Lake Mead is a reservoir formed by the Hoover Dam on the Colorado River in the Southwestern
United States. It is located in the states of Nevada, and Arizona, 24 miles east of Las Vegas.
It is the largest reservoir in the US in terms of water capacity. Lake Mead provides water to the
states of Arizona, California, and Nevada as well as some of Mexico, providing sustenance to nearly
20 million people, and large areas of farmland. At maximum capacity, Lake Mead is 112 miles long,
and 532 feet at its greatest depth. Lake Mead has a surface elevation of 1,229 feet above sea level.
The surface area is 247 square miles, and Lake Mead contains 28.23 million acre-feet of water.
The lake has remained below full capacity since 1983 due to drought and increased water demand.
As of 16 March 2022, Lake Mead held 31.01% of full capacity at 8.753 million acre-feet, dropping
below the reservoir's previous all-time low of 9.328 million acre-feet recorded in July 2016.
In a draft 2022 Colorado River annual operating plan, released by the U.S. Bureau of Reclamation,
a "Shortage Condition" is expected to be declared for 2022, due to the lake level falling below
1,075 feet, which will result in a projected 4.44% curtailment in downstream water delivery.
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. Lloyd Joseph Hudlow, an engineer with the Bureau of Reclamation,
came to Boulder City in March 1933 to assist in the survey and ended up as the project manager.
Lake Mead was established as the Boulder Dam Recreation Area in 1936, administered by the
National Park Service. The name was changed to the Lake Mead National Recreation Area in 1947,
and Lake Mohave and the Shivwits Plateau were later added to 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,
the last resident of which left the town in 1938. The ruins of St. Thomas are sometimes visible when
the water level in Lake Mead drops below normal. Lake Mead also covered the sites of the Colorado
River landings of Callville, and Oroville, Nevada, and the river crossing of Bonelli's Ferry, between
Arizona, and Nevada. At lower water levels, 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. Nine main access points to the lake are available.
On the west are three roads from the Las Vegas metropolitan area. Access from the northwest
from Interstate 15 is through the Valley of Fire State Park, and the Moapa River Indian Reservation
to the Overton Arm of the lake. 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 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, the Pearce Ferry Bay, and launch ramp, and about 55 miles of the Colorado River
within the lower Grand Canyon, extending to the foot of 240 Mile Rapids (north of Peach Springs,
Arizona). In addition, two small basins, the Muddy River Inlet and the Virgin River Basin are flooded
when the lake is high enough that these two rivers flow into the lake. As of February 2015,
these basins remain dry. Jagged mountain ranges surround the lake, offering a scenic backdrop,
especially at sunset. Two mountain ranges are within view of the Boulder Basin, the River
Mountains, oriented northwest to southeast, and the Muddy Mountains oriented west to northeast.
Bonelli Peak lies to the east of the Virgin Basin. Las Vegas Bay is the terminus for the Las
Vegas Wash which is the sole outflow from the Las Vegas Valley. Lake Mead receives the majority of
its water from snowmelt in the Colorado, Wyoming, and Utah Rocky Mountains. Inflows to the lake are
largely moderated by the upstream Glen Canyon Dam, which is required to release 8.23 million
acre-feet of water each year to Lake Mead. Hoover Dam is required to release 9 million acre-feet of
water each year, with the difference made up by tributaries that join Colorado below Glen Canyon
or flow into Lake Mead. Outflow, which includes evaporation, and delivery to Arizona, California,
Nevada, and Mexico from Lake Mead is generally in the range of 9.5 to 9.7 million acre-feet,
resulting in a net annual deficit of about 1.2 million acre-feet. The decreasing water
level is due to the loss of the surplus water that once made up for the annual overdraft.
In June 2010, the lake was at 39% of its capacity, and on November 30, 2010, it reached 1,081 ft,
setting a new record monthly low. From mid-May 2011 to January 22, 2012, Lake Mead's water
elevation increased from 1,095.5 to 1,134 feet after heavy snowmelt in the Rocky Mountains
prompted the release of an extra 3.3 million acre-feet from Glen Canyon into Lake Mead.
