Bathymetric Survey of Imja Lake, Nepal in 2012
By Marcelo A. Somos-Valenzuela, Daene C. McKinney, Alton C. Byers, David R. Rounce
Glacier lakes in high mountain regions of the world are at risk of glacial lake outburst floods (GLOFs) due to climate change. This report describes a sonar bathymetric survey of Imja glacial lake in Nepal’s Sagarmatha (Everest) National Park.
A GLOF is a sudden release of a large amount of lake water into a downstream watercourse, usually triggered by ice avalanches that create surge waves. These floods can cause severe damage to downstream communities, infrastructure and agriculture.
The survey found that Imja lake's maximum depth has increased from 98 meters to 116 meters since 2002, and its volume has grown from an estimated 35 million cubic meters to 63.8 million cubic meters. Most of the expansion of the lake in recent years has taken place in the glacier terminus lake interface to the east. This is losing more than 200 meters of glacial ice per year, compared to about 34 meters per year in 2007.
The authors say this suggests that the lake has now evolved to a moderately dangerous status primarily on the basis of increased water volume. This nearly doubled in the decade before the survey, making it one of the most rapidly growing glacial lakes in Nepal.
The survey was done as part of USAID’s High Mountains Adaptation Partnership (HiMAP) project in Nepal and Peru.
Download File 1.05 MB