| 英文摘要: | A cheap and simple piece of equipment could be the answer to a natural hazard in the high mountains of Asia. Glacial lakes are at danger of bursting and threaten lives and property. The pairing of Som Gurung, of the Royal University of Bhutan, with Stephen Hughes and Les Dawes, both from the Science and Engineering Faculty and Institute for Future Environments, Queensland University of Technology, sparked the idea of using Hughes's earlier work on siphons for water movement in natural systems (Phys. Educ. 45, 162–166; 2010) to address this serious problem.
Increased temperatures globally are causing glacier retreat, and the meltwater is filling and expanding the glacial lakes, potentially leading to glacial lake outburst floods. Glacial lakes vary in size and their walls are often formed by the moraine — soil and rock debris, up to boulder size, which has been pushed along by the glacier edge. The outburst floods can be triggered by a breakdown of the natural dam wall or by an avalanche of rock or snow displacing large volumes of water from the lake. These events can come at a high cost. In October 1994, glacial lake Lugge Tsho in northern Bhutan experienced an outburst flood when the moraine dam wall failed due to increased melt water pressure (Mt. Res. Dev. 16, 77–81; 1996). Without warning, the 18 million cubic metres of flood water reached the village of Punakha, approximately 86 km downstream, causing massive damage and resulted in the loss of 21 lives.
“Currently there are 26 glaciers [in Bhutan] at risk [of an outburst flood] and there may be several more” said Hughes. Work is being done to reduce the risk of outburst floods, but it is dangerous and labour intensive. Teams of people work with simple tools, moving rocks and debris to facilitate controlled drainage and reduce lake water levels (Nature 461, 1042–1046; 2009, and UNDP http://go.nature.com/Hl7qvl).
STEPHEN HUGHES |