2024

Can precipitation intermittency predict flooding?

Livneh B, Bjarke NR, Modi PA, Furman A, Ficklin D, Pflug JM et al. Can precipitation intermittency predict flooding? Science of the Total Environment. 2024 Oct 1;945:173824. https://doi.org/10.1016/j.scitotenv.2024.173824
 

A mystery has emerged as to why patterns of increasing extreme rainfall have not been accompanied by similar levels of flooding, garnering growing attention given concerns over future flood risks. Antecedent moisture conditions have been proposed as the missing explanatory factor. Yet, reasons for moisture variability prior to flooding remain largely unstudied. Here, we evaluate the potential utility of precipitation intermittency, defined as the dry spell length prior to a flood, to explain the variability of flooding over 108 watersheds from 1950 to 2022. Flood magnitude is shown to be sensitive to intermittency, particularly in arid and semi-arid regions (PET/P > 0.84) and for basins with low soil field capacity (<0.31 m3/m3). Following extended dry spells >20 days, floods are only possible from the most intense storms, whereas a wider range of storms can produce flooding for shorter intermittency. The flood probability decreases by approximately 0.5 % for each additional day of dry spell, with overall flood probabilities being up to 30 % lower following extended dry periods. These results underscore the potential utility of precipitation intermittency for diagnosing current and future flood risks.

@article{1ef1d693d57f45e597d2a0bdb20d2def,
title = "Can precipitation intermittency predict flooding?",
abstract = "A mystery has emerged as to why patterns of increasing extreme rainfall have not been accompanied by similar levels of flooding, garnering growing attention given concerns over future flood risks. Antecedent moisture conditions have been proposed as the missing explanatory factor. Yet, reasons for moisture variability prior to flooding remain largely unstudied. Here, we evaluate the potential utility of precipitation intermittency, defined as the dry spell length prior to a flood, to explain the variability of flooding over 108 watersheds from 1950 to 2022. Flood magnitude is shown to be sensitive to intermittency, particularly in arid and semi-arid regions (PET/P > 0.84) and for basins with low soil field capacity (<0.31 m3/m3). Following extended dry spells >20 days, floods are only possible from the most intense storms, whereas a wider range of storms can produce flooding for shorter intermittency. The flood probability decreases by approximately 0.5 % for each additional day of dry spell, with overall flood probabilities being up to 30 % lower following extended dry periods. These results underscore the potential utility of precipitation intermittency for diagnosing current and future flood risks.",
keywords = "Antecedent moisture conditions, Flood prediction, Global change attribution, Land surface processes, Precipitation intermittency",
author = "Ben Livneh and Bjarke, {Nels R.} and Modi, {Parthkumar A.} and Alex Furman and Darren Ficklin and Pflug, {Justin M.} and Karnauskas, {Kristopher B.}",
note = "Publisher Copyright: {\textcopyright} 2024",
year = "2024",
month = oct,
day = "1",
doi = "10.1016/j.scitotenv.2024.173824",
language = "אנגלית",
volume = "945",
journal = "Science of the Total Environment",
issn = "0048-9697",
publisher = "Elsevier",

}

Comparison of reactive transport and non-equilibrium modeling approaches for the estimation of nitrate leaching under large water application events

Murphy NP, Furman A, Moshe SB, Dahlke HE. Comparison of reactive transport and non-equilibrium modeling approaches for the estimation of nitrate leaching under large water application events. Journal of Hydrology. 2024 Jan;628:130583. https://doi.org/10.1016/j.jhydrol.2023.130583
 

In agricultural ecosystems, nitrate (NO3) leaching is the most widespread loss pathway and non-point source of nitrogen (N) to surface water and groundwater. NO3 leaching in rain-fed and irrigated agricultural systems has been extensively modeled using different numerical approaches of varying complexity. Most numerical modeling studies use simplified zero-order or first-order kinetics when optimizing N budgets. Few studies consider the impacts of temperature, soil moisture and other environmental conditions on biogeochemical reaction rates. In this study, we simulate NO3 leaching and biogeochemical processes in two soil columns under large water application events (groundwater recharge events) using a 1D non-equilibrium (e.g. mobile-immobile) reactive transport HP1 (HYDRUS-1D and PHREEQC) model. We compare this calibrated model to several other calibrated models representing simpler HYDRUS nitrate leaching modeling approaches (uniform flow, non-reactive, zero- and first-order kinetics). Results show that the incorporation of conditional environmental factors such as temperature, soil moisture, and a proxy for oxic/anoxic conditions (percent pore-space filled) results in superior model performance representing the timing and magnitude of important biogeochemical processes when estimating cumulative NO3 leached from the shallow vadose zone. In addition, using a physical non-equilibrium (i.e. dual-porosity type, mobile-immobile solute transport) approach improves model performance when estimating residual NO3 in the soil profile after water application events.

@article{6266286c5b46495489c9679331d0ec7a,
title = "Comparison of reactive transport and non-equilibrium modeling approaches for the estimation of nitrate leaching under large water application events",
abstract = "In agricultural ecosystems, nitrate (NO3–) leaching is the most widespread loss pathway and non-point source of nitrogen (N) to surface water and groundwater. NO3– leaching in rain-fed and irrigated agricultural systems has been extensively modeled using different numerical approaches of varying complexity. Most numerical modeling studies use simplified zero-order or first-order kinetics when optimizing N budgets. Few studies consider the impacts of temperature, soil moisture and other environmental conditions on biogeochemical reaction rates. In this study, we simulate NO3– leaching and biogeochemical processes in two soil columns under large water application events (groundwater recharge events) using a 1D non-equilibrium (e.g. mobile-immobile) reactive transport HP1 (HYDRUS-1D and PHREEQC) model. We compare this calibrated model to several other calibrated models representing simpler HYDRUS nitrate leaching modeling approaches (uniform flow, non-reactive, zero- and first-order kinetics). Results show that the incorporation of conditional environmental factors such as temperature, soil moisture, and a proxy for oxic/anoxic conditions (percent pore-space filled) results in superior model performance representing the timing and magnitude of important biogeochemical processes when estimating cumulative NO3– leached from the shallow vadose zone. In addition, using a physical non-equilibrium (i.e. dual-porosity type, mobile-immobile solute transport) approach improves model performance when estimating residual NO3– in the soil profile after water application events.",
keywords = "HYDRUS, Model comparison, Nitrogen, PHREEQC, Reactive transport modeling",
author = "Murphy, {Nicholas P.} and Alex Furman and Moshe, {Shany Ben} and Dahlke, {Helen E.}",
note = "Publisher Copyright: {\textcopyright} 2023 The Author(s)",
year = "2024",
month = jan,
doi = "10.1016/j.jhydrol.2023.130583",
language = "אנגלית",
volume = "628",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",

}

2023

Improving soil aquifer treatment efficiency using air injection into the subsurface

Arad I, Ziner A, Ben Moshe S, Weisbrod N, Furman A. Improving soil aquifer treatment efficiency using air injection into the subsurface. Hydrology and Earth System Sciences. 2023 Jul 10;27(13):2509-2522. https://doi.org/10.5194/hess-27-2509-2023
 

Soil aquifer treatment (SAT) is an effective and sustainable technology for wastewater or stormwater treatment, storage, and reuse. During SAT, the vadose zone acts as a pseudo-reactor in which physical and biochemical processes are utilized to improve the infiltrated-water quality. Dissolved oxygen (DO) is necessary for aerobic microbial oxidation of carbon and nitrogen species in the effluent. Therefore, to enhance aeration, SAT is generally operated in flooding and drying cycles. While long drying periods (DPs) lead to better oxidizing conditions and improve water quality, they reduce recharge volumes. As the population grows, the quantity of effluent directed to SAT sites increases, and increasing recharge volumes become a concern and often a limiting factor for SAT usage. In this study, direct subsurface air injection SAT (Air-SAT) was tested as an alternative to long-DP operation. Six long-column experiments were conducted (2 m column) that aimed to examine the effect of air injection on the soil's water content, oxidation-reduction potential (ORP), DO concentrations, infiltrated amounts, and ultimate outflow quality. In addition to basic parameters, such as dissolved organic C (DOC) and N species, the effluent quality analysis also included an examination of three emerging water contaminants: ibuprofen, carbamazepine, and 1H-benzotriazole. Pulsed-air-injection experiments were conducted during continuous flooding using different operation modes (i.e., air pulse durations, frequencies, and airflow rates). Our results show that Air-SAT operation doubled the time during which infiltration was possible (i.e., the infiltration was continuous with no downtime) and allowed up to a 46 % higher mean infiltration rate in some cases. As a result, the infiltration volumes in the Air-SAT modes were 47 %-203 % higher than conventional flooding-drying operation (FDO). A longer air pulse duration (60 min vs. 8 min) and higher airflow rate (∼2 L min-1 vs. ∼1 L min-1) led to a higher mean infiltration rate, whereas a high pulse frequency (4.5 h-1) led to a lower mean infiltration rate compared with low-frequency operation (24 h-1). Air injection also allowed good recovery of the ORP and DO levels in the soil, especially in the high-frequency Air-SAT experiments, where steady aerobic conditions were maintained during most of the flooding. Consequently, the mean DOC, total Kjeldahl N (TKN), and ibuprofen removal values in these experiments were up to 9 %, 40 %, and 65 % higher than those with FDO, respectively. However, high-frequency Air-SAT during continuous flooding also led to significant deterioration of the mean infiltration rate, probably due to enhanced biological clogging. Hence, it may be more feasible and beneficial to combine it with conventional FDO, allowing a steady infiltration rate and increased recharge volumes while sustaining high effluent quality. While these results still need to be verified at full scale, they highlight the possibility of using air injection to minimize the DP length and alleviate the pressure on existing SAT sites.

@article{5c9e6080a20d4c5ca07a7ee85322a35e,
title = "Improving soil aquifer treatment efficiency using air injection into the subsurface",
abstract = "Soil aquifer treatment (SAT) is an effective and sustainable technology for wastewater or stormwater treatment, storage, and reuse. During SAT, the vadose zone acts as a pseudo-reactor in which physical and biochemical processes are utilized to improve the infiltrated-water quality. Dissolved oxygen (DO) is necessary for aerobic microbial oxidation of carbon and nitrogen species in the effluent. Therefore, to enhance aeration, SAT is generally operated in flooding and drying cycles. While long drying periods (DPs) lead to better oxidizing conditions and improve water quality, they reduce recharge volumes. As the population grows, the quantity of effluent directed to SAT sites increases, and increasing recharge volumes become a concern and often a limiting factor for SAT usage. In this study, direct subsurface air injection SAT (Air-SAT) was tested as an alternative to long-DP operation. Six long-column experiments were conducted (2 m column) that aimed to examine the effect of air injection on the soil's water content, oxidation-reduction potential (ORP), DO concentrations, infiltrated amounts, and ultimate outflow quality. In addition to basic parameters, such as dissolved organic C (DOC) and N species, the effluent quality analysis also included an examination of three emerging water contaminants: ibuprofen, carbamazepine, and 1H-benzotriazole. Pulsed-air-injection experiments were conducted during continuous flooding using different operation modes (i.e., air pulse durations, frequencies, and airflow rates). Our results show that Air-SAT operation doubled the time during which infiltration was possible (i.e., the infiltration was continuous with no downtime) and allowed up to a 46 % higher mean infiltration rate in some cases. As a result, the infiltration volumes in the Air-SAT modes were 47 %-203 % higher than conventional flooding-drying operation (FDO). A longer air pulse duration (60 min vs. 8 min) and higher airflow rate (∼2 L min-1 vs. ∼1 L min-1) led to a higher mean infiltration rate, whereas a high pulse frequency (4.5 h-1) led to a lower mean infiltration rate compared with low-frequency operation (24 h-1). Air injection also allowed good recovery of the ORP and DO levels in the soil, especially in the high-frequency Air-SAT experiments, where steady aerobic conditions were maintained during most of the flooding. Consequently, the mean DOC, total Kjeldahl N (TKN), and ibuprofen removal values in these experiments were up to 9 %, 40 %, and 65 % higher than those with FDO, respectively. However, high-frequency Air-SAT during continuous flooding also led to significant deterioration of the mean infiltration rate, probably due to enhanced biological clogging. Hence, it may be more feasible and beneficial to combine it with conventional FDO, allowing a steady infiltration rate and increased recharge volumes while sustaining high effluent quality. While these results still need to be verified at full scale, they highlight the possibility of using air injection to minimize the DP length and alleviate the pressure on existing SAT sites.",
author = "Ido Arad and Aviya Ziner and {Ben Moshe}, Shany and Noam Weisbrod and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2023 Ido Arad et al.",
year = "2023",
month = jul,
day = "10",
doi = "10.5194/hess-27-2509-2023",
language = "אנגלית",
volume = "27",
pages = "2509--2522",
journal = "Hydrology and Earth System Sciences",
issn = "1027-5606",
publisher = "European Geosciences Union",
number = "13",

}

Statistical analysis for biogeochemical processes in a sandy column with dynamic hydrologic regimes using spectral induced polarization (SIP) and self-potential (SP)

Zhang Z, Furman A. Statistical analysis for biogeochemical processes in a sandy column with dynamic hydrologic regimes using spectral induced polarization (SIP) and self-potential (SP). Geophysical Journal International. 2023 Apr 1;233(1):564-585. https://doi.org/10.1093/gji/ggac452
 

The capillary fringe (CF) is characterized by transient and steep redox gradients and is thought to be a hot spot for biogeochemical processes. Understanding chemical fate and transport in the CF is significant, however, biogeochemical dynamics at the CF are poorly understood because of the difficulty to measure representatively with high spatio-temporal resolution at depths under dynamic hydrologic regimes. Hydrogeophysics is a developing field that uses minimally intrusive and quick response methods to monitor hydrological properties. Two geoelectrical methods [spectral induced polarization (SIP) and self-potential (SP)], which are sensitive to the solid-liquid interfaces (SIP) and biogeochemical processes (SP) can address the above difficulty. The challenge lies on linking the geoelectrical responses with biogeochemical processes, where many different processes contribute to the signals. We conducted a soil column experiment under five hydrologic regimes focusing on nitrogen transformations with SIP and SP measurements: (1) a static regime with a stable water level; (2) an infiltration regime with periodic pulse infiltration events with a constant water level and (3) fluctuating regimes with water level fluctuations under three drying-wetting frequencies (6/12/18-day-cycle). This is the first large lab-scale work in a well-controlled and highly instrumented soil column. The dynamic hydrologic conditions stimulated complex biogeochemical processes at the CF, and therefore the SIP and SP signals result from many physical and biogeochemical processes. Therefore, we relied on statistical analysis in this study for a novel interpretation. Spearman correlation analysis supported water content played the most important role in real conductivity (σ′) dynamics in the vadose zone, whereas fluid conductivity dominated σ′ in the saturated zone. Both correlation analysis and spatial moment analysis implicated that water content was the driving factor for both σ′ and imaginary conductivity (σ″). A multiple linear regression model indicated the gradient of redox potential, the gradient of soil matric potential and water content were the three main influencing factors for the SP signals. We proposed that the water level fluctuation can efficiently facilitate microbial electron transfer through ions transport between the different redox zones, and aggregate redox processes to create SP signal gradients. Depth zonation analysis, using six environmental indexes (Eh and nitrogen species; water content; real conductivity; imaginary conductivity; SP signal; microbial community composition), suggested that water content induced by soil hydrology was the most dominant factor, captured by all the indexes. In turn, it led to indirect inference on biogeochemical processes and resultant geoelectrical signals. Applying geoelectrical methods to such biogeochemical processes will not only lead to a better understanding of the mechanistic meanings of the geoelectrical signals, but also build relationships between geoelectrical signals and biogeochemical parameters to facilitate a novel way to monitor biogeochemical processes.

@article{b15e06ea74414614ba359015ef83c5d0,
title = "Statistical analysis for biogeochemical processes in a sandy column with dynamic hydrologic regimes using spectral induced polarization (SIP) and self-potential (SP)",
abstract = "The capillary fringe (CF) is characterized by transient and steep redox gradients and is thought to be a hot spot for biogeochemical processes. Understanding chemical fate and transport in the CF is significant, however, biogeochemical dynamics at the CF are poorly understood because of the difficulty to measure representatively with high spatio-temporal resolution at depths under dynamic hydrologic regimes. Hydrogeophysics is a developing field that uses minimally intrusive and quick response methods to monitor hydrological properties. Two geoelectrical methods [spectral induced polarization (SIP) and self-potential (SP)], which are sensitive to the solid-liquid interfaces (SIP) and biogeochemical processes (SP) can address the above difficulty. The challenge lies on linking the geoelectrical responses with biogeochemical processes, where many different processes contribute to the signals. We conducted a soil column experiment under five hydrologic regimes focusing on nitrogen transformations with SIP and SP measurements: (1) a static regime with a stable water level; (2) an infiltration regime with periodic pulse infiltration events with a constant water level and (3) fluctuating regimes with water level fluctuations under three drying-wetting frequencies (6/12/18-day-cycle). This is the first large lab-scale work in a well-controlled and highly instrumented soil column. The dynamic hydrologic conditions stimulated complex biogeochemical processes at the CF, and therefore the SIP and SP signals result from many physical and biogeochemical processes. Therefore, we relied on statistical analysis in this study for a novel interpretation. Spearman correlation analysis supported water content played the most important role in real conductivity (σ′) dynamics in the vadose zone, whereas fluid conductivity dominated σ′ in the saturated zone. Both correlation analysis and spatial moment analysis implicated that water content was the driving factor for both σ′ and imaginary conductivity (σ″). A multiple linear regression model indicated the gradient of redox potential, the gradient of soil matric potential and water content were the three main influencing factors for the SP signals. We proposed that the water level fluctuation can efficiently facilitate microbial electron transfer through ions transport between the different redox zones, and aggregate redox processes to create SP signal gradients. Depth zonation analysis, using six environmental indexes (Eh and nitrogen species; water content; real conductivity; imaginary conductivity; SP signal; microbial community composition), suggested that water content induced by soil hydrology was the most dominant factor, captured by all the indexes. In turn, it led to indirect inference on biogeochemical processes and resultant geoelectrical signals. Applying geoelectrical methods to such biogeochemical processes will not only lead to a better understanding of the mechanistic meanings of the geoelectrical signals, but also build relationships between geoelectrical signals and biogeochemical parameters to facilitate a novel way to monitor biogeochemical processes.",
keywords = "Drying-wetting, Electrical properties, Hotspots, Hydrogeophysics, Statistical methods, Water level fluctuation",
author = "Zengyu Zhang and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society.",
year = "2023",
month = apr,
day = "1",
doi = "10.1093/gji/ggac452",
language = "אנגלית",
volume = "233",
pages = "564--585",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Oxford University Press",
number = "1",

}

Elucidating the relationship between gaseous O2 and redox potential in a soil aquifer treatment system using data driven approaches and an oxygen diffusion model

Turkeltaub T, Mannheim R, Furman A, Weisbrod N. Elucidating the relationship between gaseous O2 and redox potential in a soil aquifer treatment system using data driven approaches and an oxygen diffusion model. Journal of Hydrology. 2023 Mar;618:129168. https://doi.org/10.1016/j.jhydrol.2023.129168
 

Knowledge concerning the redox potential (Eh) conditions in the vadose zone of a soil aquifer treatment (SAT) system constitutes valuable information for assessing water quality and operational efficiency. The complex nature of Eh conditions in SAT limits the ability to predict and quantify them using detailed models. Alternatively, data-driven models can be used for predictions and relationship analysis. Hourly measurements of Eh, volumetric water content (θ), soil temperature (T), and gaseous oxygen (O2) were obtained at multiple depths of a SAT vadose zone. A correlation analysis showed that O2 correlated with Eh for most temporal components. Only the monthly component of T and the daily component of θ were correlated with Eh. A detailed multiple linear regression (MLR) analysis illustrated that the gaseous O2, at shallow depths, can explain the majority (above 80%) of the Eh variability. The MLR curve demonstrated breakpoints in the Eh response to O2 at shallow depths, which were identified using a piecewise regression. These breakpoints explain, in part, the different stages of microbial activity throughout the SAT wetting and drying cycles. Combining an oxygen transport analytical model with the piecewise regression enabled the Eh prediction through easy-to-acquire T and θ measurements. At deeper depths, the Eh–O2 relationship demonstrates a step-function characteristic, which indicates that the changes in Eh occur due to the arrival of a low-Eh solution. Thus, the Eh dynamic in the SAT vadose zone is mostly controlled by aerobic conditions.

@article{d8aaab72e2f74a95b09935ea5dbfdfdf,
title = "Elucidating the relationship between gaseous O2 and redox potential in a soil aquifer treatment system using data driven approaches and an oxygen diffusion model",
abstract = "Knowledge concerning the redox potential (Eh) conditions in the vadose zone of a soil aquifer treatment (SAT) system constitutes valuable information for assessing water quality and operational efficiency. The complex nature of Eh conditions in SAT limits the ability to predict and quantify them using detailed models. Alternatively, data-driven models can be used for predictions and relationship analysis. Hourly measurements of Eh, volumetric water content (θ), soil temperature (T), and gaseous oxygen (O2) were obtained at multiple depths of a SAT vadose zone. A correlation analysis showed that O2 correlated with Eh for most temporal components. Only the monthly component of T and the daily component of θ were correlated with Eh. A detailed multiple linear regression (MLR) analysis illustrated that the gaseous O2, at shallow depths, can explain the majority (above 80%) of the Eh variability. The MLR curve demonstrated breakpoints in the Eh response to O2 at shallow depths, which were identified using a piecewise regression. These breakpoints explain, in part, the different stages of microbial activity throughout the SAT wetting and drying cycles. Combining an oxygen transport analytical model with the piecewise regression enabled the Eh prediction through easy-to-acquire T and θ measurements. At deeper depths, the Eh–O2 relationship demonstrates a step-function characteristic, which indicates that the changes in Eh occur due to the arrival of a low-Eh solution. Thus, the Eh dynamic in the SAT vadose zone is mostly controlled by aerobic conditions.",
author = "Tuvia Turkeltaub and Ron Mannheim and Alex Furman and Noam Weisbrod",
note = "Publisher Copyright: {\textcopyright} 2023 Elsevier B.V.",
year = "2023",
month = mar,
doi = "10.1016/j.jhydrol.2023.129168",
language = "אנגלית",
volume = "618",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",

}

Application of TDR in compacted clay soils: Issues of dry density, water content range, and calibration

Nachum S, Talesnick M, Furman A. Application of TDR in compacted clay soils: Issues of dry density, water content range, and calibration. Canadian Geotechnical Journal. 2023 Mar;60(3):321-333. https://doi.org/10.1139/cgj-2021-0428
 

The paper deals with three issues relevant to the application of TDR methods for monitoring water content in compacted clay soils: (i) the dependence on dry density, (ii) the ability to monitor changes in water content in clay soil approaching saturation, and (iii) difficulties in performing efficient and reliable calibrations. A calibration scheme which inherently controls dry density of the specimen has been developed and applied. The methodology creates continuous calibration curves over a range of volumetric water content from a single test specimen. The new approach has been applied in monitoring the advance of a wetting front through a compacted swelling clay in a laboratory environment.

@article{83b8b1b115524dd088e5e3b99ca8535e,
title = "Application of TDR in compacted clay soils: Issues of dry density, water content range, and calibration",
abstract = "The paper deals with three issues relevant to the application of TDR methods for monitoring water content in compacted clay soils: (i) the dependence on dry density, (ii) the ability to monitor changes in water content in clay soil approaching saturation, and (iii) difficulties in performing efficient and reliable calibrations. A calibration scheme which inherently controls dry density of the specimen has been developed and applied. The methodology creates continuous calibration curves over a range of volumetric water content from a single test specimen. The new approach has been applied in monitoring the advance of a wetting front through a compacted swelling clay in a laboratory environment.",
keywords = "TDR technique, clay soil, water content",
author = "Shay Nachum and Mark Talesnick and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2022 The Author(s).",
year = "2023",
month = mar,
doi = "10.1139/cgj-2021-0428",
language = "אנגלית",
volume = "60",
pages = "321--333",
journal = "Canadian Geotechnical Journal",
issn = "0008-3674",
publisher = "National Research Council of Canada",
number = "3",

}

Modeling of irrigation and related processes with HYDRUS

Lazarovitch N, Kisekka I, Oker TE, Brunetti G, Wöhling T, Xianyue L et al. Modeling of irrigation and related processes with HYDRUS. In Sparks DL, editor, Advances in Agronomy. Academic Press Inc. 2023. p. 79-181. (Advances in Agronomy). https://doi.org/10.1016/bs.agron.2023.05.002
 

Future agriculture calls for increased input (e.g., water, nutrients, pesticides) use efficiency while maintaining or improving productivity, minimizing environmental impacts, and increasing profitability. Complete understanding of complex irrigation systems requires laborious, time-consuming, and expensive field investigations, which invariably involve only a limited number of treatments. On the other hand, fully calibrated process-based models, such as HYDRUS, can quickly evaluate different irrigation management strategies without the need for labor-intensive fieldwork and have become valuable research tools for predicting complex and interactive water flow and solute transport processes in and below the root zone. HYDRUS codes have been used worldwide in several hundreds of studies evaluating various types of irrigation (e.g., sprinkler, furrow, basin, and surface and subsurface drip), their scheduling (e.g., the timing of irrigation and its amount), and solute-related factors (e.g., fertigation, chemigation, salinization, and sodification). The objective of this manuscript is to review the current modeling capabilities of HYDRUS to evaluate various irrigation methods and related processes. The manuscript starts with a section describing governing flow and transport equations solved numerically by the HYDRUS codes, the corresponding initial and boundary conditions, and related factors such as soil hydraulic properties and root water and nutrient uptake. Modeling of different irrigation techniques is described in subsequent sections, followed by sections dealing with solute-related topics such as fertigation, chemigation, and salinization/sodification. Topics, including the effects of spatial variability, optimization of irrigation systems, and special irrigation methods, are covered in the later sections. The manuscript emphasizes the advantages and opportunities of HYDRUS in describing various processes in the root zone of irrigated plants that support sustainable irrigated agriculture. All the project files of the discussed examples and their descriptions are available for download at https://www.pc-progress.com/en/Default.aspx?hyd5-AdvancesInAgronomy.

