[ad_1]
After rapidly growing in volume just a few years earlier, northwest Iran’s Lake Urmia nearly dried out in autumn 2023. The largest lake in the Middle East and one of the largest hypersaline lakes on Earth at its greatest extent, Lake Urmia has for the most part transformed into a vast, dry salt flat.
On September 7, 2023, the OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image (right) of the desiccated lakebed. It stands in contrast to the image from three years earlier (left), acquired by the OLI on Landsat 8 on September 8, 2020, when water filled most of the basin and salt deposits were only visible around the perimeter of the lake. The replenishment followed a period of above-average precipitation that sent a surge of freshwater into the basin, expanding its watery footprint. Drier conditions have since brought levels back down.
The longer-term trend for Urmia has been one toward drying. In 1995, Lake Urmia reached a high-water mark; then in the ensuing two decades, the lake level dropped more than 7 meters (23 feet) and lost approximately 90 percent of its area. Consecutive droughts, agricultural water use, and dam construction on rivers feeding the lake have contributed to the decline.
A shrinking Lake Urmia has implications for ecological and human health. The lake, its islands, and surrounding wetlands comprise valuable habitat and are recognized as a UNESCO Biosphere Reserve, Ramsar site, and national park. The area provides breeding grounds for waterbirds such as flamingos, white pelicans, and white-headed ducks, as well as a stopover for migratory species. However, with low lake levels, what water remains becomes more saline and taxes the populations of brine shrimp and other food sources for larger animals.
A shrinking lake also increases the likelihood of dust from the exposed lakebed becoming swept up by winds and degrading air quality. Recent studies have linked the low water levels in Lake Urmia with respiratory health impacts among the local population.
The relative effects of climate, water usage, and dams on Lake Urmia’s water level is a topic of debate. The lake did see some recovery during a 10-year restoration program beginning in 2013. However, the efficacy of that effort has been difficult to parse since strong rains also fell during that period. Some research has concluded that climatic factors were primarily responsible for the recovery.
NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.
[ad_2]
