Time Scale for Rapid Draining of a Surficial Lake Into the Greenland Ice Sheet

Rice, James R.; Tsai, Victor C.; Fernandes, Matheus C.; Platt, John R.

doi:10.1115/1.4030325

Cited by 5 publications

(7 citation statements)

References 14 publications

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“…The modeled drainage rate of the lake is faster than the measured rate (Figure b), suggesting that the modeled blister also expands faster than it does in reality. Recent modeling by Rice et al [] suggests that creep opening of the englacial hydraulic fracture prior to rapid lake drainage produces a better match between measured and modeled lake drainage rates, but as we assume the lake hydrofracture opens only at the beginning of lake drainage, we do not include this process. The maximum uplift produced with the blister model is less than that seen by the GPS.…”

Section: Results and Analysismentioning

confidence: 99%

Modeling of subglacial hydrological development following rapid supraglacial lake drainage

Dow

Kulessa

Rutt

et al. 2015

J. Geophys. Res. Earth Surf.

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The rapid drainage of supraglacial lakes injects substantial volumes of water to the bed of the Greenland ice sheet over short timescales. The effect of these water pulses on the development of basal hydrological systems is largely unknown. To address this, we develop a lake drainage model incorporating both (1) a subglacial radial flux element driven by elastic hydraulic jacking and (2) downstream drainage through a linked channelized and distributed system. Here we present the model and examine whether substantial, efficient subglacial channels can form during or following lake drainage events and their effect on the water pressure in the surrounding distributed system. We force the model with field data from a lake drainage site, 70 km from the terminus of Russell Glacier in West Greenland. The model outputs suggest that efficient subglacial channels do not readily form in the vicinity of the lake during rapid drainage and instead water is evacuated primarily by a transient turbulent sheet and the distributed system. Following lake drainage, channels grow but are not large enough to reduce the water pressure in the surrounding distributed system, unless preexisting channels are present throughout the domain. Our results have implications for the analysis of subglacial hydrological systems in regions where rapid lake drainage provides the primary mechanism for surface-to-bed connections.Key PointsModel for subglacial hydrological analysis of rapid lake drainage eventsLimited subglacial channel growth during and following rapid lake drainagePersistence of distributed drainage in inland areas where channel growth is limited

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Section: Results and Analysismentioning

confidence: 99%

Modeling of subglacial hydrological development following rapid supraglacial lake drainage

Dow

Kulessa

Rutt

et al. 2015

J. Geophys. Res. Earth Surf.

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“…While we make no attempt here to model the transport of melt water to the base of the glacier (see e.g. Rice et al (2015)), our model suggests that, in the presence of a poroelastic subglacial till, an initial, small, melt-water flux to the base may locally increase the pore-pressure within the till. After a characteristic time, summarised in table 1, this melt water flux is sufficient to lift the base of the ice sheet off the till, a point certainly concomitant with an enhancement of basal sliding.…”

Section: Geophysical Implicationsmentioning

confidence: 97%

“…Note that Q(t) is simply a parameter in this model: we do not attempt to incorporate any description of how fluid propagates through the ice to its base (see, e.g. Rice et al 2015).…”

Section: Model Setupmentioning

confidence: 99%

The influence of a poroelastic till on rapid subglacial flooding and cavity formation

2018

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We develop a model of the rapid propagation of water at the contact between elastic glacial ice and a poroelastic subglacial till, motivated by observations of the rapid drainage of supraglacial lakes in Greenland. By treating the ice as an elastic bending beam, the fluid dynamics of contact with the subglacial hydrological network, which is modelled as a saturated poroelastic till, can be examined in detail. The model describes the formation and dynamics of an axisymmetric subglacial cavity, and the spread of pore pressure, in response to injection of fluid. A combination of numerical simulation and asymptotic analysis is used to describe these dynamics for both a rigid and a deformable porous till, and for both laminar and turbulent fluid flow. For constant injection rates and laminar flow, the cavity is isostatic and its spread is controlled by bending of the ice and suction of pore water in the vicinity of the ice–till contact. For a deformable till, this control can be modified: generically, a flexural wave that is initially trapped in advance of the contact point relaxes over time by diffusion of pore pressure ahead of the cavity. While the dynamics are found to be relatively insensitive to the properties of the subglacial till during injection with a constant flux, significant dependence on the till properties is manifest during the subsequent spread of a constant volume. A simple hybrid turbulent–laminar model is presented to account for fast injection rates of water: in this case, self-similar turbulent propagation can initially control the spread of the cavity, but there is a transition to laminar control in the vicinity of the ice–till contact point as the flow slows. Finally, the model results are compared with recent geophysical observations of the rapid drainage of supraglacial lakes in Greenland; the comparison provides qualitative agreement and raises suggestions for future quantitative comparison.

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“…The zero toughness limiting flow regime solutions presented here are also applicable in other contexts where the characteristic Reynolds number is truly large, such as in the case of rapid lake drainage at glacier beds (Rice et al. 2015).…”

Section: Discussionmentioning

confidence: 93%

Slickwater hydraulic fracture propagation: near-tip and radial geometry solutions

Lecampion

Zia

2019

J. Fluid Mech.

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We quantify the importance of turbulent flow on the propagation of hydraulic fractures (HF) accounting for the addition of friction reducing agents to the fracturing fluid (slickwater fluid). The addition in small quantities of a high molecular weight polymer to water is sufficient to drastically reduce friction of turbulent flow. The maximum drag reduction (MDR) asymptote is always reached during industrial-like injections. The energy required for pumping is thus drastically reduced, allowing for high volume high rate hydraulic fracturing operations at a reasonable cost. We investigate the propagation of a hydraulic fracture propagating in an elastic impermeable homogeneous solid under a constant (and possibly very high) injection rate accounting for laminar and turbulent flow conditions with or without the addition of friction reducers. We solve the near-tip HF problem and estimate the extent of the laminar boundary layer near the fracture tip as a function of a tip Reynolds number for slickwater. We obtain different propagation scalings and transition time scales. This allows us to easily quantify the growth of a radial HF from the early-time turbulent regime(s) to the late-time laminar regimes. Depending on the material and injection parameters, some propagation regimes may actually be bypassed. We derive both accurate and approximate solutions for the growth of radial HF in the different limiting flow regimes (turbulent smooth, rough, MDR) for the zero fracture toughness limit (corresponding to the early stage of propagation of a radial HF). We also investigate numerically the transition(s) between the early-time MDR regime to the late-time laminar regimes (viscosity and toughness) for slickwater fluid. Our results indicate that the effect of turbulent flow on high rate slickwater HF propagation is limited and matters only at early times (at most during the first minutes for industrial hydraulic fracturing operations).

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Time Scale for Rapid Draining of a Surficial Lake Into the Greenland Ice Sheet

Cited by 5 publications

References 14 publications

Modeling of subglacial hydrological development following rapid supraglacial lake drainage

Modeling of subglacial hydrological development following rapid supraglacial lake drainage

The influence of a poroelastic till on rapid subglacial flooding and cavity formation

Slickwater hydraulic fracture propagation: near-tip and radial geometry solutions

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