A: Lake Powell is only 13% of the National Recreation Area, but one of the largest man-made lakes in North America. At full pool (3700' elevation) it is 186 miles (299 km) long, has 1960 miles (3161 km) of shoreline, over 96 major side canyons, and a capacity of 27 million acre-feet (32 million cubic meters). Its maximum depth (at Glen Canyon Dam) is 561 feet (171 m).