A model for interaction between conduits and surrounding hydraulically connected distributed drainage based on geomorphological evidence from Keewatin, Canada

Abstract. We identify and map visible traces of subglacial meltwater drainage around the former Keewatin Ice Divide, Canada, from high-resolution Arctic Digital Elevation Model (ArcticDEM) data. We find similarities in the characteristics and spatial locations of landforms traditionally treated separately (i.e. meltwater channels, meltwater tracks and eskers) and propose that creating an integrated map of meltwater routes captures a more holistic picture of the large-scale drainage in this area. We propose the grouping of meltwater channels and meltwater tracks under the term meltwater corridor and suggest that these features in the order of 10s–100s m wide, commonly surrounding eskers and transitioning along flow between different types, represent the interaction between a central conduit (the esker) and surrounding hydraulically connected distributed drainage system (the meltwater corridor). Our proposed model is based on contemporary observations and modelling which suggest that connections between conduits and the surrounding distributed drainage system within the ablation zone occur as a result of overpressurisation of the conduit. The widespread aerial coverage of meltwater corridors (5 %–36 % of the bed) provides constraints on the extent of basal uncoupling induced by basal water pressure fluctuations. Geomorphic work resulting from repeated connection to the surrounding hydraulically connected distributed drainage system suggests that basal sediment can be widely accessed and evacuated by meltwater.

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Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

10.5194/tc-2020-10 ◽

2020 ◽

Cited By ~ 1

Author(s):

Emma L. M. Lewington ◽

Stephen J. Livingstone ◽

Chris D. Clark ◽

Andrew J. Sole ◽

Robert D. Storrar

Keyword(s):

Spatial Distribution ◽

Dynamic Response ◽

Large Scale ◽

Water Pressure ◽

Pressure Fluctuations ◽

Drainage System ◽

Different Types ◽

Form Part ◽

Subglacial Meltwater ◽

Subglacial Drainage

Abstract. We identify and map traces of subglacial meltwater drainage around the former Keewatin Ice Divide, Canada from ArcticDEM data. Meltwater tracks, tunnel valleys and esker splays exhibit several key similarities, including width, spacing, their association with eskers and transitions to and from different types, which together suggest they form part of an integrated drainage signature. We collectively term these features &apos;meltwater corridors&apos; and propose a new model for their formation, based on observations from contemporary ice masses, of pressure fluctuations surrounding a central conduit. We suggest that eskers record the imprint of a central conduit and meltwater corridors the interaction with the surrounding distributed drainage system. The widespread aerial coverage of meltwater corridors (5–36 % of the bed) provides constraints on the extent of basal uncoupling induced by basal water pressure fluctuations and variations in spatial distribution and evolution of the subglacial drainage system, which will modulate the ice dynamic response.

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Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

10.5194/egusphere-egu2020-5861 ◽

2020 ◽

Author(s):

Emma Lewington ◽

Stephen Livingstone ◽

Chris Clark ◽

Andrew Sole ◽

Robert Storrar

Keyword(s):

Large Scale ◽

Water Pressure ◽

Pressure Fluctuations ◽

Ice Sheet ◽

Drainage System ◽

Spatial Location ◽

Variable Pressure ◽

Ice Sheet Dynamics ◽

Subglacial Meltwater ◽

Subglacial Drainage

Despite being widely studied, subglacial meltwater landforms are typically mapped and investigated individually, thus the drainage system as a whole remains poorly understood. Here, we identify and map all visible traces of subglacial meltwater flow across the Keewatin sector of the former Laurentide Ice Sheet from the ArcticDEM, generating significant new insights into the connectedness of the drainage system.Due to similarities in spacing, morphometry and spatial location, we suggest that the 100s-1000s m wide features often flanking and connecting sections of eskers (i.e. tunnel valleys, meltwater tracks and esker splays) are varying expressions of the same phenomena and collectively term these features &#8216;meltwater corridors&#8217;. Based on observations from contemporary ice masses, we propose a new formation model based on the pressure fluctuations surrounding a central conduit, in which the esker records the imprint of the central conduit and the wider meltwater corridors the interactions with the surrounding distributed drainage system, or variable pressure axis (VPA).We suggest that the widespread aerial coverage of meltwater corridors across the Keewatin sector provides constraints on the extent of basal uncoupling induced by basal water pressure fluctuation and variations in spatial distribution and evolution of the subglacial drainage system, which have important implications for ice sheet dynamics.&#160;