@inbook{52e2f7d123c34d3abdfde9cc4a1c171f,
title = "Modeling of irrigation and related processes with HYDRUS",
abstract = "Future agriculture calls for increased input (e.g., water, nutrients, pesticides) use efficiency while maintaining or improving productivity, minimizing environmental impacts, and increasing profitability. Complete understanding of complex irrigation systems requires laborious, time-consuming, and expensive field investigations, which invariably involve only a limited number of treatments. On the other hand, fully calibrated process-based models, such as HYDRUS, can quickly evaluate different irrigation management strategies without the need for labor-intensive fieldwork and have become valuable research tools for predicting complex and interactive water flow and solute transport processes in and below the root zone. HYDRUS codes have been used worldwide in several hundreds of studies evaluating various types of irrigation (e.g., sprinkler, furrow, basin, and surface and subsurface drip), their scheduling (e.g., the timing of irrigation and its amount), and solute-related factors (e.g., fertigation, chemigation, salinization, and sodification). The objective of this manuscript is to review the current modeling capabilities of HYDRUS to evaluate various irrigation methods and related processes. The manuscript starts with a section describing governing flow and transport equations solved numerically by the HYDRUS codes, the corresponding initial and boundary conditions, and related factors such as soil hydraulic properties and root water and nutrient uptake. Modeling of different irrigation techniques is described in subsequent sections, followed by sections dealing with solute-related topics such as fertigation, chemigation, and salinization/sodification. Topics, including the effects of spatial variability, optimization of irrigation systems, and special irrigation methods, are covered in the later sections. The manuscript emphasizes the advantages and opportunities of HYDRUS in describing various processes in the root zone of irrigated plants that support sustainable irrigated agriculture. All the project files of the discussed examples and their descriptions are available for download at https://www.pc-progress.com/en/Default.aspx?hyd5-AdvancesInAgronomy.",
keywords = "Chemigation, Drip, Fertigation, Furrow, HYDRUS, Irrigation, Salinity, Sprinkler",
author = "Naftali Lazarovitch and Isaya Kisekka and Oker, {Tobias E.} and Giuseppe Brunetti and Thomas W{\"o}hling and Li Xianyue and Li Yong and Skaggs, {Todd H.} and Alex Furman and Salini Sasidharan and Iael Raij-Hoffman and Ji{\v r}{\'i} {\v S}imůnek",
note = "Publisher Copyright: {\textcopyright} 2023 Elsevier Inc.",
year = "2023",
month = jan,
doi = "10.1016/bs.agron.2023.05.002",
language = "אנגלית",
isbn = "9780443192661",
series = "Advances in Agronomy",
publisher = "Academic Press Inc.",
pages = "79--181",
editor = "Sparks, {Donald L.}",
booktitle = "Advances in Agronomy",

}

2022

Real-time monitoring of organic contaminant adsorption in activated carbon filters using spectral induced polarization

Ben Moshe S, Furman A. Real-time monitoring of organic contaminant adsorption in activated carbon filters using spectral induced polarization. Water Research. 2022 Apr 1;212:118103. https://doi.org/10.1016/j.watres.2022.118103
 

Real-time, in-situ monitoring of adsorption processes in activated carbon (AC) filters may advance the effectiveness, reliability and economical value of such systems. In this study, the applicability of spectral induced polarization (SIP) as a real-time monitoring tool was examined. The adsorption of anionic and cationic organic dyes to commercial-AC filter was examined using a set of breakthrough experiments combined with continuous SIP monitoring. The imaginary part of the complex electrical conductivity decreased in the range of 0.25−2.5Hz for both dyes. During the adsorption of the cationic dye, a new peak developed in the range of 7−40Hz, suggesting the dominance of surface processes that are not explained by the classic stern-layer polarization theory. The recorded imaginary conductivity values were used as a proxy for adsorbed dye concentration in the calibration process of a reactive transport model. The model confirmed that SIP can successfully be used for real-time monitoring of the dye progression through the filter. The applicability of SIP as an effective monitoring tool was also shown for cyclic operation (adsorption-desorption cycles).

@article{ad0952ae064643819af0821d2c160d2f,
title = "Real-time monitoring of organic contaminant adsorption in activated carbon filters using spectral induced polarization",
abstract = "Real-time, in-situ monitoring of adsorption processes in activated carbon (AC) filters may advance the effectiveness, reliability and economical value of such systems. In this study, the applicability of spectral induced polarization (SIP) as a real-time monitoring tool was examined. The adsorption of anionic and cationic organic dyes to commercial-AC filter was examined using a set of breakthrough experiments combined with continuous SIP monitoring. The imaginary part of the complex electrical conductivity decreased in the range of 0.25−2.5Hz for both dyes. During the adsorption of the cationic dye, a new peak developed in the range of 7−40Hz, suggesting the dominance of surface processes that are not explained by the classic stern-layer polarization theory. The recorded imaginary conductivity values were used as a proxy for adsorbed dye concentration in the calibration process of a reactive transport model. The model confirmed that SIP can successfully be used for real-time monitoring of the dye progression through the filter. The applicability of SIP as an effective monitoring tool was also shown for cyclic operation (adsorption-desorption cycles).",
keywords = "Activated carbon, Adsorption, Organic dyes, Real-time monitoring, Spectral induced polarization, Water purification",
author = "{Ben Moshe}, Shany and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2022 Elsevier Ltd",
year = "2022",
month = apr,
day = "1",
doi = "10.1016/j.watres.2022.118103",
language = "אנגלית",
volume = "212",
journal = "Water Research",
issn = "0043-1354",
publisher = "Elsevier Ltd.",

}

Continuous monitoring of a soil aquifer treatment system's physico-chemical conditions to optimize operational performance

Turkeltaub T, Furman A, Mannheim R, Weisbrod N. Continuous monitoring of a soil aquifer treatment system's physico-chemical conditions to optimize operational performance. Hydrology and Earth System Sciences. 2022 Mar 23;26(6):1565-1578. https://doi.org/10.5194/hess-26-1565-2022
 

Soil aquifer treatment (SAT) is a tertiary process for wastewater treatment, where the wastewater infiltrates through a thick vadose zone for purification and storage in the underneath aquifer. SAT infiltration basins are typically flooded intermittently, while maintaining a fixed ratio between the wetting and the drying stages. However, infiltration basins exhibit different physical and chemical properties, limiting the generalization of SAT operation to attain optimal efficiency. Since frequent sampling of the soil pore water to verify the SAT's biodegradation efficiency can be arduous, continuous monitoring of the SAT vadose zone's physico-chemical conditions is required. In this study, redox potential (Eh) was continuously monitored, together with other variables, such as volumetric water content (θ), soil temperature, and gaseous oxygen (O2), at multiple depths of a SAT vadose zone throughout the year and while the system was constrained to different operational modes. Hydrological models were calibrated and validated to water content observations, and they illustrated the seasonal changes in water infiltration. Furthermore, it was shown that, under long wetting stages during winter, there was a reduction in the SAT's drainage capabilities. The Eh observations, under long wetting stages, demonstrated larger variability and very negative values as ambient temperature increased. Assembling the daily Eh observations illustrated that a wetting stage should cease after about 30ĝ€¯h, once suboxic conditions are established. A drying stage's optimal duration should be 36ĝ€¯h, according to the Eh and O2 observations during summer and winter. Ultimately, the study shows that the length of wetting and drying stages should be defined separately, rather than by adhering to the wettingĝ€¯/ĝ€¯drying ratio.

@article{76afbfc74d204c048a30dbd2f6fc3904,
title = "Continuous monitoring of a soil aquifer treatment system's physico-chemical conditions to optimize operational performance",
abstract = "Soil aquifer treatment (SAT) is a tertiary process for wastewater treatment, where the wastewater infiltrates through a thick vadose zone for purification and storage in the underneath aquifer. SAT infiltration basins are typically flooded intermittently, while maintaining a fixed ratio between the wetting and the drying stages. However, infiltration basins exhibit different physical and chemical properties, limiting the generalization of SAT operation to attain optimal efficiency. Since frequent sampling of the soil pore water to verify the SAT's biodegradation efficiency can be arduous, continuous monitoring of the SAT vadose zone's physico-chemical conditions is required. In this study, redox potential (Eh) was continuously monitored, together with other variables, such as volumetric water content (θ), soil temperature, and gaseous oxygen (O2), at multiple depths of a SAT vadose zone throughout the year and while the system was constrained to different operational modes. Hydrological models were calibrated and validated to water content observations, and they illustrated the seasonal changes in water infiltration. Furthermore, it was shown that, under long wetting stages during winter, there was a reduction in the SAT's drainage capabilities. The Eh observations, under long wetting stages, demonstrated larger variability and very negative values as ambient temperature increased. Assembling the daily Eh observations illustrated that a wetting stage should cease after about 30ĝ€¯h, once suboxic conditions are established. A drying stage's optimal duration should be 36ĝ€¯h, according to the Eh and O2 observations during summer and winter. Ultimately, the study shows that the length of wetting and drying stages should be defined separately, rather than by adhering to the wettingĝ€¯/ĝ€¯drying ratio.",
author = "Tuvia Turkeltaub and Alex Furman and Ron Mannheim and Noam Weisbrod",
note = "Publisher Copyright: {\textcopyright} Copyright: ",
year = "2022",
month = mar,
day = "23",
doi = "10.5194/hess-26-1565-2022",
language = "אנגלית",
volume = "26",
pages = "1565--1578",
journal = "Hydrology and Earth System Sciences",
issn = "1027-5606",
publisher = "European Geosciences Union",
number = "6",

}

On the use of orchards to support soil aquifer treatment systems

Grinshpan M, Turkeltaub T, Furman A, Raveh E, Weisbrod N. On the use of orchards to support soil aquifer treatment systems. Agricultural Water Management. 2022 Feb 1;260:107315. https://doi.org/10.1016/j.agwat.2021.107315
 

Soil aquifer treatment (SAT) is a practice used to enhance groundwater storage through intermittent percolation of treated wastewater effluent in designated infiltration basins. Due to proximity to urban regions, land availability for SAT infiltration basins is a limiting factor. Furthermore, with the growing population, SAT systems are faced with an increase in effluent volumes meant for recharge. The present study experimentally explores, for the first time, the feasibility of the short-term flooding of a citrus orchard with secondary effluent, as an alternative for an additional dedicated infiltration area for SAT, namely agricultural soil aquifer treatment (Ag-SAT). Orange trees were planted in two different agricultural setups, on flat soil and atop a ridge. Sporadic intermittent winter flooding experiments, lasting 24 and 48 h, were conducted. Volumetric water content (VWC) and oxidation-reduction conditions were continuously monitored. Concurrently, water samples were collected and analyzed for total organic carbon and nitrogen species, along with leaf health measurements. Results were compared to an adjacent control plot, where no flooding with effluent was applied. Contaminant removal rates under the ridge setup resembled active SAT basins. Moreover, chemical analysis of the water samples and VWC readings demonstrated that higher water quality and faster root zone aeration (following flooding) were obtained under the ridge, which appears to be the better Ag-SAT setup. According to a principal component analysis (PCA), the dissolved oxygen explains 75% of the variability of effluent chemistry under the ridge, illustrating that oxic conditions prevailed in this setup. This study demonstrates that while many other concerns still need to be addressed, using agricultural plots as recharge basins for SAT during the winter appears to be a promising way to supplement recharge basins while having no impact on tree health.

@article{1fa1569ce0a748d1bd8784e3b84e3cb0,
title = "On the use of orchards to support soil aquifer treatment systems",
abstract = "Soil aquifer treatment (SAT) is a practice used to enhance groundwater storage through intermittent percolation of treated wastewater effluent in designated infiltration basins. Due to proximity to urban regions, land availability for SAT infiltration basins is a limiting factor. Furthermore, with the growing population, SAT systems are faced with an increase in effluent volumes meant for recharge. The present study experimentally explores, for the first time, the feasibility of the short-term flooding of a citrus orchard with secondary effluent, as an alternative for an additional dedicated infiltration area for SAT, namely agricultural soil aquifer treatment (Ag-SAT). Orange trees were planted in two different agricultural setups, on flat soil and atop a ridge. Sporadic intermittent winter flooding experiments, lasting 24 and 48 h, were conducted. Volumetric water content (VWC) and oxidation-reduction conditions were continuously monitored. Concurrently, water samples were collected and analyzed for total organic carbon and nitrogen species, along with leaf health measurements. Results were compared to an adjacent control plot, where no flooding with effluent was applied. Contaminant removal rates under the ridge setup resembled active SAT basins. Moreover, chemical analysis of the water samples and VWC readings demonstrated that higher water quality and faster root zone aeration (following flooding) were obtained under the ridge, which appears to be the better Ag-SAT setup. According to a principal component analysis (PCA), the dissolved oxygen explains 75% of the variability of effluent chemistry under the ridge, illustrating that oxic conditions prevailed in this setup. This study demonstrates that while many other concerns still need to be addressed, using agricultural plots as recharge basins for SAT during the winter appears to be a promising way to supplement recharge basins while having no impact on tree health.",
keywords = "Agricultural managed aquifer recharge (Ag-MAR), Agricultural soil aquifer treatment (Ag-SAT), Orchard flooding, Treated wastewater (TWW)",
author = "Maayan Grinshpan and Tuvia Turkeltaub and Alex Furman and Eran Raveh and Noam Weisbrod",
note = "Publisher Copyright: {\textcopyright} 2021 Elsevier B.V.",
year = "2022",
month = feb,
day = "1",
doi = "10.1016/j.agwat.2021.107315",
language = "אנגלית",
volume = "260",
journal = "Agricultural Water Management",
issn = "0378-3774",
publisher = "Elsevier",

}

2021

Redox dynamics at a dynamic capillary fringe for nitrogen cycling in a sandy column

Zhang Z, Furman A. Redox dynamics at a dynamic capillary fringe for nitrogen cycling in a sandy column. Journal of Hydrology. 2021 Dec;603:126899. https://doi.org/10.1016/j.jhydrol.2021.126899
 

The capillary fringe (CF) is the last barrier for groundwater protection. Studies investigating the effects of cyclic groundwater fluctuation on nitrogen transformations, a critical biogenic element, in soil systems received less attention relative to near-surface and groundwater processes. We conducted an experiment in a highly instrumented 91-cm sandy soil column under five hydrologic regimes: (1) stagnant system with a static water level, (2) periodic pulsed infiltration with a constant water level, and (3) groundwater fluctuation under three frequencies (6/ 12/ 18-day-cycle). Under groundwater fluctuation regimes, the soil column can be divided into four zones: aerobic zone (10–30 cm), hypoxic zone (40–50 cm), anoxic zone (60–70 cm), and anaerobic zone (80–100 cm). The stable high Eh occurred in the aerobic and hypoxic zones, while the stable low Eh appeared in the anaerobic zone. The Eh at the upper anoxic zone (60 cm) appeared to show a strong cyclic pattern and the Eh at the lower anoxic zone (70 cm) gradually decreased until it reached values similar to the anaerobic zone. Nitrate overwhelmed other nitrogen species in the aerobic and hypoxic zones. The lower boundary of the nitrate-dominant zone was sensitive to the water level, which means that oxygen supply depends on the water level fluctuation. Ammonium dominated the anoxic and anaerobic zones, and the upper boundary of the high ammonium zone was constant, which implies that denitrification reached the maximum capacity in the anaerobic zone. The dominance of a single species in these zones suggests incomplete cycling of nitrogen. In contrast, nitrogen removal was enhanced with increasing frequency of groundwater fluctuation. Low total nitrogen concentration was observed at the hypoxic and anoxic zones boundary, due to the co-occurrence of nitrification and denitrification. The ratio of dissolved organic carbon to dissolved inorganic nitrogen can indicate the relative strength of nitrification–denitrification, subsequently distinguish the zonation of nitrogen status in this soil system. Additionally, ferrous sulfide particles accumulated at the anaerobic zone with intensified reducing condition, which deserves more attention. The observations presented in this study strengthen the understanding that the CF acts as a hot-spot and occasionally as a hot-moment, which is of great importance to chemical cycling, highlighting the role of groundwater fluctuation in mass transfer across the CF.

@article{02f3f93b4e52422d8865c8a3c58c2fc5,
title = "Redox dynamics at a dynamic capillary fringe for nitrogen cycling in a sandy column",
abstract = "The capillary fringe (CF) is the last barrier for groundwater protection. Studies investigating the effects of cyclic groundwater fluctuation on nitrogen transformations, a critical biogenic element, in soil systems received less attention relative to near-surface and groundwater processes. We conducted an experiment in a highly instrumented 91-cm sandy soil column under five hydrologic regimes: (1) stagnant system with a static water level, (2) periodic pulsed infiltration with a constant water level, and (3) groundwater fluctuation under three frequencies (6/ 12/ 18-day-cycle). Under groundwater fluctuation regimes, the soil column can be divided into four zones: aerobic zone (10–30 cm), hypoxic zone (40–50 cm), anoxic zone (60–70 cm), and anaerobic zone (80–100 cm). The stable high Eh occurred in the aerobic and hypoxic zones, while the stable low Eh appeared in the anaerobic zone. The Eh at the upper anoxic zone (60 cm) appeared to show a strong cyclic pattern and the Eh at the lower anoxic zone (70 cm) gradually decreased until it reached values similar to the anaerobic zone. Nitrate overwhelmed other nitrogen species in the aerobic and hypoxic zones. The lower boundary of the nitrate-dominant zone was sensitive to the water level, which means that oxygen supply depends on the water level fluctuation. Ammonium dominated the anoxic and anaerobic zones, and the upper boundary of the high ammonium zone was constant, which implies that denitrification reached the maximum capacity in the anaerobic zone. The dominance of a single species in these zones suggests incomplete cycling of nitrogen. In contrast, nitrogen removal was enhanced with increasing frequency of groundwater fluctuation. Low total nitrogen concentration was observed at the hypoxic and anoxic zones boundary, due to the co-occurrence of nitrification and denitrification. The ratio of dissolved organic carbon to dissolved inorganic nitrogen can indicate the relative strength of nitrification–denitrification, subsequently distinguish the zonation of nitrogen status in this soil system. Additionally, ferrous sulfide particles accumulated at the anaerobic zone with intensified reducing condition, which deserves more attention. The observations presented in this study strengthen the understanding that the CF acts as a hot-spot and occasionally as a hot-moment, which is of great importance to chemical cycling, highlighting the role of groundwater fluctuation in mass transfer across the CF.",
keywords = "Capillary fringe, Drying-wetting, Nitrogen transformation, Organic carbon, Unsaturated zone, Water table fluctuation",
author = "Zengyu Zhang and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2021 Elsevier B.V.",
year = "2021",
month = dec,
doi = "10.1016/j.jhydrol.2021.126899",
language = "אנגלית",
volume = "603",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",

}

From managed aquifer recharge to soil aquifer treatment on agricultural soils: Concepts and challenges

Grinshpan M, Furman A, Dahlke HE, Raveh E, Weisbrod N. From managed aquifer recharge to soil aquifer treatment on agricultural soils: Concepts and challenges. Agricultural Water Management. 2021 Sep 1;255:106991. https://doi.org/10.1016/j.agwat.2021.106991
 

Water is a limiting factor for economic and social development in most arid and semi-arid regions on Earth. The deliberate recharge of depleted aquifer storage and later recovery, known as managed aquifer recharge (MAR), is an important tool for water management and sustainability. Increasing stresses on groundwater and subsequent overdrafts have sparked the development of several advanced MAR technologies, including soil aquifer treatment (SAT). SAT is a method that recharges wastewater effluent through intermittent percolation in infiltration basins. Another emerging MAR approach currently explored is the off-season flooding of agricultural lands, known as agricultural MAR, or Ag-MAR. Utilizing agricultural fields as temporary infiltration basins during periods of dormancy increases the availability of land resources for groundwater recharge, rather than designating land explicitly for MAR. As land resources for SAT become limited and the amount of available treated wastewater (TWW) increases, we propose the idea of agricultural SAT, or Ag-SAT, as a combination of SAT and Ag-MAR. This review paper aims to provide an in-depth look into the approach and application of Ag-MAR and the possibilities of integrating Ag-MAR with SAT. Ag-SAT comprises the off-season flooding of agricultural land using TWW for groundwater recharge and subsequent reuse. Ag-SAT could provide alternative infiltration sites for SAT where available surface area dedicated to infiltration is becoming a limiting factor. Additionally, the treated wastewater could potentially provide nutrients to agricultural fields during the flooding cycles. Potential advantages, disadvantages, and knowledge gaps related to Ag-SAT are presented and discussed.

@article{ba194c020d104ebaabbadb07ba0b1b82,
title = "From managed aquifer recharge to soil aquifer treatment on agricultural soils: Concepts and challenges",
abstract = "Water is a limiting factor for economic and social development in most arid and semi-arid regions on Earth. The deliberate recharge of depleted aquifer storage and later recovery, known as managed aquifer recharge (MAR), is an important tool for water management and sustainability. Increasing stresses on groundwater and subsequent overdrafts have sparked the development of several advanced MAR technologies, including soil aquifer treatment (SAT). SAT is a method that recharges wastewater effluent through intermittent percolation in infiltration basins. Another emerging MAR approach currently explored is the off-season flooding of agricultural lands, known as agricultural MAR, or Ag-MAR. Utilizing agricultural fields as temporary infiltration basins during periods of dormancy increases the availability of land resources for groundwater recharge, rather than designating land explicitly for MAR. As land resources for SAT become limited and the amount of available treated wastewater (TWW) increases, we propose the idea of agricultural SAT, or Ag-SAT, as a combination of SAT and Ag-MAR. This review paper aims to provide an in-depth look into the approach and application of Ag-MAR and the possibilities of integrating Ag-MAR with SAT. Ag-SAT comprises the off-season flooding of agricultural land using TWW for groundwater recharge and subsequent reuse. Ag-SAT could provide alternative infiltration sites for SAT where available surface area dedicated to infiltration is becoming a limiting factor. Additionally, the treated wastewater could potentially provide nutrients to agricultural fields during the flooding cycles. Potential advantages, disadvantages, and knowledge gaps related to Ag-SAT are presented and discussed.",
keywords = "Agricultural managed aquifer recharge, Agricultural soil aquifer treatment, Groundwater sustainability, Treated wastewater irrigation, Water reclamation",
author = "Maayan Grinshpan and Alex Furman and Dahlke, {Helen E.} and Eran Raveh and Noam Weisbrod",
note = "Publisher Copyright: {\textcopyright} 2021 Elsevier B.V.",
year = "2021",
month = sep,
day = "1",
doi = "10.1016/j.agwat.2021.106991",
language = "אנגלית",
volume = "255",
journal = "Agricultural Water Management",
issn = "0378-3774",
publisher = "Elsevier",

}

Geophysically based analysis of breakthrough curves and ion exchange processes in soil

Moshe SB, Kessouri P, Erlich D, Furman A. Geophysically based analysis of breakthrough curves and ion exchange processes in soil. Hydrology and Earth System Sciences. 2021 Jun 8;25(6):3041-3052. https://doi.org/10.5194/hess-25-3041-2021
 

Breakthrough curves (BTCs) are a valuable tool for qualitative and quantitative examination of transport patterns in porous media. Although breakthrough (BT) experiments are simple, they often require extensive sampling and multi-component chemical analysis. In this work, we examine spectral induced polarization (SIP) signals measured along a soil column during BT experiments in homogeneous and heterogeneous soil profiles. Soil profiles were equilibrated with an NaCl background solution, and then a constant flow of either CaCl2 or ZnCl2 solution was applied. The SIP signature was recorded, and complementary ion analysis was performed on the collected outflow samples. Our results confirm that changes to the pore-water composition, ion exchange processes and profile heterogeneity are detectable by SIP: the real part of the SIP-based BTCs clearly indicated the BT of the non-reactive ions as well as the retarded BT of cations. The imaginary part of the SIP-based curves changed in response to the alteration of ion mobility around the electrical double layer (EDL) and indicated the initiation and the termination of the cation exchange reaction. Finally, both the real and imaginary components of the complex conductivity changed in response to the presence of a coarser textured layer in the heterogeneous profile.

