Modeling and field evidence of finger formation and finger recurrence in a water repellent sandy soil

Ritsema, C.J.; Dekker, L.W.; Nieber, John L.; Steenhuis, Tammo S.

doi:10.1029/97wr02407

Cited by 181 publications

(112 citation statements)

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“…Water repellency may favour formation of finger flow as suggested by Ritsema, 1994, 2000;Ritsema et al, 1998) for soils in the Netherlands, and by Blume et al (2008a) for volcanic as soils in a pristine catchment in Chile. Zehe et al (2007) performed 53 sprinkling experiments with 50 mm in one hour to shed light on the control of antecedent soil moisture on overland flow generation in a landscape comprising hydrophobic soils in southern Switzerland.…”

Section: Water Repellency Overland Flow and Infiltrationmentioning

confidence: 99%

“…The term preferential flow was coined upon realising that water flow and solute transport in non-capillary soil structures were much faster than would be expected from classical theory of flow and transport in porous media (Beven and Germann, 1982;Germann, 1990;Roth et al, 1991). In coarse grained soils wetting front instability may lead to fingered flow, especially during conditions when water repellence is involved (Ritsema et al, 1998;Blume et al, 2008a). Or (Or, 2008) suggests that fingers start to form when the Bond numberwhich relates gravity, capillary forces and viscous forces, becomes smaller than 0.2.…”

Section: Infiltration and Vertical Preferential Flowmentioning

confidence: 99%

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Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

Zehe¹,

Sivapalan

2009

Hydrol. Earth Syst. Sci.

196

139

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Abstract. In this paper we review threshold behaviour in environmental systems, which are often associated with the onset of floods, contamination and erosion events, and other degenerative processes. Key objectives of this review are to a) suggest indicators for detecting threshold behavior, b) discuss their implications for predictability, c) distinguish different forms of threshold behavior and their underlying controls, and d) hypothesise on possible reasons for why threshold behaviour might occur. Threshold behaviour involves a fast qualitative change of either a single process or the response of a system. For elementary phenomena this switch occurs when boundary conditions (e.g., energy inputs) or system states as expressed by dimensionless quantities (e.g. the Reynolds number) exceed threshold values. Mixing, water movement or depletion of thermodynamic gradients becomes much more efficient as a result. Intermittency is a very good indicator for detecting event scale threshold behavior in hydrological systems. Predictability of intermittent processes/system responses is inherently low for combinations of systems states and/or boundary conditions that push the system close to a threshold. Post hoc identification of "cause-effect relations" to explain when the system became critical is inherently difficult because of our limited ability to perform observations under controlled identical experimental conditions. In this review, we distinguish three forms of threshold behavior. The first one is threshold behavior at the Correspondence to: E. Zehe (e.zehe@bv.tum.de) process level that is controlled by the interplay of local soil characteristics and states, vegetation and the rainfall forcing. Overland flow formation, particle detachment and preferential flow are examples of this. The second form of threshold behaviour is the response of systems of intermediate complexity -e.g., catchment runoff response and sediment yield -governed by the redistribution of water and sediments in space and time. These are controlled by the topological architecture of the catchments that interacts with system states and the boundary conditions. Crossing the response thresholds means to establish connectedness of surface or subsurface flow paths to the catchment outlet. Subsurface stormflow in humid areas, overland flow and erosion in semi-arid and arid areas are examples, and explain that crossing local process thresholds is necessary but not sufficient to trigger a system response threshold. The third form of threshold behaviour involves changes in the "architecture" of human geoecosystems, which experience various disturbances. As a result substantial change in hydrological functioning of a system is induced, when the disturbances exceed the resilience of the geo-ecosystem. We present examples from savannah ecosystems, humid agricultural systems, mining activities affecting rainfall runoff in forested areas, badlands formation in Spain, and the restoration of the Upper Rhine river basin as examples of this phenomenon. This fun...

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Section: Water Repellency Overland Flow and Infiltrationmentioning

confidence: 99%

Section: Infiltration and Vertical Preferential Flowmentioning

confidence: 99%

Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

Zehe¹,

Sivapalan

2009

Hydrol. Earth Syst. Sci.

196

139

View full text Add to dashboard Cite

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“…Once water reaches the more hydrophilic subsoils, lateral diffusive flow of water can occur, allowing a slow wetting of surface layers from the moist soil below (Doerr et al 2000). In undisturbed soils, preferential flow pathways tend to persist once established and water flow recurs along the same pathways during subsequent rainfall events (Ritsema et al 1998). Because large volumes of soil remain dry, plants are unable to access nutrients contained therein, resulting in poor early nutrientuse efficiency in these soils.…”

Section: Causes (Hydrophobic Compounds) Occurrence and Measurementmentioning

confidence: 99%

Management options for water-repellent soils in Australian dryland agriculture

Roper

Davies²,

Blackwell³

et al. 2015

Soil Res.

