Moraine dam breach and glacial lake outburst flood generation by physical and numerical models

Begam, Sazeda; Sen, Debabrata; Dey, Subhasish

doi:10.1016/j.jhydrol.2018.06.038

Cited by 52 publications

(16 citation statements)

References 63 publications

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“…For embankment and moraine-dammed lakes, there are two main approaches to computing dam failure: (i) numerical models based on mass and momentum balance equations supplemented by erosion laws (Begam et al, 2018;Castro-Orgaz & Hager, 2013;Faeh, 2007;Larocque et al, 2013), and (ii) conceptual models based on a series of differential equations accounting for the various processes at play (Capart, 2013;Peter et al, 2018;Walder & O'Connor, 1997). For ice-dammed lakes, the water's change phase should also be considered.…”

Section: Drainage and Dam Breakmentioning

confidence: 99%

Hydraulic Reconstruction of the 1818 Giétro Glacial Lake Outburst Flood

Ancey

Bardou

Funk

et al. 2019

Water Resources Research

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In the spring of 1818, ice avalanches from the Giétro Glacier created an ice dam, which in turn formed a glacial lake in the Drance Valley (Canton of Valais, Switzerland). Today, its maximum volume is estimated to have been 25×106 m3. Cantonal authorities commissioned an engineer named Ignaz Venetz to mitigate the risk of the ice dam's failure. He supervised the construction of a tunnel through which a large volume of water was drained as the lake rose (9×106 m3 according to his estimates and 11×106 m3 according to our model). After 2.5 days of slow drainage, the ice dam failed on 16 June 1818 and caused major flooding in the Drance Valley up to 40 km downstream, resulting in about 40 deaths. Venetz's lake monitoring notes, numerous testimonies gathered in the disaster's aftermath, and our field survey have made it possible to collect a wealth of information on this event, which is one of the world's major documented glacial lake outburst floods. Reconstructing major outburst floods remains challenging because not only do they involve enormous volumes of water spreading over long distances but they are also associated with additional physical processes such as massive erosion; intense transport of ice, sediment, and debris; and damage to vegetation and buildings. This paper attempts to reconstruct the 1818 Giétro flood by focusing on its water component. We develop a simple model to estimate the initial hydrograph during the slow drainage and failure phases. The flood's features are deduced by solving the shallow‐water equations numerically. The computational framework involves six free parameters, of which five are constrained by physical considerations. Using iterative manual parameter adjustments, we matched the numerical simulations to the historical data. We found that the peak discharge was close to 14,500 m3/s, the flood's front velocity was about 6 m/s, and flow depth varied considerably along the River Drance's bed (from 30 m just downstream of the ice dam to 2 m on the alluvial fan, 24 km west of the dam). To achieve a good agreement between computations and historical data, we had to select a high value for the Manning friction coefficient n (with n as large as 0.08 s/m1/3). As the Drance Valley is narrow, high flow resistance caused the flood's leading edge to behave like a plug, moving at a fairly constant velocity, with little dependence on what happened behind it. This result may explain why a simple flood routing model is able to reproduce the flood's features, because in an Alpine valley, a lateral spreading of the water volume is limited.

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Section: Drainage and Dam Breakmentioning

confidence: 99%

Hydraulic Reconstruction of the 1818 Giétro Glacial Lake Outburst Flood

Ancey

Bardou

Funk

et al. 2019

Water Resources Research

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“…Second, the dam break process was considered as a process where dam materials were eroded by the overtopping flow [47]. The excavation of diversion channels prolongs the dam break time, and reduces the water level and upstream water storage capacity when the artificially induced overtopping occurs.…”

Section: Discussionmentioning

confidence: 99%

“…There are three reasons why another landslide was referenced here. Firstly, the excavation of a diversion channel was also used for this landslide to discharge Second, the dam break process was considered as a process where dam materials were eroded by the overtopping flow [47]. The excavation of diversion channels prolongs the dam break time, and reduces the water level and upstream water storage capacity when the artificially induced overtopping occurs.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Description of the Hydrodynamic Process after Barrier Lake Formation and Emergency Responses Implementation

