Daene McKinney has been to the high-mountain lakes of Nepal many times. Ten research trips in the last five years – but nothing could prepare him for this.
“The first thing we run into are buildings that have walls crumbling or missing or buildings that are flattened to the ground,” McKinney said. “That was pretty startling. At first you try to understand what you’re looking at. Then you realize just how much damage there is.”
McKinney, Ph.D., P.E., D.WRE, M.ASCE, an active member of ASCE’s Environmental and Water Resources Institute, returned in early August to his Austin, TX, home after leading a research team on a two-month mission to study potential new threats to Nepal’s mountain villages following the deadly, devastating 7.8-magnitude earthquake that struck April 25.
The High Mountain Adaptation Partnership team conducted detailed remote-sensing and field-based surveys to assess how the earthquake and aftershocks may have heightened the extreme flooding menace posed by glacial flowing in landslide-dammed lakes. Aiding in the HiMAP team’s work was the Nepal Department of Hydrology and Meteorology, the International Centre for Integrated Mountain Development, the U.S. Agency for International Development, and the Nepalese Army.
“We had a very strong connection to this problem,” said McKinney, who has been studying the lakes for nearly a decade. “My whole motivation [as a civil engineer] is to be able to reach out to people in various places that have problems but don’t have the resources to solve them. This was a perfect opportunity to put the money where the mouth is and get over there at a time when they needed people with specific skills to assess the situation after the earthquake.”
McKinney’s past trips to the region focused on the effects of climate change – specifically, the thinning and retreat of the glaciers leaving behind moraines that act as dams on the extremely large lakes that dot the Himalayan Mountains in the Khumbu region of Nepal. The lakes are growing, increasing the risk of flooding (known as glacial lake outburst floods) to the nearby villages. The earthquake only amplified those concerns and the community’s fears.
McKinney was last in Nepal just seven months earlier, but the eight-day trek up to Imja Lake was a much different trip this summer.
“It was very disconcerting to see that everyone was having to live in makeshift tarp-and-tent structures,” McKinney said. “They were very scared to go back in their buildings, and they were very scared that the lake was going to burst.”
Rumors ran rampant of new landslides, flooding lakes, 100-foot tall walls of water pouring down, McKinney said. “People were really anxious.”
Remarkably, the surveys by McKinney’s team produced relatively good news. The lakes, though obviously affected by the earthquake and increasingly dangerous, have remained fundamentally intact.
“A lot of people have said it’s because of the moraines,” said McKinney, referring to the naturally formed glacial dams. “The glaciers were pushing this stuff like a snow plow, the rocks and the debris in front of them, and about 60 years ago they started to retreat. The material has shaken and settled, so it’s not as unstable as you would think.”
As the team moved lake to lake, the notion that this could have been much worse was a recurring theme. Consider:
• A 15-year-old spillway at one lake held up under the strain of the earthquake, revealing only repairable cracks.
• A relatively new small lake broke through its bottom and drained into an area beneath a glacier, causing a river to flood, but with limited damage.
• The earthquake touched off an avalanche that tumbled off a high glacier into a lake below, pushing water out. Fortunately, damage was mostly contained as the outburst remained within a perimeter carved out by a similar event of nearly 30 years ago.
Concerns remain, related mainly to ongoing climate change. The research team noted much change at Imja Lake in the eight months since its previous visit.
“Ice from the glaciers is melting. The topography of the ground is changing. Sinkholes open up,” McKinney said. “The earthquake had exacerbated that problem. There were more slumps and cracks than you would expect.”
ASCE and EWRI helped finance the mission, with additional funding from the USAID’s Climate Change Resilient Development project. HiMAP has since received a three-year National Science Foundation grant to continue its work in the region. McKinney anticipates a possible return this October with another trip next spring.
He emphasized the need for continued cooperation between the scientific community and local residents.
“These things are going to keep happening,” McKinney said. “It’s a very earthquake-prone area. Landslides happen every summer during the monsoon. The lakes are continuing to get bigger.
“We saw a big need for the community there to have better information. They need information on disaster planning and management. They really didn’t know where the safe locations were. It’s one of the things we’re going to be working on with our ongoing research.”