Effects of Glen Canyon Dam on Riparian Vegetation in the Grand Canyon

Sandbar at River Mile 55 (55 miles downstream from Lees Ferry) on the Colorado River. The floodflows of 1983 eroded the vegetation from this bar, which was still nearly free of vegetation when this photograph was taken in October 1987.

Same sandbar in November 1990. In the absence of flooding, vegetation has recolonized the bar.

Before Glen Canyon Dam was built, riparian (near-water) vegetation was scoured from the river banks during seasonal high flows.

Following dam construction, protection from annual high flows permitted riparian vegetation to develop at lower elevations in a new zone that provides more than 1,000 acres of additional habitat for native wildlife.

Marshes probably did not occur in Glen and Grand Canyons before dam construction, but now are present and greatly enhance the plant diversity in the river corridor.

Various plants in the riparian zone and many of the animals supported by it have cultural significance to Native Americans.

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