Cline Library

In 1994 veteran river runners joined scientists from the United States Geological Survey (USGS) and a group of historians and archivists on an expedition down the Colorado River. The participants discussed and compared environmental and experiential changes before and after the construction of Glen Canyon Dam and documented their findings with photographs, rephotography to document environmental impacts, and oral histories detailing past experiences on the river.

The USGS's Robert H. Webb, Theodore S. Melis, and Richard A. Valdez noted lower water temperatures, fewer sediment-laden flows, sand bar erosion, invasion of non-native tamarisk trees, reduction in driftwood, development of marshes, increase in non-native fish at the expense of native fishes, and increase in water bird populations. Additionally, they found evidence suggesting increases in the frequency of debris flows in the Grand Canyon, decreases in bat populations, and higher swallow and bighorn sheep populations. Perhaps more significantly, the observations and experiences gained from the trip and interviews help offer additional perspectives for Colorado River management. (From the Cline Library).

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