Hydrology

The Las Vegas Valley is a bowl-shaped basin surrounded by rugged mountain ranges. The entire hydrographic basin is 1,600 square miles. The western edge of the Valley is located approximately five miles west of Lake Mead, which is an impoundment on the Colorado River. The Valley occupies a structural basin in the Basin and Range Province of the northern Mojave Desert, and most shallow ground water and all surface flows are tributary to Lake Mead via the Las Vegas Wash.

The Valley is bounded virtually on all sides by mountain ranges that reach a maximum elevation of almost 12,000 feet above sea level (in the Spring Mountains to the west). The Valley floor elevation ranges from about 3,000 feet in the west at the mountain front to 1,500 feet in the east at the outflow of the Valley.

The Las Vegas Wash has four major flow components: Reclaimed Water, Urban Runoff, Shallow Ground Water and Stormwater. These flows travel to the Wash through one of the tributaries, then flow into Lake Mead on the Colorado River.