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Role of discrete recharge from the supraglacial drainage system for modelling of subglacial conduits pattern of Svalbard polythermal glaciers

10.5194/tc-2017-219 ◽

2018 ◽

Cited By ~ 2

Author(s):

Léo Decaux ◽

Mariusz Grabiec ◽

Dariusz Ignatiuk ◽

Jacek Jania

Keyword(s):

Water Pressure ◽

Drainage System ◽

Stable State ◽

Water Runoff ◽

Digital Elevation ◽

Water Recharge ◽

Frontal Zones ◽

Theoretical Pattern ◽

Elevation Model ◽

Subglacial Drainage

Abstract. Being a determinant factor of the glacier’s dynamic, subglacial water behavior needs a special attention.Water flowing from the glacier’s surface is the principal source supplying the subglacial drainage system. Therefore, insight into the state and evolution of the supraglacial drainage system is crucial for recognition of recharge pattern of the englacial and subglacial drainage pathways. Climate warming causes increased ablation generating higher amount of meltwater and thinning of glacier. Decadal timescale evolution of the supraglacial drainage leads to some modifications of the system in opposition to its nearly stable state on an annual timescale. For two studied glaciers Hansbreen and Werenskioldbreen in southern Svalbard surface meltwater is the main runoff component. During the ablation season 2015, 72.5 % of the total amount was provided by meltwater and 27.5 % by precipitations. Supraglacial catchments were determined on the high resolution digital elevation model using standard watershed modelling tool in ArcGIS, for each water-input area (WIA). Spatialized water runoff calculations for all the main WIAs have been done. Having data on the water sources from catchments delimited on glacier’s surface, modelling of a theoretical pattern of subglacial conduits was done considering discrete water recharge via moulins, shear fractures or crevasses. Classical modelling with an assumption of homogeneous water supply was done for comparison. Several water pressure conditions have been taken into account as well. Results show that models of subglacial drainage system with homogeneous water recharge are more realistic for tidewater glaciers with rather broad permeable firn areas and creased frontal zones, while discrete water recharge models are better for land-terminating glaciers with almost continuous impermeable superficial cold ice layer. Subglacial channel models are assumed to be valid for a minimum period of two decades taking into account evolution of supraglacial drainage system and ice thickness changes of Svalbard polythermal glaciers.

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A Multidimensional and Multiscale Model for Pressure Analysis in a Reservoir-Pipe-Valve System

Journal of Pressure Vessel Technology ◽

10.1115/1.4044117 ◽

2019 ◽

Vol 141 (5) ◽

Author(s):

Feng Jie Zheng ◽

Chao Yong Zong ◽

William Dempster ◽

Fu Zheng Qu ◽

Xue Guan Song

Keyword(s):

Large Scale ◽

Pressure Fluctuations ◽

Three Dimensional ◽

Multiscale Model ◽

Computational Time ◽

Small Scale ◽

Dimensional System ◽

Cfd Model ◽

Computationally Efficient ◽

Proposed Model

Reservoir-pipe-valve (RPV) systems are widely used in many industrial processes. The pressure in an RPV system plays an important role in the safe operation of the system, especially during the sudden operations such as rapid valve opening or closing. To investigate the pressure response, with particular interest in the pressure fluctuations in an RPV system, a multidimensional and multiscale model combining the method of characteristics (MOC) and computational fluid dynamics (CFD) method is proposed. In the model, the reservoir is modeled as a zero-dimensional virtual point, the pipe is modeled as a one-dimensional system using the MOC, and the valve is modeled using a three-dimensional CFD model. An interface model is used to connect the multidimensional and multiscale model. Based on the model, a transient simulation of the turbulent flow in an RPV system is conducted in which not only the pressure fluctuation in the pipe but also the detailed pressure distribution in the valve is obtained. The results show that the proposed model is in good agreement when compared with a high fidelity CFD model used to represent both large-scale and small-scale spaces. As expected, the proposed model is significantly more computationally efficient than the CFD model. This demonstrates the feasibility of analyzing complex RPV systems within an affordable computational time.

