Lake Mead on the Colorado River is one of the most intensely used reservoirs in the western United States, providing recreational watercraft activities and domestic drinking, industrial, and irrigation water for over 22 million users. The quality of this water must be maintained to guarantee a reliable and safe resource for its many uses. Inflow into Lake Mead primarily is from the Colorado River; however, about 3 percent of the inflow is from tributaries on the northern side of the Lake and from Las Vegas Wash on the northwest side of the Lake.

The U.S. Geological Survey, in cooperation with the National Park Service and the Southern Nevada Water Authority, is currently collecting water-quality data in the Boulder Basin of Lake Mead near Sentinel Island. Meteorological data is also being collected near Sentinel Island in cooperation with the Clark County Water Reclamation District. Discontinued stations that collected water-quality and meteorological data were located in: (1) Las Vegas Bay (Sites 1-4), (2) Overton Arm Basin near the confluence of the Muddy and Virgin Rivers, (3) Temple Basin near the Temple Bar Marina and (4) Virgin Basin, near the Narrows, which separates the Virgin and Boulder Basins. Water-quality and meteorological data are available on this web site for past and current stations and can be accessed under the Near-Real Time & Quality-Assured Data tab.