@article{a1702285c0234775bff35817fc62c9c8,
title = "Geophysically based analysis of breakthrough curves and ion exchange processes in soil",
abstract = "Breakthrough curves (BTCs) are a valuable tool for qualitative and quantitative examination of transport patterns in porous media. Although breakthrough (BT) experiments are simple, they often require extensive sampling and multi-component chemical analysis. In this work, we examine spectral induced polarization (SIP) signals measured along a soil column during BT experiments in homogeneous and heterogeneous soil profiles. Soil profiles were equilibrated with an NaCl background solution, and then a constant flow of either CaCl2 or ZnCl2 solution was applied. The SIP signature was recorded, and complementary ion analysis was performed on the collected outflow samples. Our results confirm that changes to the pore-water composition, ion exchange processes and profile heterogeneity are detectable by SIP: the real part of the SIP-based BTCs clearly indicated the BT of the non-reactive ions as well as the retarded BT of cations. The imaginary part of the SIP-based curves changed in response to the alteration of ion mobility around the electrical double layer (EDL) and indicated the initiation and the termination of the cation exchange reaction. Finally, both the real and imaginary components of the complex conductivity changed in response to the presence of a coarser textured layer in the heterogeneous profile.",
author = "Moshe, {Shany Ben} and Pauline Kessouri and Dana Erlich and Alex Furman",
note = "Publisher Copyright: {\textcopyright} Author(s) 2021.",
year = "2021",
month = jun,
day = "8",
doi = "10.5194/hess-25-3041-2021",
language = "אנגלית",
volume = "25",
pages = "3041--3052",
journal = "Hydrology and Earth System Sciences",
issn = "1027-5606",
publisher = "European Geosciences Union",
number = "6",

}

Soil redox dynamics under dynamic hydrologic regimes - A review

Zhang Z, Furman A. Soil redox dynamics under dynamic hydrologic regimes - A review. Science of the Total Environment. 2021 Apr 1;763:143026. https://doi.org/10.1016/j.scitotenv.2020.143026
 

Electron transfer (redox) reactions, mediated by soil microbiota, modulate elemental cycling and, in part, establish the redox poise of soil systems. Understanding soil redox processes significantly improves our ability to characterize coupled biogeochemical cycling in soils and aids in soil health management. Redox-sensitive species exhibit different reactivity, mobility, and toxicity subjected to their redox state. Thus, it is crucial to quantify the redox potential (Eh) in soils and to characterize the dominant redox couples therein. Several, often coupled, external drivers, can influence Eh. Among these factors, soil hydrology dominates. It controls soil physical properties that in turn further regulates Eh. Soil spatial heterogeneity and temporally dynamic hydrologic regimes yield complex distributions of Eh. Soil redox processes have been studied under various environmental conditions, including relatively static and dynamic hydrologic regimes. Our focus here is on dynamic, variably water-saturated environments. Herein, we review previous studies on soil redox dynamics, with a specific focus on dynamic hydrologic regimes, provide recommendations on knowledge gaps, and targeted future research needs and directions. We review (1) the role of soil redox conditions on the soil chemical-species cycling of organic carbon, nitrogen, phosphorus, redox-active metals, and organic contaminants; (2) interactions between microbial activity and redox state in the near-surface and deep subsurface soil, and biomolecular methods to reveal the role of microbes in the redox processes; (3) the effects of dynamic hydrologic regimes on chemical-species cycling and microbial dynamics; (4) the experimental setups for mimicking different hydrologic regimes at both laboratory and field scales. Finally, we identify the current knowledge gaps related to the study of soil redox dynamics under different hydrologic regimes: (1) fluctuating conditions in the deep subsurface; (2) the use of biomolecular tools to understand soil biogeochemical processes beyond nitrogen; (3) limited current field measurements and potential alternative experimental setups.

@article{3765575b734141a798a5eb920cfbc396,
title = "Soil redox dynamics under dynamic hydrologic regimes - A review",
abstract = "Electron transfer (redox) reactions, mediated by soil microbiota, modulate elemental cycling and, in part, establish the redox poise of soil systems. Understanding soil redox processes significantly improves our ability to characterize coupled biogeochemical cycling in soils and aids in soil health management. Redox-sensitive species exhibit different reactivity, mobility, and toxicity subjected to their redox state. Thus, it is crucial to quantify the redox potential (Eh) in soils and to characterize the dominant redox couples therein. Several, often coupled, external drivers, can influence Eh. Among these factors, soil hydrology dominates. It controls soil physical properties that in turn further regulates Eh. Soil spatial heterogeneity and temporally dynamic hydrologic regimes yield complex distributions of Eh. Soil redox processes have been studied under various environmental conditions, including relatively static and dynamic hydrologic regimes. Our focus here is on dynamic, variably water-saturated environments. Herein, we review previous studies on soil redox dynamics, with a specific focus on dynamic hydrologic regimes, provide recommendations on knowledge gaps, and targeted future research needs and directions. We review (1) the role of soil redox conditions on the soil chemical-species cycling of organic carbon, nitrogen, phosphorus, redox-active metals, and organic contaminants; (2) interactions between microbial activity and redox state in the near-surface and deep subsurface soil, and biomolecular methods to reveal the role of microbes in the redox processes; (3) the effects of dynamic hydrologic regimes on chemical-species cycling and microbial dynamics; (4) the experimental setups for mimicking different hydrologic regimes at both laboratory and field scales. Finally, we identify the current knowledge gaps related to the study of soil redox dynamics under different hydrologic regimes: (1) fluctuating conditions in the deep subsurface; (2) the use of biomolecular tools to understand soil biogeochemical processes beyond nitrogen; (3) limited current field measurements and potential alternative experimental setups.",
keywords = "Anaerobic microsite, Capillary fringe, Chemical-species cycling, Drying-wetting, Microbial function, Redox potential",
author = "Zengyu Zhang and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2020 Elsevier B.V.",
year = "2021",
month = apr,
day = "1",
doi = "10.1016/j.scitotenv.2020.143026",
language = "אנגלית",
volume = "763",
journal = "Science of the Total Environment",
issn = "0048-9697",
publisher = "Elsevier",

}

Optimization of soil aquifer treatment (SAT) operation using a reactive transport model

Ben Moshe S, Weisbrod N, Furman A. Optimization of soil aquifer treatment (SAT) operation using a reactive transport model. Vadose Zone Journal. 2021;20(1):e20095. https://doi.org/10.1002/vzj2.20095
 

In this work, a numerical model was developed with the aim to study the effect of drying period (DP) duration on the biogeochemical state of a soil aquifer treatment (SAT) system, and to enhance its functionality accordingly. The model was calibrated and verified using data series from long-column experiments, and sensitivity analysis was performed. Considering unsaturated water flow, air movement, solute transport, and the main microbial-mediated kinetic reactions relevant to SAT, we examined outflow quality and reaction rates in response to seven DP durations while the flooding period (FP) durations were kept constant. The results show that extension of the aerobically active region occurs in response to longer DPs and suggest that very long DPs (>3 times the FPs) may not pose further advantage compared with medium-length DPs (2.5–3 times the flooding periods). A simple optimization process was demonstrated for the experimental SAT system presented, considering outflow quality vs. infiltrated volume. An optimum was obtained at DP/FP ratio of ∼2.8. Although these results are system specific, similar biogeochemical models may be modified and used for hydraulic operation optimization in other SAT sites.

@article{8ba2c26924a2404e8c83fe451bb11bec,
title = "Optimization of soil aquifer treatment (SAT) operation using a reactive transport model",
abstract = "In this work, a numerical model was developed with the aim to study the effect of drying period (DP) duration on the biogeochemical state of a soil aquifer treatment (SAT) system, and to enhance its functionality accordingly. The model was calibrated and verified using data series from long-column experiments, and sensitivity analysis was performed. Considering unsaturated water flow, air movement, solute transport, and the main microbial-mediated kinetic reactions relevant to SAT, we examined outflow quality and reaction rates in response to seven DP durations while the flooding period (FP) durations were kept constant. The results show that extension of the aerobically active region occurs in response to longer DPs and suggest that very long DPs (>3 times the FPs) may not pose further advantage compared with medium-length DPs (2.5–3 times the flooding periods). A simple optimization process was demonstrated for the experimental SAT system presented, considering outflow quality vs. infiltrated volume. An optimum was obtained at DP/FP ratio of ∼2.8. Although these results are system specific, similar biogeochemical models may be modified and used for hydraulic operation optimization in other SAT sites.",
author = "{Ben Moshe}, Shany and Noam Weisbrod and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2021 The Authors. Vadose Zone Journal published by Wiley Periodicals LLC on behalf of Soil Science Society of America",
year = "2021",
doi = "10.1002/vzj2.20095",
language = "אנגלית",
volume = "20",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "1",

}

2020

Rethinking wastewater risks and monitoring in light of the COVID-19 pandemic

Bogler A, Packman A, Furman A, Gross A, Kushmaro A, Ronen A et al. Rethinking wastewater risks and monitoring in light of the COVID-19 pandemic. Nature Sustainability. 2020 Dec;3(12):981-990. https://doi.org/10.1038/s41893-020-00605-2
 

The COVID-19 pandemic has severely impacted public health and the worldwide economy. Converging evidence from the current pandemic, previous outbreaks and controlled experiments indicates that SARS-CoVs are present in wastewater for several days, leading to potential health risks via waterborne and aerosolized wastewater pathways. Conventional wastewater treatment provides only partial removal of SARS-CoVs, thus safe disposal or reuse will depend on the efficacy of final disinfection. This underscores the need for a risk assessment and management framework tailored to SARS-CoV-2 transmission via wastewater, including new tools for environmental surveillance, ensuring adequate disinfection as a component of overall COVID-19 pandemic containment.

@article{985fc1ac3086448d9f816e564418807e,
title = "Rethinking wastewater risks and monitoring in light of the COVID-19 pandemic",
abstract = "The COVID-19 pandemic has severely impacted public health and the worldwide economy. Converging evidence from the current pandemic, previous outbreaks and controlled experiments indicates that SARS-CoVs are present in wastewater for several days, leading to potential health risks via waterborne and aerosolized wastewater pathways. Conventional wastewater treatment provides only partial removal of SARS-CoVs, thus safe disposal or reuse will depend on the efficacy of final disinfection. This underscores the need for a risk assessment and management framework tailored to SARS-CoV-2 transmission via wastewater, including new tools for environmental surveillance, ensuring adequate disinfection as a component of overall COVID-19 pandemic containment.",
author = "Anne Bogler and Aaron Packman and Alex Furman and Amit Gross and Ariel Kushmaro and Avner Ronen and Christophe Dagot and Colin Hill and Dalit Vaizel-Ohayon and Eberhard Morgenroth and Enrico Bertuzzo and George Wells and Kiperwas, {Hadas Raanan} and Harald Horn and Ido Negev and Ines Zucker and Itay Bar-Or and Jacob Moran-Gilad and Balcazar, {Jose Luis} and Kyle Bibby and Menachem Elimelech and Noam Weisbrod and Oded Nir and Oded Sued and Osnat Gillor and Alvarez, {Pedro J.} and Sandra Crameri and Shai Arnon and Sharon Walker and Sima Yaron and Nguyen, {Thanh H.} and Yakir Berchenko and Yunxia Hu and Zeev Ronen and Edo Bar-Zeev",
note = "Publisher Copyright: {\textcopyright} 2020, Springer Nature Limited.",
year = "2020",
month = dec,
doi = "10.1038/s41893-020-00605-2",
language = "אנגלית",
volume = "3",
pages = "981--990",
journal = "Nature Sustainability",
issn = "2398-9629",
publisher = "Nature Publishing Group",
number = "12",

}

On the role of operational dynamics in biogeochemical efficiency of a soil aquifer treatment system

Ben Moshe S, Weisbrod N, Barquero F, Sallwey J, Orgad O, Furman A. On the role of operational dynamics in biogeochemical efficiency of a soil aquifer treatment system. Hydrology and Earth System Sciences. 2020 Jan 28;24(1):417-426. https://doi.org/10.5194/hess-24-417-2020
 

Sustainable irrigation with treated wastewater (TWW) is a promising solution for water scarcity in arid and semi-arid regions. Soil aquifer treatment (SAT) provides a solution for both the need for tertiary treatment and seasonal storage of wastewater. Stresses over land use and the need to control the obtained water quality makes the optimization of SAT of great importance. This study looks into the influence of SAT systems' operational dynamics (i.e., flooding and drying periods) as well as some aspects of the inflow biochemical composition on their biogeochemical state and the ultimate outflow quality. A series of four long-column experiments was conducted, aiming to examine the effect of different flooding/drying period ratios on dissolved oxygen (DO) concentrations, oxidation-reduction potential (ORP) and outflow composition. Flooding periods were kept constant at 60&thinsp;min for all experiments while drying periods (DPs) were 2.5 and 4 times the duration of the flooding periods. Our results show that the longer DPs had a significant advantage over the shorter periods in terms of DO concentrations and ORP in the upper parts of the column as well as in the deeper parts, which indicates that larger volumes of the profile were able to maintain aerobic conditions. DO concentrations in the deeper parts of the column stabilized at <span classCombining double low line"inline-formula">ĝ1/43</span>-4&thinsp;mg&thinsp;L<span classCombining double low line"inline-formula">-1</span> for the longer DPs compared to <span classCombining double low line"inline-formula">ĝ1/41</span>-2&thinsp;mg&thinsp;L<span classCombining double low line"inline-formula">-1</span> for the shorter DPs. This advantage was also evident in outflow composition that showed significantly lower concentrations of <span classCombining double low line"inline-formula"><math xmlnsCombining double low line"http://www.w3.org/1998/Math/MathML" idCombining double low line"M5" displayCombining double low line"inline" overflowCombining double low line"scroll" dspmathCombining double low line"mathml"><mrow classCombining double low line"chem"><msubsup><mi mathvariantCombining double low line"normal">NH</mi><mn mathvariantCombining double low line"normal">4</mn><mo>+</mo></msubsup></mrow></math><span><svg:svg xmlns:svgCombining double low line"http://www.w3.org/2000/svg" widthCombining double low line"24pt" heightCombining double low line"15pt" classCombining double low line"svg-formula" dspmathCombining double low line"mathimg" md5hashCombining double low line"68d940fa21d9c6691de36bd82f3e56d8"><svg:image xmlns:xlinkCombining double low line"http://www.w3.org/1999/xlink" xlink:hrefCombining double low line"hess-24-417-2020-ie00001.svg" widthCombining double low line"24pt" heightCombining double low line"15pt" srcCombining double low line"hess-24-417-2020-ie00001.png"/></svg:svg></span></span>-N, dissolved organic carbon (DOC) and total Kjeldahl nitrogen (TKN) for the longer DPs (<span classCombining double low line"inline-formula">ĝ1/40.03</span>, <span classCombining double low line"inline-formula">ĝ1/41.65</span> and <span classCombining double low line"inline-formula">ĝ1/40.62</span>&thinsp;mg&thinsp;L<span classCombining double low line"inline-formula">-1</span> respectively) compared to the shorter DPs (<span classCombining double low line"inline-formula">ĝ1/40.5</span>, <span classCombining double low line"inline-formula">ĝ1/44.4</span> and <span classCombining double low line"inline-formula">ĝ1/43.8</span>&thinsp;mg&thinsp;L<span classCombining double low line"inline-formula">-1</span>, respectively). Comparing experimental ORP values in response to different DPs to field measurements obtained in one of the SAT ponds of the SHAFDAN, Israel, we found that despite the large-scale differences between the experimental 1-D system and the field 3-D conditions, ORP trends in response to changes in DP, qualitatively match. We conclude that longer DP not only ensure oxidizing conditions close to the surface, but also enlarge the active (oxidizing) region of the SAT. While those results still need to be verified at full scale, they suggest that SAT can be treated as a pseudo-reactor that to a great extent could be manipulated hydraulically to achieve the desired water quality while increasing the recharge volumes.

@article{38327a6488cb4ae4b25893d4131abf6f,
title = "On the role of operational dynamics in biogeochemical efficiency of a soil aquifer treatment system",
abstract = "Sustainable irrigation with treated wastewater (TWW) is a promising solution for water scarcity in arid and semi-arid regions. Soil aquifer treatment (SAT) provides a solution for both the need for tertiary treatment and seasonal storage of wastewater. Stresses over land use and the need to control the obtained water quality makes the optimization of SAT of great importance. This study looks into the influence of SAT systems' operational dynamics (i.e., flooding and drying periods) as well as some aspects of the inflow biochemical composition on their biogeochemical state and the ultimate outflow quality. A series of four long-column experiments was conducted, aiming to examine the effect of different flooding/drying period ratios on dissolved oxygen (DO) concentrations, oxidation-reduction potential (ORP) and outflow composition. Flooding periods were kept constant at 60&thinsp;min for all experiments while drying periods (DPs) were 2.5 and 4 times the duration of the flooding periods. Our results show that the longer DPs had a significant advantage over the shorter periods in terms of DO concentrations and ORP in the upper parts of the column as well as in the deeper parts, which indicates that larger volumes of the profile were able to maintain aerobic conditions. DO concentrations in the deeper parts of the column stabilized at ĝ1/43-4&thinsp;mg&thinsp;L-1 for the longer DPs compared to ĝ1/41-2&thinsp;mg&thinsp;L-1 for the shorter DPs. This advantage was also evident in outflow composition that showed significantly lower concentrations of NH4+-N, dissolved organic carbon (DOC) and total Kjeldahl nitrogen (TKN) for the longer DPs (ĝ1/40.03, ĝ1/41.65 and ĝ1/40.62&thinsp;mg&thinsp;L-1 respectively) compared to the shorter DPs (ĝ1/40.5, ĝ1/44.4 and ĝ1/43.8&thinsp;mg&thinsp;L-1, respectively). Comparing experimental ORP values in response to different DPs to field measurements obtained in one of the SAT ponds of the SHAFDAN, Israel, we found that despite the large-scale differences between the experimental 1-D system and the field 3-D conditions, ORP trends in response to changes in DP, qualitatively match. We conclude that longer DP not only ensure oxidizing conditions close to the surface, but also enlarge the active (oxidizing) region of the SAT. While those results still need to be verified at full scale, they suggest that SAT can be treated as a pseudo-reactor that to a great extent could be manipulated hydraulically to achieve the desired water quality while increasing the recharge volumes.",
author = "{Ben Moshe}, Shany and Noam Weisbrod and Felix Barquero and Jana Sallwey and Ofri Orgad and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2020. This work is distributed under the Creative Commons Attribution 4.0 License.",
year = "2020",
month = jan,
day = "28",
doi = "10.5194/hess-24-417-2020",
language = "אנגלית",
volume = "24",
pages = "417--426",
journal = "Hydrology and Earth System Sciences",
issn = "1027-5606",
publisher = "European Geosciences Union",
number = "1",

}

2019

Impact of pore structure and morphology on flow and transport characteristics in randomly repacked grains with different angularities

Xiong Y, Long X, Huang G, Furman A. Impact of pore structure and morphology on flow and transport characteristics in randomly repacked grains with different angularities. Soils and Foundations. 2019 Dec;59(6):1992-2006. https://doi.org/10.1016/j.sandf.2019.10.002
 

The flow and transport behaviors in porous media are closely linked to the structure and morphology of the pore space. A fundamental objective of most studies of porous media is to link the pore structure to the hydraulic functions, such as the permeability, capillary pressure and diffusivity, which are necessary for engineering applications. In this paper, an attempt is made to build a direct link between the hydraulic functions and the morphological measures of diverse porous media. Porous columns with different structures and morphologies are generated by randomly packing grains with different shapes and sizes. The pore structure of the repacked porous media is visualized through X-ray computed tomography and quantified by a series of parameters, including the set of Minkowski functionals, diverse characteristic pore sizes, geometric tortuosity and fractal dimension. The intrinsic permeability, molecular diffusivity and apparent thermal conductivity of the repacked porous media are simulated numerically. The Minkowski functionals have the capacity to characterize the microscale complex pore domain of the porous media in a macroscale way. A good linear relationship is shown among the effective pore size, nominal opening dimension and critical pore neck size obtained from the morphological analysis regardless of the shapes and sizes of the grains. The three different pores may serve as the characteristic pore correlation to the intrinsic permeability. The Kozeny-Carman equation can be used to mimic the intrinsic permeability and to serve as a quality-control tool for porous media with different grain angularities. A topologically based model can generally provide a single relationship for porous media randomly repacked with grains of different angularities. The molecular diffusivity of angular grains is found to be larger than that of round ones. The molecular diffusivity is linearly related to the porosity and fractal dimension. Porous media repacked with round grains tend to attain denser packing, a higher number of contacts per unit volume and higher thermal conductivity than media packed with angular particles. The apparent thermal conductivity has a negative linear correlation to the porosity and fractal dimension of porous media with different grain morphologies.

@article{240a6c9ef6f041e6a046f70ff412aec6,
title = "Impact of pore structure and morphology on flow and transport characteristics in randomly repacked grains with different angularities",
abstract = "The flow and transport behaviors in porous media are closely linked to the structure and morphology of the pore space. A fundamental objective of most studies of porous media is to link the pore structure to the hydraulic functions, such as the permeability, capillary pressure and diffusivity, which are necessary for engineering applications. In this paper, an attempt is made to build a direct link between the hydraulic functions and the morphological measures of diverse porous media. Porous columns with different structures and morphologies are generated by randomly packing grains with different shapes and sizes. The pore structure of the repacked porous media is visualized through X-ray computed tomography and quantified by a series of parameters, including the set of Minkowski functionals, diverse characteristic pore sizes, geometric tortuosity and fractal dimension. The intrinsic permeability, molecular diffusivity and apparent thermal conductivity of the repacked porous media are simulated numerically. The Minkowski functionals have the capacity to characterize the microscale complex pore domain of the porous media in a macroscale way. A good linear relationship is shown among the effective pore size, nominal opening dimension and critical pore neck size obtained from the morphological analysis regardless of the shapes and sizes of the grains. The three different pores may serve as the characteristic pore correlation to the intrinsic permeability. The Kozeny-Carman equation can be used to mimic the intrinsic permeability and to serve as a quality-control tool for porous media with different grain angularities. A topologically based model can generally provide a single relationship for porous media randomly repacked with grains of different angularities. The molecular diffusivity of angular grains is found to be larger than that of round ones. The molecular diffusivity is linearly related to the porosity and fractal dimension. Porous media repacked with round grains tend to attain denser packing, a higher number of contacts per unit volume and higher thermal conductivity than media packed with angular particles. The apparent thermal conductivity has a negative linear correlation to the porosity and fractal dimension of porous media with different grain morphologies.",
keywords = "Geometric tortuosity, Grain shape, Intrinsic permeability, Minkowski measure, Molecular diffusivity",
author = "Yunwu Xiong and Xiaoxu Long and Guanhua Huang and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2019",
year = "2019",
month = dec,
doi = "10.1016/j.sandf.2019.10.002",
language = "אנגלית",
volume = "59",
pages = "1992--2006",
journal = "Soils and Foundations",
issn = "0038-0806",
publisher = "Japanese Geotechnical Society",
number = "6",

}

Bacterial Stern layer diffusion: experimental determination with spectral induced polarization and sensitivity to nitrite toxicity

Mellage A, Smeaton CM, Furman A, Atekwana EA, Rezanezhad F, Van Cappellen P. Bacterial Stern layer diffusion: experimental determination with spectral induced polarization and sensitivity to nitrite toxicity. Near Surface Geophysics. 2019 Dec 1;17(6):623-635. https://doi.org/10.1002/nsg.12058
 

Spectral induced polarization signatures have been used as proxies for microbial abundance in subsurface environments, by taking advantage of the charged properties of microbial cell membranes. The method's applicability, however, remains qualitative, and signal interpretation ambiguous. The adoption of spectral induced polarization as a robust geo-microbiological tool for monitoring microbial dynamics in porous media requires the development of quantitative relationships between biogeochemical targets and spectral induced polarization parameters, such as biomass density and imaginary conductivity (σ″). Furthermore, deriving cell density information from electrical signals in porous media necessitates a detailed understanding of the nature of the cell membrane surface charge dynamics. We present results from a fully saturated sand-filled column reactor experiment where Shewanella oneidensis growth during nitrate reduction to ammonium was monitored using spectral induced polarization. While our results further confirm the direct dependence of σ″ on changing cell density, Cole–Cole derived relaxation times also record the changing surface charging properties of the cells, ascribed to toxic stress due to nitrite accumulation. Concurrent estimates of cell size yield the first measurement-derived estimation of the apparent surface ion diffusion coefficient for cells (Ds = 5.4 ±1.3 µm2 s−1), strengthening the link between spectral induced polarization and electrochemical cell polarization. Our analysis provides a theoretical framework on which to build σ″–cell density relations using bench-scale experiments, leading to eventual robust non-destructive monitoring of in situ microbial growth dynamics.

