Lake Urmia

Lake Urmia is an endorheic salt lake located in the Azerbaijan region of Iran.

An endorheic lake is a body of water that does not flow into an ocean. Instead, it is part of a closed drainage basin. This lake sits near the Armenian border and south of the Caspian Sea. At its greatest extent, it was the largest lake in the Middle East. It was also once the sixth-largest saltwater lake on Earth. The lake was once very large, with a length of 255 kilometers and a width of 48 kilometers. It also had a maximum depth of 120 meters.

The chemistry of the water is very unique and intense. The main cations, or positively charged ions, include sodium, potassium, calcium, lithium, and magnesium. The main anions, or negatively charged ions, are chloride, sulfate, and bicarbonate. The concentration of sodium and chloride is roughly four times higher than natural seawater. This high salinity has reached more than 300 g/L in recent years. Because the water is so salty, the lake no longer sustains any fish species. However, it remains a vital habitat for Artemia urmiana. These are small crustaceans that serve as a food source for migratory birds.

The ecology of the lake is quite diverse despite the salt. Scientists have recorded 62 species of bacteria and 42 species of microfungi. There are 20 species of phytoplankton and 311 species of plants. The lake supports 226 species of birds, including large populations of flamingos. It also hosts 27 species of amphibians and reptiles and 24 species of mammals.

Because of this biodiversity, the area is a UNESCO Biosphere Reserve. The Iranian Department of Environment also protects it as a national park.

Many factors have caused the lake to shrink rapidly. Persistent general drought in Iran has reduced the water supply. Humans have also built dams on the rivers that flow into the lake. Pumping groundwater from the surrounding area has further lowered the water levels. In 2008, the Urmia Lake Bridge and causeway were completed.

This construction disconnected the northern and southern halves of the lake. This change altered the hydrodynamic and ecological characteristics of the region. Experts warned that this could turn the lake into a salt marsh.

The history of the region stretches back thousands of years. Archaeologists have excavated prehistoric sites like Yanik Tepe on the east shore. This area has been settled as far back as 6000 BC. Other important sites include Dalma Tepe, Teppe Hasanlu, and Geoy Tepe. In the 9th century BCE, Assyrian records mentioned the area. The name "Urmia" may have several different origins. Some suggest it comes from the Neo-Aramaic words for "city" and "water." Others link it to Indo-Iranian words meaning "wavy" or "undulating."

Efforts to save the lake have involved many different groups. In 2014, Iran approved a 14 trillion rial recovery program. This program aimed to improve water management and reduce agricultural water use. The Food and Agriculture Organization of the United Nations also joined the effort. They worked on an integrated programme for sustainable water resources management. One project involved growing plants like Nitraria and Tamarix. These plants are grown to slow down the wind. This helps stop salt particles from blowing across the land.

Despite these efforts, the lake has faced extreme changes. By late 2017, the lake had shrunk to only 10% of its former size. The water volume was only 1/60 of what it was in 1998. While there was a brief period of filling in 2019, the trend reversed again. A combination of drought and administrative mismanagement caused water levels to drop once more.

Satellite imagery from NASA shows a very serious situation. By September 2025, the images indicated the lake had almost entirely dried up. This loss has caused environmental protests from people in Iran and abroad.