Lake Mead
| Lake Mead Hoover Dam |
|||||||||
|---|---|---|---|---|---|---|---|---|---|
 |
|||||||||
|
|||||||||
|
|||||||||
| Coordinates | 36 ° 3 '35 " N , 114 ° 46' 35" W | ||||||||
| Data on the structure | |||||||||
| Data on the reservoir | |||||||||
| Altitude (at congestion destination ) | 372.28 m | ||||||||
| Water surface | 639 km² | ||||||||
| Reservoir length | 170 km | ||||||||
| Maximum depth | 149 m | ||||||||
| Storage space | 35,175 million m³ | ||||||||
| For information on the dam, see Hoover Dam | |||||||||
 |
|||||||||
| Lake Mead National Recreation Area | |||
|---|---|---|---|
 |
|||
|
|||
| Location: | Nevada , Arizona , United States | ||
| Next city: | Las Vegas | ||
| Surface: | 6,053 km² | ||
| Founding: | October 8, 1964 | ||
| Visitors: | 6,396,682 (2011) | ||
_location_map.svg)
The Lake Mead is a 1936 of completed dam the Colorado River downstream from the Grand Canyon in the Black Canyon . The lake is dammed by the Hoover Dam . It is located about 50 kilometers southeast of Las Vegas , on the border of the US states of Arizona and Nevada, and is used to generate hydropower and as a reservoir for the drinking water supply in Southern California and for irrigated agriculture in Arizona, Nevada and California.
Lake Mead is considered to be the most important reservoir in the United States because of its size and the functions it provides to the western United States.
The reservoir
With a length of 170 km, a depth of up to 149 m, an area of 640 km² and a storage volume of up to 34.9 billion m³, it is the largest man-made lake in the United States. It is dammed by the Hoover Dam , because of the construction of which several communities had to be abandoned and evacuated, including the town of St. Thomas in Nevada, the ruins of which can still be seen when the water level of Lake Mead is low.
Lake Mead is named after Elwood Mead , who served as Commissioner from 1924 to 1936 in the Bureau of Reclamation , a subdivision of the Home Office, and was responsible for the Boulder Canyon Project , which led to the construction of the Hoover Dam.
Investigations of the area in 2012 rated the water quality of Lake Mead as good, the role as a habitat for endangered animal species as important and the stock of anglers as sufficient. In the 1990s, threats to water quality from inadequate sewage treatment plants in the rapidly growing city of Las Vegas and chemical pollution from industrial operations in the area were identified. Since then, various government, Nevada and federal agencies have been working together to reduce the dangers. A 2013 report by the United States Geological Survey described the protective measures as a significant improvement in the situation. The Las Vegas wastewater treatment plants were expanded and wetlands were renatured in the Vegas Wash , an only seasonal water-bearing inflow to the lake. Today, the region's industry no longer discharges any pollutants into the tributaries of the lakes, contaminated sites in the form of soils that were contaminated by previous companies are being remedied.
The level of Lake Mead has sunk almost continuously since it was last completely filled (2000), with the exception of the winter of 2010/2011, the increases caused by the snowmelt in the Rocky Mountains could never offset the extraction over the summer months. As a result of the drought in the western United States , the annual average water level in Lake Mead fell particularly sharply between 2012 and 2016. In 2012 it was 1,122 feet (342 m) above sea level. d. M. , in 2016 it was only 1077 feet (328 m). The lowest level to date since the reservoir was first completely filled (1941) was measured on July 1, 2016 at 1,071.61 feet. The level has been rising slowly since 2016, but is still far from being completely filled. Even the record winter of 2019/2020 was only able to raise the water level to 1099 feet, which is over 35 m below a complete filling.
The critical level was set to be less than 1075 feet in January; should this value be fallen short of, the allocation of the water between the states of California, Nevada and Arizona would have to be determined and thus rationed. If the water level falls below 1025 feet, power generation at Hoover Dam would be problematic.
Because of the shallow banks in many places, the amount of water in Lake Mead drops significantly more than the relative loss of height at the dam shows: The amount of water contained in the lake is only about half as large at a fill level of 1,100 feet as when it was completely filled in 1220 Feet, at 1050 feet, it would be just over a third. Another problem of Lake Mead is sediment input: By removing the water from the surface in still waters, no sediment is removed, while a lot of sediment is brought in from the inflow. As a result, Lake Mead has already lost nearly 10% of its capacity since 1935.
Lake Mead National Recreation Area
Lake Mead is located in the center of the Lake Mead National Recreation Area , a recreation and nature reserve under the administration of the US federal agency National Park Service . The area also includes Lake Mohave on Colorado below Lake Mead, as well as larger parts of the three deserts Mojave Desert , Great Basin and Sonoran Desert , which merge around Lake Mead.
Lake Mead is both a recreational area for the residents of Las Vegas and a destination for national tourists, and in 2011 it ranked fourth in all federally administered recreational and protected areas, or sixth if the recreational roads were also included.
The primary uses of Lake Mead National Recreation Area are commercial boat excursions, rented motor boats for short tours, or renting houseboats for overnight stays on the water. There are also fishing and swimming , as well as hiking in the surrounding deserts.
The park is mainly geared towards day visitors, so apart from the houseboats and several campsites, there are no accommodations in the park itself and very few in the immediate vicinity.
Due to its proximity to Las Vegas, the park rangers' educational offerings reach many schools, especially elementary schools. In short lectures and excursions, the children are taught plants and animals, ecological relationships and the basics of nature conservation .
To the east of the Lake Mead National Recreation Area is the Gold Butte National Monument .
Web links
- National Park Service: Lake Mead National Recreation Area (official site; English)
- United States Geological Survey: A Synthesis of Aquatic Science for Management of Lakes Mead and Mohave , January 2013
- NASA satellite images of water loss: Comparison between May 1984 and May 2016
- Lake Mead in the United States Geological Survey's Geographic Names Information System
Individual evidence
- ↑ a b Summary of the USGS report on Nationalparkstraveler: Report On Lake Mead National Recreation Area's Aquatic Health Holds Mostly Good News , February 15, 2013
- ↑ United States Geological Survey: A Synthesis of Aquatic Science for Management of Lakes Mead and Mohave , January 2013
- ↑ water-data.com: Lake Mead Water Database , July 2020
- ^ Marie-Astrid Langer: Fears about America's largest reservoir . In: Neue Zürcher Zeitung , August 6, 2015. Accessed February 1, 2017.
- ↑ https://www.nps.gov/lake/learn/nature/storage-capacity-of-lake-mead.htm
- ^ National Park Service: Public Use Statistics - Annual Abstract 2011