@article{f8e70a0a52274a258e3b25f44afc2496,
title = "Bacterial Stern layer diffusion: experimental determination with spectral induced polarization and sensitivity to nitrite toxicity",
abstract = "Spectral induced polarization signatures have been used as proxies for microbial abundance in subsurface environments, by taking advantage of the charged properties of microbial cell membranes. The method's applicability, however, remains qualitative, and signal interpretation ambiguous. The adoption of spectral induced polarization as a robust geo-microbiological tool for monitoring microbial dynamics in porous media requires the development of quantitative relationships between biogeochemical targets and spectral induced polarization parameters, such as biomass density and imaginary conductivity (σ″). Furthermore, deriving cell density information from electrical signals in porous media necessitates a detailed understanding of the nature of the cell membrane surface charge dynamics. We present results from a fully saturated sand-filled column reactor experiment where Shewanella oneidensis growth during nitrate reduction to ammonium was monitored using spectral induced polarization. While our results further confirm the direct dependence of σ″ on changing cell density, Cole–Cole derived relaxation times also record the changing surface charging properties of the cells, ascribed to toxic stress due to nitrite accumulation. Concurrent estimates of cell size yield the first measurement-derived estimation of the apparent surface ion diffusion coefficient for cells (Ds = 5.4 ±1.3 µm2 s−1), strengthening the link between spectral induced polarization and electrochemical cell polarization. Our analysis provides a theoretical framework on which to build σ″–cell density relations using bench-scale experiments, leading to eventual robust non-destructive monitoring of in situ microbial growth dynamics.",
keywords = "Environmental, Induced Polarization, Shallow Subsurface",
author = "Adrian Mellage and Smeaton, {Christina M.} and Alex Furman and Atekwana, {Estella A.} and Fereidoun Rezanezhad and {Van Cappellen}, Philippe",
note = "Publisher Copyright: {\textcopyright} 2019 The Authors. Near Surface Geophysics published by John Wiley & Sons Ltd on behalf of European Association of Geoscientists & Engineers.",
year = "2019",
month = dec,
day = "1",
doi = "10.1002/nsg.12058",
language = "אנגלית",
volume = "17",
pages = "623--635",
journal = "Near Surface Geophysics",
issn = "1569-4445",
publisher = "EAGE Publishing BV",
number = "6",

}

Induced polarization applied to biogeophysics: recent advances and future prospects

Kessouri P, Furman A, Huisman JA, Martin T, Mellage A, Ntarlagiannis D et al. Induced polarization applied to biogeophysics: recent advances and future prospects. Near Surface Geophysics. 2019 Dec 1;17(6):595-621. https://doi.org/10.1002/nsg.12072
 

This paper provides an update on the fast-evolving field of the induced polarization method applied to biogeophysics. It emphasizes recent advances in the understanding of the induced polarization signals stemming from biological materials and their activity, points out new developments and applications, and identifies existing knowledge gaps. The focus of this review is on the application of induced polarization to study living organisms: soil microorganisms and plants (both roots and stems). We first discuss observed links between the induced polarization signal and microbial cell structure, activity and biofilm formation. We provide an up-to-date conceptual model of the electrical behaviour of the microbial cells and biofilms under the influence of an external electrical field. We also review the latest biogeophysical studies, including work on hydrocarbon biodegradation, contaminant sequestration, soil strengthening and peatland characterization. We then elaborate on the induced polarization signature of the plant-root zone, relying on a conceptual model for the generation of biogeophysical signals from a plant-root cell. First laboratory experiments show that single roots and root system are highly polarizable. They also present encouraging results for imaging root systems embedded in a medium, and gaining information on the mass density distribution, the structure or the physiological characteristics of root systems. In addition, we highlight the application of induced polarization to characterize wood and tree structures through tomography of the stem. Finally, we discuss up- and down-scaling between laboratory and field studies, as well as joint interpretation of induced polarization and other environmental data. We emphasize the need for intermediate-scale studies and the benefits of using induced polarization as a time-lapse monitoring method. We conclude with the promising integration of induced polarization in interdisciplinary mechanistic models to better understand and quantify subsurface biogeochemical processes.

@article{4e87fb86f46f4cb3b02042f0ed6d751d,
title = "Induced polarization applied to biogeophysics: recent advances and future prospects",
abstract = "This paper provides an update on the fast-evolving field of the induced polarization method applied to biogeophysics. It emphasizes recent advances in the understanding of the induced polarization signals stemming from biological materials and their activity, points out new developments and applications, and identifies existing knowledge gaps. The focus of this review is on the application of induced polarization to study living organisms: soil microorganisms and plants (both roots and stems). We first discuss observed links between the induced polarization signal and microbial cell structure, activity and biofilm formation. We provide an up-to-date conceptual model of the electrical behaviour of the microbial cells and biofilms under the influence of an external electrical field. We also review the latest biogeophysical studies, including work on hydrocarbon biodegradation, contaminant sequestration, soil strengthening and peatland characterization. We then elaborate on the induced polarization signature of the plant-root zone, relying on a conceptual model for the generation of biogeophysical signals from a plant-root cell. First laboratory experiments show that single roots and root system are highly polarizable. They also present encouraging results for imaging root systems embedded in a medium, and gaining information on the mass density distribution, the structure or the physiological characteristics of root systems. In addition, we highlight the application of induced polarization to characterize wood and tree structures through tomography of the stem. Finally, we discuss up- and down-scaling between laboratory and field studies, as well as joint interpretation of induced polarization and other environmental data. We emphasize the need for intermediate-scale studies and the benefits of using induced polarization as a time-lapse monitoring method. We conclude with the promising integration of induced polarization in interdisciplinary mechanistic models to better understand and quantify subsurface biogeochemical processes.",
keywords = "Complex conductivity, Hydrogeophysics, IP, Induced polarization, Pollution",
author = "P. Kessouri and A. Furman and Huisman, {J. A.} and T. Martin and A. Mellage and D. Ntarlagiannis and M. B{\"u}cker and S. Ehosioke and P. Fernandez and A. Flores-Orozco and A. Kemna and F. Nguyen and T. Pilawski and S. Saneiyan and M. Schmutz and N. Schwartz and M. Weigand and Y. Wu and C. Zhang and E. Placencia-Gomez",
note = "Publisher Copyright: {\textcopyright} 2019 European Association of Geoscientists & Engineers",
year = "2019",
month = dec,
day = "1",
doi = "10.1002/nsg.12072",
language = "אנגלית",
volume = "17",
pages = "595--621",
journal = "Near Surface Geophysics",
issn = "1569-4445",
publisher = "EAGE Publishing BV",
number = "6",

}

Soil Properties and Plant Growth Response to Litter in a Prolonged Enclosed Grassland of Loess Plateau, China

Xiong Y, Yu B, Bai M, Zhang X, Huang G, Furman A. Soil Properties and Plant Growth Response to Litter in a Prolonged Enclosed Grassland of Loess Plateau, China. Journal of Earth Science. 2019 Oct 1;30(5):1041-1048. https://doi.org/10.1007/s12583-019-1017-3
 

The enclosure and ungrazing practices for grassland management result in accumulation of plant litter on soil surface thus affecting the available soil water and nutrients for plant production. We experimentally investigated the effects of litter on soil properties and plant growth in a prolonged enclosure grassland of Loess Plateau, China. Three different litter manipulations were conducted including removal of all litter, an untreated in-situ control with original litter levels, and a double litter treatment. Litter treatment experiments demonstrated that plant litter affected the superficial soil water. Soil water content in plots with in-situ or double litter is generally higher than that with litter removal. The depletion of soil water up to five days post rainfall is fastest in litter removal plots for the top soil, but no evident difference for the deep ones. Different litter treatments have no significant impact on soil total carbon, nitrogen as well as carbon/nitrogen ratio for consecutive two years experiments. Both above- and below-ground biomasses in plots of litter removal were less than those in the plots of in-situ and double litter treatment. Litter affects plant production mainly through the mechanical barrier regulating root zone soil moisture. Therefore, prolonged litter manipulation experiments are desirable to understand the long-term response of plant growth on litter from nutrient aspect.

@article{1eb70011b0fd452c837a040bbe13c57c,
title = "Soil Properties and Plant Growth Response to Litter in a Prolonged Enclosed Grassland of Loess Plateau, China",
abstract = "The enclosure and ungrazing practices for grassland management result in accumulation of plant litter on soil surface thus affecting the available soil water and nutrients for plant production. We experimentally investigated the effects of litter on soil properties and plant growth in a prolonged enclosure grassland of Loess Plateau, China. Three different litter manipulations were conducted including removal of all litter, an untreated in-situ control with original litter levels, and a double litter treatment. Litter treatment experiments demonstrated that plant litter affected the superficial soil water. Soil water content in plots with in-situ or double litter is generally higher than that with litter removal. The depletion of soil water up to five days post rainfall is fastest in litter removal plots for the top soil, but no evident difference for the deep ones. Different litter treatments have no significant impact on soil total carbon, nitrogen as well as carbon/nitrogen ratio for consecutive two years experiments. Both above- and below-ground biomasses in plots of litter removal were less than those in the plots of in-situ and double litter treatment. Litter affects plant production mainly through the mechanical barrier regulating root zone soil moisture. Therefore, prolonged litter manipulation experiments are desirable to understand the long-term response of plant growth on litter from nutrient aspect.",
keywords = "Stripa bungeana, litter manipulation, soil moisture, ungrazed grassland",
author = "Yunwu Xiong and Bing Yu and Mengting Bai and Xueyang Zhang and Guanhua Huang and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2019, China University of Geosciences (Wuhan) and Springer Verlag GmbH Germany, Part of Springer Nature.",
year = "2019",
month = oct,
day = "1",
doi = "10.1007/s12583-019-1017-3",
language = "אנגלית",
volume = "30",
pages = "1041--1048",
journal = "Journal of Earth Science",
issn = "1674-487X",
publisher = "China University of Geosciences",
number = "5",

}

2018

Sampling at high spatial and temporal resolutions with an experimental chamber

Ouaknin H, Weisbrod N, Furman A. Sampling at high spatial and temporal resolutions with an experimental chamber. European Journal of Soil Science. 2018 Jul;69(4):742-745. https://doi.org/10.1111/ejss.12686
 

Summary: Laboratory-scale studies of the dynamics of soil biogeochemical processes often require destructive sampling for chemical, biological and genetic analyses. The consequences are either ‘end-of-experiment’ sampling or a set-up with multiple experiments in parallel, of which some are sacrificed over time. We propose an alternative experimental set-up to enable matrix sampling and monitoring at high spatiotemporal resolution of chemical, biological and physical properties. A customized experimental chamber was constructed, including an array of sensors on one side and hundreds of sampling ports on the other. A vertical unidirectional flow regime was maintained in the chamber, and soil samples were collected through ports that were not adjacent laterally to ones used in an earlier sampling campaign. We give an example of an experiment with such a chamber in which the environmental conditions (matric head and redox) were kept almost uniform in the horizontal dimension. Under these conditions nitrogen cycling was also almost the same in the lateral dimension. This system offers a unique combination of high spatial and temporal resolution sensors in the same system that is destructively sampled. Highlights: A new experimental chamber allows high-resolution sampling In unidirectional flow, sacrificial sampling can be avoided.

@article{d9d3773eb9ed48dc9b07da296fd746a8,
title = "Sampling at high spatial and temporal resolutions with an experimental chamber",
abstract = "Summary: Laboratory-scale studies of the dynamics of soil biogeochemical processes often require destructive sampling for chemical, biological and genetic analyses. The consequences are either {\textquoteleft}end-of-experiment{\textquoteright} sampling or a set-up with multiple experiments in parallel, of which some are sacrificed over time. We propose an alternative experimental set-up to enable matrix sampling and monitoring at high spatiotemporal resolution of chemical, biological and physical properties. A customized experimental chamber was constructed, including an array of sensors on one side and hundreds of sampling ports on the other. A vertical unidirectional flow regime was maintained in the chamber, and soil samples were collected through ports that were not adjacent laterally to ones used in an earlier sampling campaign. We give an example of an experiment with such a chamber in which the environmental conditions (matric head and redox) were kept almost uniform in the horizontal dimension. Under these conditions nitrogen cycling was also almost the same in the lateral dimension. This system offers a unique combination of high spatial and temporal resolution sensors in the same system that is destructively sampled. Highlights: A new experimental chamber allows high-resolution sampling In unidirectional flow, sacrificial sampling can be avoided.",
author = "H. Ouaknin and N. Weisbrod and A. Furman",
note = "Publisher Copyright: {\textcopyright} 2018 British Society of Soil Science",
year = "2018",
month = jul,
doi = "10.1111/ejss.12686",
language = "אנגלית",
volume = "69",
pages = "742--745",
journal = "European Journal of Soil Science",
issn = "1351-0754",
publisher = "Wiley-Blackwell Publishing Ltd",
number = "4",

}

Effect of near-surface wind speed and gustiness on horizontal and vertical porous medium gas transport and gas exchange with the atmosphere

Poulsen TG, Furman A, Liberzon D. Effect of near-surface wind speed and gustiness on horizontal and vertical porous medium gas transport and gas exchange with the atmosphere. European Journal of Soil Science. 2018 Mar;69(2):279-289. https://doi.org/10.1111/ejss.12531
 

Effects of wind speed and wind gustiness on horizontal and vertical subsurface gas transport and subsurface–atmosphere gas exchange were investigated experimentally using a 40 cm × 40 cm, 35-cm-deep stainless steel container, filled with a dry granular porous medium (crushed basalt) of 2–4-mm grain size. Experiments used CO2 and O2 as tracer gases and were conducted under both steady and gusty wind at speeds ranging from 0 to 5.6 m s−1. Tracer gas breakthrough curves were measured at 20 locations within the porous medium to assess both horizontal and vertical gas movement. Results indicated that horizontal gas movement in wind-exposed porous materials is important, especially near the wind-exposed surface, and suggested considerable effects of both wind speed and wind gustiness on both horizontal and vertical gas transport inside the porous medium as well as subsurface–atmospheric gas exchange. Although wind-induced subsurface gas transport is likely to be multidimensional, one-dimensional model simulations indicated that vertical transport is an adequate approximation of the resulting average gas transport and exchange with the atmosphere over a larger area. Highlights: Experimental assessment of near-surface gas movement in wind-exposed porous medium Near-surface gas movement in wind-exposed porous media occurs both horizontally and vertically. Wind speed and wind gustiness affect gas movement near the soil–atmosphere interface. Wind-induced bulk subsurface-to-atmosphere gas mass transport may be approximated as vertical.

@article{b965e8d476394e0987501c22e4ff5424,
title = "Effect of near-surface wind speed and gustiness on horizontal and vertical porous medium gas transport and gas exchange with the atmosphere",
abstract = "Effects of wind speed and wind gustiness on horizontal and vertical subsurface gas transport and subsurface–atmosphere gas exchange were investigated experimentally using a 40 cm × 40 cm, 35-cm-deep stainless steel container, filled with a dry granular porous medium (crushed basalt) of 2–4-mm grain size. Experiments used CO2 and O2 as tracer gases and were conducted under both steady and gusty wind at speeds ranging from 0 to 5.6 m s−1. Tracer gas breakthrough curves were measured at 20 locations within the porous medium to assess both horizontal and vertical gas movement. Results indicated that horizontal gas movement in wind-exposed porous materials is important, especially near the wind-exposed surface, and suggested considerable effects of both wind speed and wind gustiness on both horizontal and vertical gas transport inside the porous medium as well as subsurface–atmospheric gas exchange. Although wind-induced subsurface gas transport is likely to be multidimensional, one-dimensional model simulations indicated that vertical transport is an adequate approximation of the resulting average gas transport and exchange with the atmosphere over a larger area. Highlights: Experimental assessment of near-surface gas movement in wind-exposed porous medium Near-surface gas movement in wind-exposed porous media occurs both horizontally and vertically. Wind speed and wind gustiness affect gas movement near the soil–atmosphere interface. Wind-induced bulk subsurface-to-atmosphere gas mass transport may be approximated as vertical.",
author = "Poulsen, {T. G.} and A. Furman and D. Liberzon",
note = "Publisher Copyright: {\textcopyright} 2018 British Society of Soil Science",
year = "2018",
month = mar,
doi = "10.1111/ejss.12531",
language = "אנגלית",
volume = "69",
pages = "279--289",
journal = "European Journal of Soil Science",
issn = "1351-0754",
publisher = "Wiley-Blackwell Publishing Ltd",
number = "2",

}

Linking Spectral Induced Polarization (SIP) and Subsurface Microbial Processes: Results from Sand Column Incubation Experiments

Mellage A, Smeaton CM, Furman A, Atekwana EA, Rezanezhad F, Van Cappellen P. Linking Spectral Induced Polarization (SIP) and Subsurface Microbial Processes: Results from Sand Column Incubation Experiments. Environmental Science and Technology. 2018 Feb 20;52(4):2081-2090. https://doi.org/10.1021/acs.est.7b04420
 

Geophysical techniques, such as spectral induced polarization (SIP), offer potentially powerful approaches for in situ monitoring of subsurface biogeochemistry. The successful implementation of these techniques as monitoring tools for reactive transport phenomena, however, requires the deconvolution of multiple contributions to measured signals. Here, we present SIP spectra and complementary biogeochemical data obtained in saturated columns packed with alternating layers of ferrihydrite-coated and pure quartz sand, and inoculated with Shewanella oneidensis supplemented with lactate and nitrate. A biomass-explicit diffusion-reaction model is fitted to the experimental biogeochemical data. Overall, the results highlight that (1) the temporal response of the measured imaginary conductivity peaks parallels the microbial growth and decay dynamics in the columns, and (2) SIP is sensitive to changes in microbial abundance and cell surface charging properties, even at relatively low cell densities (<108 cells mL-1). Relaxation times (τ) derived using the Cole-Cole model vary with the dominant electron accepting process, nitrate or ferric iron reduction. The observed range of τ values, 0.012-0.107 s, yields effective polarization diameters in the range 1-3 μm, that is, 2 orders of magnitude smaller than the smallest quartz grains in the columns, suggesting that polarization of the bacterial cells controls the observed chargeability and relaxation dynamics in the experiments.

@article{9b3402ee9b0d4213bbf1cf349a5482f6,
title = "Linking Spectral Induced Polarization (SIP) and Subsurface Microbial Processes: Results from Sand Column Incubation Experiments",
abstract = "Geophysical techniques, such as spectral induced polarization (SIP), offer potentially powerful approaches for in situ monitoring of subsurface biogeochemistry. The successful implementation of these techniques as monitoring tools for reactive transport phenomena, however, requires the deconvolution of multiple contributions to measured signals. Here, we present SIP spectra and complementary biogeochemical data obtained in saturated columns packed with alternating layers of ferrihydrite-coated and pure quartz sand, and inoculated with Shewanella oneidensis supplemented with lactate and nitrate. A biomass-explicit diffusion-reaction model is fitted to the experimental biogeochemical data. Overall, the results highlight that (1) the temporal response of the measured imaginary conductivity peaks parallels the microbial growth and decay dynamics in the columns, and (2) SIP is sensitive to changes in microbial abundance and cell surface charging properties, even at relatively low cell densities (<108 cells mL-1). Relaxation times (τ) derived using the Cole-Cole model vary with the dominant electron accepting process, nitrate or ferric iron reduction. The observed range of τ values, 0.012-0.107 s, yields effective polarization diameters in the range 1-3 μm, that is, 2 orders of magnitude smaller than the smallest quartz grains in the columns, suggesting that polarization of the bacterial cells controls the observed chargeability and relaxation dynamics in the experiments.",
author = "Adrian Mellage and Smeaton, {Christina M.} and Alex Furman and Atekwana, {Estella A.} and Fereidoun Rezanezhad and {Van Cappellen}, Philippe",
note = "Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",
year = "2018",
month = feb,
day = "20",
doi = "10.1021/acs.est.7b04420",
language = "אנגלית",
volume = "52",
pages = "2081--2090",
journal = "Environmental Science and Technology",
issn = "0013-936X",
publisher = "American Chemical Society",
number = "4",

}

2017

Quantitative assessment of the heterogeneity and reproducibility of repacked silica sand columns

Xiong Y, Dai J, Zhang X, Huang G, Furman A. Quantitative assessment of the heterogeneity and reproducibility of repacked silica sand columns. Vadose Zone Journal. 2017 Dec;16(13):1-10. https://doi.org/10.2136/vzj2017.06.0120
 

Column experiments are widely used for mechanism and application studies in different fields. A major challenge and an advantage of the repacked porous column are its uniformity and reproducibility. Bulk density is a commonly used parameter to evaluate the uniformity and consistency of random packing. The internal structure of pore space is usually ignored and lumped into the bulk density. However, flow and transport characteristics of the repacked porous media are not fully defined from the bulk density but also depend on the internal structure. In this paper, we quantitatively assessed the heterogeneity and reproducibility of repacked sand columns using integral geometry methodology. X-ray computed tomography is applied to visualize the pore space of the column repacked with different silica sands. The acquired tomography images are processed and quantitatively analyzed using Minkowski measures. The Minkowski functionals combined with the granulometric density function were applied to describe the spatial heterogeneity of microstructures. The results have demonstrated that the Minkowski functionals proportional to the well-known geometric quantities are able to characterize the average geometrical properties of complex pore space. The pore size distributions of sand column are obtained through morphological opening operation. The two-parameter Weibull distribution has been found reasonably describe the granulometric density acquired from the morphology analysis. The Minkowski densities joint with the critical pore diameter as well as parameters of Weibull function at different locations of each column have demonstrated the heterogeneity of the sand column. The small variation in the finer sand column indicates the heterogeneity is relatively smaller than that of the coarser ones. The relatively small differences among the repetitions of finer sand columns suggest more reliable reproducibility in comparison to the coarser sand columns.

@article{f6508661e4604d1ba868323ffe579994,
title = "Quantitative assessment of the heterogeneity and reproducibility of repacked silica sand columns",
abstract = "Column experiments are widely used for mechanism and application studies in different fields. A major challenge and an advantage of the repacked porous column are its uniformity and reproducibility. Bulk density is a commonly used parameter to evaluate the uniformity and consistency of random packing. The internal structure of pore space is usually ignored and lumped into the bulk density. However, flow and transport characteristics of the repacked porous media are not fully defined from the bulk density but also depend on the internal structure. In this paper, we quantitatively assessed the heterogeneity and reproducibility of repacked sand columns using integral geometry methodology. X-ray computed tomography is applied to visualize the pore space of the column repacked with different silica sands. The acquired tomography images are processed and quantitatively analyzed using Minkowski measures. The Minkowski functionals combined with the granulometric density function were applied to describe the spatial heterogeneity of microstructures. The results have demonstrated that the Minkowski functionals proportional to the well-known geometric quantities are able to characterize the average geometrical properties of complex pore space. The pore size distributions of sand column are obtained through morphological opening operation. The two-parameter Weibull distribution has been found reasonably describe the granulometric density acquired from the morphology analysis. The Minkowski densities joint with the critical pore diameter as well as parameters of Weibull function at different locations of each column have demonstrated the heterogeneity of the sand column. The small variation in the finer sand column indicates the heterogeneity is relatively smaller than that of the coarser ones. The relatively small differences among the repetitions of finer sand columns suggest more reliable reproducibility in comparison to the coarser sand columns.",
author = "Yunwu Xiong and Jiayu Dai and Xueyang Zhang and Guanhua Huang and Alex Furman",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2017",
month = dec,
doi = "10.2136/vzj2017.06.0120",
language = "אנגלית",
volume = "16",
pages = "1--10",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "13",

}

High-resolution measurement of topographic changes in agricultural soils

Oz I, Arav R, Filin S, Assouline S, Furman A. High-resolution measurement of topographic changes in agricultural soils. Vadose Zone Journal. 2017 Dec;16(12). https://doi.org/10.2136/vzj2017.07.0138
 

Terrestrial lidar technology provides accurate surface data at high spatial resolution. This study examined the ability of lidar scanners to evaluate soil erosion and deposition at high spatial and temporal resolutions. Lidar scans were conducted in six field plots with three different tillage systems during two rain seasons, focusing on four major rainfall events. Results show that the lidar scanner identifies changes in the surface elevation in the case of rill erosion within the furrows. In these cases, the high-quality quantitative data can assist practical decision-making and can contribute to the calibration of physically based erosion models. In other cases, however, the results show that the ability of the lidar scanners to detect erosion and deposition processes is limited. The reasons for this limitation are the minor effect of sheet erosion on flat surfaces and soil swelling and shrinking occurring during and after rainfall events. Swelling–shrinking and soil compaction processes need to be taken into account during lidar scanning, as their magnitude is comparable to that of soil loss by erosion. On the other hand, the ability to measure these processes allows investigation of the dynamics of surface processes during wetting and drying sequences. The results showed also that the effect of the rainfall pattern was stronger when the rainfall intensity and the initial soil moisture were higher, and that rill erosion is more important when the furrows are parallel to the slope direction, while deposition is accentuated when the furrows are perpendicular to the slope.

@article{d9e5f63918664f9a8fd90d05caf74e9f,
title = "High-resolution measurement of topographic changes in agricultural soils",
abstract = "Terrestrial lidar technology provides accurate surface data at high spatial resolution. This study examined the ability of lidar scanners to evaluate soil erosion and deposition at high spatial and temporal resolutions. Lidar scans were conducted in six field plots with three different tillage systems during two rain seasons, focusing on four major rainfall events. Results show that the lidar scanner identifies changes in the surface elevation in the case of rill erosion within the furrows. In these cases, the high-quality quantitative data can assist practical decision-making and can contribute to the calibration of physically based erosion models. In other cases, however, the results show that the ability of the lidar scanners to detect erosion and deposition processes is limited. The reasons for this limitation are the minor effect of sheet erosion on flat surfaces and soil swelling and shrinking occurring during and after rainfall events. Swelling–shrinking and soil compaction processes need to be taken into account during lidar scanning, as their magnitude is comparable to that of soil loss by erosion. On the other hand, the ability to measure these processes allows investigation of the dynamics of surface processes during wetting and drying sequences. The results showed also that the effect of the rainfall pattern was stronger when the rainfall intensity and the initial soil moisture were higher, and that rill erosion is more important when the furrows are parallel to the slope direction, while deposition is accentuated when the furrows are perpendicular to the slope.",
author = "I. Oz and R. Arav and S. Filin and S. Assouline and A. Furman",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2017",
month = dec,
doi = "10.2136/vzj2017.07.0138",
language = "אנגלית",
volume = "16",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "12",

}

Effects of wind speed and wind gustiness on subsurface gas transport

Poulsen TG, Furman A, Liberzon D. Effects of wind speed and wind gustiness on subsurface gas transport. Vadose Zone Journal. 2017 Nov;16(11). https://doi.org/10.2136/vzj2017.04.0079
 

The impact of near-surface wind speed and wind speed fluctuations (gustiness) on subsurface gas transport and exchange with the atmosphere was investigated with a focus on assessing the extent of vertical and horizontal gas transport in the subsurface. Investigations involved the use of a 40- by 40-cm, 35-cm-deep stainless steel container filled with a dry granular porous medium (2–4-mm grain size), applying CO2 and O2 as tracer gases. Experiments were performed under controlled (laboratory) conditions for different wind speeds (0–5.6 m s−1) under both gusty and non-gusty wind conditions. Horizontal gas movement in the porous medium both parallel and perpendicular to the wind direction was controlled via a set of separation walls that could be installed inside the porous medium to assess the importance of horizontal gas velocities in the porous medium. Results indicate that average wind speed was the most important parameter controlling porous medium gas transport, especially near the surface. However, at greater depths, wind gustiness and horizontal gas movement also had significant impacts on the overall gas transport.

