Kashmir’s Wular & Dal Lake Shrinking, NASA Releases Satellite Images

‘Bordered by towering Himalayan Mountains, Eutrophication, Land Conversion among reasons for decline of water bodies’

The National Aeronautics and Space Administration (NASA) shared images of two major water bodies in Kashmir Valley—Wular Lake and Dal Lake—saying the lakes have been declining in recent years.

NASA on their Twitter handle earlier this week wrote, “Lakes Wular and Dal, surrounded by the high Himalaya Mountains, supply water for drinking and irrigation in northern India, but the lakes have been declining in recent years.”

In another tweet, it was mentioned that these pictures of Kashmir’s Wular and Dal Lakes were captured by the Operational Land Imager (OLI) on the Landsat 8 satellite on June 23, 2020. 

Explaining the captured images, Emily Cassidy in a report published on the NASA earth observatory website, two lakes surrounded by the high Himalayan Mountains are remnants of a much larger ancient lake in India’s Kashmir Valley. While the freshwater lakes are some of the largest in the Jammu and Kashmir region of northern India, in recent years they have been in decline. 

It explains that the two lakes—Wular and Dal—are visible in this image, acquired on June 23, 2020, by the Operational Land Imager (OLI) on Landsat 8. Both lakes regulate water flowing down from Himalayan glaciers and along the Jhelum River, supplying water for drinking and irrigation.

The news report states that the Dal, in the lower right of the image, is the smaller of the two water bodies. Dal is located in the heart of Srinagar—the largest city in the valley. Floating houseboats, markets, and marshes lure tourists to the lake. It is surrounded by terraced gardens—laid out in the 16th and 17th centuries by Mughal emperors—that are lined with fountains and planted with a variety of flowers, herbs, and aromatic plants.

Wular Lake, to the left in the image, is the largest freshwater lake in India, and among the largest in Asia. This 17-square-mile (45-square-kilometer) lake along the Jhelum River provides fish and freshwater to nearby residents. Several wetlands are located on the fringes of the lake and serve as a habitat for migratory birds, such as ducks, shorebirds, geese, and cranes. Because of its significance for biodiversity and livelihoods, Ramsar International designated the lake as a “wetland of international importance” in 1990.

Influx of sediment & nutrients

Cassidy explains that bright green flora stands out in the image on the eastern side of Wular. An influx of sediment and nutrients into the lake over the past few decades has contributed to the rapid growth of algae and aquatic vegetation.

Eutrophication

The news report states that the lake is now suffering from eutrophication—an overgrowth of plants and algae that can eventually cause oxygen depletion in aquatic environments.

Sediment & Nutrient Loads

As per the report, the conversion of forests to paved urban areas is a major driver of the change in water quality. Land conversion has delivered heavy sediment and nutrient loads into the lake, and untreated sewage from urban areas has also contributed. Researchers in India used water samples and data from Landsat satellites to assess the biological health of the lake. They found that about 57 percent of Wular Lake was eutrophic in 2018.

Highlighting that some of the bright green areas on the eastern side of Wular Lake used to be open water. Nutrient-rich sediment and aquatic vegetation have filled in parts of the lake and contributed to its shrinking in recent decades. 

Shrinking Size

In a 2022 study, researchers in India—using data from the Indian Space Research Organization’s (ISRO) LISS-IV instrument—found that Wular Lake’s open water area had shrunk in size by about one-quarter between 2008 and 2019.

Land Conversion to Urban Development 

The smaller Dal Lake has suffered a similar fate in response to land cover change. Researchers in Srinagar found that land conversion to urban development in the basin had worsened the lake’s water quality and contributed to its reduced size. They found that between 1980 and 2018 the lake shrunk in area by 25 percent, states the news report.

As per NASA, Wanmei Liang took the photograph for NASA Earth Observatory using Landsat data from the US Geological Survey.

Keep Reading

• Mystic Dal Lake turning into a swamp lake due to pollution
• Dal lake and Wular Lake’s water holding capacity reduced by 40 to 70%
• CSE report counters home ministry’s claim on Dal lake’s water quality
• Reasons behind thousands of dead fish found in Kashmir’s Dal Lake

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