Kathmandu. About 3 lakh people are at risk due to the devastating floods of the Himalayan river. In this way, the highest number of people at risk are Nepal.
This is according to a study report titled ‘Increasing Exposure to Potential Flooding in High Mountain Catchments’ published in Scientific Reports. According to the study, about 300,000 people may be living in flood-affected areas due to the mountains spread across Nepal, India and China. The study shows that between 2016 and 2023, the total area covered by buildings in the potentially flood-prone areas increased by about 45 percent.
According to a press release from Springer Nature, a new study found that flooding from mountainous regions is typically caused by seasonal monsoons, excessive rainfall or the flow of waste from glacial lakes, or flash floods (which are rare but destructive). Climate change is projected to increase the severity of these events. Whereas steep and narrow valleys in mountainous areas can increase flood levels and their after-effects.
The research team from several organizations evaluated changes in buildings and people at risk of potential flooding in areas up to 50 km below 1,361 glaciers in Nepal and neighboring India and China from 2016 to 2023. The results show that from 2016 to 2023, the total area covered by buildings in potentially flood-prone areas increased by about 45 percent.
The team used 5 datasets validated with manually recorded data to estimate the total building footprint (the area covered by the bases of all existing buildings) in these areas. The estimated footprint of buildings within 50 vertical meters of the river increased by 45.75 percent from 12.38 to 18.04 square kilometers. In areas with high risk of glacial lake outburst flooding, the footprint increased by 77.78 percent from 0.72 to 1.28 square kilometers.
The researchers then used a calculated building footprint to estimate that in 2026, about 293,800 people (18 percent of the population of the study area) may be living in buildings that are at risk of potential flooding. This includes an estimated 100,500 people in Nepal. Of these, 22,800 live within 10 meters of the river. The population living in flood-prone areas is projected to increase by 17,900 (6 percent) between 2015 and 2030.
The researchers say that estimates of total building footprint and population growth are highly uncertain. They emphasize the need for a more accurate building database to better assess risk.
“Overall, our results highlight the increased risk of flooding from river and glacial lake eruptions in the Himalayan catchment and emphasize the importance of verifying open datasets before using them in risk assessments,” the research team concluded. -Agency
