A recent survey of 362 archaeological sites along the Colorado River through Grand Canyon shows most of them are eroding due to the influence of Glen Canyon Dam. KNAU’s Melissa Sevigny reports.
Stone dwellings, roasting pits, and other culturally significant sites in the Grand Canyon are protected by windblown river sand. But when Glen Canyon Dam was built six decades ago, it trapped the sediment, leaving the sites exposed to erosion.
Joel Sankey of the U.S. Geological Survey is the study’s lead author. "Back in 1973 there were 98 sites that we thought of as belonging to the best-case scenario condition, having that potential to be preserved in place by that windblown river sand," he says. "Today there’s actually only 4 of those sites that we consider to be in a best-case scenario."
The results of the survey point to the need for regular high flow releases from Glen Canyon Dam which rebuild sandbars and provide a source of sediment.
Sankey also suggests periodic low river flows to expose the sand in the river channel.
