Glacial lake changes and the identification of potentially dangerous glacial lakes (PDGLs) under warming climate in the Dibang River Basin, Eastern Himalaya, India

Abstract

Climate warming has caused accelerated glacier recession in the Eastern Himalayas. This phenomenon has consequently resulted in the development of new glacial lakes and expansion of the existing ones. The outbursts of these lakes has the potential to cause flashfloods with negative impacts for the downstream community. This study used Remote Sensing data products to develop a glacial lake database of Dibang River Basin for the year 2020. The multi-temporal Landsat series data was used to examine the surficial changes in glacial lakes larger than 0.1 km². The key parameters derived from previous glacial lake studies were used to identify the Potentially Dangerous Glacial Lakes (PDGLs) and conduct their hazard assessment. Finally, the Indian Monsoon Data Assimilation and Analysis (IMDAA) data was used to analyze the Temperature and Precipitation trends from 1980 to 2020 to understand timpact of climate change on lake behaviour. Our findings reveal that the study region has 403 glacial lakes with a total area of 55.73 km² in 2020. The area of selected glacial lakes has increased from 29.96 km² in 1985 to 32.56 km² in 2020 at a rate of 0.07 km² per year. Twelve (12) lakes were identified as PDGLs in the study region. After applying the weighted index method, 4 lakes among them were categorized as high, 5 as medium and 3 as low hazard glacial lakes. The Mann Kendal test of T_min, T_max and T_mean revealed an increasing trend with a Z statics value of >0, whereas mean precipitation on the contrary showed a significant decreasing trend with a Z statics value of <0. The changes in climatic variables (i.e., temperature and precipitation) indicate that the warmer conditions prevail in the region, causing glacier shrinking and retreat, formation of new lakes and expansion of existing ones. Hence, we propose the continuous monitoring and assessment of high hazard glacial lakes for the prevention and mitigation of Glacier Lake Outburst Floods (GLOFs) in the study region.

Keywords:

• Glacial Lake inventory
• lake expansion
• PDGLs
• hazard assessment: IMDAA
• Dibang River Basin-Eastern Himalayas-India

Acknowledgements

The authors are thankful to the European Space Agency (ESA) and United States Geological Survey (USGS) for freely providing the satellite data used in this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 http://cgwb.gov.in/District_Profile/Arunachal/Dibang%20Valley.pdf

2 https://en.wikipedia.org/wiki/Dibang_River