scholarly journals Two-Dimensional Liquid Water Flow through Snow at the Plot Scale in Continental Snowpacks: Simulations and Field Data Comparisons

2020 ◽  
Author(s):  
Ryan W. Webb ◽  
Keith S. Jennings ◽  
Stefan Finsterle ◽  
Steven R. Fassnacht
Keyword(s):  
Water Flow ◽  
Liquid Water ◽  
Water Movement ◽  
Ground Surface ◽  
Two Dimensional ◽  
Flow Paths ◽  
Sloping Ground ◽  
Spatial And Temporal Scales ◽  
Northern Colorado ◽  
Flow Through

Abstract. Modelling the multi-dimensional flow of liquid water through snow has been limited in spatial and temporal scales to date. Here we present simulations using the iTOUGH2 model informed by the model SNOWPACK, referred to as SnowTOUGH. We use SnowTOUGH to simulate snow metamorphism, melt/freeze processes, and liquid water movement in two-dimensional snowpacks at the plot scale (20 m) on a sloping ground surface during multi-day observation periods at three field sites in northern Colorado, USA. Model results compare well with subalpine and alpine sites, but not a treeline site. Results show the importance of longitudinal (i.e. parallel to ground surface in the downslope direction) intra-snowpack flow paths, particularly during times when the snow surface (i.e. snow-atmosphere interface) is not actively melting. Simulations show that longitudinal flow can occur at rates orders of magnitude greater than vertically downward percolating water flow (a ratio of > 250 : 1) as a result of hydraulic barriers.

scholarly journals Two-dimensional liquid water flow through snow at the plot scale in continental snowpacks: simulations and field data comparisons

2021 ◽  
Vol 15 (3) ◽  
pp. 1423-1434
Author(s):  
Ryan W. Webb ◽  
Keith Jennings ◽  
Stefan Finsterle ◽  
Steven R. Fassnacht
Keyword(s):  
Water Flow ◽  
Liquid Water ◽  
Water Movement ◽  
Ground Surface ◽  
Two Dimensional ◽  
Longitudinal Flow ◽  
Flow Paths ◽  
Sloping Ground ◽  
Spatial And Temporal Scales ◽  
A Site

Abstract. Modeling the multidimensional flow of liquid water through snow has been limited in spatial and temporal scales to date. Here, we present simulations using the inverse TOUGH2 (iTOUGH2) model informed by the model SNOWPACK, referred to as SnowTOUGH. We use SnowTOUGH to simulate snow metamorphism, melt/freeze processes, and liquid water movement in two-dimensional snowpacks at the plot scale (20 m) on a sloping ground surface during multi-day observation periods at three field sites in northern Colorado, USA. Model results compare well with sites below the treeline and above the treeline but not at a site near the treeline. Results show the importance of longitudinal intra-snowpack flow paths (i.e., parallel to ground surface in the downslope direction and sometimes referred to as lateral flow), particularly during times when the snow surface (i.e., snow–atmosphere interface) is not actively melting. At our above-treeline site, simulations show that longitudinal flow can occur at rates orders of magnitude greater than vertically downward percolating water flow at a mean ratio of 75:1 as a result of hydraulic barriers that divert flow. Our near-treeline site simulations resulted in slightly less longitudinal flow than vertically percolating water, and the below-treeline site resulted in negligible longitudinal flow of liquid water. These results show the increasing influence of longitudinal intra-snowpack flow paths with elevation, similar to field observations. Results of this study suggest that intra-snowpack longitudinal flow may be an important process for consideration in hydrologic modeling for higher-elevation headwater catchments.

scholarly journals Computing water flow through complex landscapes – Part 2: Finding hierarchies in depressions and morphological segmentations

2020 ◽  
Vol 8 (2) ◽  
pp. 431-445
Author(s):  
Richard Barnes ◽  
Kerry L. Callaghan ◽  
Andrew D. Wickert
Keyword(s):  
Water Flow ◽  
Hydrological Modeling ◽  
Dynamic Models ◽  
Terrain Analysis ◽  
Flow Paths ◽  
Topographic Complexity ◽  
Morphological Segmentation ◽  
Surface Water Flow ◽  
Digital Elevation ◽  
Flow Through