Wang

Tan

Shu

et al. 2021

Water

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Barrier lakes are secondary disasters with associated landslides and debris flow that can cause serious damage to the downstream populations and areas. Existing studies are lacking in comprehensive descriptions of the rescue process, where the main channel streamflow varies and topographic erosion develops, as well as engineering disposal performs. This paper aimed to theoretically investigate the formation and emergency responses to barrier lakes using on-the-spot investigation and calculus theory. The results showed that the formation of a barrier lake led to a sudden variation in the flow-change rate (normal to infinite). However, after implementing emergency measures, this rate returned to normal. The whole rescue process could be regarded as the accumulation of disposal effects. Volume changes in the main streams were expressed by a differential equation of the lake surface area and water level variations. In addition, a corresponding theoretical description of flow discharges was also given when engineering measures such as the excavation of diversion channels and engineering blasting were adopted. Specifically, the theoretical expressions of flow discharge were given respectively in the developing stage and breach stable stage after the excavation of diversion channels. The flow discharge through certain sections was also described theoretically when engineering blasting was chosen to widen and deepen the cross-section of the diversion channels. Overall, this paper mathematicizes and theorizes the existing emergency measures, which helps to better understand their implementation principles and application requirements.

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“…Seasonal flooding, as well as glacial lake outburst floods (GLOFs) are common in glacial systems, especially wet-based valley glaciers (e.g., Davies et al, 2003;Dessouki, 2009;Cui et al, 2010;Begam et al, 2018;Neupane et al, 2019). The rapid release of a large volume of water during outburst flood events produces a variety of deposits.…”

Section: Outburst Flood Depositsmentioning

confidence: 99%

Detecting upland glaciation in Earth’s pre-Pleistocene record

et al. 2022

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Earth has sustained continental glaciation several times in its past. Because continental glaciers ground to low elevations, sedimentary records of ice contact can be preserved from regions that were below base level, or subject to subsidence. In such regions, glaciated pavements, ice-contact deposits such as glacial till with striated clasts, and glaciolacustrine or glaciomarine strata with dropstones reveal clear signs of former glaciation. But assessing upland (mountain) glaciation poses particular challenges because elevated regions typically erode, and thus have extraordinarily poor preservation potential. Here we propose approaches for detecting the former presence of glaciation in the absence or near-absence of ice-contact indicators; we apply this specifically to the problem of detecting upland glaciation, and consider the implications for Earth’s climate system. Where even piedmont regions are eroded, pro- and periglacial phenomena will constitute the primary record of upland glaciation. Striations on large (pebble and larger) clasts survive only a few km of fluvial transport, but microtextures developed on quartz sand survive longer distances of transport, and record high-stress fractures consistent with glaciation. Proglacial fluvial systems can be difficult to distinguish from non-glacial systems, but a preponderance of facies signaling abundant water and sediment, such as hyperconcentrated flood flows, non-cohesive fine-grained debris flows, and/or large-scale and coarse-grained cross-stratification are consistent with proglacial conditions, especially in combination with evidence for cold temperatures, such as rip-up clasts composed of noncohesive sediment, indicating frozen conditions, and/or evidence for a predominance of physical over chemical weathering. Other indicators of freezing (periglacial) conditions include frozen-ground phenomena such as fossil ice wedges and ice crystals. Voluminous loess deposits and eolian-marine silt/mudstone characterized by silt modes, a significant proportion of primary silicate minerals, and a provenance from non-silt precursors can indicate the operation of glacial grinding, even though such deposits may be far removed from the site(s) of glaciation. Ultimately, in the absence of unambiguous ice-contact indicators, inferences of glaciation must be grounded on an array of observations that together record abundant meltwater, temperatures capable of sustaining glaciation, and glacial weathering (e.g., glacial grinding). If such arguments are viable, they can bolster the accuracy of past climate models, and guide climate modelers in assessing the types of forcings that could enable glaciation at elevation, as well as the extent to which (extensive) upland glaciation might have influenced global climate.

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Moraine dam breach and glacial lake outburst flood generation by physical and numerical models

Cited by 52 publications

References 63 publications

Hydraulic Reconstruction of the 1818 Giétro Glacial Lake Outburst Flood

Hydraulic Reconstruction of the 1818 Giétro Glacial Lake Outburst Flood

Theoretical Description of the Hydrodynamic Process after Barrier Lake Formation and Emergency Responses Implementation

Detecting upland glaciation in Earth’s pre-Pleistocene record

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