scholarly journals Modelling capillary hysteresis effects on preferential flow through melting and cold layered snowpacks

2017 ◽  
Vol 107 ◽  
pp. 250-264 ◽  
Author(s):  
Nicolas R. Leroux ◽  
John W. Pomeroy
Keyword(s):  
Preferential Flow ◽  
Capillary Hysteresis ◽  
Flow Through

scholarly journals Effects of preferential flow on snowmelt partitioning and groundwater recharge in frozen soils

2019 ◽  
Vol 23 (12) ◽  
pp. 5017-5031 ◽  
Author(s):  
Aaron A. Mohammed ◽  
Igor Pavlovskii ◽  
Edwin E. Cey ◽  
Masaki Hayashi
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Preferential Flow ◽  
Frozen Soil ◽  
Time Lags ◽  
Runoff Generation ◽  
Frozen Ground ◽  
Soil Matrix ◽  
Frozen Soils ◽  
Flow Through

Abstract. Snowmelt is a major source of groundwater recharge in cold regions. Throughout many landscapes snowmelt occurs when the ground is still frozen; thus frozen soil processes play an important role in snowmelt routing, and, by extension, the timing and magnitude of recharge. This study investigated the vadose zone dynamics governing snowmelt infiltration and groundwater recharge at three grassland sites in the Canadian Prairies over the winter and spring of 2017. The region is characterized by numerous topographic depressions where the ponding of snowmelt runoff results in focused infiltration and recharge. Water balance estimates showed infiltration was the dominant sink (35 %–85 %) of snowmelt under uplands (i.e. areas outside of depressions), even when the ground was frozen, with soil moisture responses indicating flow through the frozen layer. The refreezing of infiltrated meltwater during winter melt events enhanced runoff generation in subsequent melt events. At one site, time lags of up to 3 d between snow cover depletion on uplands and ponding in depressions demonstrated the role of a shallow subsurface transmission pathway or interflow through frozen soil in routing snowmelt from uplands to depressions. At all sites, depression-focused infiltration and recharge began before complete ground thaw and a significant portion (45 %–100 %) occurred while the ground was partially frozen. Relatively rapid infiltration rates and non-sequential soil moisture and groundwater responses, observed prior to ground thaw, indicated preferential flow through frozen soils. The preferential flow dynamics are attributed to macropore networks within the grassland soils, which allow infiltrated meltwater to bypass portions of the frozen soil matrix and facilitate both the lateral transport of meltwater between topographic positions and groundwater recharge through frozen ground. Both of these flow paths may facilitate preferential mass transport to groundwater.

Cracking and vertical preferential flow through landfill clay liners

2016 ◽  
Vol 206 ◽  
pp. 33-41 ◽  
Author(s):  
J.H. Li ◽  
L. Li ◽  
R. Chen ◽  
D.Q. Li
Keyword(s):  
Preferential Flow ◽  
Clay Liners ◽  
Flow Through

Internal Erosion of Soil Pipes: Still More Questions Than Answers

2020 ◽  
Author(s):  
Glenn Wilson ◽  
Anita Bernatek-Jakiel ◽  
John L. Nieber ◽  
Garey A. Fox
Keyword(s):  
Sediment Transport ◽  
Preferential Flow ◽  
Critical Shear Stress ◽  
Solution Chemistry ◽  
Internal Erosion ◽  
Transport Capacity ◽  
Sediment Transport Capacity ◽  
Flow Through ◽  
Mass Failure ◽  
Soil Pipe

<p>Internal erosion of soil pipes can be a very important process in gully erosion as well as other mass failure events such as sinkholes, landslides and levee/dam breaching. Flow through preferential flow paths such as macropores can be rapid enough to exceed the soil critical shear stress and cause detachment of particles from the walls of the flow path, i.e. internal erosion. Development of a soil pipe from enlargement of a macropore results in more rapid flow and thus greater internal erosion, particularly mass failure of aggregates from pipe walls and roofs. If the sediment transport capacity of the pipe is exceeded, the pipe will plug causing back-pressure to build up within the soil pipe, which can foster hillslope instability. However, limited research has been conducted on particle and aggregate detachment within soil pipes as well as transport of sediment through soil pipes. The objective of this paper is to present observations of little known and poorly described processes involved in pipeflow and the resulting internal erosion of soil pipes. Many of the processes involved in internal erosion of soil pipes are assumed based upon processes observed in surface and stream erosion studies but are so poorly quantified for soil pipes that they are yet to be transferable. For example, the role of solution chemistry on sediment detachment from pipe walls has been quantified to a limited extent but little has been done on the effects of seepage forces on particle detachment in pipes and even less done on sediment transport capacity of soil pipes. Recent advances have included: development of suspended sediment and bedload rating curves for soil pipeflows but the results are crude and warrant further study. Quantification of the interactive effects of surface flow in channels with flow through soil pipes below channels on headcut migration and gully widening is in its infancy. Other processes, such as air-entrapment in creating or temporarily plugging pipes, have been suggested as important but lack quantification. These processes and others combine to result in internal erosion of soil pipes but they must be better understood and quantified in order to develop the next generation of soil erosion models and landscape morphology prediction technologies.</p>

scholarly journals Subsurface Lateral Flow in Texture-Contrast (Duplex) Soils and Catchments with Shallow Bedrock