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Abstract. Water-repellent ('non-wetting') soils are a major constraint to agricultural production in southern and south-west Australia, affecting >10 Mha of arable sandy soils. The major symptom is dry patches of surface soil, even after substantial rainfall, directly affecting agricultural production through uneven crop and pasture germination, and reduced nutrient availability. In addition, staggered weed germination impedes effective weed control, and delayed crop and pasture germination increases the risk of wind erosion. Water repellency is caused by waxy organic compounds derived from the breakdown of organic matter mostly of plant origin. It is more prevalent in soils with a sandy surface texture; their low particle surface area : volume ratio means that a smaller amount of waxy organic compounds can effectively cover a greater proportion of the particle surface area than in a fine-textured soil. Water repellency commonly occurs in sandy duplex soils (Sodosols and Chromosols) and deep sandy soils (Tenosols) but can also occur in Calcarosols, Kurosols and Podosols that have a sandy surface texture. Severity of water repellency has intensified in some areas with the adoption of no-till farming, which leads to the accumulation of soil organic matter (and hence waxy compounds) at the soil surface. Growers have also noticed worsening repellency after 'dry' or early sowing when break-of-season rains have been unreliable.Management strategies for water repellency fall into three categories: (i) amelioration, the properties of surface soils are changed; (ii) mitigation, water repellency is managed to allow crop and pasture production; (iii) avoidance, severely affected or poorly producing areas are removed from annual production and sown to perennial forage. Amelioration techniques include claying, deep cultivation with tools such as rotary spaders, or one-off soil inversion with mouldboard ploughs. These techniques can be expensive, but produce substantial, long-lasting benefits. However, they carry significant environmental risks if not adopted correctly. Mitigation strategies include furrow-seeding, application of wetting agents (surfactants), no-till with stubble retention, on-row seeding, and stimulating natural microbial degradation of waxy compounds. These are much cheaper than amelioration strategies, but have smaller and sometimes inconsistent impacts on crop production. For any given farm, economic analysis suggests that small patches of water repellency might best be ameliorated, but large areas should be treated initially with mitigation strategies. Further research is required to determine the long-term impacts of cultivation treatments, seeding systems and chemical and biological amendments on the expression and management of water repellency in an agricultural context.

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“…However, Richards' equation is unable to simulate fingering phenomenon [25][26][27], thus extensions are normally added to account for certain aspects of multiphase flow [28]. Previous studies [2,6,12,24,29,30] have proposed models to explain experiments based on parameters that condition wetting front instability, such as water repellency [3,7,14] and water redistribution [31]. However, to our knowledge, most studies on infiltration have focused on morphology of the water channels that form during infiltration.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of gravity-driven water channels under steady rainfall

et al. 2014

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We investigate the formation of fingered flow in dry granular media under simulated rainfall using a quasi-twodimensional experimental setup composed of a random close packing of monodisperse glass beads.Using controlled experiments, we analyze the finger instabilities that develop from the wetting front as a function of fundamental granular (particle size) and fluid properties (rainfall, viscosity). These finger instabilities act as precursors for water channels, which serve as outlets for water drainage. We look into the characteristics of the homogeneous wetting front and channel size as well as estimate relevant time scales involved in the instability formation and the velocity of the channel fingertip. We compare our experimental results with that of the wellknown prediction developed by Parlange and Hill [D. E. Hill and J. Y. Parlange, Soil Sci. Soc. Am. Proc. 36, 697 (1972)]. This model is based on linear stability analysis of the growth of perturbations arising at the interface between two immiscible fluids. Results show that, in terms of morphology, experiments agree with the proposed model. However, in terms of kinetics we nevertheless account for another term that describes the homogenization of the wetting front. This result shows that the manner we introduce the fluid to a porous medium can also influence the formation of finger instabilities. The results also help us to calculate the ideal flow rate needed for homogeneous distribution of water in the soil and minimization of runoff, given the grain size, fluid density, and fluid viscosity. This could have applications in optimizing use of irrigation water. We investigate the formation of fingered flow in dry granular media under simulated rainfall using a quasitwo-dimensional experimental setup composed of a random close packing of monodisperse glass beads. Disciplines Physical Sciences and Mathematics | PhysicsUsing controlled experiments, we analyze the finger instabilities that develop from the wetting front as a function of fundamental granular (particle size) and fluid properties (rainfall, viscosity). These finger instabilities act as precursors for water channels, which serve as outlets for water drainage. We look into the characteristics of the homogeneous wetting front and channel size as well as estimate relevant time scales involved in the instability formation and the velocity of the channel fingertip. We compare our experimental results with that of the well-known prediction developed by Parlange and Hill [D. E. Hill and J. Y. Parlange, Soil Sci. Soc. Am. Proc. 36, 697 (1972)]. This model is based on linear stability analysis of the growth of perturbations arising at the interface between two immiscible fluids. Results show that, in terms of morphology, experiments agree with the proposed model. However, in terms of kinetics we nevertheless account for another term that describes the homogenization of the wetting front. This result shows that the manner we introduce the fluid to a porous medium can also influence the formation...

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Modeling and field evidence of finger formation and finger recurrence in a water repellent sandy soil

Cited by 181 publications

References 52 publications

Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

Management options for water-repellent soils in Australian dryland agriculture

Kinetics of gravity-driven water channels under steady rainfall

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