@article{0327edc428c24712b26a37e94975c152,
title = "Effects of wind speed and wind gustiness on subsurface gas transport",
abstract = "The impact of near-surface wind speed and wind speed fluctuations (gustiness) on subsurface gas transport and exchange with the atmosphere was investigated with a focus on assessing the extent of vertical and horizontal gas transport in the subsurface. Investigations involved the use of a 40- by 40-cm, 35-cm-deep stainless steel container filled with a dry granular porous medium (2–4-mm grain size), applying CO2 and O2 as tracer gases. Experiments were performed under controlled (laboratory) conditions for different wind speeds (0–5.6 m s−1) under both gusty and non-gusty wind conditions. Horizontal gas movement in the porous medium both parallel and perpendicular to the wind direction was controlled via a set of separation walls that could be installed inside the porous medium to assess the importance of horizontal gas velocities in the porous medium. Results indicate that average wind speed was the most important parameter controlling porous medium gas transport, especially near the surface. However, at greater depths, wind gustiness and horizontal gas movement also had significant impacts on the overall gas transport.",
author = "Poulsen, {Tjalfe G.} and Alex Furman and Dan Liberzon",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2017",
month = nov,
doi = "10.2136/vzj2017.04.0079",
language = "אנגלית",
volume = "16",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "11",

}

Relating wind-induced gas exchange to near-surface wind speed characteristics in porous media

Poulsen TG, Pourber A, Furman A, Papadikis K. Relating wind-induced gas exchange to near-surface wind speed characteristics in porous media. Vadose Zone Journal. 2017;16(8). https://doi.org/10.2136/vzj2017.02.0039
 

The impact of near-surface wind speed characteristics on dry porous media gas transport and gas exchange across the medium surface were investigated experimentally using four different porous media subjected to 11 wind conditions with different wind speed characteristics. The tracer gases were O2 and CO2, applied with constant concentrations at the medium surface. Tracer gas breakthrough curves (gas concentrations as a function of time) were measured at multiple depths inside the porous media. Tracer gas breakthrough time (the time required for the gas concentration at a given depth to reach 50% of the surface concentration) was used as a measure of the gas exchange rate. Potential relationships between breakthrough time and wind speed characteristics in terms of average wind speed, wind speed standard deviation, and wind speed power spectrum properties in three dimensions were investigated. Statistical analyses indicated that wind speed had a very significant impact on breakthrough time and that the characteristics for the wind speed component perpendicular to the porous medium surface were especially important.

@article{d608c071b5434d3ab065df32daf07c1f,
title = "Relating wind-induced gas exchange to near-surface wind speed characteristics in porous media",
abstract = "The impact of near-surface wind speed characteristics on dry porous media gas transport and gas exchange across the medium surface were investigated experimentally using four different porous media subjected to 11 wind conditions with different wind speed characteristics. The tracer gases were O2 and CO2, applied with constant concentrations at the medium surface. Tracer gas breakthrough curves (gas concentrations as a function of time) were measured at multiple depths inside the porous media. Tracer gas breakthrough time (the time required for the gas concentration at a given depth to reach 50% of the surface concentration) was used as a measure of the gas exchange rate. Potential relationships between breakthrough time and wind speed characteristics in terms of average wind speed, wind speed standard deviation, and wind speed power spectrum properties in three dimensions were investigated. Statistical analyses indicated that wind speed had a very significant impact on breakthrough time and that the characteristics for the wind speed component perpendicular to the porous medium surface were especially important.",
author = "Poulsen, {Tjalfe G.} and Alfie Pourber and Alex Furman and Konstantinos Papadikis",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2017",
doi = "10.2136/vzj2017.02.0039",
language = "אנגלית",
volume = "16",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "8",

}

2016

Time-lapse electrical imaging of water infiltration in the context of soil aquifer treatment

Haaken K, Furman A, Weisbrod N, Kemna A. Time-lapse electrical imaging of water infiltration in the context of soil aquifer treatment. Vadose Zone Journal. 2016 Nov;15(11):1-12. https://doi.org/10.2136/vzj2016.04.0028
 

In this study, we investigated the ability of online geoelectrical monitoring to characterize water dynamics in the context of soil aquifer treatment (SAT). In spring 2014, we conducted several infiltration experiments at the Shafdan SAT facility in Israel, where treated wastewater is recurrently infiltrated through large ponds into the sandy coastal plain aquifer. Temporally dense electrical resistivity tomography (ERT) measurements were collected to investigate vadose zone flow processes and the influence of heterogeneous sedimentation on the infiltration pattern. Measurements of water content as well as cross-hole ground-penetrating radar (GPR) profiles and lithological analyses from boreholes were used to support the ERT results. The observed electrical responses reflect the high temporal dynamics in subsurface water content associated with the applied infiltration-drying cycles. Individual apparent resistivity monitoring data captured general temporal dynamics, providing an easy and cost-effective means for infiltration monitoring. Time-lapse ERT results reveal different temporal dynamics in regions of the subsurface as a result of spatially varying hydraulic properties. We propose to use, based on a simple quantitative parametric description, the imaged temporal behavior of electrical conductivity to discriminate zones with different hydraulic properties, which represents a new approach for aquifer zonation based on the observed process dynamics. Our results demonstrate that time-lapse ERT is a powerful tool for the monitoring of SAT water infiltration with high spatiotemporal resolution. The provided information may be used for assessing and optimizing applied infiltration-drying cycles and, thus, for more effective SAT management.

@article{fd144d0ee0e043479da06424348ccb62,
title = "Time-lapse electrical imaging of water infiltration in the context of soil aquifer treatment",
abstract = "In this study, we investigated the ability of online geoelectrical monitoring to characterize water dynamics in the context of soil aquifer treatment (SAT). In spring 2014, we conducted several infiltration experiments at the Shafdan SAT facility in Israel, where treated wastewater is recurrently infiltrated through large ponds into the sandy coastal plain aquifer. Temporally dense electrical resistivity tomography (ERT) measurements were collected to investigate vadose zone flow processes and the influence of heterogeneous sedimentation on the infiltration pattern. Measurements of water content as well as cross-hole ground-penetrating radar (GPR) profiles and lithological analyses from boreholes were used to support the ERT results. The observed electrical responses reflect the high temporal dynamics in subsurface water content associated with the applied infiltration-drying cycles. Individual apparent resistivity monitoring data captured general temporal dynamics, providing an easy and cost-effective means for infiltration monitoring. Time-lapse ERT results reveal different temporal dynamics in regions of the subsurface as a result of spatially varying hydraulic properties. We propose to use, based on a simple quantitative parametric description, the imaged temporal behavior of electrical conductivity to discriminate zones with different hydraulic properties, which represents a new approach for aquifer zonation based on the observed process dynamics. Our results demonstrate that time-lapse ERT is a powerful tool for the monitoring of SAT water infiltration with high spatiotemporal resolution. The provided information may be used for assessing and optimizing applied infiltration-drying cycles and, thus, for more effective SAT management.",
author = "Klaus Haaken and Alex Furman and Noam Weisbrod and Andreas Kemna",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2016",
month = nov,
doi = "10.2136/vzj2016.04.0028",
language = "אנגלית",
volume = "15",
pages = "1--12",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "11",

}

Infiltration under confined air conditions: Impact of inclined soil surface

Mizrahi G, Furman A, Weisbrod N. Infiltration under confined air conditions: Impact of inclined soil surface. Vadose Zone Journal. 2016 Sep;15(9). https://doi.org/10.2136/vzj2016.04.0034
 

Entrapped air effects on infiltration under ponding condition are important in many engineered systems such as soil aquifer treatment and managed aquifer recharge. Earlier studies found that under ponding conditions, air is compressed until it reaches a pressure that enables it to be released, typically by intermittent bubbling through the surface. Entrapped air can reduce infiltration by 70 to 90%. Previous studies considered a flat soil surface topography and mostly vertical one-dimensional flow. The objective of this study was to investigate the effect of irregular, inclined surface topography on infiltration, hypothesizing that non-flat surface geometry may lead to preferential release of the confined air and subsequently increase infiltration. In a series of column experiments, we investigated the infiltration rates of flat and inclined soil surfaces. Our results indicate a clear infiltration rate increase of about 50% for an inclined surface. Further, we observed a clear difference in the air-pressure dynamics, indicating that under an inclined surface, air is being released continuously, while under flat surface conditions, air is being released intermittently. This behavior is explained by differences in the air-breaking and air-closing values across the soil column, while the air pressure is practically uniform beneath the wetting front.

@article{3eb7c3a666774ad7993df835996f6d33,
title = "Infiltration under confined air conditions: Impact of inclined soil surface",
abstract = "Entrapped air effects on infiltration under ponding condition are important in many engineered systems such as soil aquifer treatment and managed aquifer recharge. Earlier studies found that under ponding conditions, air is compressed until it reaches a pressure that enables it to be released, typically by intermittent bubbling through the surface. Entrapped air can reduce infiltration by 70 to 90%. Previous studies considered a flat soil surface topography and mostly vertical one-dimensional flow. The objective of this study was to investigate the effect of irregular, inclined surface topography on infiltration, hypothesizing that non-flat surface geometry may lead to preferential release of the confined air and subsequently increase infiltration. In a series of column experiments, we investigated the infiltration rates of flat and inclined soil surfaces. Our results indicate a clear infiltration rate increase of about 50% for an inclined surface. Further, we observed a clear difference in the air-pressure dynamics, indicating that under an inclined surface, air is being released continuously, while under flat surface conditions, air is being released intermittently. This behavior is explained by differences in the air-breaking and air-closing values across the soil column, while the air pressure is practically uniform beneath the wetting front.",
author = "Guy Mizrahi and Alex Furman and Noam Weisbrod",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2016",
month = sep,
doi = "10.2136/vzj2016.04.0034",
language = "אנגלית",
volume = "15",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "9",

}

Biofilm effect on soil hydraulic properties: Experimental investigation using soil-grown real biofilm

Volk E, Iden SC, Furman A, Durner W, Rosenzweig R. Biofilm effect on soil hydraulic properties: Experimental investigation using soil-grown real biofilm. Water Resources Research. 2016 Aug 1;52(8):5813-5828. https://doi.org/10.1002/2016WR018866
 

Understanding the influence of attached microbial biomass on water flow in variably saturated soils is crucial for many engineered flow systems. So far, the investigation of the effects of microbial biomass has been mainly limited to water-saturated systems. We have assessed the influence of biofilms on the soil hydraulic properties under variably saturated conditions. A sandy soil was incubated with Pseudomonas Putida and the hydraulic properties of the incubated soil were determined by a combination of methods. Our results show a stronger soil water retention in the inoculated soil as compared to the control. The increase in volumetric water content reaches approximately 0.015 cm3 cm−3 but is only moderately correlated with the carbon deficit, a proxy for biofilm quantity, and less with the cell viable counts. The presence of biofilm reduced the saturated hydraulic conductivity of the soil by up to one order of magnitude. Under unsaturated conditions, the hydraulic conductivity was only reduced by a factor of four. This means that relative water conductance in biofilm-affected soils is higher compared to the clean soil at low water contents, and that the unsaturated hydraulic conductivity curve of biofilm-affected soil cannot be predicted by simply scaling the saturated hydraulic conductivity. A flexible parameterization of the soil hydraulic functions accounting for capillary and noncapillary flow was needed to adequately describe the observed properties over the entire wetness range. More research is needed to address the exact flow mechanisms in biofilm-affected, unsaturated soil and how they are related to effective system properties.

@article{3a7c391823e4497b9f5ee6e815dbaff3,
title = "Biofilm effect on soil hydraulic properties: Experimental investigation using soil-grown real biofilm",
abstract = "Understanding the influence of attached microbial biomass on water flow in variably saturated soils is crucial for many engineered flow systems. So far, the investigation of the effects of microbial biomass has been mainly limited to water-saturated systems. We have assessed the influence of biofilms on the soil hydraulic properties under variably saturated conditions. A sandy soil was incubated with Pseudomonas Putida and the hydraulic properties of the incubated soil were determined by a combination of methods. Our results show a stronger soil water retention in the inoculated soil as compared to the control. The increase in volumetric water content reaches approximately 0.015 cm3 cm−3 but is only moderately correlated with the carbon deficit, a proxy for biofilm quantity, and less with the cell viable counts. The presence of biofilm reduced the saturated hydraulic conductivity of the soil by up to one order of magnitude. Under unsaturated conditions, the hydraulic conductivity was only reduced by a factor of four. This means that relative water conductance in biofilm-affected soils is higher compared to the clean soil at low water contents, and that the unsaturated hydraulic conductivity curve of biofilm-affected soil cannot be predicted by simply scaling the saturated hydraulic conductivity. A flexible parameterization of the soil hydraulic functions accounting for capillary and noncapillary flow was needed to adequately describe the observed properties over the entire wetness range. More research is needed to address the exact flow mechanisms in biofilm-affected, unsaturated soil and how they are related to effective system properties.",
keywords = "biofilm, hydraulic conductivity, hydraulic properties, retention, soil",
author = "Elazar Volk and Iden, {Sascha C.} and Alex Furman and Wolfgang Durner and Ravid Rosenzweig",
note = "Publisher Copyright: {\textcopyright} 2016. American Geophysical Union. All Rights Reserved.",
year = "2016",
month = aug,
day = "1",
doi = "10.1002/2016WR018866",
language = "אנגלית",
volume = "52",
pages = "5813--5828",
journal = "Water Resources Research",
issn = "0043-1397",
publisher = "Wiley-Blackwell",
number = "8",

}

בריאות קרקע בישראל – פיתוח וגיבוש של מדד רב-גורמי לאפיון בריאות קרקע חקלאית ובחינתו במספר ממשקים משמרים

אשל ג, לוי ג, ירמיהו א, צרור ל, שטינברגר י, פורמן א et al. בריאות קרקע בישראל – פיתוח וגיבוש של מדד רב-גורמי לאפיון בריאות קרקע חקלאית ובחינתו במספר ממשקים משמרים. אקולוגיה וסביבה. 2016;7(2):93-94.
 
המאמר מתאר מיזם שיהווה כלי בעל מדדים כמותיים, המותאמים לאזורנו לצורך קביעת מדיניות ולניטור מצב בריאות הקרקע. הניטור יאפשר גם לקבוע ממשקים לשימור או לשיפור בריאות הקרקע.
@article{177b73d140c845afa66ad0edc9a16515,
title = "בריאות קרקע בישראל – פיתוח וגיבוש של מדד רב-גורמי לאפיון בריאות קרקע חקלאית ובחינתו במספר ממשקים משמרים",
abstract = "המאמר מתאר מיזם שיהווה כלי בעל מדדים כמותיים, המותאמים לאזורנו לצורך קביעת מדיניות ולניטור מצב בריאות הקרקע. הניטור יאפשר גם לקבוע ממשקים לשימור או לשיפור בריאות הקרקע.",
author = "גיל אשל and גיא לוי and אורי ירמיהו and לאה צרור and יוסף שטינברגר and אלכס פורמן and חנן איזנברג and מישאל, {יעל גולדה} and מיכאל בוריסובר and טל סבוראי",
note = "נושא הגליון: תזונה מקיימת",
year = "2016",
language = "עברית",
volume = "7",
pages = "93--94",
journal = "אקולוגיה וסביבה",
number = "2",

}

השפעת חיפוי פני השטח בפרדס צעיר על חידור מי גשמים לקרקע: [חלק שני]

שקולניק ט, פורמן א, אגוזי ר, אשל ג. השפעת חיפוי פני השטח בפרדס צעיר על חידור מי גשמים לקרקע: [חלק שני]. עלון הנוטע. 2016.
 
פרדסים צעירים חשופים לפגיעות הנובעות מממשק הגידול המקובל היום, שבו מרבית השטח הנטוע נשאר חשוף. אחת הפגיעות שנצפתה הינה היווצרות קרום אטום מעל פני השטח, שעלול להפחית את חידור מי הגשם ובהתאמה להגביר את הנגר. שינוי מאזן המים הכרחי כדי למנוע פגיעה סביבתית וחקלאית. במחקר זה נבחנו שלושה ממשקי גידול, במטרה לבדוק את השפעתם על יכולת חדירת המים אל הקרקע. (מתוך המאמר)
@article{931a7c8add924daaa6e1a27cf7439d13,
title = "השפעת חיפוי פני השטח בפרדס צעיר על חידור מי גשמים לקרקע: [חלק שני]",
abstract = "פרדסים צעירים חשופים לפגיעות הנובעות מממשק הגידול המקובל היום, שבו מרבית השטח הנטוע נשאר חשוף. אחת הפגיעות שנצפתה הינה היווצרות קרום אטום מעל פני השטח, שעלול להפחית את חידור מי הגשם ובהתאמה להגביר את הנגר. שינוי מאזן המים הכרחי כדי למנוע פגיעה סביבתית וחקלאית. במחקר זה נבחנו שלושה ממשקי גידול, במטרה לבדוק את השפעתם על יכולת חדירת המים אל הקרקע. (מתוך המאמר)",
author = "טל שקולניק and אלכס פורמן and רועי אגוזי and גיל אשל",
note = "למאמר שלושה חלקים: החלק הראשון התפרסם בגיליון ס{"}ט, 11 (כסלו תשע{"}ו, נובמבר 2015), עמ' 32-36; החלק השלישי התפרסם בגיליון ע', 12 (כסלו תשע{"}ז, דצמבר 2016), עמ' 38-43.",
year = "2016",
language = "עברית",
journal = "עלון הנוטע",
issn = "0333-8886",

}

2015

An assimilated time domain reflectometry probe

Ouaknin H, Meyouhas Y, Weisbrod N, Furman A. An assimilated time domain reflectometry probe. Vadose Zone Journal. 2015 Dec;14(12). https://doi.org/10.2136/vzj2014.06.0086
 

Time domain reflectometry (TDR) is a simple and popular method for measuring soil water content. The TDR measures a weighted average of the dielectric permittivity of the soil along and around a probe. Under some experimental or technical restrictions, the penetration of the probe into the studied domain is undesirable or impossible. Here, we experimentally investigate the feasibility of measuring a material’s water content by only touching it. Such a configuration, where the probe is not fully inserted into the measured domain, leads to a far-from-uniform distribution of the dielectric permittivity around the probe. A laboratory experiment was conducted, comparing wall-embedded TDR (wall probe [WP]) measurements with those of a regular TDR probe (standard probe [SP]). Five different soils were examined (sand, “Hamra” [red loamy sand], loess, pure quartz, and clayey soil). For all soils, the WP measurements apparently underestimated water content. This is because it averages soil permittivity of the domain of interest (soil) with that of the probe host material, typically of lower dielectric permittivity. A linear relation between the water content as measured by the WP and the SP was found for all the soils. For most soils and for the non-marginal water contents, the true soil permittivity (and hence the water content) was roughly twice that measured by the WP. However, the measurement was found to be highly sensitive to the exact location of the probe at the material interface. We conclude that the wall-assimilated probe can be used with minimal calibration to measure water content without penetration into the measured domain, but high caution should be used with respect to the exact location of the probe at the wall–soil interface.

@article{823dbc11da9b41a395b327b5edc04a62,
title = "An assimilated time domain reflectometry probe",
abstract = "Time domain reflectometry (TDR) is a simple and popular method for measuring soil water content. The TDR measures a weighted average of the dielectric permittivity of the soil along and around a probe. Under some experimental or technical restrictions, the penetration of the probe into the studied domain is undesirable or impossible. Here, we experimentally investigate the feasibility of measuring a material{\textquoteright}s water content by only touching it. Such a configuration, where the probe is not fully inserted into the measured domain, leads to a far-from-uniform distribution of the dielectric permittivity around the probe. A laboratory experiment was conducted, comparing wall-embedded TDR (wall probe [WP]) measurements with those of a regular TDR probe (standard probe [SP]). Five different soils were examined (sand, “Hamra” [red loamy sand], loess, pure quartz, and clayey soil). For all soils, the WP measurements apparently underestimated water content. This is because it averages soil permittivity of the domain of interest (soil) with that of the probe host material, typically of lower dielectric permittivity. A linear relation between the water content as measured by the WP and the SP was found for all the soils. For most soils and for the non-marginal water contents, the true soil permittivity (and hence the water content) was roughly twice that measured by the WP. However, the measurement was found to be highly sensitive to the exact location of the probe at the material interface. We conclude that the wall-assimilated probe can be used with minimal calibration to measure water content without penetration into the measured domain, but high caution should be used with respect to the exact location of the probe at the wall–soil interface.",
author = "Hanna Ouaknin and Yael Meyouhas and Noam Weisbrod and Alex Furman",
note = "Publisher Copyright: {\textcopyright} Soil Science Society of America.",
year = "2015",
month = dec,
doi = "10.2136/vzj2014.06.0086",
language = "אנגלית",
volume = "14",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "12",

}

Mapping underground layers in the super arid Gidron Wadi using electrical resistivity tomography (ERT)

Winters G, Ryvkin I, Rudkov T, Moreno Z, Furman A. Mapping underground layers in the super arid Gidron Wadi using electrical resistivity tomography (ERT). Journal of Arid Environments. 2015 Oct 1;121:79-83. https://doi.org/10.1016/j.jaridenv.2015.05.008
 

Along the arid Arava, southern Israel, acacia trees are considered keystone species. Based on survival of acacias through drought years that have not seen a single rainfall or flood, it is assumed that acacias endure the local harsh conditions by drawing water from deep underground water reservoirs. Studying water use of acacias has so far been done by exposing root systems or by isotopic water measurements, both problematic methods.We present a new application of a two-dimensional direct current electrical resistivity tomography (ERT) to measure the electrical resistivity of the subsurface. We applied the ERT device to two fixed 100m transects cutting across (north-south) and along (west-east) the super arid Gidron Wadi during March, April and August 2013. An inversion model was used to create a map of electrical resistivity of the layers below ground, an indirect indicator of the underground water content. We identified a conductive layer located at ~7-10m below ground in all surveys. Although we could not identify changes to this apparent perched aquifer, such a layer may be a secondary source of water for acacias that can explain their survival in drought years. Further ERT-aided studies are needed to correlate acacia distribution and ecophysiological state with perched aquifers, even if quantitative analysis of their replenishment in such desert environments is not trivial.

@article{4372e7da7b8b4c819f59b094999fa491,
title = "Mapping underground layers in the super arid Gidron Wadi using electrical resistivity tomography (ERT)",
abstract = "Along the arid Arava, southern Israel, acacia trees are considered keystone species. Based on survival of acacias through drought years that have not seen a single rainfall or flood, it is assumed that acacias endure the local harsh conditions by drawing water from deep underground water reservoirs. Studying water use of acacias has so far been done by exposing root systems or by isotopic water measurements, both problematic methods.We present a new application of a two-dimensional direct current electrical resistivity tomography (ERT) to measure the electrical resistivity of the subsurface. We applied the ERT device to two fixed 100m transects cutting across (north-south) and along (west-east) the super arid Gidron Wadi during March, April and August 2013. An inversion model was used to create a map of electrical resistivity of the layers below ground, an indirect indicator of the underground water content. We identified a conductive layer located at ~7-10m below ground in all surveys. Although we could not identify changes to this apparent perched aquifer, such a layer may be a secondary source of water for acacias that can explain their survival in drought years. Further ERT-aided studies are needed to correlate acacia distribution and ecophysiological state with perched aquifers, even if quantitative analysis of their replenishment in such desert environments is not trivial.",
keywords = "Acacia raddiana, Acacia tortilis, Arava, Ecophysiology, Electrical resistivity tomography (ERT), Flash floods, Underground water, Water use",
author = "Gidon Winters and Ina Ryvkin and Tali Rudkov and Ziv Moreno and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2015 Elsevier Ltd.",
year = "2015",
month = oct,
day = "1",
doi = "10.1016/j.jaridenv.2015.05.008",
language = "אנגלית",
volume = "121",
pages = "79--83",
journal = "Journal of Arid Environments",
issn = "0140-1963",
publisher = "Academic Press Inc.",

}

Hydro-geophysical monitoring of orchard root zone dynamics in semi-arid region

Moreno Z, Arnon-Zur A, Furman A. Hydro-geophysical monitoring of orchard root zone dynamics in semi-arid region. Irrigation Science. 2015 Jul 9;33(4):303-318. https://doi.org/10.1007/s00271-015-0467-3
 

Monitoring the moisture patterns at the root zone is necessary for agricultural, hydrological, and environmental applications. Conventional monitoring methods are usually invasive, destructive, and only sample at a small spatial scale. Electrical resistivity tomography (ERT) can set an alternative or be complementary to common traditional methods in evaluating the moisture content and its spatiotemporal patterns. In this study, we used the ERT method to monitor the hydro-geophysical dynamics under a drip-irrigated citrus orchard in a semi-arid region. Geophysical surveys were performed monthly for over a year. The obtained data from the electrical measurements were inverted to produce 2D tomograms of the bulk electrical conductivity. Calibrations of the petrophysical relations were conducted using both laboratory and field procedures. The obtained electrical results, and especially their temporal dynamics, cannot always be explained using the common assumption of uniform spatiotemporal distribution of the pore water electrical conductivity. To separate the two main components of the petrophysical relations, namely water content and pore water conductivity, we used a modeling approach. A coupled flow and transport model was calibrated using the electrical conductivity measurements, allowing separation of the contribution of the water content and pore water electrical conductivity to the bulk electrical conductivity. This allowed explaining the temporal dynamics of the measured electrical signal and a better understanding of the water and solute dynamics in the root zone.

