The Rebounding Lake Mead Water Level and Its Causes

Water levels in Lake Mead are at their lowest point since April 1937, when the reservoir was still being filled for the first time, continuing a 22-year downward trend. Only 27% of Lake Mead’s capacity was reached as of July 18, 2022.

Millions of people in seven states, tribal territories, and northern Mexico get water from the biggest reservoir in the United States. Additionally, it currently serves as a striking example of climate change and what may be the longest drought in the American West in the last 12 centuries.

The drought is affecting 74 percent of the nine Western states, with 35 percent of the region experiencing severe or exceptional dryness. In Colorado, the state that contains the headwaters of the Colorado River, 83 percent of the state is now experiencing a drought, and several areas had below-average snowpack last winter.

The natural-color photos above were taken by Landsat 7 and Landsat 8 on July 6, 2000, and July 3, 2022. A view from Landsat 8 on July 8, 2021 is also seen in the detailed photos below (middle). The mineralized portions of the lakeshore that were submerged while the reservoir was closer to capacity are visible along the shorelines in 2021 and 2022. The occurrence is often called a “bathtub ring.”


The U.S. Bureau of Reclamation (USBR), which oversees Lake Mead, Lake Powell, and other areas of the Colorado River watershed, provided the lake elevation information below. The Hoover Dam’s water level was 1199.97 feet (317.4 metres) above sea level at the end of July 2000, and it was 1041.30 feet (317.4 metres) above sea level as of July 18, 2022. (341 meters). For the hydroelectric turbines at the dam to continue running normally, lake levels need remain above 1000 feet.

Near the dam, Lake Mead would rise 1,220 feet (372 metres) and carry 9.3 trillion gallons (36 trillion litres) of water at full capacity. The summers of 1983 and 1999 were the last time the lake was close to capacity.

Each year, around 10% of the water in Lake Mead originates from local precipitation and groundwater, while the other 90% comes from snowmelt in the Rocky Mountains that flows via Lake Powell, Glen Canyon, and the Grand Canyon before entering the Colorado River. About 40 million people—most notably residents of the cities of San Diego, Las Vegas, Phoenix, and Los Angeles—as well as 4 to 5 million acres of agriculture in the Southwest—have access to water and electricity because to the management of the Colorado River basin by USBR and other organisations. Through legislation like the 1922 Colorado River Compact, the river’s water is distributed among states (including indigenous territory) and Mexico.

The Colorado river system as a whole is at 35 percent capacity, while Lake Powell, which is located above Lake Mead, is now just 27 percent full. State water allocations will be reduced in 2022, according to a USBR announcement made in August 2021. Additional modelling and negotiations are being done for 2023 allocations. The Colorado River basin states were given an emergency request by USBR in June 2022 to cut their water use by 2 million to 4 million acre-feet over the next 18 months.

In addition to being an important supply of drinking water and irrigation for the Southwest, Lake Mead is a popular boating destination and national recreation area. The National Park Service reports that five of the six boat ramps/launches are now closed. The Park Service said on its website that “reshaping of the park’s shorelines has been caused by declining water levels owing to climate change and 20 years of prolonged drought.” Due to the geography and anticipated fall in water levels, expanding launch ramps will become more challenging and costly as Lake Mead continues to shrink.

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