In 2012, and 2013, the Colorado River basin experienced its worst consecutive water years
on record, prompting a low Glen Canyon release in 2014 – the lowest since 1963,
during the initial filling of Lake Powell – in the interest of recovering the level of the upstream
reservoir, which had fallen to less than 40% capacity as a result of the drought. Consequently,
Lake Mead's level fell significantly, reaching a new record low in 2014, 2015, and 2016. In 2014,
its record low was 1,081 feet on July 10, 2014. On June 23, 2015, Lake Mead reached another new
record low when it briefly fell below 1,075 feet, the first official "drought trigger" elevation,
for the first time since the lake was filled. If the lake is below this elevation at the
beginning of the water year, an official shortage declaration by the Bureau of Reclamation will
enforce water rationing in Arizona, and Nevada. The water year begins October 1 to coincide with
seasonal Rocky Mountain snowfall, which produces most of the Colorado River's flow. Lake Mead's
water level rebounded a few feet by October 2015 and avoided triggering the drought restrictions.
However, the water level started falling in Spring 2016 and fell below the drought trigger
level of 1,075 feet again in May 2016. It fell to a new record low of 1,071.60 feet on July 1,
2016, before beginning to rebound slowly. Drought restrictions were narrowly avoided again when the
lake level rose above 1,075 feet on September 28, 2016, three days before the deadline,
and the Bureau of Land Reclamation did not issue a shortage declaration. A reprieve
from the steady annual decline occurred in 2017 when lake levels rose throughout the year due
to heavier than normal snowfall in the Rocky Mountains. As a result of the large snowmelt,
the lake regained the water levels it had in 2015 with a seasonal high of 1,089.77 feet.
The seasonal low of 1,078.96 feet in 2017 was close to that experienced in 2014,
safely above the drought trigger. However, that level was still 36 feet below the seasonal
low experienced in 2012, and the lake was projected to begin falling again in 2018.
Despite those and other predictions of an impending shortage determination by 2020,
a snowpack of 140% of average in the Upper Colorado River basin as of April 2019 resulted
in 128% above average inflow into Lake Powell, resulting in a 1,090.20-foot water level on Lake
Mead. In December 2019, the Lake Mead water level reached 1,090.47 feet, about ten feet
(three meters) above projections. As of April 2020, the water level stood at 1,096.39 feet,
again benefiting from an above-average mountain snowpack. Since 2018, Lake Mead's water levels
have remained well above the 1,075-foot level that would trigger a shortage determination. In
May 2020, the Bureau of Reclamation expected that the continued Colorado River basin drought would
yield a Lake Mead level of 1,084.39 feet by 2022. On January 1, 2022, the level was 1,066.39 feet,
the lowest level since 1937 when the reservoir was initially filled. As a result of the decreasing
water level, marinas and boat launch ramps have either had to be relocated to another area of
the lake or have closed down permanently. The Las Vegas Bay Marina was relocated in 2002,
and the Lake Mead Marina was relocated in 2008 to Hemenway Harbor. Overton Marina, and Echo Bay
Marina have 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. Las Vegas Boat Harbor and
Lake Mead Marina in Hemenway Harbor/Horsepower Cove remain open, along with Callville Bay Marina,
Temple Bar Marina, Boulder Launch Area (former location of the Lake Mead Marina), and the South
Cove launch ramp. Changing rainfall patterns, climate variability, high levels of evaporation,
reduced snowmelt runoff, and current water use patterns are putting pressure on water management
resources at Lake Mead as the population relying on it for water, and the Hoover
Dam for electricity, continues to increase. To lower the minimum lake level necessary to
generate electricity from 1,050 feet Hoover Dam was retrofitted with wide-head turbines,
designed to work efficiently with less flow in 2015, and 2016. If water levels continue to drop,
Hoover Dam would cease generating electricity when the water level falls below 950 feet, and the lake
would stabilize at a level of 895 feet when the water reaches the lowest water outlet of the dam.
In order to ensure that the city of Las Vegas will continue to be able to draw its drinking
water from Lake Mead, nearly $1.5 billion was spent on building a new water intake tunnel
in the middle of the lake at the elevation of 860 feet. The 3-mile tunnel took seven years to build
under the lake, and was put into operation in late 2015. According to a 2016 estimate, about 6% of
Lake Mead's water evaporates annually. Covering 6 percent of Lake Mead with floating photovoltaics
has a potential generating capacity of 3,400 megawatts, which is comparable to the capacity
of Hoover Dam, and would also reduce water lost to evaporation in the covered area by as much as 90%.