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Stability Improvement Method for Embankment Dam with Respect to Conduit Cracks

Applied Sciences ◽

10.3390/app12020567 ◽

2022 ◽

Vol 12 (2) ◽

pp. 567

Author(s):

Young-Hak Lee ◽

Jung-Hyun Ryu ◽

Joon Heo ◽

Jae-Woong Shim ◽

Dal-Won Lee

Keyword(s):

Large Scale ◽

Pore Water Pressure ◽

Water Pressure ◽

Three Dimensional ◽

Internal Erosion ◽

Scale Model ◽

Seepage Analysis ◽

Large Scale Model ◽

Proposed Model ◽

Improvement Method

In recent years, as the number of reservoir embankments constructed has increased, embankment failures due to cracks in aging conduits have also increased. In this study, a crack in a conduit was modeled based on the current conduit design model, and the risk of internal erosion was analyzed using a large-scale model test and three-dimensional deformation–seepage analysis. The results show that when cracks existed in the conduit, soil erosion and cavitation occurred near the crack area, which made the conduit extremely vulnerable to internal erosion. Herein, a model is proposed that can reduce internal erosion by applying a layer of sand and geotextiles on the upper part of the conduit located close to the downstream slope. In the proposed model, only partial erosion occurred inside the conduit, and no cavitation appeared near the crack in the conduit. The results suggest that internal erosion can be suppressed when the water pressure acting intensively on the crack in the conduit is dispersed by the drainage layer. To validate these results, the pore water pressure, seepage line, and hydraulic gradient were investigated to confirm the erosion phenomenon and reinforcement effect.

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Fusion Analysis of Optical Satellite Images and Digital Elevation Model for Quantifying Volume in Debris Flow Disaster

Remote Sensing ◽

10.3390/rs11091096 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1096 ◽

Cited By ~ 2

Author(s):

Hiroyuki Miura

Keyword(s):

Debris Flow ◽

Digital Elevation Model ◽

Large Scale ◽

Satellite Images ◽

Erosion Depth ◽

Digital Elevation ◽

Elevation Model ◽

Fusion Analysis ◽

Optical Satellite Images ◽

Debris Flow Disaster

Rapid identification of affected areas and volumes in a large-scale debris flow disaster is important for early-stage recovery and debris management planning. This study introduces a methodology for fusion analysis of optical satellite images and digital elevation model (DEM) for simplified quantification of volumes in a debris flow event. The LiDAR data, the pre- and post-event Sentinel-2 images and the pre-event DEM in Hiroshima, Japan affected by the debris flow disaster on July 2018 are analyzed in this study. Erosion depth by the debris flows is empirically modeled from the pre- and post-event LiDAR-derived DEMs. Erosion areas are detected from the change detection of the satellite images and the DEM-based debris flow propagation analysis by providing predefined sources. The volumes and their pattern are estimated from the detected erosion areas by multiplying the empirical erosion depth. The result of the volume estimations show good agreement with the LiDAR-derived volumes.

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A new method for supporting interpretation of paleochannels in a large scale — Detrended Digital Elevation Model Interpretation

Geomorphology ◽

10.1016/j.geomorph.2020.107374 ◽

2020 ◽

Vol 369 ◽

pp. 107374

Author(s):

Shuyan Zhang ◽

Yong Ma ◽

Fu Chen ◽

Jianbo Liu ◽

Fulong Chen ◽

...

Keyword(s):

Digital Elevation Model ◽

Large Scale ◽

New Method ◽

Model Interpretation ◽

Digital Elevation ◽

Elevation Model

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Role of discrete water recharge from supraglacial drainage systems in modeling patterns of subglacial conduits in Svalbard glaciers

The Cryosphere ◽

10.5194/tc-13-735-2019 ◽

2019 ◽

Vol 13 (3) ◽

pp. 735-752 ◽

Cited By ~ 4

Author(s):

Léo Decaux ◽

Mariusz Grabiec ◽

Dariusz Ignatiuk ◽

Jacek Jania

Keyword(s):

