Hydropower dams cool rivers in the Mekong River basin, satellites show

UW News –

Hydropower dams, which use flowing water to turn a series of turbines to generate electricity, provide a source of energy that doesn’t rely on fossil fuels. But they also disrupt the flow of rivers, and impact the fish and people that live there.

Scientists have been monitoring many environmental effects of dams, including how they affect a river’s temperature — and could potentially threaten the fish downstream.

Researchers at the University of Washington were interested in studying how several hydropower dams affected the temperature of three major rivers in Southeast Asia’s Mekong River basin. Since 2001, each river has seen the construction of at least one major dam, with more planned. The three rivers converge into the Mekong River, which people rely on for fish and irrigation for rice and other crops.

Using 30 years of satellite data, the team discovered 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. The researchers published their findings Feb. 13 in the journal Environmental Research Letters. The team is also speaking about related research Feb. 15 at the American Association for the Advancement of Science annual meeting in Seattle.

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