Bishop Canyon, Utah. The lower reaches of the Escalante Canyons was flooded by the waters of Lake Powell when Glen Canyon Dam was finished in 1963. The waters of the Colorado River backed up into Bishop Canyon, shown here, and were 35-feet deep at this location when the reservoir last topped off in 1999. The recent drought in the West dropped the water level of Lake Powell to a point 145-feet below its high-water mark in the spring of 2005. Two years of above-average snowpack have since raised the level of the reservoir about 60 feet. With increasing demands on the Colorado River, it will take many, many years of above-average snowfall to fill Lake Powell to its normal elevation of 3700 feet above sea level.