The term 'Glen Canyon Structure' refers to the Glen Canyon DAM, a concrete arch-gravity DAM on the Colorado River in northern Arizona. The DAM was built between 1956 and 1966 and is the second-tallest DAM in the United States. It impounds Lake Powell, one of the largest man-made reservoirs in the country. The DAM is named after Glen Canyon, a series of deep sandstone gorges that were flooded by the reservoir. The DAM serves to provide hydroelectric power, regulate water flow, and prevent flooding downstream.