Mono Lake

Mono Lake is an ancient soda lake located in eastern California, United States, situated between the Great Basin and the Sierra Nevada mountain range. Covering an area of approximately 70 square kilometers, the lake naturally exhibits high salinity and alkalinity due to its closed-basin characteristics.^【1】

The lake has an average depth of about 43 meters and lies at an elevation of approximately 1,939 meters (6,382.2 feet) above sea level.^【2】 Furthermore, Mono Lake and its surrounding region have supported human settlement for thousands of years. The Kutzadika’a Paiute, recognized as the indigenous people of the area, were the first inhabitants and natural stewards of the Mono Basin. In the mid-19th century, prospectors and pioneers arrived in the region, attempting to sustain their livelihoods using local resources.^【3】

Geography and Geology

Mono Lake lies on a high desert landscape approximately 40 kilometers wide, bordered by the eastern flank of the Sierra Nevada mountains and the arid Great Basin of California. The lake’s surface area varies between 150 and 190 square kilometers depending on water levels.^【4】

The Mono Basin is a closed basin with no outflow. The tufa towers rising from the lake’s surface and visible above the water are limestone formations created by chemical interactions between the lake’s saline water and freshwater inflows. Additionally, the lake basin contains volcanic islands, glacially carved canyons, and the youngest volcanic chains in North America.

Ecosystem and Biodiversity

Mono Lake is an environment unsuitable for fish life due to its high salinity and alkalinity. However, it hosts trillions of brine shrimp (Artemia) and alkali flies, which serve as a vital food source for millions of migratory and resident waterbirds. The lake’s freshwater sources support forests of cottonwood and willow trees along its shores.

More than 100 bird species have been observed in and around the lake. During the fall migration, up to one million waterbirds use Mono Lake. These include shorebirds, grebes, gulls, ducks, and geese. Notable species include Wilson’s Phalaropes (accounting for 10–14% of the world population) and Red-necked Phalaropes (accounting for 2–3% of the world population). Other significant species are American Avocets, Western Sandpipers, Spotted Sandpipers, Black-necked Stilts, and the threatened Snowy Plover. Additionally, Eared Grebes (approximately 30% of the world population) and California Gulls are abundant in the lake. Eighty-five percent of the California Gull population nests on the islands of Mono Lake, making this colony the second largest in the United States.^【5】

Mono Lake (Flickr)

Water Use and Environmental Change

In 1941, the Los Angeles Department of Water and Power (DWP) began diverting water from Mono Lake to meet the needs of Los Angeles. As a result of this water diversion, the lake level dropped by approximately 14 meters over the next 40 years, losing half its volume and doubling its salinity. The decline in water level exposed tufa towers and caused significant negative impacts on the ecosystem. The survival of nesting California Gull populations, air quality, and overall biodiversity in the lake’s vicinity were adversely affected.^【6】

Conservation Efforts

The threat of Mono Lake’s disappearance prompted various citizen advocacy movements and environmental regulations. Rules were established to regulate the Los Angeles Department of Water and Power’s water exports, with the goal of raising the lake level back to approximately 1,939 meters above sea level. These efforts have partially restored the lake’s ecological health. According to current data, as of November 1, 2025, Mono Lake stands at an elevation of 6,382.2 feet above sea level.^【7】

Conservation Status and Management

Mono Lake and its surrounding area are protected as a state reserve, with the tufa tower region specifically classified under IUCN Category V (Protected Landscape/Seascape). The management of the region is crucial for ensuring ecosystem sustainability and the continuity of scientific research.