I drove up through a cut in Echo Cliffs on my way to Page, Arizona.
On top of the Echo Cliffs there lies another exposed layer of sandstone, a little different than below. Windblown sand was deposited about 170 million years ago during the Middle Jurassic creating large-scale cross-bedding (angled lines) seen on exposed sandstone.
Glen Canyon Dam
Glen Canyon Dam, built between 1956 and 1966, stands 710 feet high, 25 feet wide at the top and 300 feet wide at the base. The dam provides water, electricity, flood control and recreation to millions of people.
The dam also radically changed the ecosystem of the Colorado River. Below the dam the water temperature dropped at least 20 degrees F causing the loss of some native fish. Without periodic flooding to wash away and redeposit sediments the entire riparian habitat changed, including the establishment of non-native plants.
Glen Canyon Dam backed up the river 186 miles creating a reservoir called Lake Powell with about 100 major side canyons and five marinas. This flooding buried many Native American ruins and outstanding geologic features.