@article{7844993954bf4028bf9016f1af555edf,
title = "Hydro-geophysical monitoring of orchard root zone dynamics in semi-arid region",
abstract = "Monitoring the moisture patterns at the root zone is necessary for agricultural, hydrological, and environmental applications. Conventional monitoring methods are usually invasive, destructive, and only sample at a small spatial scale. Electrical resistivity tomography (ERT) can set an alternative or be complementary to common traditional methods in evaluating the moisture content and its spatiotemporal patterns. In this study, we used the ERT method to monitor the hydro-geophysical dynamics under a drip-irrigated citrus orchard in a semi-arid region. Geophysical surveys were performed monthly for over a year. The obtained data from the electrical measurements were inverted to produce 2D tomograms of the bulk electrical conductivity. Calibrations of the petrophysical relations were conducted using both laboratory and field procedures. The obtained electrical results, and especially their temporal dynamics, cannot always be explained using the common assumption of uniform spatiotemporal distribution of the pore water electrical conductivity. To separate the two main components of the petrophysical relations, namely water content and pore water conductivity, we used a modeling approach. A coupled flow and transport model was calibrated using the electrical conductivity measurements, allowing separation of the contribution of the water content and pore water electrical conductivity to the bulk electrical conductivity. This allowed explaining the temporal dynamics of the measured electrical signal and a better understanding of the water and solute dynamics in the root zone.",
author = "Ziv Moreno and Ali Arnon-Zur and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2015, Springer-Verlag Berlin Heidelberg.",
year = "2015",
month = jul,
day = "9",
doi = "10.1007/s00271-015-0467-3",
language = "אנגלית",
volume = "33",
pages = "303--318",
journal = "Irrigation Science",
issn = "0342-7188",
publisher = "Springer Verlag",
number = "4",

}

Electrical resistivity tomography of the root zone

Furman A, Arnon-Zur A, Assouline S. Electrical resistivity tomography of the root zone. In Soil- Water- Root Processes: Advances in Tomography and Imaging. wiley. 2015. p. 223-245 https://doi.org/10.2136/sssaspecpub61.c11
 

Understanding root scale processes and primarily those related to uptake in the root zone is very important for proper development of agricultural practices and efficient irrigation management. Such understanding requires an ability to map in high spatial and temporal resolution at the root zone. Electrical resistivity tomography (ERT) is a geophysical method that is very sensitive to the amount of water in the soil, which makes it highly suitable for root zone mapping and monitoring. In this chapter, we review the methodology and some past applications, and through several case studies we demonstrate the limitations of the method for root zone mapping. We identify the cases for which the method is mature or close to mature, that are related mostly to relatively large-scale root zone (trees) and slow (natural) processes, and others (small-scale, high-resolution, and fast processes) for which the technology in our opinion is still limited. Among the major limitations of the technology, we identify several as most important, including the need to develop (water flow) process-based constraints to replace non-process-based ones, the need to develop small scale electrodes for dry conditions, and the need to consider time varying processes in petrophysical relations. We believe that ERT, being a relatively cheap nondestructive noninvasive method for root zone mapping, can already be used at the field scale for various agronomic applications, while as a research tool some improvements are still needed.

@inbook{4209f233021e402a909c2d9dee1528e6,
title = "Electrical resistivity tomography of the root zone",
abstract = "Understanding root scale processes and primarily those related to uptake in the root zone is very important for proper development of agricultural practices and efficient irrigation management. Such understanding requires an ability to map in high spatial and temporal resolution at the root zone. Electrical resistivity tomography (ERT) is a geophysical method that is very sensitive to the amount of water in the soil, which makes it highly suitable for root zone mapping and monitoring. In this chapter, we review the methodology and some past applications, and through several case studies we demonstrate the limitations of the method for root zone mapping. We identify the cases for which the method is mature or close to mature, that are related mostly to relatively large-scale root zone (trees) and slow (natural) processes, and others (small-scale, high-resolution, and fast processes) for which the technology in our opinion is still limited. Among the major limitations of the technology, we identify several as most important, including the need to develop (water flow) process-based constraints to replace non-process-based ones, the need to develop small scale electrodes for dry conditions, and the need to consider time varying processes in petrophysical relations. We believe that ERT, being a relatively cheap nondestructive noninvasive method for root zone mapping, can already be used at the field scale for various agronomic applications, while as a research tool some improvements are still needed.",
keywords = "Agricultural practice, Electrical resistivity tomography, Irrigation management, Root scale process, Root zone, Root zone mapping, Spatial resolution, Temporal resolution",
author = "Alex Furman and Ali Arnon-Zur and Shmuel Assouline",
note = "Publisher Copyright: {\textcopyright} 2013 by Soil Science Society of America, Inc.",
year = "2015",
month = jan,
day = "1",
doi = "10.2136/sssaspecpub61.c11",
language = "אנגלית",
isbn = "9780891189589",
pages = "223--245",
booktitle = "Soil- Water- Root Processes",
publisher = "wiley",

}

השפעת חיפוי קרקע על היווצרות נגר עילי בפרדסים: [חלק ראשון]

אגוזי ר, אשל ג, פורמן א. השפעת חיפוי קרקע על היווצרות נגר עילי בפרדסים: [חלק ראשון]. עלון הנוטע. 2015;ס"ט(11):32-36.
 
הבנת תהליכי היווצרות הנגר העילי בפרדסים ומטעים חשובה להבנת תהליכי סחיפת הקרקע ומניעתם. מאמר זה מדווח על ניסוי הבוחן את השפעת חיפוי הקרקע על היווצרות הנגר בפרדס. הממצאים המדווחים הינם אירועים מייצגים מתוך חמש שנות מדידה של גשם ונגר בפרדס של הקליף אור שניטע על גדודיות בקרקע חמרה. הניסוי בחן ארבעה ממשקים של חיפוי קרקע: קרקע חשופה בהדברה כימית; קרקע בחיפוי חלקי עם גידול כיסוי של שיבולת שועל + בקיה במרכז השורה; חיפוי מלא של הגדודית בשבבי עץ ומרכז השורה באמצעות זריעה של צמחיית בר עשבונית מקומית. נמצא שחיפוי קרקע מלא בין השורות ועל הגדודית, בשני הטיפולים, הפחית במאות אחוזים את ספיקות השיא ובעשרות אחוזים את מספר אירועי הזרימה ונפחי הנגר היוצאים משורת הפרדס. חיפוי הגדודית נמצא קריטי לריסון נפחי הנגר היוצאים מהשורה באירועי גשם גדולים ובינוניים. תוצאות מחקר זה מצביעות על כך שחיפוי מלא עשוי להיות כלי יעיל בהתמודדות עם שינויי אקלים צפויים לאזורנו בדגש על אירועי גשם עוצמתיים. מאמר זה, ראשון בסדרת מאמרים בנושאים אלה, יתמקד בהשפעת ממשק חיפוי הקרקע בנטיעה צעירה של פרדס מזן אור בקרקע חמרה על תהליכי היווצרות נגר עילי. (מתוך המאמר)
@article{8c65fad5473d47c8b6b20a9ccf48c420,
title = "השפעת חיפוי קרקע על היווצרות נגר עילי בפרדסים: [חלק ראשון]",
abstract = "הבנת תהליכי היווצרות הנגר העילי בפרדסים ומטעים חשובה להבנת תהליכי סחיפת הקרקע ומניעתם. מאמר זה מדווח על ניסוי הבוחן את השפעת חיפוי הקרקע על היווצרות הנגר בפרדס. הממצאים המדווחים הינם אירועים מייצגים מתוך חמש שנות מדידה של גשם ונגר בפרדס של הקליף אור שניטע על גדודיות בקרקע חמרה. הניסוי בחן ארבעה ממשקים של חיפוי קרקע: קרקע חשופה בהדברה כימית; קרקע בחיפוי חלקי עם גידול כיסוי של שיבולת שועל + בקיה במרכז השורה; חיפוי מלא של הגדודית בשבבי עץ ומרכז השורה באמצעות זריעה של צמחיית בר עשבונית מקומית. נמצא שחיפוי קרקע מלא בין השורות ועל הגדודית, בשני הטיפולים, הפחית במאות אחוזים את ספיקות השיא ובעשרות אחוזים את מספר אירועי הזרימה ונפחי הנגר היוצאים משורת הפרדס. חיפוי הגדודית נמצא קריטי לריסון נפחי הנגר היוצאים מהשורה באירועי גשם גדולים ובינוניים. תוצאות מחקר זה מצביעות על כך שחיפוי מלא עשוי להיות כלי יעיל בהתמודדות עם שינויי אקלים צפויים לאזורנו בדגש על אירועי גשם עוצמתיים. מאמר זה, ראשון בסדרת מאמרים בנושאים אלה, יתמקד בהשפעת ממשק חיפוי הקרקע בנטיעה צעירה של פרדס מזן אור בקרקע חמרה על תהליכי היווצרות נגר עילי. (מתוך המאמר)",
author = "רועי אגוזי and גיל אשל and אלכס פורמן",
note = "למאמר שלושה חלקים: החלק השני התפרסם בגיליון ע', 3 (אדר תשע{"}ו, מרץ 2016) עמ' 44-48; החלק השלישי התפרסם בגיליון ע', 12 (כסלו תשע{"}ז, דצמבר 2016), עמ' 38-43.",
year = "2015",
language = "עברית",
volume = "ס{"}ט",
pages = "32--36",
journal = "עלון הנוטע",
issn = "0333-8886",
number = "11",

}

2014

Snow surface energy and mass balance in a warm temperate climate mountain

Sade R, Rimmer A, Litaor MI, Shamir E, Furman A. Snow surface energy and mass balance in a warm temperate climate mountain. Journal of Hydrology. 2014 Nov 7;519(PA):848-862. https://doi.org/10.1016/j.jhydrol.2014.07.048
 

In warm temperate mountain regions where water is often scarce vapor losses from the snow-surface can substantially limit snowmelt. Therefore, understanding the key snow dynamic processes that affect water availability in these mountains is essential. We studied the snowpack energy and mass balance in Mt. Hermon, Israel using a comprehensive field campaign during 2010/11. We analyzed the snowpack energy and mass balance during the winter of 2010/11 in a Deep Snow Patch (DSP), and in the Bulan valley experiment area (BVEA), where both windswept locations and lee-side (deep snowpack) locations were examined. We applied for this analysis an energy and mass balance snow model that was forced by input from two meteorological stations. The calibration of the model for the DSP and BVEA was based on surveyed snow water equivalent data, and melting cycles that were measured with time-lapse cameras, respectively. Using a step function to describe wind speed over the DSP we showed that the turbulent fluxes were influenced by changes in snowpack height. The turbulent fluxes were found as the dominant energy fluxes at the snow-surface. During winter, vapor losses varied between 46% and 82% of the total ablation. Consequently, latent heat flux consumed much of the available energy at the snow-surface, greatly limiting melting rate to 1mmday-1. During spring, vapor flux was positive which enhanced condensation, resulting in an average melting flux of 86 mm day-1. The spatial variation in the vapor flux at the BVEA due to terrain orientation yield variation in space of the available water at the bottom of the snowpack.

@article{73160bd45c514402b1cc003d9066df44,
title = "Snow surface energy and mass balance in a warm temperate climate mountain",
abstract = "In warm temperate mountain regions where water is often scarce vapor losses from the snow-surface can substantially limit snowmelt. Therefore, understanding the key snow dynamic processes that affect water availability in these mountains is essential. We studied the snowpack energy and mass balance in Mt. Hermon, Israel using a comprehensive field campaign during 2010/11. We analyzed the snowpack energy and mass balance during the winter of 2010/11 in a Deep Snow Patch (DSP), and in the Bulan valley experiment area (BVEA), where both windswept locations and lee-side (deep snowpack) locations were examined. We applied for this analysis an energy and mass balance snow model that was forced by input from two meteorological stations. The calibration of the model for the DSP and BVEA was based on surveyed snow water equivalent data, and melting cycles that were measured with time-lapse cameras, respectively. Using a step function to describe wind speed over the DSP we showed that the turbulent fluxes were influenced by changes in snowpack height. The turbulent fluxes were found as the dominant energy fluxes at the snow-surface. During winter, vapor losses varied between 46% and 82% of the total ablation. Consequently, latent heat flux consumed much of the available energy at the snow-surface, greatly limiting melting rate to 1mmday-1. During spring, vapor flux was positive which enhanced condensation, resulting in an average melting flux of 86 mm day-1. The spatial variation in the vapor flux at the BVEA due to terrain orientation yield variation in space of the available water at the bottom of the snowpack.",
keywords = "Mt. Hermon, Snowpack energy and mass balance, Turbulent fluxes, Vapor losses, Warm temperate climate",
author = "Rotem Sade and Alon Rimmer and Litaor, {M. Iggy} and Eylon Shamir and Alex Furman",
note = "Publisher Copyright: {\textcopyright} 2014 Elsevier B.V.",
year = "2014",
month = nov,
day = "7",
doi = "10.1016/j.jhydrol.2014.07.048",
language = "אנגלית",
volume = "519",
pages = "848--862",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",
number = "PA",

}

Interpolation of extensive routine water pollution monitoring datasets: Methodology and discussion of implications for aquifer management

Yuval, Rimon Y, Graber ER, Furman A. Interpolation of extensive routine water pollution monitoring datasets: Methodology and discussion of implications for aquifer management. Environmental Sciences: Processes and Impacts. 2014 Aug;16(8):2007-2017. https://doi.org/10.1039/c4em00190g
 

A large fraction of the fresh water available for human use is stored in groundwater aquifers. Since human activities such as mining, agriculture, industry and urbanisation often result in incursion of various pollutants to groundwater, routine monitoring of water quality is an indispensable component of judicious aquifer management. Unfortunately, groundwater pollution monitoring is expensive and usually cannot cover an aquifer with the spatial resolution necessary for making adequate management decisions. Interpolation of monitoring data is thus an important tool for supplementing monitoring observations. However, interpolating routine groundwater pollution data poses a special problem due to the nature of the observations. The data from a producing aquifer usually includes many zero pollution concentration values from the clean parts of the aquifer but may span a wide range of values (up to a few orders of magnitude) in the polluted areas. This manuscript presents a methodology that can cope with such datasets and use them to produce maps that present the pollution plumes but also delineates the clean areas that are fit for production. A method for assessing the quality of mapping in a way which is suitable to the data's dynamic range of values is also presented. A local variant of inverse distance weighting is employed to interpolate the data. Inclusion zones around the interpolation points ensure that only relevant observations contribute to each interpolated concentration. Using inclusion zones improves the accuracy of the mapping but results in interpolation grid points which are not assigned a value. The inherent trade-off between the interpolation accuracy and coverage is demonstrated using both circular and elliptical inclusion zones. A leave-one-out cross testing is used to assess and compare the performance of the interpolations. The methodology is demonstrated using groundwater pollution monitoring data from the coastal aquifer along the Israeli shoreline. The implications for aquifer management are discussed. This journal is

@article{1b49de1dedf342c58c24151fce490f90,
title = "Interpolation of extensive routine water pollution monitoring datasets: Methodology and discussion of implications for aquifer management",
abstract = "A large fraction of the fresh water available for human use is stored in groundwater aquifers. Since human activities such as mining, agriculture, industry and urbanisation often result in incursion of various pollutants to groundwater, routine monitoring of water quality is an indispensable component of judicious aquifer management. Unfortunately, groundwater pollution monitoring is expensive and usually cannot cover an aquifer with the spatial resolution necessary for making adequate management decisions. Interpolation of monitoring data is thus an important tool for supplementing monitoring observations. However, interpolating routine groundwater pollution data poses a special problem due to the nature of the observations. The data from a producing aquifer usually includes many zero pollution concentration values from the clean parts of the aquifer but may span a wide range of values (up to a few orders of magnitude) in the polluted areas. This manuscript presents a methodology that can cope with such datasets and use them to produce maps that present the pollution plumes but also delineates the clean areas that are fit for production. A method for assessing the quality of mapping in a way which is suitable to the data's dynamic range of values is also presented. A local variant of inverse distance weighting is employed to interpolate the data. Inclusion zones around the interpolation points ensure that only relevant observations contribute to each interpolated concentration. Using inclusion zones improves the accuracy of the mapping but results in interpolation grid points which are not assigned a value. The inherent trade-off between the interpolation accuracy and coverage is demonstrated using both circular and elliptical inclusion zones. A leave-one-out cross testing is used to assess and compare the performance of the interpolations. The methodology is demonstrated using groundwater pollution monitoring data from the coastal aquifer along the Israeli shoreline. The implications for aquifer management are discussed. This journal is",
author = "Yuval and Yaara Rimon and Graber, {Ellen R.} and Alex Furman",
year = "2014",
month = aug,
doi = "10.1039/c4em00190g",
language = "אנגלית",
volume = "16",
pages = "2007--2017",
journal = "Environmental Sciences: Processes and Impacts",
issn = "2050-7887",
publisher = "Royal Society of Chemistry",
number = "8",

}

Modeling biofilm dynamics and hydraulic properties in variably saturated soils using a channel network model

Rosenzweig R, Furman A, Dosoretz C, Shavit U. Modeling biofilm dynamics and hydraulic properties in variably saturated soils using a channel network model. Water Resources Research. 2014 Jul;50(7):5678-5697. https://doi.org/10.1002/2013WR015211
 

Biofilm effects on water flow in unsaturated environments have largely been ignored in the past. However, intensive engineered systems that involve elevated organic loads such as wastewater irrigation, effluent recharge, and bioremediation processes make understanding how biofilms affect flow highly important. In the current work, we present a channel-network model that incorporates water flow, substrate transport, and biofilm dynamics to simulate the alteration of soil hydraulic properties, namely water retention and conductivity. The change in hydraulic properties due to biofilm growth is not trivial and depends highly on the spatial distribution of the biofilm development. Our results indicate that the substrate mass transfer coefficient across the water-biofilm interface dominates the spatiotemporal distribution of biofilm. High mass transfer coefficients lead to uncontrolled biofilm growth close to the substrate source, resulting in preferential clogging of the soil. Low mass transfer coefficients, on the other hand, lead to a more uniform biofilm distribution. The first scenario leads to a dramatic reduction of the hydraulic conductivity with almost no change in water retention, whereas the second scenario has a smaller effect on conductivity but a larger influence on retention. The current modeling approach identifies key factors that still need to be studied and opens the way for simulation and optimization of processes involving significant biological activity in unsaturated soils. Key Points A pore network was used to simulate coupled water flow and biofilm dynamics Mass transfer at the water-biofilm interface controls biofilm dynamics High mass transfer coefficient leads to severe clogging

@article{1882d43616e2461f826bc3c5aee8a203,
title = "Modeling biofilm dynamics and hydraulic properties in variably saturated soils using a channel network model",
abstract = "Biofilm effects on water flow in unsaturated environments have largely been ignored in the past. However, intensive engineered systems that involve elevated organic loads such as wastewater irrigation, effluent recharge, and bioremediation processes make understanding how biofilms affect flow highly important. In the current work, we present a channel-network model that incorporates water flow, substrate transport, and biofilm dynamics to simulate the alteration of soil hydraulic properties, namely water retention and conductivity. The change in hydraulic properties due to biofilm growth is not trivial and depends highly on the spatial distribution of the biofilm development. Our results indicate that the substrate mass transfer coefficient across the water-biofilm interface dominates the spatiotemporal distribution of biofilm. High mass transfer coefficients lead to uncontrolled biofilm growth close to the substrate source, resulting in preferential clogging of the soil. Low mass transfer coefficients, on the other hand, lead to a more uniform biofilm distribution. The first scenario leads to a dramatic reduction of the hydraulic conductivity with almost no change in water retention, whereas the second scenario has a smaller effect on conductivity but a larger influence on retention. The current modeling approach identifies key factors that still need to be studied and opens the way for simulation and optimization of processes involving significant biological activity in unsaturated soils. Key Points A pore network was used to simulate coupled water flow and biofilm dynamics Mass transfer at the water-biofilm interface controls biofilm dynamics High mass transfer coefficient leads to severe clogging",
keywords = "biofilm, pore network model, soil hydraulic properties",
author = "Ravid Rosenzweig and Alex Furman and Carlos Dosoretz and Uri Shavit",
year = "2014",
month = jul,
doi = "10.1002/2013WR015211",
language = "אנגלית",
volume = "50",
pages = "5678--5697",
journal = "Water Resources Research",
issn = "0043-1397",
publisher = "Wiley-Blackwell",
number = "7",

}

The effect of organic acid on the spectral-induced polarization response of soil

Schwartz N, Shalem T, Furman A. The effect of organic acid on the spectral-induced polarization response of soil. Geophysical Journal International. 2014 Apr;197(1):269-276. https://doi.org/10.1093/gji/ggt529
 

In spectral-induced polarization (SIP) studies of sites contaminated by organic hydrocarbons, it was shown that biodegradation by-products in general, and organic acids in particular, significantly alter the SIP signature of the subsurface. Still a systematic study that considers the effect of organic acid on the physicochemical and electrical (SIP) properties of the soil is missing. The goal of this work is to relate between the effect of organic acid on the physicochemical properties of the soil, and the soil electrical properties. To do so, we measured the temporal changes of the soil chemical (ion content) and electrical (low-frequency SIP) properties in response to influx of organic acid at different concentrations, gradually altering the soil pH. Our results showthat organic acid reduces the soil pH, enhances mineralweathering and consequently reduces both the in-phase and quadrature conductivity. At the pH rangewhere mineral weathering is most significant (pH 6-4.5) a negative linear relation between the soil pH and the soil formation factor was found, suggesting that mineral weathering changes the pore space geometry and hence affecting the in-phase electrical conductivity. In addition, we attribute the reduction in the quadrature conductivity to an exchange process between the natural cation adsorbed on the mineral surface and hydronium, and to changes in the width of the pore bottleneck that results from the mineral weathering. Overall, our results allow a better understanding of the SIP signature of soil undergoing acidification process in general and as biodegradation process in particular.

@article{88653b280ef342be9a6a8a0ea7aa68e6,
title = "The effect of organic acid on the spectral-induced polarization response of soil",
abstract = "In spectral-induced polarization (SIP) studies of sites contaminated by organic hydrocarbons, it was shown that biodegradation by-products in general, and organic acids in particular, significantly alter the SIP signature of the subsurface. Still a systematic study that considers the effect of organic acid on the physicochemical and electrical (SIP) properties of the soil is missing. The goal of this work is to relate between the effect of organic acid on the physicochemical properties of the soil, and the soil electrical properties. To do so, we measured the temporal changes of the soil chemical (ion content) and electrical (low-frequency SIP) properties in response to influx of organic acid at different concentrations, gradually altering the soil pH. Our results showthat organic acid reduces the soil pH, enhances mineralweathering and consequently reduces both the in-phase and quadrature conductivity. At the pH rangewhere mineral weathering is most significant (pH 6-4.5) a negative linear relation between the soil pH and the soil formation factor was found, suggesting that mineral weathering changes the pore space geometry and hence affecting the in-phase electrical conductivity. In addition, we attribute the reduction in the quadrature conductivity to an exchange process between the natural cation adsorbed on the mineral surface and hydronium, and to changes in the width of the pore bottleneck that results from the mineral weathering. Overall, our results allow a better understanding of the SIP signature of soil undergoing acidification process in general and as biodegradation process in particular.",
keywords = "Electrical properties, Hydrogeophysics, Hydrology",
author = "N. Schwartz and T. Shalem and A. Furman",
year = "2014",
month = apr,
doi = "10.1093/gji/ggt529",
language = "אנגלית",
volume = "197",
pages = "269--276",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Oxford University Press",
number = "1",

}

On the spectral induced polarization signature of soil organic matter

Schwartz N, Furman A. On the spectral induced polarization signature of soil organic matter. Geophysical Journal International. 2014 Jan 1;200(1):589-595. https://doi.org/10.1093/gji/ggu410
 

Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soilOMon the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same soil, one with calcium as the dominant cation and the other with sodium, with different concentration of OMwere performed. Our results show that despite the high CEC of OM, a decrease in polarization and an increase in relaxation time with increasing concentration of OM is observed. For the soil with calcium as the dominant cation, the decreases in polarization and the increase in relaxation time were stronger. We explain these non-trivial results by accounting for the interactions between the OM and the soil minerals. We suggest that the formation of organo-mineral complexes reduce ionic mobility, explaining both the decrease in polarization and the increase in relaxation time. These results demonstrate the important role of OM on SIP response of soil, and call for a further research in order to establish a new polarization model that will include the impact of OM on soil polarization.

