Monitoring infiltration and subsurface stormflow in layered slope deposits with 3D ERT and hydrometric measurements – the capillary barrier effect as crucial factor

Abstract. Identifying principles of water movement in the shallow subsurface is crucial for adequate process-based hydrological models. Hillslopes are the essential interface for water movement in catchments. The shallow subsurface on slopes typically consist of different layers with varying characteristics. The aim of this study was to draw conclusion about the infiltration behaviour, to identify water flow pathways and derive general validity about the water movement on a hillslope with periglacial slope deposits (cover beds), where the layers differ in their sedimentological and hydrological properties. Especially the described varying influence of the basal layer (LB) as impeding layer on the one hand and as a remarkable pathway for rapid subsurface stormflow on the other. We used a time lapse 3D ERT approach combined with punctual hydrometric data to trace the spreading and the progression of an irrigation plume in layered slope deposits during two irrigation experiments. This multi-technical approach enables us to connect the high spatial resolution of the 3D ERT with the high temporal resolution of the hydrometric devices. Infiltration through the uppermost layer was dominated by preferential flow, whereas the water flow in the deeper layers was mainly matrix flow. Subsurface stormflow due to impeding characteristic of the underlying layer occurs in form of "organic layer interflow" and at the interface to the first basal layer (LB1). However, the main driving factor for subsurface stormflow is the formation of a capillary barrier at the interface to the second basal layer (LB2). The capillary barrier prevents water from entering the deeper layer under unsaturated conditions and diverts the seepage water according to the slope inclination. With higher saturation the capillary barrier breaks down and water reaches the highly conductive deeper layer. This highlights the importance of the capillary barrier effect for the prevention or activation of different flow pathways under variable hydrological conditions.

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Impacts of a capillary barrier on infiltration and subsurface stormflow in layered slope deposits monitored with 3-D ERT and hydrometric measurements

Hydrology and Earth System Sciences ◽

10.5194/hess-21-5181-2017 ◽

2017 ◽

Vol 21 (10) ◽

pp. 5181-5199 ◽

Cited By ~ 8

Author(s):

Rico Hübner ◽

Thomas Günther ◽

Katja Heller ◽

Ursula Noell ◽

Arno Kleber

Keyword(s):

Water Flow ◽

Water Movement ◽

Basal Layer ◽

Organic Layer ◽

Seepage Water ◽

Capillary Barrier ◽

Shallow Subsurface ◽

Layered Slope ◽

Slope Deposits ◽

Flow Pathways

Abstract. Identifying principles of water movement in the shallow subsurface is crucial for adequate process-based hydrological models. Hillslopes are the essential interface for water movement in catchments. The shallow subsurface on slopes typically consists of different layers with varying characteristics. The aim of this study was to draw conclusions about the infiltration behaviour, to identify water flow pathways and derive some general interpretations for the validity of the water movement on a hillslope with periglacial slope deposits (cover beds), where the layers differ in their sedimentological and hydrological properties. Especially the described varying influence of the basal layer (LB) as an impeding layer on the one hand and as a remarkable pathway for rapid subsurface stormflow on the other. We used a time lapse 3-D electrical resistivity tomography (ERT) approach combined with punctual hydrometric data to trace the spreading and the progression of an irrigation plume in layered slope deposits during two irrigation experiments. This multi-technical approach enables us to connect the high spatial resolution of the 3-D ERT with the high temporal resolution of the hydrometric devices. Infiltration through the uppermost layer was dominated by preferential flow, whereas the water flow in the deeper layers was mainly matrix flow. Subsurface stormflow due to impeding characteristic of the underlying layer occurs in form of organic layer interflow and at the interface to the first basal layer (LB1). However, the main driving factor for subsurface stormflow is the formation of a capillary barrier at the interface to the second basal layer (LB2). The capillary barrier prevents water from entering the deeper layer under unsaturated conditions and diverts the seepage water according to the slope inclination. With higher saturation, the capillary barrier breaks down and water reaches the highly conductive deeper layer. This highlights the importance of the capillary barrier effect for the prevention or activation of different flow pathways under variable hydrological conditions.

