Lake Mead

Lake Mead
Location	Clark County, Nevada / Mohave County, Arizona
Coordinates	36°03′35″N 114°46′35″W / 36.05972°N 114.77639°W / 36.05972; -114.77639Coordinates: 36°03′35″N 114°46′35″W / 36.05972°N 114.77639°W / 36.05972; -114.77639
Lake type	reservoir
Primary  inflows	Colorado River
Primary  outflows	Colorado River
Basin  countries	United States
Max. length	110 mi (180 km)
Surface area	248 sq mi (640 km2)
Max. depth	500 ft (165 m)
Water volume	35.2 km3 (28,500,000 acre·ft)
Shore  length1	550 mi (885 km)
1 Shore length is not a well-defined measure.

Lake Mead is the largest reservoir in the United States. It is located on the Colorado River about 30 miles (48 km) southeast of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by water impounded by the Hoover Dam, it extends 112 miles (180 km) behind the dam, holding approximately 28.5 million acre feet (35 km³) of water. The water held in Lake Mead is released to communities in Southern California^[1] and Nevada, via aqueducts.

History

Elwood Mead

The lake was named after Elwood Mead, who was the commissioner of the U.S. Bureau of Reclamation from 1924 to 1936 during the planning and construction of the Boulder Canyon Project that created the dam and lake. Lake Mead was established as the Boulder Dam Recreation Area in 1936, administrated by the National Park Service. It was then changed to the Lake Mead National Recreation Area in 1964, this time including Lake Mohave and the Shivwits Plateau under its jurisdiction. Both lakes and the surrounding area offer year-round recreation options. The accumulated water from Hoover Dam forced the evacuation of several communities, most notably St. Thomas, Nevada, whose last resident left the town in 1938.^[2] The ruins of St. Thomas are sometimes visible when the water level in Lake Mead drops below normal.^[2]

During drought a high-water mark or "bathtub ring" is visible in photos that show the shoreline of Lake Mead. The bathtub ring is white because of the deposition of minerals on previously submerged surfaces.^[3]

Geography

Lake Mead, May 2, 2006

Lake Mead from space, November 1985. North is facing downward to the right. The Colorado River can be seen leading southward away from the lake on the top left. The Hoover Dam is located where the river meets the lake.

Access from the northwest from Interstate 15 is through Valley of Fire State Park and the Moapa River Indian Reservation.

The lake is divided into several bodies. The large body closest to the Hoover Dam is Boulder Basin. The narrow channel, which was once known as Boulder Canyon and the original planned site for the dam is now known as The Narrows, connects Boulder Basin to Virgin Basin to the east. The Virgin River and Muddy River empty into the Overton Arm, which is connected to the northern part of the Virgin Basin. The next basin to the east is Temple Basin, and following that is Gregg Basin, which is connected to the Temple Basin by the Virgin Canyon. When the lake levels are high enough, a section of the lake farther upstream from the Gregg Basin is flooded, which includes Grand Wash Bay and the Pearce Ferry Bay and launch ramp. In addition, there are two tiny basins, the Muddy River Inlet and the Virgin River Basin, that are flooded when the lake is high enough where these two rivers flow into the lake. As of now, however, these basins remain dry.

Jagged mountain ranges surround the lake, offering somewhat of a startling but beautiful backdrop, especially at sunset. There are two mountain ranges within view of the Boulder Basin, the River Mountains, oriented north-west to south-east and the Muddy Mountains, oriented west to north-east. From the Virgin Basin, you can view the majestic Bonelli Peak towards the east.

Las Vegas Bay is the terminus for the Las Vegas Wash which is the sole outflow from the Las Vegas Valley.

Drought

Lake Mead as seen from the Hoover Dam clearly showing the "bathtub ring"

As of May 2009, the lake is currently at 43 percent of its capacity, threatening to make the Las Vegas valley's primary raw water intake inoperable. There remains a mystery of the water levels though, considering upstream Lake Powell has been raising its water levels. If the lake doesn't receive enough inflow this spring, problems may arise later this summer.^[4] Arrangements are underway to pipe water from elsewhere in Nevada by 2011, but since the primary raw water intake at Lake Mead could become inoperable as soon as 2010 based on current drought and user projections, Las Vegas could suffer crippling water shortages in the interim.^[4] Lake Mead draws a majority of its water from snow melt in the Western Colorado Rockies. Since 2000 the water level has been dropping at a fairly steady rate due to less than average snowfall. As a result, marinas and boat launch ramps have either needed to be moved to another part of the lake or have closed down completely. The Las Vegas Bay Marina and the Lake Mead Marinas were relocated a few years ago to Hemenway Harbor. Overton Marina has been closed due to low levels in the northern part of the Overton Arm. Government Wash, Las Vegas Bay, and Pearce Ferry boat launch ramps have also been closed. The marinas that remain open include Hemenway Boat Harbor, Callville Bay Marina, Echo Bay Marina, and Temple Bar Marina, along with the Boulder Launch Area (former location of the Lake Mead Marina) and the South Cove launch ramp.^[5]

Further research in February 2008 by the University of California in San Diego led researchers to conclude that, if future climate changes as projected and water use "is not curtailed," Lake Mead's water level could drop below the dead storage elevation by 2021, and that the reservoir could drop below minimum power pool elevation as early as 2017. ^[6]

Recreation

Lake Mead Marina, a place to rent or fuel boats. Note, the marina has been moved to Hemenway Harbor due to low water levels.

Lake Mead offers many types of recreation to locals and visitors. Boating is the most popular. Additional activities include fishing, water skiing, swimming and relaxing in the sun. There are several marinas on the lake that rent luxury houseboats: Forever Resorts and Seven Crowns. With other smaller ones that rent small boats. The area also has many coves with rocky cliffs and sandy beaches to explore. There are several small to medium-sized islands in the lake area depending on the water level. In addition, the Alan Bible Visitor Center has a small cactus garden of plants native to the Mojave Desert.

B-29 Crash

At the bottom of the lake is a B-29 Superfortress that crashed while performing secret experiments. It has been acknowledged that one of the then classified instruments on board used to take atmosphere measurements was called "Suntracker".^[7]

See also

United States portal

• List of reservoirs and dams in the United States

References

External links

Wikimedia Commons has media related to: Lake Mead National Recreation Area

• http://lakemead.water-data.com Lake Mead Water Database
• Lake Mead National Recreation Area - National Park Service
• Arizona lakes water level report
• Lake Mead water levels graph Historical and current water levels in Lake Mead