@article{d056a8a7e03e43dcaff600b46e7308ff,
title = "On the spectral induced polarization signature of soil organic matter",
abstract = "Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soilOMon the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same soil, one with calcium as the dominant cation and the other with sodium, with different concentration of OMwere performed. Our results show that despite the high CEC of OM, a decrease in polarization and an increase in relaxation time with increasing concentration of OM is observed. For the soil with calcium as the dominant cation, the decreases in polarization and the increase in relaxation time were stronger. We explain these non-trivial results by accounting for the interactions between the OM and the soil minerals. We suggest that the formation of organo-mineral complexes reduce ionic mobility, explaining both the decrease in polarization and the increase in relaxation time. These results demonstrate the important role of OM on SIP response of soil, and call for a further research in order to establish a new polarization model that will include the impact of OM on soil polarization.",
keywords = "Electrical properties, Hydrogeophysics, Hydrology",
author = "N. Schwartz and A. Furman",
note = "Publisher Copyright: {\textcopyright} The Authors 2014. Published by Oxford University Press on behalf of the Royal Astronomical Society.",
year = "2014",
month = jan,
day = "1",
doi = "10.1093/gji/ggu410",
language = "אנגלית",
volume = "200",
pages = "589--595",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Oxford University Press",
number = "1",

}

2013

The effect of free-phase NAPL on the spectral induced polarization signature of variably saturated soil

Shefer I, Schwartz N, Furman A. The effect of free-phase NAPL on the spectral induced polarization signature of variably saturated soil. Water Resources Research. 2013 Oct;49(10):6229-6237. https://doi.org/10.1002/wrcr.20502
 

In this study, the influence of a free phase nonaqueous phase liquid (NAPL), decane, on the soil's SIP signature was experimentally investigated. The complex electrical conductivity was determined using the SIP measurement system and compared between two main treatment types: clean and decane contaminated. Complementary chemical and temporal measurements were conducted. The results show a clear decrease in the imaginary part of the complex conductivity for the decane contaminated soil. Moreover, a shift of the relaxation frequency was observed for the contaminated soil. Our chemical analysis suggests that there was no change in the chemical composition of the Stern layer, and clearly, the grain size distribution did not change as well. Therefore, these results are attributed to membrane polarization. The decane addition to the unsaturated porous media changes the pore-scale liquid phase distribution, thus affecting membrane polarization. Further, the electrical signature is a time-related process associated with liquid phase arrangement time. The findings of this study can enable a better understanding of the SIP response for soils contaminated with free-phase organic compounds. Key Points Free-phase NAPL contaminant reduce soil polarization Membrane polarization dominates SIP of free-phase NAPL contaminated soil Relaxation time affected by the geometry of the conductive fluid phase

@article{c8cd6c6c24464c3bace57e6123d1b0c2,
title = "The effect of free-phase NAPL on the spectral induced polarization signature of variably saturated soil",
abstract = "In this study, the influence of a free phase nonaqueous phase liquid (NAPL), decane, on the soil's SIP signature was experimentally investigated. The complex electrical conductivity was determined using the SIP measurement system and compared between two main treatment types: clean and decane contaminated. Complementary chemical and temporal measurements were conducted. The results show a clear decrease in the imaginary part of the complex conductivity for the decane contaminated soil. Moreover, a shift of the relaxation frequency was observed for the contaminated soil. Our chemical analysis suggests that there was no change in the chemical composition of the Stern layer, and clearly, the grain size distribution did not change as well. Therefore, these results are attributed to membrane polarization. The decane addition to the unsaturated porous media changes the pore-scale liquid phase distribution, thus affecting membrane polarization. Further, the electrical signature is a time-related process associated with liquid phase arrangement time. The findings of this study can enable a better understanding of the SIP response for soils contaminated with free-phase organic compounds. Key Points Free-phase NAPL contaminant reduce soil polarization Membrane polarization dominates SIP of free-phase NAPL contaminated soil Relaxation time affected by the geometry of the conductive fluid phase",
keywords = "NAPL, contamination, hydrogeophysics, membrane polarization, soil, spectral induce polarization",
author = "I. Shefer and N. Schwartz and A. Furman",
year = "2013",
month = oct,
doi = "10.1002/wrcr.20502",
language = "אנגלית",
volume = "49",
pages = "6229--6237",
journal = "Water Resources Research",
issn = "0043-1397",
publisher = "Wiley-Blackwell",
number = "10",

}

A channel network model as a framework for characterizing variably saturated flow in biofilm-affected soils

Rosenzweig R, Furman A, Shavit U. A channel network model as a framework for characterizing variably saturated flow in biofilm-affected soils. Vadose Zone Journal. 2013 May;12(2). https://doi.org/10.2136/vzj2012.0079
 

A channel network model is developed to study the flow in biofilm-aff ected soils under variably saturated conditions. The effect of the biofilm spatial distribution on the network hydraulic properties is investigated by using three synthetic scenarios. It is shown that the biofilm spatial distribution has a profound effect on the network flow. Understanding and predicting the hydraulic properties of biofilm-aff ected porous media is of high importance in bioremediation, filtration, and bioreactors. In this study, a channel network model was applied for characterizing the variably saturated flow in biofilm-aff ected soils. The soil pores are represented by a network of interconnected channels having a triangular cross-section in which the shape of the water surface is determined by the matric head. The channel network model provides a better representation of the pore space than the capillary bundle model by accounting for pore connectivity and allowing for dual occupancy at individual pores. The effect of the biofilm on the network hydraulic properties was analyzed by considering three synthetic scenarios for the biofilm spatial distribution. The first scenario assumed that the biofilms fully clogged the smallest pores; the second scenario assumed that the biofilm covered all pore walls in a layer of uniform thickness; and the third scenario assumed that the biofilm covered a uniform fraction of the pore cross-sectional area. We showed that the biofilm spatial distribution has a significant effect on the flow and hydraulic properties. Moreover, pore connectivity plays a significant role when considering flow in biofilm-affected soils and therefore must be taken into account. Finally, the simulations demonstrated that the effect of biofilms on the hydraulic properties of the network is a complicated and nonlinear function that depends not only on the biofilm scenario but also on the saturation.

@article{67b690db4dd247cb8abe7c4f0f571292,
title = "A channel network model as a framework for characterizing variably saturated flow in biofilm-affected soils",
abstract = "A channel network model is developed to study the flow in biofilm-aff ected soils under variably saturated conditions. The effect of the biofilm spatial distribution on the network hydraulic properties is investigated by using three synthetic scenarios. It is shown that the biofilm spatial distribution has a profound effect on the network flow. Understanding and predicting the hydraulic properties of biofilm-aff ected porous media is of high importance in bioremediation, filtration, and bioreactors. In this study, a channel network model was applied for characterizing the variably saturated flow in biofilm-aff ected soils. The soil pores are represented by a network of interconnected channels having a triangular cross-section in which the shape of the water surface is determined by the matric head. The channel network model provides a better representation of the pore space than the capillary bundle model by accounting for pore connectivity and allowing for dual occupancy at individual pores. The effect of the biofilm on the network hydraulic properties was analyzed by considering three synthetic scenarios for the biofilm spatial distribution. The first scenario assumed that the biofilms fully clogged the smallest pores; the second scenario assumed that the biofilm covered all pore walls in a layer of uniform thickness; and the third scenario assumed that the biofilm covered a uniform fraction of the pore cross-sectional area. We showed that the biofilm spatial distribution has a significant effect on the flow and hydraulic properties. Moreover, pore connectivity plays a significant role when considering flow in biofilm-affected soils and therefore must be taken into account. Finally, the simulations demonstrated that the effect of biofilms on the hydraulic properties of the network is a complicated and nonlinear function that depends not only on the biofilm scenario but also on the saturation.",
author = "Ravid Rosenzweig and Alex Furman and Uri Shavit",
year = "2013",
month = may,
doi = "10.2136/vzj2012.0079",
language = "אנגלית",
volume = "12",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "2",

}

Groundwater Management in Israel

Furman A, Abbo H. Groundwater Management in Israel. In Global Issues in Water Policy. Springer. 2013. p. 125-136. (Global Issues in Water Policy). https://doi.org/10.1007/978-94-007-5911-4_8
 

In recent years, groundwater (GW) is becoming increasingly important due to population growth, preparation for climate change, flood control, and above all water quality awareness. While in far and recent history most of the water for agricultural and domestic use was of surface origin, in the recent few decades, the portion of groundwater used in many countries is significantly higher than the portion of surface water used. This makes the study of groundwater and related fields such as vadose zone hydrology, subsurface contaminant fate and transport of high importance.

@inbook{317c067b556d43148b798c5a95387e14,
title = "Groundwater Management in Israel",
abstract = "In recent years, groundwater (GW) is becoming increasingly important due to population growth, preparation for climate change, flood control, and above all water quality awareness. While in far and recent history most of the water for agricultural and domestic use was of surface origin, in the recent few decades, the portion of groundwater used in many countries is significantly higher than the portion of surface water used. This makes the study of groundwater and related fields such as vadose zone hydrology, subsurface contaminant fate and transport of high importance.",
keywords = "Artificial Recharge, Freshwater Consumption, Natural Water Source, Soil Aquifer Treatment, Vadose Zone",
author = "Alex Furman and Hila Abbo",
note = "Publisher Copyright: {\textcopyright} 2013, Springer Science+Business Media Dordrecht.",
year = "2013",
doi = "10.1007/978-94-007-5911-4_8",
language = "אנגלית",
series = "Global Issues in Water Policy",
publisher = "Springer",
pages = "125--136",
booktitle = "Global Issues in Water Policy",

}

2012

Spectral induced polarization signature of soil contaminated by organic pollutant: Experiment and modeling

Schwartz N, Furman A. Spectral induced polarization signature of soil contaminated by organic pollutant: Experiment and modeling. Journal of Geophysical Research: Solid Earth. 2012 Oct 1;117(10):B10203. https://doi.org/10.1029/2012JB009543
 

The spectral induced polarization (SIP) signature of soil contaminated with organic pollutant was studied. Using a flow column experiment, the effect of crystal violet (CV, a polar organic pollutant) on the temporal change of the SIP response over a broad frequency range (1 mHz to 45 KHz) was determined. Complimentary measurements were used to determine the effect of CV on the chemical composition of both the pore water and the solid surface. In addition, analysis of the experimental results was carried out by using both chemical complexation and induced polarization models. Our results shows that adsorption of CV to the mineral surface resulted in release of inorganic ions to the soil solution, increasing the solution electrical conductivity and therefore also the real part of the complex conductivity. Despite the increase in the real part of the complex conductivity, the imaginary part of the complex conductivity decreased with increasing concentration of adsorbed CV. Using the Revil induced polarization model, we were able to show that the contribution of the adsorbed CV to the polarization of the soil is negligible, and that the main process affecting the polarization is the decrease in the density of the inorganic surface species. The results of this study can be used to better interpret SIP signature of soils contaminated by organic compounds.

@article{f67b9e0b7d324bc4a218bef7fd15088f,
title = "Spectral induced polarization signature of soil contaminated by organic pollutant: Experiment and modeling",
abstract = "The spectral induced polarization (SIP) signature of soil contaminated with organic pollutant was studied. Using a flow column experiment, the effect of crystal violet (CV, a polar organic pollutant) on the temporal change of the SIP response over a broad frequency range (1 mHz to 45 KHz) was determined. Complimentary measurements were used to determine the effect of CV on the chemical composition of both the pore water and the solid surface. In addition, analysis of the experimental results was carried out by using both chemical complexation and induced polarization models. Our results shows that adsorption of CV to the mineral surface resulted in release of inorganic ions to the soil solution, increasing the solution electrical conductivity and therefore also the real part of the complex conductivity. Despite the increase in the real part of the complex conductivity, the imaginary part of the complex conductivity decreased with increasing concentration of adsorbed CV. Using the Revil induced polarization model, we were able to show that the contribution of the adsorbed CV to the polarization of the soil is negligible, and that the main process affecting the polarization is the decrease in the density of the inorganic surface species. The results of this study can be used to better interpret SIP signature of soils contaminated by organic compounds.",
author = "N. Schwartz and A. Furman",
year = "2012",
month = oct,
day = "1",
doi = "10.1029/2012JB009543",
language = "אנגלית",
volume = "117",
journal = "Journal of Geophysical Research: Solid Earth",
issn = "2169-9313",
publisher = "Wiley-Blackwell",
number = "10",

}

The effect of NAPL on the electrical properties of unsaturated porous media

Schwartz N, Huisman JA, Furman A. The effect of NAPL on the electrical properties of unsaturated porous media. Geophysical Journal International. 2012 Mar;188(3):1007-1011. https://doi.org/10.1111/j.1365-246X.2011.05332.x
 

The spectral induced polarization signature of porous media contaminated with non-aqueous phase liquid (NAPL) was studied. Using an accurate measurement system, the complex electrical conductivity of unsaturated porous media contaminated with either diesel fuel or motor oil at a constant water saturation was determined. Counter intuitively, the results show that replacing air with NAPL increases the real part of the complex conductivity of unsaturated porous media. We interpret the results in terms of electrochemical polarization, and suggest that polar compounds contained in the NAPL adsorb to the mineral surface leading to release of inorganic ions to the pore water, which affects both the fluid and surface conductivity. In addition, we observed a decrease in the polarization followed by further addition of NAPL, which we relate to a lower mobility of the adsorbed polar compound. This study allows a better understanding of the electrical signature of NAPL contaminated porous media, especially in variably saturated conditions.

@article{188e56c307be4f949b4f7d46dbf8b963,
title = "The effect of NAPL on the electrical properties of unsaturated porous media",
abstract = "The spectral induced polarization signature of porous media contaminated with non-aqueous phase liquid (NAPL) was studied. Using an accurate measurement system, the complex electrical conductivity of unsaturated porous media contaminated with either diesel fuel or motor oil at a constant water saturation was determined. Counter intuitively, the results show that replacing air with NAPL increases the real part of the complex conductivity of unsaturated porous media. We interpret the results in terms of electrochemical polarization, and suggest that polar compounds contained in the NAPL adsorb to the mineral surface leading to release of inorganic ions to the pore water, which affects both the fluid and surface conductivity. In addition, we observed a decrease in the polarization followed by further addition of NAPL, which we relate to a lower mobility of the adsorbed polar compound. This study allows a better understanding of the electrical signature of NAPL contaminated porous media, especially in variably saturated conditions.",
keywords = "Electrical properties, Electromagnetic theory, Hydrogeophysics",
author = "N. Schwartz and Huisman, {J. A.} and A. Furman",
year = "2012",
month = mar,
doi = "10.1111/j.1365-246X.2011.05332.x",
language = "אנגלית",
volume = "188",
pages = "1007--1011",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Oxford University Press",
number = "3",

}

Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils

Xiong Y, Furman A, Wallach R. Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils. Journal of Hydrology. 2012 Feb 23;422-423:30-42. https://doi.org/10.1016/j.jhydrol.2011.12.010
 

Water repellency has a significant impact on water flow patterns in the soil profile. Transient 2D flow in wettable and natural water-repellent soils was monitored in a transparent flow chamber. The substantial differences in plume shape and spatial water content distribution during the wetting and subsequent redistribution stages were related to the variation of contact angle while in contact with water. The observed plumes shape, internal water content distribution in general and the saturation overshoot behind the wetting front in particular in the repellent soils were associated with unstable flow. Moment analysis was applied to characterize the measured plumes during the wetting and subsequent redistribution. The center of mass and spatial variances determined for the measured evolving plumes were fitted by a model that accounts for capillary and gravitational driving forces in a medium of temporally varying wettability. Ellipses defined around the stable and unstable plumes' centers of mass and whose semi-axes represented a particular number of spatial variances were used to characterize plume shape and internal moisture distribution. A single probability curve was able to characterize the corresponding fractions of the total added water in the different ellipses for all measured plumes, which testify the competence and advantage of the moment analysis method.

@article{d02158fb1bbe45408131f8e201df47a8,
title = "Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils",
abstract = "Water repellency has a significant impact on water flow patterns in the soil profile. Transient 2D flow in wettable and natural water-repellent soils was monitored in a transparent flow chamber. The substantial differences in plume shape and spatial water content distribution during the wetting and subsequent redistribution stages were related to the variation of contact angle while in contact with water. The observed plumes shape, internal water content distribution in general and the saturation overshoot behind the wetting front in particular in the repellent soils were associated with unstable flow. Moment analysis was applied to characterize the measured plumes during the wetting and subsequent redistribution. The center of mass and spatial variances determined for the measured evolving plumes were fitted by a model that accounts for capillary and gravitational driving forces in a medium of temporally varying wettability. Ellipses defined around the stable and unstable plumes' centers of mass and whose semi-axes represented a particular number of spatial variances were used to characterize plume shape and internal moisture distribution. A single probability curve was able to characterize the corresponding fractions of the total added water in the different ellipses for all measured plumes, which testify the competence and advantage of the moment analysis method.",
keywords = "Drip irrigation, Moment analysis, Unstable flow, Water-repellent soil",
author = "Yunwu Xiong and Alex Furman and Rony Wallach",
note = "Funding Information: This research was supported by research Grant US-3662-05R from BARD, the United States-Israel Binational Agricultural Research and Development Fund.",
year = "2012",
month = feb,
day = "23",
doi = "10.1016/j.jhydrol.2011.12.010",
language = "אנגלית",
volume = "422-423",
pages = "30--42",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",

}

Impact of water regime and growing conditions on soil-plant interactions: From single plant to field scale

Assouline S, Möller M, Furman A, Narkis K, Silber A. Impact of water regime and growing conditions on soil-plant interactions: From single plant to field scale. Vadose Zone Journal. 2012;11(3). https://doi.org/10.2136/vzj2012.0006
 

Global water resources quantities and qualities are declining, but at the same time, a strong demand for higher agricultural productivity continues to emerge due to population growth. This calls for a significant increase of irrigation and fertilization efficiencies and requires improving our understanding of the interactions between plants and their physical environment. The main objective of this study is to analyze the combined effect of varying drip irrigation management techniques and growing conditions (media properties and container volumes) on soil-plant interactions. In a series of experiments, irrigation flow rates and intervals ranging from 2 d to 10 min were applied to the vegetative stage of a test crop (bell pepper [Capsicum annuum L. 'Selika']) cultivated under different growing conditions- sand and perlite in buckets, perlite in containers, and loamy and under field conditions. Data on soil water regime, plant water uptake, and plant development were monitored in each setup. Large differences were observed both in terms of root and canopy development in response to the different application rates and frequencies. The prevailing irrigation management reflects on the soil water content dynamics, and consequently, on the plant water uptake and growth. Sap flow rates measurements indicated that higher irrigation frequency or lower water application rates increased plant water uptake rates. However, in most of the cases (except for the sand) it also led to a lower root mass and a smaller root mass/leaf area ratio. Interestingly, in the single plant per bucket experiments, a larger leaf area seemed conditioned on a larger root mass, while the opposite was the case in those two experiments where plants were grown in rows (perlite in containers and loamy sand field), where most prolific canopy development was supported by the smallest root mass. Integrating findings across the different experiments, we introduce the concept of mean daily available water volume per plant as the product of container/bucket volume and mean daily water content in the medium to express the joint effect of constraints imposed by the physical volume of growing medium and their specific hydraulic properties. Mean daily available water volume per plant was found to be positively correlated with the dry root mass to leaf area ratio.

@article{3b859764b75f4b97909a0d7f2e3caf3b,
title = "Impact of water regime and growing conditions on soil-plant interactions: From single plant to field scale",
abstract = "Global water resources quantities and qualities are declining, but at the same time, a strong demand for higher agricultural productivity continues to emerge due to population growth. This calls for a significant increase of irrigation and fertilization efficiencies and requires improving our understanding of the interactions between plants and their physical environment. The main objective of this study is to analyze the combined effect of varying drip irrigation management techniques and growing conditions (media properties and container volumes) on soil-plant interactions. In a series of experiments, irrigation flow rates and intervals ranging from 2 d to 10 min were applied to the vegetative stage of a test crop (bell pepper [Capsicum annuum L. 'Selika']) cultivated under different growing conditions- sand and perlite in buckets, perlite in containers, and loamy and under field conditions. Data on soil water regime, plant water uptake, and plant development were monitored in each setup. Large differences were observed both in terms of root and canopy development in response to the different application rates and frequencies. The prevailing irrigation management reflects on the soil water content dynamics, and consequently, on the plant water uptake and growth. Sap flow rates measurements indicated that higher irrigation frequency or lower water application rates increased plant water uptake rates. However, in most of the cases (except for the sand) it also led to a lower root mass and a smaller root mass/leaf area ratio. Interestingly, in the single plant per bucket experiments, a larger leaf area seemed conditioned on a larger root mass, while the opposite was the case in those two experiments where plants were grown in rows (perlite in containers and loamy sand field), where most prolific canopy development was supported by the smallest root mass. Integrating findings across the different experiments, we introduce the concept of mean daily available water volume per plant as the product of container/bucket volume and mean daily water content in the medium to express the joint effect of constraints imposed by the physical volume of growing medium and their specific hydraulic properties. Mean daily available water volume per plant was found to be positively correlated with the dry root mass to leaf area ratio.",
author = "S. Assouline and M. M{\"o}ller and A. Furman and K. Narkis and A. Silber",
year = "2012",
doi = "10.2136/vzj2012.0006",
language = "אנגלית",
volume = "11",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "3",

}

Water retention curves of biofilm-affected soils using xanthan as an analogue

Rosenzweig R, Shavit U, Furman A. Water retention curves of biofilm-affected soils using xanthan as an analogue. Soil Science Society of America Journal. 2012 Jan;76(1):61-69. https://doi.org/10.2136/sssaj2011.0155
 

This study investigated the effect of biofilms and, in particular, that of extracellular polymeric substances (EPS) on the hydraulic properties of porous media under unsaturated conditions. The quantitative understanding of the way biological activity alters hydraulic properties is a major key in understanding and engineering relevant systems such as soil aquifer treatment, bioremediation, and wastewater irrigation. Using an EPS analog (xanthan) we explored the effect of EPS on the water retention function of two sandy soils. The result was a significant increase in the water content at any given matric head that could reach 270% of its value within pure soil. For most of the water content range, we successfully modeled the effect of the EPS as a linear superposition of the original pure soil and the xanthan retention curves. Finally, we examined two mechanisms that can attribute to modification of the water retention curve: the EPS holding capacity and alteration of the soils' pore-size distribution; in our case, it appears that the first mechanism was dominant.

@article{d30bc1444c7245a7b9633ef7a8cf2243,
title = "Water retention curves of biofilm-affected soils using xanthan as an analogue",
abstract = "This study investigated the effect of biofilms and, in particular, that of extracellular polymeric substances (EPS) on the hydraulic properties of porous media under unsaturated conditions. The quantitative understanding of the way biological activity alters hydraulic properties is a major key in understanding and engineering relevant systems such as soil aquifer treatment, bioremediation, and wastewater irrigation. Using an EPS analog (xanthan) we explored the effect of EPS on the water retention function of two sandy soils. The result was a significant increase in the water content at any given matric head that could reach 270% of its value within pure soil. For most of the water content range, we successfully modeled the effect of the EPS as a linear superposition of the original pure soil and the xanthan retention curves. Finally, we examined two mechanisms that can attribute to modification of the water retention curve: the EPS holding capacity and alteration of the soils' pore-size distribution; in our case, it appears that the first mechanism was dominant.",
author = "Ravid Rosenzweig and Uri Shavit and Alex Furman",
year = "2012",
month = jan,
doi = "10.2136/sssaj2011.0155",
language = "אנגלית",
volume = "76",
pages = "61--69",
journal = "Soil Science Society of America Journal",
issn = "0361-5995",
publisher = "Soil Science Society of America",
number = "1",

}

2011

Modeling multidimensional flow in wettable and water-repellent soils using artificial neural networks

Xiong Y, Wallach R, Furman A. Modeling multidimensional flow in wettable and water-repellent soils using artificial neural networks. Journal of Hydrology. 2011 Nov 15;410(1-2):92-104. https://doi.org/10.1016/j.jhydrol.2011.09.019
 

This study examined the use of three different classes of artificial neural networks for modeling water flow in wettable and water-repellent soils, using both synthetic numerical data and experimentally measured data. The 1D self-organizing maps (SOM) successfully rendered the moisture contour in the transition zone of the wetting plumes for all soil types at different flow rates. Due to SOMs inability to generate external output data, multilayer perceptrons (MLP) and modular neural networks (MNN), respectively, were combined with SOM to predict the moisture contour for both wettable and water-repellent soils. Due to dimensionality reduction, the 1D SOM failed to capture high moisture content classes of water-repellent soils with anomalous wetting patterns, whereas spatial moment analysis succeeded in providing an accurate, albeit indirect, description. Hence, the MLP and MNN networks were applied to predict the spatial moments. The comparison between the predicted and the experimental measures demonstrated the capability of the MLP and SOM to predict the spatial moments. Comparison of the two different artificial neural networks indicated no significant difference between their results.