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A preliminary exploration of the micro-scale behaviour of capillary barrier effect using microfluidics

Géotechnique ◽

10.1680/jgeot.21.00117 ◽

2021 ◽

pp. 1-25

Author(s):

Liang-Tong Zhan ◽

Guang-Yao Li ◽

Bate Bate ◽

Yun-Min Chen

Keyword(s):

Porous Media ◽

Water Flow ◽

Water Movement ◽

Barrier Effect ◽

Capillary Barrier ◽

Micro Scale ◽

Flow Processes ◽

Basic Physics ◽

Throat Width ◽

Coarse Porous Media

Capillary barrier effect (CBE) is employed in a large number of geotechnical applications to decrease deep percolation or increase slope stability. However, the micro-scale behaviour of CBE is rarely investigated, and thus hampers the scientific design of capillary barrier systems. This study uses microfluidics to explore the micro-scale behaviour of CBE. Capillarity-driven water flow processes from fine to coarse porous media with different pore topologies and sizes were performed and analysed. The experimental results demonstrate that the basic physics of CBE is the preferential water movement into the fine porous media due to the larger capillarity. The effects of CBE on water flow processes can be identified as delaying the occurrence of breakthrough into the coarse porous media and increasing the water storage of the fine porous media. The CBE can impede the increase of the normalized length and decrease the normalized width of the water front, suggesting that the two normalized parameters are potential indicators to assess the performance of CBE at micro scale. CBE can be formed in square and honeycomb networks with the ratio of coarse to fine pore throat width larger than 2.0 when gravity is neglected, and its performance can be affected by pore topology and size.

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Monitoring hillslope moisture dynamics with surface ERT and hydrometric point measurement: a case study from Ore Mountains, Germany

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-11-5859-2014 ◽

2014 ◽

Vol 11 (6) ◽

pp. 5859-5903 ◽

Cited By ~ 1

Author(s):

R. Hübner ◽

K. Heller ◽

T. Günther ◽

A. Kleber

Keyword(s):

Water Content ◽

Water Movement ◽

Close Correlation ◽

Seepage Water ◽

Strong Response ◽

Archie’S Law ◽

Shallow Subsurface ◽

Flow Pathways ◽

Hillslope Scale ◽

Moisture Dynamics

Abstract. Hillslopes are one of the basic units that mainly control water movement and flow pathways within catchments. The structure of their shallow subsurface affects water balance, e.g. infiltration, retention, and runoff. Nevertheless, there is still a gap of knowledge of the hydrological dynamics on hillslopes, notably due to the lack of generalization and transferability. To improve the knowledge of hydrological responses on hillslopes with periglacial cover beds, hydrometrical measurements have been carried out on a small spring catchment in the eastern Ore Mountains since November 2007. In addition, surface ERT measurements of several profiles were applied to enhance resolution of punctual hydrometric data. From May to December 2008 geoelectrical monitoring in nearly weekly intervals was implemented to trace seasonal moisture dynamics on the hillslope scale. To obtain the link between water content and resistivity, the parameters of Archie's law were determined using different core samples. To optimize inversion parameters and methods, the derived spatial and temporal water content distribution was compared to tensiometer data and resulting in remarkable coincidence. The measured resistivity shows a close correlation with precipitation. Depending on the amount and intensity of rain, different depths were affected by seepage water. Three different types of response to different amounts of precipitation (small, medium, high), could be differentiated. A period with a small amount causes a short interruption of the drying pattern at the surface in summer, whereas a medium amount induces a distinctive reaction at shallow depth (<0.9 m), and a high amount results in a strong response reaching down to 2 m.

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True colors – changing perceptions of hydrological processes at a hillslope prone to slide

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-8233-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 8233-8277 ◽

Cited By ~ 1

Author(s):

P. Schneider ◽

L. Strouhal ◽

S. Pool ◽

J. Seibert

Keyword(s):

