China
Africa
Explore chapters and articles related to this topic
Glaciers and Glacial Lake Outburst Flood Risk Modeling For Flood Management
Published in Ajai Singh, Wastewater Reuse and Watershed Management, 2019
Nity Tirkey, P. K. Parhi, A. K. Lohani
In the Himalayas, during the retreating phase, a large number of lakes are being formed either at the snout of the glacier as a result of damming of the moronic material known as moraine-dammed lakes or supraglacial lakes formed in the glacier surface area. Most of these lakes are formed by the accumulation of vast amounts of water from the melting of snow and by blockade of end moraines located in the down valleys close to the glaciers. In addition, the lakes can also be formed due to landslides causing artificial blocks in the waterways. The sudden break of a moraine/block may generate the discharge of large volumes of water and debris from these glacial lakes and water bodies causing flash floods namely GLOF. The sudden bursts of lakes can happen due to erosion, a buildup of water pressure, an avalanche of rock or heavy snow, an earthquake, or if a large enough portion of a glacier breaks off and massively displaces the waters in a glacial lake at its base (Figure 13.2).
Jimmie Creek run-of-river project—geohazard and seepage control design of intake structure
Published in Jean-Pierre Tournier, Tony Bennett, Johanne Bibeau, Sustainable and Safe Dams Around the World, 2019
Four terminal moraines in the upper catchment blocked or reduced the flow of Exit Creek for some period, creating a small moraine dammed lake. Lake sediments were noted (though not confirmed in the field) in the 1964 air photo above the upper terminal moraine. Based on morphology of the remaining moraine, we expect that the lake was drained during a dam outburst flood and subsequent debris flow event prior to 1948. No terminal moraines remain intact and the threat of a similar event looking forward is low to non-existent. Overall, terrain in the Exit Creek watershed has been stabilizing over the last century.
Review of moraine dam failure mechanism
Published in Geomatics, Natural Hazards and Risk, 2019
Robin Neupane, Huayong Chen, Chunran Cao
Climate change leads to unorthodox changes in weather pattern which is a serious issue for cryosphere as they are more vulnerable compared to other parts of the world (IPCC, 2013). It results in rapid melting of a glacier and extreme rainfall. These conditions act as catalyst to the formation of moraine dammed lakes if provided with suitable concave landform (depression) (Clague and Evans, 2000), formed typically between glacier snout and end moraines (Costa and Schuster, 1988). Glacial lakes containing a huge volume of water behind weak moraine dams possess high probability of glacial lake outburst events (Richardson and Reynolds, 2000; Benn et al. 2012). Displacement and seiche waves are induced by triggers of glacial lake outburst floods: ice avalanche (Vuichard and Zimmermann, 1987), rock avalanche, and calving from terminal face of lake terminating glacier (Richardson and Reynolds, 2000), which can overtop the dam and begin the dam breaching process (Westoby et al. 2014). These outburst floods can release huge volume of water rapidly that can produce deep and high velocity flow possessing a massive erosion and transportation capacity over extensive areas (Anacona et al. 2015). Therefore, they can develop quickly into debris flow with densities of about 1.5 tm−3 (Emmer and Vilimek, 2013), exacerbating the disaster. The susceptibility of a given lake to outburst floods is not constant and may change significantly over time, especially due to changes in the lake (dam) setting and the setting of the lake’s surroundings (Emmer et al. 2018), and some researchers also infer that there will be a substantial increase in GLOF incidence throughout the twenty-first century as glaciers and lakes respond more dynamically to anthropogenic climate warming (Harrison et al. 2018). The threat of potential disaster possessed by such a large volume of water behind a weak and unstable structure cannot be neglected.
Assessment of the water quality of Glacier-fed lake Neel Tal of Garhwal Himalaya, India
Published in Water Science, 2019
High altitude lakes including the glacier-fed lakes are the major source of drinking water for the trekkers, sages, and wildlife in the Himalayan region for their sustainability and livelihood. According to the United Nations Conference on Sustainable Development (UNCSD, 2012) which was held at Rio de Janeiro in Brazil, “the mountain ecosystem plays a key role in fulfilling the water requirement to a large population of the world”. The hydrologic status of water of a lake in terms of quality and quantity is the results of complex processes of physical, chemical and biological inputs (Singh et al.,2008). The lakes of Himalayan region are either rain-fed, spring-fed, ground-water fed or glacier-fed/snow-fed. Mostly, all the lakes which are located above an altitude of 3,500 m above m.s.l. are considered to be glacier-fed (WWF, 2005). The source of water for such type of glacier-fed lakes is the melting of ice or snow from a nearby glacier (Fairbridge, 1968). Water is one of the most important natural resources on the Earth, which is commonly shared by all the living organisms present on the Earth. The glacier-fed lakes are generally having clean and fresh water with no such pollutants and contaminants, because of its location at a very high altitude. A glacier-fed lake is defined as water mass existing in a sufficient amount and extending with a free surface in, under, beside, and/or in front of a glacier and originating from glacier activities and/or retreating processes of a glacier (Dimri et al., 2016). Generally, two types of glacier-fed lakes are found, that are moraine-dammed lakes and ice dammed lakes. In moraine-dammed, due to the continuous flow of water by melting of ice/snow, a tarn has been created which is covered by the large boulders, and the melted water has been stored in that tarn. This type of lake is known as moraine-dammed lake. When an iceberg or large block of ice breaks down and erodes the land and melts, filling the space with melted water that has been created by the iceberg. Such types of lake are dammed by ice without lateral moraine. All the lakes are associated with debris over on glacier ice that caused differential melting and increased surface irregularities in developed lakes (Ageta et al., 2000).