Study suggests small dams have more negative effects than large dams

Small hydropower plant in Fugong County discharges water (Credit: Kelly Kibler)

A recent study suggests that small dams may have a greater impact on rivers than large dams, as they divert more water away from rivers, according to a press release from the American Geophysical Union.

Researchers from Oregon State University studied China’s Nu River, which is home to a variety of dams in the river main stem and its tributaries.  In total, 31 small dams were evaluated and compared to four large dams in the main river stem.

The research team compared dam impacts to habitat loss, river channel lengths, land affected and landslide risks among 14 total factors.  They found small dams had a greater negative impact in nine out of 14 categories.

Small dams, used to divert water to hydropower stations, had some of the most profound impacts on rivers. Many diminished water supplies downstream.

Image: A small hydropower plant in Fugong County discharges water from a tributary into the main channel of the Nu River. (Credit: Kelly Kibler)