Tracer Experiment ◽

Swiss Alps ◽

Hydrological Processes ◽

Blue Dye ◽

Organic Layer ◽

Front Range ◽

Infiltration Capacity ◽

Shallow Subsurface ◽

Lateral Drainage ◽

Flow Velocities

Abstract. This study investigated runoff formation processes of a pre-alpine hillslope prone to slide. The experimental pasture plot (40 m × 60 m) is located in the northern front range of the Swiss Alps on a 30° steep hillslope (1180 m a.s.l., 1500+ mm annual precipitation). A gleysol (H-Go-Gr) overlies weathered marlstone and conglomerate of subalpine molasse. We conducted sprinkling experiments on a subplot (10 m × 10 m) with variable rainfall intensities. During both experiments fluorescein line-tracer injections into the topsoil, and sodium chloride (NaCl) injections into the sprinkling water were used to monitor flow velocities in the soil. The observed flow velocities for fluorescein in the soil were 1.2 and 1.4 × 10−3 m s−1. The NaCl breakthrough occurred almost simultaneously in all monitored discharge levels (0.05, 0.25 and 1 m depth), indicating a high infiltration capacity and efficient drainage of the soil. These initial observations suggested "transmissivity feedback", a form of subsurface stormflow, as the dominant runoff process. However, the results of a brilliant blue dye tracer experiment completely changed our perceptions of the hillslope's hydrological processes. Excavation of the dye-stained soils highlighted the dominance of "organic layer interflow", a form of shallow subsurface stormflow. The dye stained the entire H horizon, vertical soil fractures, and macropores (mostly worm burrows) up to 50 cm depth. Lateral drainage in the subsoil or at the soil–bedrock interface was not observed, and thus was limited to the organic topsoil. In the context of shallow landslides, the subsoil (Go/Gr) acted as an infiltration and exfiltration barrier, which produced significant lateral saturated drainage in the topsoil (H) and possibly a confined aquifer in the bedrock.

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Aboveground and Belowground Colonization of Vegetation on a 17-Year-Old Cover with Capillary Barrier Effect Built on a Boreal Mine Tailings Storage Facility

Minerals ◽

10.3390/min10080704 ◽

2020 ◽

Vol 10 (8) ◽

pp. 704 ◽

Cited By ~ 1

Author(s):

Alex Proteau ◽

Marie Guittonny ◽

Bruno Bussière ◽

Abdelkabir Maqsoud

Keyword(s):

Mine Tailings ◽

Root Colonization ◽

Mine Drainage ◽

Numerical Models ◽

Mixed Forest ◽

Plant Colonization ◽

Herbaceous Species ◽

Barrier Effect ◽

Capillary Barrier ◽

Vegetation Parameters

Acid mine drainage is an important environmental risk linked to the surface storage of reactive mine tailings. To manage this problem, a cover with a capillary barrier effect (CCBE) can be used. This oxygen barrier cover relies on maintaining a fine-grained material layer (moisture-retaining layer, MRL) with a high degree of saturation. CCBEs can be colonized by surrounding plants. Plant roots pump water and could impact CCBE’s performance. This performance is predicted with unsaturated water flow numerical models in which vegetation parameters can be included. Vegetation parameters may be specific in a CCBE environment. Therefore, analyzing and quantifying the vegetation that colonizes this type of cover is necessary. Plant colonization was investigated through cover and density surveys on 12 transects on a 17-year-old CCBE in the mixed forest of Quebec, Canada. Then, aboveground vegetation and root colonization intensity at three depths in the MRL were characterized on 25 plots of five dominant vegetation types (Salix, Populus, Alnus, Picea sp., and herbaceous species). The mean root length density under plots dominated by Salix sp. was higher than in the other plots. Root colonization of the MRL was concentrated in the first 10 cm and occurred under all woody and herbaceous species as well. This work quantitatively describes, for the first time, the vegetation colonizing a CCBE both at the above- and belowground levels. These data will be useful to better predict the long-term performance of this engineered reclamation cover.

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On the Physico-Chemical Basis for the Capillary Barrier Effect

Hydrology Research ◽

10.2166/nh.1988.0020 ◽

1988 ◽

Vol 19 (5) ◽

pp. 281-292 ◽

Cited By ~ 2

Author(s):

Anders Rasmuson ◽

Jan-Christer Eriksson

Keyword(s):

Water Infiltration ◽

Hazardous Wastes ◽

Barrier Effect ◽

Capillary Barrier ◽

Simple Estimate ◽

Soil Layers ◽

Chemical Basis ◽

Water Influx ◽

Physico Chemical ◽

Coarse Soil

The capillary barrier concept, using fine and coarse soil layers to reduce water infiltration into piles of hazardous wastes, is investigated theoretically. A detailed account of the hydrological and physico-chemical basis for the phenomenon is given. It is established that the capillary barrier will, in practice, only function if the fine layer remains somewhat unsaturated, i.e. the upper menisci exist and no ponding over the fine layer occurs. Accordingly, water reaching the fine layer must be transported laterally within this layer. The pressure conditions are dependent on the length of the interface, the slope of the interface, the thickness of the fine layer, the type of soil in the fine layer, the water influx at the surface, and the total volume of water infiltrated during an infiltration event. A simple estimate shows that the capillary barrier concept is feasible only for small heaps with steep interfacial slopes.