Current Knowledge ◽

Water Pressure ◽

Drainage System ◽

Stable State ◽

Watershed Modeling ◽

Potential Gradient ◽

Water Runoff ◽

Total Runoff ◽

Water Recharge ◽

Elevation Model

Abstract. As the behavior of subglacial water plays a determining role in glacier dynamics, it requires particular attention, especially in the context of climate warming, which is increasing ablation and generating greater amounts of meltwater. On many glaciers, water flowing from the glacier's surface is the main source of supply to the subglacial drainage system. This system is largely influenced by the supraglacial drainage system, which collects meltwater and precipitation and rapidly delivers it to discrete points in the glacier bed via moulins and crevassed areas, called water input areas (WIAs). Models of patterns of subglacial conduits mainly based on the hydrological potential gradient are still regularly performed without taking into account the supraglacial drainage system. We modeled the pattern of subglacial channels in two glaciers located in Svalbard, the land-terminating Werenskioldbreen and the tidewater Hansbreen during the 2015 melt season. We modeled a spatial and a discrete water recharge in order to compare them. First, supraglacial catchments were determined for each WIA on a high-resolution digital elevation model using the standard watershed modeling tool in ArcGIS. Then, interpolated water runoff was calculated for all the main WIAs. Our model also accounts for several water pressure conditions. For our two studied glaciers, during the ablation season 2015, 72.5 % of total runoff was provided by meltwater and 27.5 % by precipitation. Changes in supraglacial drainage on a decadal timescale are observed in contrast to its nearly stable state on an annual timescale. Nevertheless, due to the specific nature of those changes, it seems to have a low impact on the subglacial system. Therefore, our models of subglacial channel are assumed to be valid for a minimum period of two decades and depend on changes in the supraglacial drainage system. Results showed that, for Svalbard tidewater glaciers with large crevassed areas, models of subglacial channels that assume spatial water recharge may be somewhat imprecise but are far from being completely incorrect, especially for the ablation zone. On the other hand, it is important to take discrete water recharge into account in the case of land-terminating Svalbard glaciers with limited crevassed areas. In all cases, considering a discrete water recharge when modeling patterns of theoretical subglacial channels seems to produce more realistic results according to current knowledge.

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A Semiautomatic Pixel-Object Method for Detecting Landslides Using Multitemporal ALOS-2 Intensity Images

Remote Sensing ◽

10.3390/rs12030561 ◽

2020 ◽

Vol 12 (3) ◽

pp. 561 ◽

Cited By ~ 1

Author(s):

Bruno Adriano ◽

Naoto Yokoya ◽

Hiroyuki Miura ◽

Masashi Matsuoka ◽

Shunichi Koshimura

Keyword(s):

Disaster Response ◽

Large Scale ◽

Reference Data ◽

Mass Movement ◽

Recovery Planning ◽

Additional Information ◽

Digital Elevation ◽

Before And After ◽

Intensity Images ◽

Elevation Model

The rapid and accurate mapping of large-scale landslides and other mass movement disasters is crucial for prompt disaster response efforts and immediate recovery planning. As such, remote sensing information, especially from synthetic aperture radar (SAR) sensors, has significant advantages over cloud-covered optical imagery and conventional field survey campaigns. In this work, we introduced an integrated pixel-object image analysis framework for landslide recognition using SAR data. The robustness of our proposed methodology was demonstrated by mapping two different source-induced landslide events, namely, the debris flows following the torrential rainfall that fell over Hiroshima, Japan, in early July 2018 and the coseismic landslide that followed the 2018 Mw6.7 Hokkaido earthquake. For both events, only a pair of SAR images acquired before and after each disaster by the Advanced Land Observing Satellite-2 (ALOS-2) was used. Additional information, such as digital elevation model (DEM) and land cover information, was employed only to constrain the damage detected in the affected areas. We verified the accuracy of our method by comparing it with the available reference data. The detection results showed an acceptable correlation with the reference data in terms of the locations of damage. Numerical evaluations indicated that our methodology could detect landslides with an accuracy exceeding 80%. In addition, the kappa coefficients for the Hiroshima and Hokkaido events were 0.30 and 0.47, respectively.

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Food Submergence Calculation and Analysis Using Digital Elevation Model and Geographical Information System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.571-572.792 ◽

2014 ◽

Vol 571-572 ◽

pp. 792-795

Author(s):

Xiao Qing Zhang ◽

Kun Hua Wu

Keyword(s):

Information System ◽

Digital Elevation Model ◽

Flood Control ◽

Large Scale ◽

Geographical Information ◽

Economic Losses ◽

Model Data ◽

Digital Elevation ◽

Elevation Model ◽

Digital Elevation Model Data

Floods usually cause large-scale loss of human life and wide spread damage to properties. Determining flood zone is the core of flood damage assessment and flood control decision. The aim of this paper is to delineate the flood inundation area and estimate economic losses arising from flood using the digital elevation model data and geographic information system techniques. Flood extent estimation showed that digital elevation model data is very precious to model inundation, however, in order to be spatially explicit flood model, high resolution DEM is necessary. Finally, Analyses for the submergence area calculation accuracy.

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