Where’s the water coming from? Underground springs! Springs are the natural exit points where groundwater flows from an aquifer to land surface and becomes surface water. Some springs, called thermal springs, are linked to natural processes happening underground, like volcanoes or magma. This makes the water that comes out really warm. Lake Mead National Recreation Area has a variety of natural hot springs across the park. One interesting spring is in Black Canyon below Hoover Dam, as shown in t