Desiccation-crack-induced salinization in deep clay sediment

Baram, Shahar; Ronen, Zeev; Kurtzman, Daniel; Kuells, Christoph; Dahan, Ofer

doi:10.5194/hessd-9-13155-2012

Cited by 8 publications

(15 citation statements)

References 55 publications

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“…Contradictory observations on matrix and preferential flow as governing mechanisms led to conceptualization of the percolation process as pore-scale dual domain flow. Coexistence of two phases within the sediment pores that are not hydraulically connected and do not reach chemical equilibrium is well supported by results from extensive monitoring of a deep vadose zone [15,21]. Today interpretation of the flow and transport processes from the chemical composition of sediment samples is a common methodology in vadose zone hydrology.…”

Section: Solute Transportmentioning

confidence: 87%

“…However, in natural field conditions the lithologic heterogeneity as well as the erratic nature of water availability on land surface dictated frequent variation in the profile water content and consequent flow pattern [11][12][13]. In addition, natural variation in water content of the sediment derive dramatic changes in the chemical physical and biological state of the sediments, impacts oxygen availability, controls development of indigenous microbial communities, and alters redox potential of the sediment [14][15][16]. These variation are magnified in natural environment where the chemical composition of the percolating water (e.g.…”

Section: Vadose-zone Monitoring Technologymentioning

confidence: 99%

“…Up to now, the VMS has been successfully implemented in numerous studies on water flow and contaminant transport in the unsaturated zone in a variety of hydrological setups, including (1) flood water percolation in arid environments [11,12,21], (2) rain water percolation through thick sand and clay formations [13,22], (3) solute transport in the vadose zone [15,16,18], (4) impact of agriculture on groundwater quality [17,23], and interactive bio-remediation of contaminated vadose zone [24].…”

Section: Vadose-zone Monitoring Technologymentioning

confidence: 99%

“…Accordingly such soils are perceived safe in prevention groundwater pollution. Water percolation dynamics and contaminate transport through clayey vadose zone was studies using several vadose-zone monitoring systems which enabled continuous measurements of the temporal variation in vadose zone water-content profiles and frequent sampling of the vadose zone pore water [15,25,32]. ).…”

Section: Impact Of Clay Layers On Water Flow In the Unsaturated Zonementioning

confidence: 99%

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Real-time monitoring of the vadose zone as a key to groundwater protection from pollution hazard

Dahan¹

2015

WIT Transactions on Ecology and the Environment

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Minimization subsurface pollution is very dependent on reliable and effective monitoring tools. Today, most monitoring programs are based on observation wells that enable collection of hydrological and chemical information from the saturated part of the subsurface. As a result, identification of pollution in wells is clear evidence that the contaminants already crossed the entire vadose-zone and accumulated in the aquifer. Accordingly, an effective monitoring program must include monitoring means that provide real-time information in the unsaturated zone. Such monitoring programs may provide "early warning" for potential pollution processes that may risk groundwater quality. A vadose-zone monitoring system (VMS), which was developed recently, allows continuous monitoring of the hydrological and chemical properties of percolating water in the deep vadose zone. Data which is collected by the system allows direct measurements of the water percolation fluxes and detects the chemical evolution of the percolating water across the entire unsaturated domain. The VMS is designed for long term continuous operation in a time scale of years to decades. To date, the system has been successfully implemented in several studies on water flow and contaminant transport in various hydrological and geological setups. These include research projects on: (a) floodwater infiltration and groundwater recharge from stream channels and reservoirs, (b) impact of various agricultural regimes on quality and quantity of groundwater recharge, (c) subsurface pollution of dairy farms, (d) chemical evolution of landfill leachates, and (e) control of remediation operations in contaminated sites.

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Section: Solute Transportmentioning

confidence: 87%

Section: Vadose-zone Monitoring Technologymentioning

confidence: 99%

Section: Vadose-zone Monitoring Technologymentioning

confidence: 99%

Section: Impact Of Clay Layers On Water Flow In the Unsaturated Zonementioning

confidence: 99%

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Real-time monitoring of the vadose zone as a key to groundwater protection from pollution hazard

Dahan¹

2015

WIT Transactions on Ecology and the Environment

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“…Their implementation in intermediate and deep vadose zones has been achieved through installation in vertical and slanted boreholes (Hubbell et al, 2002; Gee et al, 2003). One of the technologies, known as a vadose zone monitoring system (VMS), has been successfully applied to monitor vadose zone infiltration processes, providing unique data on the dynamics of water and contaminant infiltration in the vadose zone (Dahan et al, 2009, 2014; Rimon et al, 2011; Amiaz et al, 2011; Baram et al, 2013; Turkeltaub et al, 2015; Fernández de Vera et al, 2015). This system provides continuous hydraulic and chemical information across the vadose zone by inserting a flexible sleeve containing customized sensors into a slanted borehole.…”

mentioning

confidence: 99%

Tracer Experiment in a Brownfield Using Geophysics and a Vadose Zone Monitoring System