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Marcus A. Hardie ◽  
Richard B. Doyle ◽  
William E. Cotching ◽  
Shaun Lisson
Keyword(s):  
Preferential Flow ◽  
Soil Surface ◽  
Field Studies ◽  
Lateral Flow ◽  
Review Of Literature ◽  
Antecedent Soil Moisture ◽  
Process Understanding ◽  
Subsurface Lateral Flow ◽  
Flow Through ◽  
Texture Contrast

Development-perched watertables and subsurface lateral flows in texture-contrast soils (duplex) are commonly believed to occur as a consequence of the hydraulic discontinuity between the A and B soil horizons. However, in catchments containing shallow bedrock, subsurface lateral flows result from a combination of preferential flow from the soil surface to the soil—bedrock interface, undulations in the bedrock topography, lateral flow through macropore networks at the soil—bedrock interface, and the influence of antecedent soil moisture on macropore connectivity. Review of literature indicates that some of these processes may also be involved in the development of subsurface lateral flow in texture contrast soils. However, the extent to which these mechanisms can be applied to texture contrast soils requires further field studies. Improved process understanding is required for modelling subsurface lateral flows in order to improve the management of waterlogging, drainage, salinity, and offsite agrochemicals movement.

Ephemeral gully erosion by preferential flow through a discontinuous soil-pipe

CATENA ◽  
2008 ◽  
Vol 73 (1) ◽  
pp. 98-106 ◽  
Author(s):  
G.V. Wilson ◽  
R.F. Cullum ◽  
M.J.M. Römkens
Keyword(s):  
Preferential Flow ◽  
Gully Erosion ◽  
Ephemeral Gully ◽  
Flow Through ◽  
Soil Pipe

scholarly journals Dissolution and precipitation of fractures in soluble rock

2016 ◽  
Author(s):  
Georg Kaufmann ◽  
Franci Gabrovšek ◽  
Douchko Romanov
Keyword(s):  
Preferential Flow ◽  
Selective Dissolution ◽  
Secondary Porosity ◽  
Flow Paths ◽  
Rock Types ◽  
Preferential Flow Paths ◽  
Soluble Rock ◽  
Flow Through ◽  
Preferential Pathways ◽  
Dissolution And Precipitation

Abstract. Soluble rocks such as limestone, anhydrite, and gypsum are characterised by their large secondary permeability, which results from the interaction of water circulating through the rock and dissolving the soluble fracture walls. This highly selective dissolution process enlarges the fractures to voids and eventually cavities, which then carry the majority of flow through an aquifer along preferential flow paths. We employ a numerical model describing the evolution of secondary porosity in a soluble rock to study the evolution of isolated fractures in different rock types. Our main focus is three-fold: The identification of shallow versus deep flow paths and their evolution for different rock types; the effect of precipitation of the dissolved material in the fracture; and finally the complication of fracture enlargement in fractures composed of several different soluble materials. Our results show that the evolution of fractures composed of limestone and gypsum is comparable, but the evolution time scale is drastically different. For anhydrite, owing to its difference in the kinetical rate law describing the removal of soluble rock, when compared to limestone and anhydrite, the evolution is even faster. Precipitation of the dissolved rock due to changes in the hydrochemical conditions can clog fractures fairly fast, thus changing the pattern of preferential pathways in the soluble aquifer, especially with depth. Finally, limestone fracture coated with gypsum, as frequently observed in caves, will result in a substantial increase in fracture enlargement with time, thus giving these fractures a hydraulic advantage over pure limestone fractures in their competition for capturing flow.

scholarly journals Numerical Simulation of Unstable Preferential Flow during Water Infiltration into Heterogeneous Dry Soil

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 909
Author(s):  
Luis Cueto-Felgueroso ◽  
María José Suarez-Navarro ◽  
Xiaojing Fu ◽  
Ruben Juanes
Keyword(s):  
Numerical Simulation ◽  
Correlation Length ◽  
Soil Structure ◽  
Preferential Flow ◽  
Soil Heterogeneity ◽  
Water Infiltration ◽  
Intrinsic Permeability ◽  
Relative Permeabilities ◽  
Flow Through ◽  
Dry Soil

