Lake Mojave facts for kids
Quick facts for kids Lake Mojave |
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 Lake Mojave
Location in California
Lake Mojave
Location in the United States
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| Location | Mojave Desert, San Bernardino County, California |
| Coordinates | 35°14′28″N 116°04′49″W / 35.24113°N 116.08017°W |
| Lake type | Glacial lake (former) |
| Primary inflows | Mojave River |
| Basin countries | United States |
| Surface elevation | 288 m (945 ft) |
Lake Mojave was a very old lake in the Mojave Desert of San Bernardino County, California. It was fed by the Mojave River. Over many thousands of years, this lake filled the areas where Silver Lake and Soda Lake are today. Scientists think its water might have eventually flowed into the Colorado River.
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Where Was Lake Mojave?
Lake Mojave was located in San Bernardino County, California. The city of Las Vegas is about 145 kilometers (90 miles) northeast of where Lake Mojave used to be.
The western side of the lake was surrounded by mountains that rose steeply. The eastern side was flatter, with gentle slopes and alluvial fans, which are fan-shaped deposits of sand and gravel.
How Big Was the Lake?
When Lake Mojave was at its biggest, it covered about 300 square kilometers (116 square miles). It held about 7 cubic kilometers (1.7 cubic miles) of water.
The lake had two main water levels, called the A stand and the B stand. The A stand was about 287 meters (942 feet) above sea level. The B stand was a bit lower, at 285.4 meters (936 feet). The lake was usually about 10 meters (33 feet) deep.
Today, Silver Lake and Soda Lake are in the same place where Lake Mojave once was. Soda Lake is higher than Silver Lake, so water tends to fill Silver Lake first. You can still see old beach ridges and shorelines that show where the ancient lake used to be.
How Did Lake Mojave Get Water?
Water Flow into the Lake
The Mojave River was the main source of water for Lake Mojave. Most of the Mojave River's water comes from the San Bernardino Mountains, about 200 kilometers (125 miles) southwest.
Long ago, the climate was wetter, and more rain fell in the mountains. This extra water, along with floods, helped create Lake Mojave. The Mojave River has flowed into the Mojave Desert for about 2 to 1.5 million years.
The Mojave River didn't always end at Lake Mojave. Sometimes it flowed into other ancient lakes like Lake Harper, Lake Manix, the Cronese Lakes, and Lake Manly. Water from Lake Manix reached Lake Mojave about 20,000 years ago. To form Lake Mojave, the river's water flow would have needed to be at least ten times higher than it is today.
Water Flow Out of the Lake
An old channel, carved into rock, served as the outlet for Lake Mojave. This channel was sometimes less than 3 meters (10 feet) wide. It ended in a dry lake bed about 5 kilometers (3 miles) away. This spillway helped keep Lake Mojave's water levels steady a long time ago.
Scientists once thought that water from Lake Mojave flowed into another freshwater lake called Lake Dumont. However, later research showed that the Lake Dumont area was actually a wetland supported by groundwater. Water from Lake Mojave eventually reached the Amargosa River and Death Valley.
What Was the Climate Like?
Today, the area around Lake Mojave is very hot and dry. Summer temperatures usually go above 30 degrees Celsius (86 degrees Fahrenheit).
The area gets very little rain, only about 78 millimeters (3 inches) per year. Most of this rain falls in winter and early spring. A small amount comes in summer from the Gulf of California and Gulf of Mexico. This low rainfall is a big contrast to how much water evaporates, which is about 2000-2500 millimeters (79-98 inches) per year.
What Lived Around Lake Mojave?
Scientists have found shells of a type of freshwater mussel called Anodonta californiensis at Lake Mojave. Tiny freshwater algae called Phacotus also grew in the lake when it was younger. Small crustaceans called Ostracods, like Limnocythere bradburyi and Limnocythere ceriotuberosa, also lived there.
The land around Lake Mojave was a mix of pinyon-juniper and Joshua tree woodlands at higher elevations. Closer to the lake, there was desert vegetation.
Today, you can find plants like creosote bush, saltbush, and Opuntia (prickly pear cactus) in the area. More plants grow in dry riverbeds and on river terraces.
When Did Lake Mojave Exist?
Lake Mojave existed between about 22,000 and 9,000 years ago.
The lake filled up before 27,000 years ago and its water levels changed over time. It was stable at its higher A-shoreline during two periods: 21,900 to 19,750 years ago, and 16,850 to 13,850 years ago. The earlier period is sometimes called Lake Mojave I, and the later periods are called Lake Mojave II.
Between 13,600 and 11,500 years ago, a spillway formed. This caused Lake Mojave to drop from its A-shoreline to the lower B-shoreline. The lake stayed at the B-shoreline until about 8,700 years ago, when it began to dry up.
Lake Mojave disappeared because of changes in the climate at the start of the Holocene period. Wind then eroded the old beach and delta deposits left by the lake.
Today, lakes only rarely form in the Lake Mojave basin. This happened in 1916–1917, 1938-1939, and 1969. The 1969 lake was even photographed and covered the old Tonopah and Tidewater railroad tracks. These temporary lakes form when there is a lot of rain in the San Bernardino Mountains.
People and Lake Mojave
The steady supply of food and fresh water, along with rocks for making tools, attracted early humans to Lake Mojave. As the lake's water levels dropped, people moved closer to the shrinking lake.
Archaeologists have found old sites around Lake Mojave. These include arrangements of basalt boulders. They also found hand axes and projectiles (like spear points) on the shores. These tools are about 10,000 to 8,000 years old. These findings are part of what is called the "Lake Mojave complex."
The "Lake Mojave complex" refers to a group of early human cultures that lived in the area between 9,000 and 6,000 BC. These cultures might have developed from the Clovis culture. They likely formed when large mammals became scarce, and people had to find new sources of food.
