Shrinking Lake Mead
June 01, 2016
Photographer: Ray Boren
Summary Author: Ray Boren
With a little imagination, it appears as if a giant of a giant has climbed from his bath in Lake Mead, on the Nevada-Arizona border, leaving behind a pale bathtub ring of mind-boggling proportions. The reality is that drought, evaporation and continued water draw-downs have left the desert lake — born of Colorado River waters impounded behind Hoover Dam east of Las Vegas — only 37 percent full. The reservoir's water level peaked in 1983. The ring of mineral residue is evidence of the 130 feet (37 m) the surface level has dropped. Lake Mead hasn't been this low since shortly after it began filling more than 80 years ago, and will continue to decline into the summer.
The photographs here were taken on May 5, 2016, near Boulder Harbor, its boat ramp now far below the top of the bathtub ring, and Boulder Beach, a few miles from the historic dam. The concrete arch dam, built from 1931-1936, itself was originally called Boulder Dam, for Boulder Canyon, before being renamed in honor of Herbert Hoover, who was the U.S. president when construction began. Along with the bathtub ring and alluvial deposits, a deep geological history surrounds Lake Mead, from lava flows dating back 6 million years ago to 1.8-billion-year-old gneiss, and evidence of eons of sedimentary strata, tectonic pressures and volcanic activity in between.
Named for Dr. Elwood Mead, a U.S. Bureau of Reclamation chairman and commissioner from 1924-1936, the reservoir is the centerpiece of the Lake Mead National Recreation Area, stretching along nearly 140 mi (225 km) of the Colorado River corridor and encompassing a 1.5 million-acre (607,028 hectares) unit of the National Park Service. Three of the four desert ecosystems in the United States meet in the recreation area: the Great Basin, Sonoran and Mojave Deserts. The vast park is popular for boating, waterskiing, personal watercraft riding, fishing, swimming, hiking and sight-seeing while Hoover Dam itself is a major tourist attraction.
Photo Details: Top - Camera Model: NIKON D3200; Lens: Sigma 150-500mm F5-6.3 DG OS APO HSM; Focal Length: 220mm (35mm equivalent: 330mm); Aperture: ƒ/5.6; Exposure Time: 0.0020 s (1/500); ISO equiv: 110. Bottom - Same except: Lens: AF-S VR Zoom-Nikkor 70-300mm f/4.5-5.6G IF-ED; Focal Length: 70mm (35mm equivalent: 105mm); Aperture: ƒ/11.0; ISO equiv: 400.