What is a Closed Lake?

Caitlin Dempsey


Closed lakes are bodies of water that do not drain into an ocean or river.  This means that no water flows out of the lake.  Instead, water is reduced within the lake via seepage into groundwater or evaporation.  

What are endorheic lakes?

Closed lakes are also referred to as endorheic basins or endorheic lakes. The word endorheic originates from two words in Ancient Greek: ἔνδον, éndon, “within” and ῥεῖν, rheîn, “to flow”.

The largest lake in the world is also the largest closed lake in the world.  This lake is the Caspian Sea with a surface area of 371,000 square kilometers (143,000 square miles).

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Endorheic Lakes Tend to be More Saline

With a flow of particulate laden water entering the lake with no comparable outflow, closed lakes tend to be more salinic than open lakes.  The amount of saline can vary greatly.  

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The Caspian Sea contains 3 parts per thousand of saline while the Dead Sea, the deepest hypersaline lake in the world, contains as much as 400 parts per thousand.

Tibetan Plateau’s Siling Lake

The largest lake on the Qinghai-Tibet Plateau (QTP) is called Siling Lake. Also called Serling Tso or Selincuo, Siling Lake is located on the northeastern part of the Tibetan Plateau in China. Siling Lake is situated at an altitude of around 14,860 feet (4,530 meters) above sea level and covers an area of approximately 703 square kilometers.

A view from the International Space State of Siling Lake in Tibet.
On December 4, 2021, the International Space Station captured this image of Siling Lake. Photo: NASA, public domain.

Since the lake has no outlets from which its water drain, Siling Lake is a high-altitude endorheic lake. Like most close lakes, Siling Lake is a saltwater lake.

Climate change and glacial melt are increasing the size of Lake Siling

About 15 inches (38 centimeters) of rain along as well as runoff from rain, snow, and glacial meltwater from the surrounding areas replenish the waters of the lake.

Since the 1970s increases in runoff entering the lake have resulted in its growth. A study that looked at changes in Lake Siling’s water storage between 2000 and 2016 found that the volume of the lake has increased at a rate of 1.2 billion meters3 per year.

While the driving forces behind this increase in lake volume are still being studied, the researchers behind this study have concluded that an increase in glacial runoff is one of the major contributing factors.

The saline nature of the lake is a result of salt concentrates left behind after evaporation.

Lake Siling is a Ramsar wetland area

The lake provides habitat to Gymnocypris selincuoensis, a fish which is endemic to Lake Siling. Gymnocypris selincuoensis is the only cyprinid fish living in Siling Lake and is adapted to the extreme cold and high altitude.

The lake is also home to the Tibet Selincuo Wetlands, a Ramsar Wetland site that provides habitat to black-necked cranes as well as two vulnerable species of eagles, the Pallas’s fish-eagle (Haliaeetus leucoryphus) and the eastern imperial eagle (Aquila heliacal).

Largest soda or alkaline lake on Earth

Lake Van in Turkey is an endorheic lake that is the largest soda or alkaline lake on Earth and is the largest lake in Turkey. 

A soda lake is a type of saline lake with a high concentration of dissolved sodium carbonate and other minerals, such as bicarbonates, chlorides, and sulfates. These lakes are typically alkaline and have a pH between 9 and 12. Lake Van’s pH is 10.

A photo taken from the International Space Station of Lake Van in Turkey.
Lake Van in Turkey is the largest soda lake on Earth. This image shows turbidity plumes in the lake. Calcium carbonate, debris, and some organic materials make up the majority of turbidity plumes, which resemble swirls of light- and dark-colored water. Photo: International Space Station, NASA, September 12, 2016, public domain.

With a surface area of 1,450 square miles (3,755 square kilometers), Lake Van is one of the world’s only endorheic lakes that are larger than 3,000 square kilometers in size.

Lake Van is home to the Van cat, a landrace domestic cat that enjoys swimming in the waters of the lake.


Feng, X., Jia, Y., Zhu, R., Chen, K., & Chen, Y. (2019). Characterization and analysis of the transcriptome in Gymnocypris selincuoensis on the Qinghai-Tibetan Plateau using single-molecule long-read sequencing and RNA-seq. DNA Research26(4), 353-363. https://doi.org/10.1093/dnares/dsz014

Tang, Y., Huo, J., Zhu, D., & Yuan, Z. (2022). Simulation of the Water Storage Capacity of Siling Co Lake on the Tibetan Plateau and Its Hydrological Response to Climate Change. Water14(19), 3175.  https://doi.org/10.3390/w14193175

Tomonaga, Y., Brennwald, M. S., Livingstone, D. M., Kwiecien, O., Randlett, M. È., Stockhecke, M., … & Kipfer, R. (2017). Porewater salinity reveals past lake-level changes in Lake Van, the Earth’s largest soda lake. Scientific Reports7(1), 313. https://doi.org/10.1038/s41598-017-00371-w


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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.