Tag Archives: hydroelectric power

The Connected Consequences of River Dams

In a case study of dams on the upper Missouri River, USGS researchers have demonstrated that an upstream dam is still a major control of river dynamics where the backwater effects of a downstream reservoir begin. In light of this finding, the conventional understanding of how a dam can influence a river may have to be adjusted to account for the fact that effects of river dams can interact with one another.

“We have known for a long time that dams have dramatic effects on river form and function,” said Jerad Bales, acting USGS Associate Director for Water. “In the past, however, the effects of dams generally have been studied individually, with relatively little attention paid to how the effects could interact along a river corridor.” (more…)

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American Eels Return to Mountain Streams after Dam Removal

Shenandoah National Park, Va. – American eels are declining across their range but are showing indications of a population revival following the removal of a large dam in Virginia.

The removal of Embrey Dam on the Rappahannock River increased American eel numbers in headwater streams nearly 100 miles away, according to research just published by U.S. Geological Survey, U.S. Fish and Wildlife Service, and National Park Service researchers.

American eels undergo long-distance migrations from their ocean spawning grounds in the Sargasso Sea to freshwater streams along the Atlantic coast from northern South America to Greenland. Dams may slow or even stop upstream eel migrations.  However, prior to this research, little was known about American eel responses to dam removal. (more…)

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