Lake Powell, Utah. A 140-foot tall "bathtub" ring stains the canyon walls in Glen Canyon as a result of a prolonged 6-year drought which at its lowest point reduced the capacity of Lake Powell to 32% of its full-pool volume in April of 2005. Renowned for its spectacular deep and narrow sandstone canyons, Glen Canyon was flooded by the waters of Lake Powell as the waters in the Colorado river began to back up when the diversion tunnels around Glen Canyon Dam were screwed shut in 1963.