Abstract. Depressions – inwardly draining regions of digital elevation models – present difficulties for terrain analysis and hydrological modeling. Analogous “depressions” also arise in image processing and morphological segmentation, where they may represent noise, features of interest, or both. Here we provide a new data structure – the depression hierarchy – that captures the full topologic and topographic complexity of depressions in a region. We treat depressions as networks in a way that is analogous to surface-water flow paths, in which individual sub-depressions merge together to form meta-depressions in a process that continues until they begin to drain externally. This hierarchy can be used to selectively fill or breach depressions or to accelerate dynamic models of hydrological flow. Complete, well-commented, open-source code and correctness tests are available on GitHub and Zenodo.

Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: II. Theory

1998 ◽  
Vol 44 (148) ◽  
pp. 563-569 ◽  
Author(s):  
Richard B. Alley ◽  
Daniel E. Lawson ◽  
Edward B. Evenson ◽  
Jeffrey C. Strasser ◽  
Grahame J. Larson
Keyword(s):  
Water Flow ◽  
Accretion Rate ◽  
Water Discharge ◽  
Steep Slope ◽  
Field Observations ◽  
Ice Accretion ◽  
Flow Paths ◽  
Basal Ice ◽  
Flow Through ◽  
Pressure Melting

AbstractSimple theory supports field observations (Lawson and others, 1998 that subGlaciol water flow out of overdeepenings can cause accretion of layered, debris-bearing ice to the bases of glaciers. The large meltwater flux into a temperate glacier at the onset of summer melting can cause rapid water flow through expanded basal cavities or other flow paths. If that flow ascends a sufficiently steep slope out of an overdeepèning, the water will supercool as the pressure-melting point rises, and basal-ice accretion will occur. Diurnal, occasional or annual fluctuations in water discharge will cause variations in accretion rate, debris content of accreted ice or subsequent diagenesis, producing layers. Under appropriate conditions, net accretion of debris-bearing basal ice will allow debris fluxes that are significant in the glacier sediment budget.

scholarly journals A 2D model for simulating heterogeneous mass and energy fluxes through melting snowpacks

2016 ◽  
Author(s):  
Nicolas R. Leroux ◽  
John W. Pomeroy
Keyword(s):  
Water Flow ◽  
Liquid Water ◽  
Preferential Flow ◽  
Initial Conditions ◽  
Surface Fluxes ◽  
Porous Media Flow ◽  
Accurate Estimation ◽  
Flow Paths ◽  
Preferential Flow Paths ◽  
The Impact

Abstract. Accurate estimation of the water flux through melting snowpacks is of primary importance for runoff prediction. Lateral flows and preferential flow pathways in porous media flow have proven critical for improving soil and groundwater flow models, but though many physically-based layered snowmelt models have been developed, only 1D matrix flow over level ground is currently accounted for in snow models. Snowmelt models that include these processes may improve snowmelt discharge timing and contributing area calculations in hydrological models. A two-dimensional snow model (SMPP – Snowmelt Model with Preferential flow Paths) is presented that simulates heat and water flows through both snowpack matrix and preferential flow paths, as well as snowmelt and refreezing of meltwater. The model assumes thermodynamic equilibrium between solid and liquid phases and uses the latest improvements made in snow science to estimate snow hydraulic and thermal properties. A finite volume method is applied to solve for the 2D heat and water equations. The use of a water entry pressure for dry snow combined with consideration of the impact of heterogeneities in surface fluxes and internal snow properties – density, grain size and layer thickness – allowed calculation of the formation of preferential flow paths in the snowpack. The simulation of water flow through preferential flow paths resulted in liquid water reaching the base of the snowpack earlier than for a homogeneous wetting front. Moreover, the preferential flow paths in the model increased the exchange of energy between the snow surface and the internal snowpack, resulting in faster warming of the snowpack. A sensitivity analysis, conducted on the snow internal properties showed that initial conditions such as density and temperature, should be carefully measured in the field to accurately estimate liquid water percolating through the snowpack. Furthermore, two empirical coefficients used in the water flow equation were showed to greatly impact model outputs. This heterogeneous flow model is an important tool to help understand snowmelt flow processes in complex and level terrains and to demonstrate how uncertainty in snowmelt-derived runoff calculations might be reduced.

Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: II. Theory

1998 ◽  
Vol 44 (148) ◽  
pp. 563-569 ◽  
Author(s):  
Richard B. Alley ◽  
Daniel E. Lawson ◽  
Edward B. Evenson ◽  
Jeffrey C. Strasser ◽  
Grahame J. Larson
Keyword(s):  
Water Flow ◽  
Accretion Rate ◽  
Water Discharge ◽  
Steep Slope ◽  
Field Observations ◽  
Ice Accretion ◽  
Flow Paths ◽  
Basal Ice ◽  
Flow Through ◽  
Pressure Melting

AbstractSimple theory supports field observations (Lawson and others, 1998 that subGlaciol water flow out of overdeepenings can cause accretion of layered, debris-bearing ice to the bases of glaciers. The large meltwater flux into a temperate glacier at the onset of summer melting can cause rapid water flow through expanded basal cavities or other flow paths. If that flow ascends a sufficiently steep slope out of an overdeepèning, the water will supercool as the pressure-melting point rises, and basal-ice accretion will occur. Diurnal, occasional or annual fluctuations in water discharge will cause variations in accretion rate, debris content of accreted ice or subsequent diagenesis, producing layers. Under appropriate conditions, net accretion of debris-bearing basal ice will allow debris fluxes that are significant in the glacier sediment budget.

Water Flow through Interlayer Channels of Two-Dimensional Materials with Various Hydrophilicities

2018 ◽  
Vol 122 (27) ◽  
pp. 15772-15779 ◽  
Author(s):  
Fang Xu ◽  
Yang Song ◽  
Mingjie Wei ◽  
Yong Wang
Keyword(s):  
Water Flow ◽  
Two Dimensional ◽  
Two Dimensional Materials ◽  
Flow Through

scholarly journals Simulating ice layer formation under the presence of preferential flow in layered snowpacks

2016 ◽  
Vol 10 (6) ◽  
pp. 2731-2744 ◽  
Author(s):  
Nander Wever ◽  
Sebastian Würzer ◽  
Charles Fierz ◽  
Michael Lehning
Keyword(s):  
Snow Cover ◽  
Water Flow ◽  
Liquid Water ◽  
Preferential Flow ◽  
Layer Formation ◽  
Flow Paths ◽  
One Dimensional ◽  
Preferential Flow Paths ◽  
Matrix Flow ◽  
Dual Domain

Abstract. For physics-based snow cover models, simulating the formation of dense ice layers inside the snowpack has been a long-time challenge. Their formation is considered to be tightly coupled to the presence of preferential flow, which is assumed to happen through flow fingering. Recent laboratory experiments and modelling techniques of liquid water flow in snow have advanced the understanding of conditions under which preferential flow paths or flow fingers form. We propose a modelling approach in the one-dimensional, multilayer snow cover model SNOWPACK for preferential flow that is based on a dual domain approach. The pore space is divided into a part that represents matrix flow and a part that represents preferential flow. Richards' equation is then solved for both domains and only water in matrix flow is subjected to phase changes. We found that preferential flow paths arriving at a layer transition in the snowpack may lead to ponding conditions, which we used to trigger a water flow from the preferential flow domain to the matrix domain. Subsequent refreezing then can form dense layers in the snowpack that regularly exceed 700 kg m−3. A comparison of simulated density profiles with biweekly snow profiles made at the Weissfluhjoch measurement site at 2536 m altitude in the Eastern Swiss Alps for 16 snow seasons showed that several ice layers that were observed in the field could be reproduced. However, many profiles remain challenging to simulate. The prediction of the early snowpack runoff also improved under the consideration of preferential flow. Our study suggests that a dual domain approach is able to describe the net effect of preferential flow on ice layer formation and liquid water flow in snow in one-dimensional, detailed, physics-based snowpack models, without the need for a full multidimensional model.

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