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Restoring a Damned River with Experimental Flooding

11/30/2018

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Lake Powell and Glen Canyon Dam
Experimental releases that mimic natural floods have nudged the Colorado River ecosystem back toward its natural state, but have not fully restored the river.
This article, and others in the series "Parks in Science History", was written by a graduate student at the University of Maryland. Follow the link below to read the full article.

https://www.nps.gov/articles/dams-grca.htm

The Glen Canyon Dam on the Colorado River in northern Arizona was completed in 1963 to produce electrical power. It created the Lake Powell reservoir and disturbed the river ecosystem in Grand Canyon National Park downstream. It is also a key player in one of the most interesting ecological experiments in decades, inspired by the work of Dr. John (Jack) Schmidt of Utah State University, and conducted by the Glen Canyon Dam Adaptive Management Program and the Department of Interior. Dr. Schmidt, and colleagues who conducted research on the river in the early 1990s, realized that many features of the river ecosystem were created and maintained by seasonal floods caused by melting snow in the Rocky Mountains. The only way those features could be restored would be to release controlled floods from the dam. Flood releases could be conducted without endangering human life or property because all of the downstream area is within a national park. The controlled experimental floods provide lessons that can be applied in other parts of the nation.

The experimental controlled floods have nudged the river ecosystem back toward its natural state in some respects. The sandbars have grown again, but some vegetation and non-native fish remain. Native habitats were improved in many places, while non-native habitat remains in others. The floods clearly helped, but didn’t fully restore the river.