Water infiltration and unsaturated flow through heterogeneous soil control the distribution of soil moisture in the vadose zone and the dynamics of groundwater recharge, providing the link between climate, biogeochemical soil processes and vegetation dynamics. Infiltration into dry soil is hydrodynamically unstable, leading to preferential flow through narrow wet regions (fingers). In this paper we use numerical simulation to study the interplay between fingering instabilities and soil heterogeneity during water infiltration. We consider soil with heterogeneous intrinsic permeability. Permeabilities are random, with point Gaussian statistics, and vary smoothly in space due to spatial correlation. The key research question is whether the presence of moderate or strong heterogeneity overwhelms the fingering instability, recovering the simple stable displacement patterns predicted by most simplified model of infiltration currently used in hydrological models from the Darcy to the basin scales. We perform detailed simulations of constant-rate infiltration into soils with isotropic and anisotropic intrinsic permeability fields. Our results demonstrate that soil heterogeneity does not suppress fingering instabilities, but it rather enhances its effect of preferential flow and channeling. Fingering patterns strongly depend on soil structure, in particular the correlation length and anisotropy of the permeability field. While the finger size and flow dynamics are only slightly controlled by correlation length in isotropic fields, layering leads to significant finger meandering and bulging, changing arrival times and wetting efficiencies. Fingering and soil heterogeneity need to be considered when upscaling the constitutive relationships of multiphase flow in porous media (relative permeability and water retention curve) from the finger to field and basin scales. While relative permeabilities remain unchanged upon upscaling for stable displacements, the inefficient wetting due to fingering leads to relative permeabilities at the field scale that are significantly different from those at the Darcy scale. These effective relative permeability functions also depend, although less strongly, on heterogeneity and soil structure.

Ponded infiltration into soil with biopores — field experiment and modeling

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Michal Dohnal ◽  
Jaromír Dušek ◽  
Tomáš Vogel ◽  
Milena Císlerová ◽  
Ľubomír Lichner ◽  
...  
Keyword(s):  
Water Flow ◽  
Preferential Flow ◽  
Water Pressure ◽  
Three Dimensional ◽  
Detailed Knowledge ◽  
Dye Tracer ◽  
Simulation Based ◽  
Flow Through ◽  
Flow Effects ◽  
Infiltration Experiment

AbstractPreferential movement of water in macropores plays an important role when the process of ponded infiltration in natural porous systems is studied. For example, the detailed knowledge of water flow through macropores is of a major importance when predicting runoff responses to rainfall events. The main objectives of this study are to detect preferential movement of water in Chernozem soil and to employ numerical modeling to describe the variably saturated flow during a field ponded infiltration experiment. The infiltration experiment was performed at the Macov experimental station (Calcari-Haplic Chernozem in Danubian Lowland, Slovakia). The experiment involved single ring ponded infiltration. At the quasi steady state phase of the experiment dye tracer was added to the infiltrating water. Then the soil profile was excavated and the penetration pattern of the applied tracer was recorded. The abundance of biopores as a product of fauna and flora was found. To quantify the preferential flow effects during the infiltration experiment, three-dimensional axisymmetric simulations were carried out by a two-dimensional dual-continuum numerical model. The water flow simulations based on measured hydraulic characteristics without consideration of preferential flow effects failed to describe the infiltration experiment adequately. The 3D axisymmetric simulation based on dual-permeability approach provided relatively realistic space-time distribution of soil water pressure below the infiltration ring.

scholarly journals Effects of preferential flow on snowmelt partitioning and groundwater recharge in frozen soils

2019 ◽  
Author(s):  
Aaron A. Mohammed ◽  
Igor Pavlovskii ◽  
Edwin E. Cey ◽  
Masaki Hayashi
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Preferential Flow ◽  
Frozen Soil ◽  
Time Lags ◽  
Runoff Generation ◽  
Frozen Ground ◽  
Soil Matrix ◽  
Frozen Soils ◽  
Flow Through

Abstract. Snowmelt is a major source of groundwater recharge in cold regions. Throughout many landscapes snowmelt occurs when ground is still frozen, thus frozen soil processes play an important role in snowmelt routing, and, by extension, on the timing and magnitude of recharge. This study investigated the vadose zone dynamics governing snowmelt infiltration and groundwater recharge at three grassland sites in the Canadian Prairies over the winter and spring of 2017. The region is characterised by numerous topographic depressions where ponding of snowmelt runoff results in focused infiltration and recharge. Water balance estimates showed infiltration was the dominant sink (35–85 %) of snowmelt under uplands (i.e. areas outside depressions), even when ground was frozen, with soil moisture responses indicating flow through the frozen layer. Refreezing of infiltrated meltwater during winter melt events enhanced runoff generation in subsequent melt events. At one site, time lags of up to 3 days between snowcover depletion on uplands and ponding in depressions demonstrated the role of shallow subsurface flow through frozen soil in routing snowmelt to depressions. At all sites, depression-focused infiltration and recharge began before ground thaw and a significant portion (45–100 %) occurred while the ground was partially frozen. Relatively rapid infiltration rates and non-sequential soil moisture and groundwater responses, observed prior to ground thaw, indicated preferential flow through frozen soils. The preferential flow dynamics are attributed to macropore networks within the grassland soils, which allow infiltrated meltwater to bypass portions of the frozen soil matrix and facilitate both lateral transport of meltwater between topographic positions and groundwater recharge through frozen ground. Both of these flowpaths may facilitate preferential mass transport to groundwater.

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