Vera

Beaujean

Jamin

et al. 2017

Vadose Zone Journal

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A saline tracer infiltration test across the fractured vadose zone of an industrial contaminated site in Belgium was monitored by combining surface and cross-borehole electrical resistivity tomography (ERT) methods with a vadose zone monitoring system (VMS). The VMS provides in situ continuous hydraulic and chemical information on the percolating tracer at multiple depths in the vadose zone. The combination of such high-resolution data with timelapse geophysical images that capture the spatiotemporal variability of the subsurface improves interpretations of flow and transport, providing a better characterization of infiltration mechanisms and preferential flow paths. The tracer infiltration test was performed over a heterogeneous vadose zone composed of backfilled materials, sands and silts, and unsaturated fractured chalk. Monitoring results during a 5-d period revealed the formation of a tracer plume in the upper backfilled deposits, while some of the tracer migrated laterally following preferential pathways. Slow vertical flow through matrix pores was found to be dominant under dry conditions. Infiltration of small quantities of rain during the test was found to have an influence on the spatial distribution of the plume. Results from long-term monitoring revealed vertical transport of the tracer toward depths that reached 4 m during a time period of 105 d. During that period, fracture and matrix flow mechanisms across the vadose zone were activated as a response to frequent rainfall episodes. The study demonstrates that the interpretation of geophysical images is improved by in situ information from the VMS.Abbreviations: ERT, electrical resistivity tomography; FTDR, flexible time domain reflectometry; VMS, vadose zone monitoring system; VSP, vadose sampling port.The detailed characterization of the contaminant distribution and percolation mechanisms of industrial contaminated soils is particularly challenging. The presence of disturbed soil, artificial ground, and abandoned infrastructures modifies flow mechanisms in the vadose zone, generating preferential flows that are difficult to identify and quantify. Additionally, temporal and spatial coverage is required to capture the physical and biochemical changes of multiple contaminants in such a dynamic system (Atekwana et al., 2000).Electrical resistivity tomography (ERT) methods are suitable for flow and transport characterization because subsurface electrical properties are influenced by parameters such as solute concentration or water saturation (Slater et al., 2000;Johnson et al., 2013). Electrical resistivity tomography measurements allow monitoring of infiltrated water during precipitation events, which have an impact on contaminant transport across the vadose zone (Descloitres et al., 2008;Clément et al., 2009;Carrière et al., 2015). The combination of ERT methods with tracer tests allows the identification of preferential flow paths and solute transport processes (Ptak et al., 2004;Robert et al., 2012). However, information provided by ERT measurement...

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Impact of switching crop type on water and solute fluxes in deep vadose zone

Turkeltaub

Kurtzman

Russak

et al. 2015

Water Resources Research

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Switching crop type and consequently changing irrigation and fertilization regimes lead to alterations in deep percolation and solute concentrations of pore water. Herein, observations from the deep vadose zone and model simulations demonstrate the changes in water, chloride, and nitrate fluxes under a commercial greenhouse following the change from tomato to lettuce cropping. The site, located above a phreatic aquifer, was monitored for 5 years. A vadose-zone monitoring system was implemented under the greenhouse and provided continuous data on both temporal variations in water content and chemical composition of the pore water at multiple depths in the deep vadose zone (up to 20 m). Following crop switching, a significant reduction in chloride concentration and dramatic increase in nitrate were observed across the unsaturated zone. The changes in chemical composition of the vadose-zone pore water appeared as sequential breakthroughs across the unsaturated zone, initiating at land surface and propagating down toward the water table. Today, 3 years after switching the crops, penetration of the impact exceeds 10 m depth. Variations in the isotopic composition of nitrate ( 18 O and 15 N) in water samples obtained from the entire vadose zone clearly support a fast leaching process and mobilization of solutes across the unsaturated zone following the change in crop type. Water flow and chloride transport models were calibrated to observations acquired during an enhanced infiltration experiment. Forward simulation runs were performed with the calibrated models, constrained to tomato and lettuce cultivation regimes as surface boundary conditions. Predicted chloride and nitrate concentrations were in agreement with the observed concentrations. The simulated water drainage and nitrogen leaching implied that the observed changes are an outcome of recommended agricultural management practices. Key Points:Changes in water and solute fluxes in the vadose zone due to crop type switch In situ real-time monitoring of water and solute fluxes in unsaturated zone Use of data from deep vadose zone for model calibration and simulationsSupporting Information: Supporting Information S1 (2015), Impact of switching crop type on water and solute fluxes in deep vadose zone, Water Resour. Res., 51, 9828-9842,

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Desiccation-crack-induced salinization in deep clay sediment

Cited by 8 publications

References 55 publications

Real-time monitoring of the vadose zone as a key to groundwater protection from pollution hazard

Real-time monitoring of the vadose zone as a key to groundwater protection from pollution hazard

Tracer Experiment in a Brownfield Using Geophysics and a Vadose Zone Monitoring System

Impact of switching crop type on water and solute fluxes in deep vadose zone

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