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The Influence of Land Roughness to Irrigation Efficiency Based on SIRMOD Model of Border Irrigation of Wheat

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.3640 ◽

2014 ◽

Vol 955-959 ◽

pp. 3640-3644

Author(s):

He Xiang Zheng ◽

Xue Song Cao ◽

Jia Bin Wu ◽

Jian Cheng Zhang

Keyword(s):

Surface Roughness ◽

Surface Water ◽

Water Flow ◽

Water Movement ◽

Field Trials ◽

Measured Data ◽

Irrigation Efficiency ◽

Movement Process ◽

Surface Water Flow

Land roughness is an important parameter of border irrigation in the surface water flow movement, it affects of the water movement process and affects irrigation efficiency, so it’s necessary combined with field surface other parameters to study irrigation field roughness to the irrigation efficiency. Agreement is good between simulated by SIRMOD model and measured values through field trials the measured data of water flow advance and regression process, and indicating with SIRMOD model can simulate border irrigation process. Four kinds of typical field surface roughness of irrigation simulation by SIRMOD model and analysis of the results obtained: land roughness difference of water flow advance and regression process influence significantly, the water flow advance and regression process is better with the small land roughness, and the curve of water flow advance and regression becomes uneven, so irrigation efficiency significant reduction with the field surface roughness increases.

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Design of Inclined Covers with Capillary Barrier Effect by S.-E. Parent and A. Cabral

Geotechnical and Geological Engineering ◽

10.1007/s10706-007-9139-2 ◽

2007 ◽

Vol 25 (6) ◽

pp. 673-678 ◽

Cited By ~ 8

Author(s):

B. Bussière ◽

M. Aubertin ◽

G. Zhan

Keyword(s):

Barrier Effect ◽

Capillary Barrier

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Phosphorus dynamics in shallow subsurface waters in an uncut and cut subcatchment of a lake on the Boreal Plain

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f00-123 ◽

2000 ◽

Vol 57 (S2) ◽

pp. 60-72 ◽

Cited By ~ 23

Author(s):

J E Evans ◽

E E Prepas ◽

K J Devito ◽

B G Kotak

Keyword(s):

Water Samples ◽

Soil Layer ◽

Organic Layer ◽

Mineral Layer ◽

Near Surface ◽

Organic C ◽

Shallow Subsurface ◽

Phosphorus Dynamics ◽

Subsurface Waters ◽

Composite Samples

Phosphorus dynamics in shallow subsurface waters (<2.5 m depth) were studied in harvested and unharvested subcatchments of a Boreal Plain lake. The organic soil layer was underlain by discontinuous layers of sand and clay glacial till. Total dissolved P (TDP) concentrations (6-798 µg·L-1) of discrete water samples from mineral layers (0.9-2.5 m deep) generally decreased with depth, were negatively related to Ca (rs < -0.7), and were lower in clay. When the groundwater table rose and saturated the organic layer, TDP concentrations increased in the composite (organic mineral layer) but not in the discrete (mineral layer) water samples, indicating that elevated TDP concentrations originate from the near-surface organic layer. TDP concentrations in composite samples were negatively correlated with water table depth (rs = -0.6) and were positively correlated with transmissivity (rs = 0.7) and dissolved organic C concentration (rs > 0.6). In the riparian buffer zone of the harvested subcatchment, TDP concentrations of composite samples decreased during high runoff, but these values remained higher than concentrations in the unharvested subcatchment. However, surface topography and variable depth to confining clay layers resulted in higher groundwater tables in the harvested subcatchment, especially in the cut area. Mean daily TDP export coefficients were similar between the unharvested (14 µg·m-2) and harvested (12 µg·m-2) subcatchments.

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