuters’ team shows the huge impact hydropower projects have on sediment flow along the Mekong River. By amazing visual storytelling they follow the longest river in Southeast Asia nearly 5,000 kilometres downstream from the Plateau of Tibet to the South China Sea.

“Studies estimate that 96% of the sediment load will be trapped once all dams proposed in the Mekong Basin are in operation”, it says.

And this was EOMAP’s part: Together with Reuters we analysed over 1,500 satellite images around four major dams. Turbidity served as a proxy for sediment levels, an approach that we had validated on various rivers before.

🛰 In this case, like in many other river monitoring cases, the view from space offers 3 key advantages:

1. Go back in time: The images for the Mekong analysis date back to the 1990s, which “allows us to calculate turbidity levels before many of the dams were built,” says our data analyst Philipp Bauer.

2. Detect changes: Comparing data over three decades makes impacts on sediment flow visible.

3. Get the big picture: Geospatial data offer a view on the entire river catchment. It also enables to investigate the impacts of each cascade.

Christopher Howe of WWF has commented as follows: “Hydro dams may, in the right places, help reduce carbon emissions. But in the case of the Mekong they trap the life force of the river, the sediment. This increases the climate vulnerability of many millions of people, huge sectors of the economy of Cambodia and Viet Nam, and the incredibly valuable and diverse biodiversity of the region.”

To reduce such drastic impacts, we have – together with European partners – developed a new toolbox. With HYPOS, we wish to support sustainable hydropower planning, for the sake of nature and people.

We congratulate Kanupriya Kapoor, Simon Scarr and their colleagues of Thomson Reuters on this great work.