Hydroelectric Dams Produce 20 Times more Methane Gas when Water Level is Low

Published on January 11, 2013 10:28 by Water Network Research, Official research team of The Water Network in Technology

Typically, at moderate sizes, power generated by dams and reservoirs is considered "green." However, a new study from Washington State University has found that during times of drawdown — a period in which the water level behind a dam is rapidly lowered — temperate reservoirs can produce up 20 times more methane than normal.

Though researchers have long known that methane levels spike in reservoirs during drawdown, this study was the first to show the relationship and put a number on the actual methane emissions.

A 2011 study published in the science journal Science found that the "ability of terrestrial ecosystems to act as carbon sinks," which contain greenhouse gasses and keep them out of the atmosphere, could be up to one quarter less than previously thought when the greenhouse gas release from reservoirs is taken into consideration.

Clearly, the problem is not negligible — particularly when we consider the number of mega-dams being constructed around the world.

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