FEB 13, 2020 1:32 PM PST

Dams in the Mekong lower river temperatures

A study discussing the environmental impacts of hydropower dams on rivers in the Mekong River basin was published recently in Environmental Research Letters. The findings from the study will be presented on February 15 at the American Association for the Advancement of Science annual meeting in Seattle.

According to researchers at the University of Washington, the presence of hydropower dams has resulted in a significant drop in temperature in three rivers in the Mekong River basin. At least one major dam has been built in each river since 2001 and more construction is planned. The Mekong River is the twelfth-longest in the world and seventh-longest in Asia. Many people depend on it for fish and irrigation for rice and other crops.

The researchers’ findings for these three rivers deviates from previous studies on other rivers. "People have modeled how far they could see a cooling effect after a hydropower dam goes in. In the U.S., that cooling tends to be localized around the dam. But what we see in the Mekong is like, 'Wow!'" said senior author Faisal Hossain, a civil and environmental engineering professor at the UW. "Everything has happened very dramatically in the last 20 years. Lots and lots of dams were just suddenly coming on, left and right. And now we can see this cooling effect that is no longer localized but continuing into the river system. We've never seen anything like it, to the best of our knowledge."

The team analyzed 30 years of satellite data to contemplate the effects of the dams on the Sekong, Sesan and Srepok rivers. The data they used came from Landsat satellite images, which looks at infrared radiation from the rivers. "With these data, we're looking at the temperature emissions from the rivers. It's like night vision: Warmer things give off more emissions, colder things give off less," said lead author Matthew Bonnema.

According to Science Daily, they found that “within one year of the opening of a major dam, downstream river temperatures during the dry season dropped by up to 3.6 degrees F (2 degrees C). The cooling persisted where the rivers meet the Mekong River, which showed, at most, a 1.4 F (0.8 C) cooling.”

Many people depend on the Mekong River Basin for their livelihoods. Photo: Pixabay

The fear is that the cooler water will impact the fish that live downstream, explain the researchers. "They're going to keep building these dams," Bonnema said. "If you look at where new dams are planned in the 3S Basin, they're building closer and closer to the Mekong. These are also big dams, which means the impacts on the Mekong will likely be more significant -- these temperature changes are going to get more dramatic. So, the question is how do we work with these dams to minimize their effect? My recommendation is that we slow down and think things through."

Sources: Environmental Research Letters, Science Daily

About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
JAN 16, 2020
Neuroscience
JAN 16, 2020
Early-life Stress and Pollution Lead to Cognitive Impairment
Children exposed to high levels of stress at home from early on and high levels of air pollution while still in the womb are more likely to develop attenti...
JAN 19, 2020
Plants & Animals
JAN 19, 2020
Flying Foxes Must be Careful of Crocodiles When Hydrating
Flying foxes absolutely despise the Sun, and with that in mind, it should come as no surprise to anyone that they look for shade whenever possible. One pro...
JAN 21, 2020
Earth & The Environment
JAN 21, 2020
Scientists Assess GHG Emissions Related to Palm Oil Land Conversion
Palm oil production remains problematic in several ways, and a new study from researchers at the University of Nottingham has quantified one of these probl...
MAR 09, 2020
Earth & The Environment
MAR 09, 2020
Can we learn from the destruction of Myanmar's mangroves?
Research from the National University of Singapore (NUS) highlights the growing concern of mangrove degradation, using Myanmar as a case study. Myanmar has...
MAR 19, 2020
Chemistry & Physics
MAR 19, 2020
The "Android" Approach to Nuclear Power
Nuclear power plants, whether you like them or not, produce a significant portion of the carbon-free electricity at the moment worldwide. With a wave of hi...
MAR 21, 2020
Chemistry & Physics
MAR 21, 2020
Ergodic Theory Earned Retired Duos the Top Prize in Maths
The Abel Prize, organized by the Norwegian Academy of Science and Letters, is the world's highest honor in mathematics. It was established in memory of...
Loading Comments...