@article{3b06af0ef8304844a77c30f13c0fba56,
title = "Modeling multidimensional flow in wettable and water-repellent soils using artificial neural networks",
abstract = "This study examined the use of three different classes of artificial neural networks for modeling water flow in wettable and water-repellent soils, using both synthetic numerical data and experimentally measured data. The 1D self-organizing maps (SOM) successfully rendered the moisture contour in the transition zone of the wetting plumes for all soil types at different flow rates. Due to SOMs inability to generate external output data, multilayer perceptrons (MLP) and modular neural networks (MNN), respectively, were combined with SOM to predict the moisture contour for both wettable and water-repellent soils. Due to dimensionality reduction, the 1D SOM failed to capture high moisture content classes of water-repellent soils with anomalous wetting patterns, whereas spatial moment analysis succeeded in providing an accurate, albeit indirect, description. Hence, the MLP and MNN networks were applied to predict the spatial moments. The comparison between the predicted and the experimental measures demonstrated the capability of the MLP and SOM to predict the spatial moments. Comparison of the two different artificial neural networks indicated no significant difference between their results.",
keywords = "Modular neural networks, Multilayer perceptrons, Self-organizing maps, Spatial moment analysis, Water-repellent soil",
author = "Yunwu Xiong and Rony Wallach and Alex Furman",
note = "Funding Information: This research was supported by research Grant US-3662-05R from BARD , the United States–Israel Binational Agricultural Research and Development Fund. ",
year = "2011",
month = nov,
day = "15",
doi = "10.1016/j.jhydrol.2011.09.019",
language = "אנגלית",
volume = "410",
pages = "92--104",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",
number = "1-2",

}

The sensitivity of snow-surface temperature equation to sloped terrain

Sade R, Rimmer A, Iggy Litaor M, Shamir E, Furman A. The sensitivity of snow-surface temperature equation to sloped terrain. Journal of Hydrology. 2011 Oct 13;408(3-4):308-313. https://doi.org/10.1016/j.jhydrol.2011.08.001
 

Snow surface temperature (SST) is a key component in the calculation of snow-surface energy balance. Common snow models have adapted a specific linearized SST equation that accounts for the energy fluxes at the snow-atmosphere interface. An inspection of this widely used equation reveals that the areal units for three of the energy fluxes disregard the effect of sloped terrain and as a result presents a unit inconsistency in the equation. The objectives of this paper are to: (1) introduce a corrected SST equation; (2) discuss the role of the SST in snow models; and (3) assess the impact of this unit inconsistency on the simulation of snow variables in various climatic conditions. Meteorological observations were used to compare results that were obtained by implementation of the original and the corrected SST equations in a point energy and mass balance snow model. The calculated SST values in the original equation tend to be higher than the calculated value in the corrected equation. As a result when the original equation is used the SST-dependent energy fluxes (i.e. sensible heat, latent heat and net long-wave radiation) into the snow are lower, which yield lower melting rates. In conclusion, while the original SST equation might be applicable in snow models for gentle terrain, it introduces substantial biases in steep terrain. Therefore, it is conservatively recommended to consider the implementation of the corrected SST equation for snow model applications in mountainous terrain that are steeper than 15°.

@article{6ebc66b18b484b16a06f9d765e79819a,
title = "The sensitivity of snow-surface temperature equation to sloped terrain",
abstract = "Snow surface temperature (SST) is a key component in the calculation of snow-surface energy balance. Common snow models have adapted a specific linearized SST equation that accounts for the energy fluxes at the snow-atmosphere interface. An inspection of this widely used equation reveals that the areal units for three of the energy fluxes disregard the effect of sloped terrain and as a result presents a unit inconsistency in the equation. The objectives of this paper are to: (1) introduce a corrected SST equation; (2) discuss the role of the SST in snow models; and (3) assess the impact of this unit inconsistency on the simulation of snow variables in various climatic conditions. Meteorological observations were used to compare results that were obtained by implementation of the original and the corrected SST equations in a point energy and mass balance snow model. The calculated SST values in the original equation tend to be higher than the calculated value in the corrected equation. As a result when the original equation is used the SST-dependent energy fluxes (i.e. sensible heat, latent heat and net long-wave radiation) into the snow are lower, which yield lower melting rates. In conclusion, while the original SST equation might be applicable in snow models for gentle terrain, it introduces substantial biases in steep terrain. Therefore, it is conservatively recommended to consider the implementation of the corrected SST equation for snow model applications in mountainous terrain that are steeper than 15°.",
keywords = "Energy balance, Mountainous terrain, Sloped terrain, Snow point model, Snow surface temperature, UEB",
author = "Rotem Sade and Alon Rimmer and {Iggy Litaor}, M. and Eylon Shamir and Alex Furman",
note = "Funding Information: This research was partly supported by the Israeli Water Authority, and partly by GLOWA - Jordan River Project, funded by the German Ministry of Science and Education (BMBF), in collaboration with the Israeli Ministry of Science and Technology (MOST). We also want to thank the two anonymous reviewers for their helpful and constructive feedback.",
year = "2011",
month = oct,
day = "13",
doi = "10.1016/j.jhydrol.2011.08.001",
language = "אנגלית",
volume = "408",
pages = "308--313",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",
number = "3-4",

}

2010

Neuro-Drip: Estimation of subsurface wetting patterns for drip irrigation using neural networks

Hinnell AC, Lazarovitch N, Furman A, Poulton M, Warrick AW. Neuro-Drip: Estimation of subsurface wetting patterns for drip irrigation using neural networks. Irrigation Science. 2010;28(6):535-544. https://doi.org/10.1007/s00271-010-0214-8
 

Design of efficient drip irrigation systems requires information about the subsurface water distribution of added water during and after infiltration. Further, this information should be readily accessible to design engineers and practitioners. Neuro-Drip combines an artificial neural network (ANN) with a statistical description of the spatio-temporal distribution of the added water from a single drip emitter to provide easily accessible, rapid illustrations of the spatial and temporal subsurface wetting patterns. In this approach, the ANN is an approximator of a flow system. The ANN is trained using close to 1,000 numerical simulations of infiltration. Moment analysis is used to encapsulate the spatial distribution of water content. In practice, the user provides soil hydraulic properties and discharge rate; the ANN is then used to estimate the depth to the center of mass of the added water, and the vertical and radial spreading around the center of mass; finally, this statistical description of the added water is used to visualize the fate of the added water during and after the infiltration event.

@article{52407a342069466d946a84e0c612605a,
title = "Neuro-Drip: Estimation of subsurface wetting patterns for drip irrigation using neural networks",
abstract = "Design of efficient drip irrigation systems requires information about the subsurface water distribution of added water during and after infiltration. Further, this information should be readily accessible to design engineers and practitioners. Neuro-Drip combines an artificial neural network (ANN) with a statistical description of the spatio-temporal distribution of the added water from a single drip emitter to provide easily accessible, rapid illustrations of the spatial and temporal subsurface wetting patterns. In this approach, the ANN is an approximator of a flow system. The ANN is trained using close to 1,000 numerical simulations of infiltration. Moment analysis is used to encapsulate the spatial distribution of water content. In practice, the user provides soil hydraulic properties and discharge rate; the ANN is then used to estimate the depth to the center of mass of the added water, and the vertical and radial spreading around the center of mass; finally, this statistical description of the added water is used to visualize the fate of the added water during and after the infiltration event.",
author = "Hinnell, {A. C.} and N. Lazarovitch and A. Furman and M. Poulton and Warrick, {A. W.}",
note = "Funding Information: Acknowledgments This work was supported by The United States-Israel Binational Agricultural Research and Development fund (BARD), Project Grant Agreement No. US-3662-05R and the Agricultural and Development Department of Netafim, Israel.",
year = "2010",
doi = "10.1007/s00271-010-0214-8",
language = "אנגלית",
volume = "28",
pages = "535--544",
journal = "Irrigation Science",
issn = "0342-7188",
publisher = "Springer Verlag",
number = "6",

}

2009

Subsurface water distribution from furrows described by moment analyses

Lazarovitch N, Warrick AW, Furman A, Zerihun D. Subsurface water distribution from furrows described by moment analyses. Journal of Irrigation and Drainage Engineering. 2009;135(1):7-12. https://doi.org/10.1061/(ASCE)0733-9437(2009)135:1(7)
 

Moment analysis techniques are applied to describe the spatial and temporal subsurface wetting patterns resulting from furrow infiltration and redistribution. These techniques are adapted from previous work with drip irrigation. The water added is considered as a "plume" with the zeroth moment representing the total volume of water applied to the domain. The first moments lead to the location of the center of the plume, and the second moments relate to the amount of spreading about the mean position. Using moments, any fraction of the applied water and its spatial extent, defined by an ellipse, can be related to a "probability" curve. Remarkably, the probability curves are, for practical purposes, identical for all times and for all of the soils considered in this study. The same observation was made in relation to the distribution of water under a dripper. The consistency of the probability relationships can be exploited to pinpoint the distribution of irrigation water under a furrow in a compact and physically meaningful way. This approach is tested with numerically generated data for infiltration from furrows in three contrasting soils. The general conclusion is that moment analysis allows a straightforward, physically meaningful description of the general pattern of moisture distribution. Potential applications of the results of moment analyses include improved irrigation management, formulation of the infiltration and redistribution process from a furrow in a neural network setting, and parameter estimation of the soil hydraulic properties.

@article{ff66845b1e1346cdbc90c62d58a9bd83,
title = "Subsurface water distribution from furrows described by moment analyses",
abstract = "Moment analysis techniques are applied to describe the spatial and temporal subsurface wetting patterns resulting from furrow infiltration and redistribution. These techniques are adapted from previous work with drip irrigation. The water added is considered as a {"}plume{"} with the zeroth moment representing the total volume of water applied to the domain. The first moments lead to the location of the center of the plume, and the second moments relate to the amount of spreading about the mean position. Using moments, any fraction of the applied water and its spatial extent, defined by an ellipse, can be related to a {"}probability{"} curve. Remarkably, the probability curves are, for practical purposes, identical for all times and for all of the soils considered in this study. The same observation was made in relation to the distribution of water under a dripper. The consistency of the probability relationships can be exploited to pinpoint the distribution of irrigation water under a furrow in a compact and physically meaningful way. This approach is tested with numerically generated data for infiltration from furrows in three contrasting soils. The general conclusion is that moment analysis allows a straightforward, physically meaningful description of the general pattern of moisture distribution. Potential applications of the results of moment analyses include improved irrigation management, formulation of the infiltration and redistribution process from a furrow in a neural network setting, and parameter estimation of the soil hydraulic properties.",
keywords = "Furrow irrigation, Moments, Neural networks, Soil water",
author = "N. Lazarovitch and Warrick, {A. W.} and A. Furman and D. Zerihun",
year = "2009",
doi = "10.1061/(ASCE)0733-9437(2009)135:1(7)",
language = "אנגלית",
volume = "135",
pages = "7--12",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "1",

}

The influence of biofilm spatial distribution scenarios on hydraulic conductivity of unsaturated soils

Rosenzweig R, Shavit U, Furman A. The influence of biofilm spatial distribution scenarios on hydraulic conductivity of unsaturated soils. Vadose Zone Journal. 2009;8(4):1080-1084. https://doi.org/10.2136/vzj2009.0017
 

The development of biofilms in unsaturated soils is likely to influence the hydraulic conductivity function. Despite its importance, this effect has received little attention. Mostafa and Van Geel (2007, Vadose Zone Journal, 6:175-185) proposed several hydraulic conductivity models that acount for the effect of bacteria in unsaturated soils. We have expanded these models by considering the change in biofilm pore-size distribution and its effect on the entire hydraulic conductivity function. Three scenarios were considered: (i) the biofilm fills the smallest pores first; (ii) a biofilm of uniform thickness coats all pore walls; and (iii) the biofilm coats the soil with a constant volume fraction of each pore. The results show that the pore-scale distribution of the biofilm has a significant effect on the hydraulic properties of the soil and therefore has to be accounted for when modeling flow and transport in biofilm-affected soils.

@article{26fc49abe44b4f57a7a53ba670ff775c,
title = "The influence of biofilm spatial distribution scenarios on hydraulic conductivity of unsaturated soils",
abstract = "The development of biofilms in unsaturated soils is likely to influence the hydraulic conductivity function. Despite its importance, this effect has received little attention. Mostafa and Van Geel (2007, Vadose Zone Journal, 6:175-185) proposed several hydraulic conductivity models that acount for the effect of bacteria in unsaturated soils. We have expanded these models by considering the change in biofilm pore-size distribution and its effect on the entire hydraulic conductivity function. Three scenarios were considered: (i) the biofilm fills the smallest pores first; (ii) a biofilm of uniform thickness coats all pore walls; and (iii) the biofilm coats the soil with a constant volume fraction of each pore. The results show that the pore-scale distribution of the biofilm has a significant effect on the hydraulic properties of the soil and therefore has to be accounted for when modeling flow and transport in biofilm-affected soils.",
keywords = "MVG, Mostafa and Van Geel (2007)",
author = "Ravid Rosenzweig and Uri Shavit and Alex Furman",
year = "2009",
doi = "10.2136/vzj2009.0017",
language = "אנגלית",
volume = "8",
pages = "1080--1084",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "4",

}

Water distribution under trickle irrigation predicted using artificial neural networks

Lazarovitch N, Poulton M, Furman A, Warrick AW. Water distribution under trickle irrigation predicted using artificial neural networks. Journal of Engineering Mathematics. 2009;64(2):207-218. https://doi.org/10.1007/s10665-009-9282-2
 

An artificial neural network (ANN) technology is presented as an alternative to physical-based modeling of subsurface water distribution from trickle emitters. Three options are explored to prepare input-output functional relations from a database created using a numerical model (HYDRUS-2D). From the database the feasibility and advantages of the three alternative options are evaluated: water-content at defined coordinates, moment analysis describing the shape of the plume, and coordinates of individual water-content contours. The best option is determined in a way by the application objectives, but results suggest that prediction using moment analyses is probably the most versatile and robust and gives an adequate picture of the subsurface distribution. Of the other two options, the direct determination of the individual water contours was subjectively judged to be more successful than predicting the water content at given coordinates, at least in terms of describing the subsurface distribution. The results can be used to estimate subsurface water distribution for essentially any soil properties, initial conditions or flow rates for trickle sources.

@article{51fb1f4923de499a8a61c75edff43c04,
title = "Water distribution under trickle irrigation predicted using artificial neural networks",
abstract = "An artificial neural network (ANN) technology is presented as an alternative to physical-based modeling of subsurface water distribution from trickle emitters. Three options are explored to prepare input-output functional relations from a database created using a numerical model (HYDRUS-2D). From the database the feasibility and advantages of the three alternative options are evaluated: water-content at defined coordinates, moment analysis describing the shape of the plume, and coordinates of individual water-content contours. The best option is determined in a way by the application objectives, but results suggest that prediction using moment analyses is probably the most versatile and robust and gives an adequate picture of the subsurface distribution. Of the other two options, the direct determination of the individual water contours was subjectively judged to be more successful than predicting the water content at given coordinates, at least in terms of describing the subsurface distribution. The results can be used to estimate subsurface water distribution for essentially any soil properties, initial conditions or flow rates for trickle sources.",
keywords = "Artificial neural networks, Drip irrigation, Spatial moments, Water flow",
author = "N. Lazarovitch and M. Poulton and A. Furman and Warrick, {A. W.}",
note = "Funding Information: Acknowledgments This work was supported by The United States–Israel Binational Agricultural Research and Development fund (BARD), Project Grant Agreement No. US-3662-05R.",
year = "2009",
doi = "10.1007/s10665-009-9282-2",
language = "אנגלית",
volume = "64",
pages = "207--218",
journal = "Journal of Engineering Mathematics",
issn = "0022-0833",
publisher = "Springer Netherlands",
number = "2",

}

2008

Modeling coupled surface-subsurface flow processes: A review

Furman A. Modeling coupled surface-subsurface flow processes: A review. Vadose Zone Journal. 2008 May;7(2):741-756. https://doi.org/10.2136/vzj2007.0065
 

Surface and subsurface flow systems are inherently unified systems that are often broken into sections for logical (e.g., time scales) and technical (e.g., analytical and computational solvability) reasons. While the basic physical laws are common to surface and subsurface systems, spatial and temporal dimensions as well as the continuum approach used for the subsurface lead to different formulations of the governing partial differential equations. While in most applications such decoupling of the systems works well and allows a very accurate and efficient description of the individual system by treating the adjacent system as a boundary condition, in the case of water flow over a porous medium, it does not. Therefore coupled models are in increasing use in this field, led mostly by watershed and surface irrigation modelers. The governing equations of each component of the coupled system and the coupling physics and mathematics are reviewed first. Three different coupling schemes are identified, namely the uncoupled (with the degenerated uncoupled scheme being a special case of the uncoupled), the iteratively coupled, and the fully coupled. Next, the different applications of the different coupling schemes, sorted by field of application, are reviewed. Finally, some research gaps are discussed, led by the need to include vertical momentum transfer and to expand the use of fully coupled models toward surface irrigation applications.

@article{1cebd3a01e0c476da38ab97a002fb062,
title = "Modeling coupled surface-subsurface flow processes: A review",
abstract = "Surface and subsurface flow systems are inherently unified systems that are often broken into sections for logical (e.g., time scales) and technical (e.g., analytical and computational solvability) reasons. While the basic physical laws are common to surface and subsurface systems, spatial and temporal dimensions as well as the continuum approach used for the subsurface lead to different formulations of the governing partial differential equations. While in most applications such decoupling of the systems works well and allows a very accurate and efficient description of the individual system by treating the adjacent system as a boundary condition, in the case of water flow over a porous medium, it does not. Therefore coupled models are in increasing use in this field, led mostly by watershed and surface irrigation modelers. The governing equations of each component of the coupled system and the coupling physics and mathematics are reviewed first. Three different coupling schemes are identified, namely the uncoupled (with the degenerated uncoupled scheme being a special case of the uncoupled), the iteratively coupled, and the fully coupled. Next, the different applications of the different coupling schemes, sorted by field of application, are reviewed. Finally, some research gaps are discussed, led by the need to include vertical momentum transfer and to expand the use of fully coupled models toward surface irrigation applications.",
author = "Alex Furman",
year = "2008",
month = may,
doi = "10.2136/vzj2007.0065",
language = "אנגלית",
volume = "7",
pages = "741--756",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "2",

}

Development of simplified solutions for modeling recession in basins

Zerihun D, Furman A, Sanchez CA, Warrick WA. Development of simplified solutions for modeling recession in basins. Journal of Irrigation and Drainage Engineering. 2008 May;134(3):327-340. https://doi.org/10.1061/(ASCE)0733-9437(2008)134:3(327)
 

In irrigation basins the decrease in the gradient of the water-surface elevation following inflow cutoff often leads to reduced rate of convergence, increased computational time, and reduced robustness of the numerical solutions of the recession phase. As the water surface levels off, the underlying physical problem simplifies, thus allowing the use of highly accurate yet simple alternate solutions to the full-numerical solution of the zero-inertia equations. For level basins, the simplification involves treating the stream as a static pool, in which water level only falls in response to infiltration. Graded basins may require partitioning the stream into a flowing and static pool, before water-surface eventually levels off over the entire stream length. Implementation of these solutions enhances computational efficiency and robustness of surface irrigation models without a concomitant loss of accuracy. This paper discusses numerical problems related to the recession phase computation in basins and proposes simplified and robust, yet highly accurate solutions. A comparison of the recession trajectories and final infiltration profiles predicted by the full-numerical solution of the zero-inertia equations, obtained by using double-precision floating-point arithmetic, and the simplified alternate solutions, which is robust enough to be implemented over a range of hardware-software capabilities, show that the two approaches yield essentially identical results. Finally, the general validity of the proposed solutions is tested by comparing predictions of recession trajectories and infiltration profiles with those obtained using a surface irrigation hydraulic model, SRFR.

@article{13a48f83620f4144a8555bca957ab44b,
title = "Development of simplified solutions for modeling recession in basins",
abstract = "In irrigation basins the decrease in the gradient of the water-surface elevation following inflow cutoff often leads to reduced rate of convergence, increased computational time, and reduced robustness of the numerical solutions of the recession phase. As the water surface levels off, the underlying physical problem simplifies, thus allowing the use of highly accurate yet simple alternate solutions to the full-numerical solution of the zero-inertia equations. For level basins, the simplification involves treating the stream as a static pool, in which water level only falls in response to infiltration. Graded basins may require partitioning the stream into a flowing and static pool, before water-surface eventually levels off over the entire stream length. Implementation of these solutions enhances computational efficiency and robustness of surface irrigation models without a concomitant loss of accuracy. This paper discusses numerical problems related to the recession phase computation in basins and proposes simplified and robust, yet highly accurate solutions. A comparison of the recession trajectories and final infiltration profiles predicted by the full-numerical solution of the zero-inertia equations, obtained by using double-precision floating-point arithmetic, and the simplified alternate solutions, which is robust enough to be implemented over a range of hardware-software capabilities, show that the two approaches yield essentially identical results. Finally, the general validity of the proposed solutions is tested by comparing predictions of recession trajectories and infiltration profiles with those obtained using a surface irrigation hydraulic model, SRFR.",
keywords = "Basins, Irrigation, Models, Recession",
author = "D. Zerihun and A. Furman and Sanchez, {C. A.} and Warrick, {W. A.}",
year = "2008",
month = may,
doi = "10.1061/(ASCE)0733-9437(2008)134:3(327)",
language = "אנגלית",
volume = "134",
pages = "327--340",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "3",

}

2007

Explicit infiltration function for furrows

Warrick AW, Lazarovitch N, Furman A, Zerihun D. Explicit infiltration function for furrows. Journal of Irrigation and Drainage Engineering. 2007 Jul;133(4):307-313. https://doi.org/10.1061/(ASCE)0733-9437(2007)133:4(307)
 

This study addresses infiltration from furrows or narrow channels. The basic approach is to develop the two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The idea is borrowed from previous applications for infiltration from disc and strip sources. The assumption is tested directly with numerical experiments using four representative soils and three furrow shapes (triangular, rectangular, and parabolic). The edge effect is the difference between the cumulative infiltration per unit of adjusted wetting perimeter and the corresponding one-dimensional infiltration. A general conclusion is that the edge effect is linearly related to time. In addition, it was observed that the two empirical parameters in the function used to relate the edge effect with time have narrow ranges and are related to soil hydraulic parameters, furrow shape, the boundary and initial conditions and additional geometric factors. The approach leads to a physically based infiltration function for irrigation furrows (or narrow channels) without the need to perform a fully two-dimensional simulation. Also, a simplified expression was found for the limiting steady-state case, which is analogous to Wooding's equation for infiltration from a shallow pond.

@article{61b8fd3199fa4dabbaf1c3aad1b2cd81,
title = "Explicit infiltration function for furrows",
abstract = "This study addresses infiltration from furrows or narrow channels. The basic approach is to develop the two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The idea is borrowed from previous applications for infiltration from disc and strip sources. The assumption is tested directly with numerical experiments using four representative soils and three furrow shapes (triangular, rectangular, and parabolic). The edge effect is the difference between the cumulative infiltration per unit of adjusted wetting perimeter and the corresponding one-dimensional infiltration. A general conclusion is that the edge effect is linearly related to time. In addition, it was observed that the two empirical parameters in the function used to relate the edge effect with time have narrow ranges and are related to soil hydraulic parameters, furrow shape, the boundary and initial conditions and additional geometric factors. The approach leads to a physically based infiltration function for irrigation furrows (or narrow channels) without the need to perform a fully two-dimensional simulation. Also, a simplified expression was found for the limiting steady-state case, which is analogous to Wooding's equation for infiltration from a shallow pond.",
keywords = "Analytical techniques, Furrow irrigation, Infiltration, Mathematical models, Two-dimensional models",
author = "Warrick, {A. W.} and N. Lazarovitch and A. Furman and D. Zerihun",
year = "2007",
month = jul,
doi = "10.1061/(ASCE)0733-9437(2007)133:4(307)",
language = "אנגלית",
volume = "133",
pages = "307--313",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "4",

}

Erratum: Subsurface water distribution from drip irrigation described by moment analyses (Vadose Zone Journal (February 2007) 6, (116-123))

Lazarovitch N, Warrick AW, Furman A, Šimůnek J. Erratum: Subsurface water distribution from drip irrigation described by moment analyses (Vadose Zone Journal (February 2007) 6, (116-123)). Vadose Zone Journal. 2007 Feb;6(1):203. https://doi.org/10.2136/vzj2006.0052er
@article{c0dbecd4a9264a8e8a0b734ccecbf74c,
title = "Erratum: Subsurface water distribution from drip irrigation described by moment analyses (Vadose Zone Journal (February 2007) 6, (116-123))",
author = "N. Lazarovitch and Warrick, {A. W.} and A. Furman and J. {\v S}imůnek",
year = "2007",
month = feb,
doi = "10.2136/vzj2006.0052er",
language = "אנגלית",
volume = "6",
pages = "203",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "1",

}

Subsurface water distribution from drip irrigation described by moment analyses

Lazarovitch N, Warrick AW, Furman A, Šimůnek J. Subsurface water distribution from drip irrigation described by moment analyses. Vadose Zone Journal. 2007 Feb;6(1):116-123. https://doi.org/10.2136/vzj2006.0052
 

Moment analysis techniques are used to describe spatial and temporal subsurface wetting patterns resulting from drip emitters. The water added is considered a "plume" with the zeroth moment representing the total volume of water applied. The first moments lead to the location of the center of the plume, and the second moments relate to the amount of spreading about the mean position. We tested this approach with numerically generated data for infiltration from surface and buried line and point sources in three contrasting soils. Ellipses (in two dimensions) or ellipsoids (in three dimensions) can be depicted about the center of the plume. Any fraction of water added can be related to a "probability" curve relating the size of the ellipse (or ellipsoid) that contains that amount of water. Remarkably, the probability curves are identical for all times and all of the contrasting soils. The consistency of the probability relationships can be exploited to pinpoint the extent of subsurface water for any fraction of the volume added. The new method can be immediately applied to the vital question of how many sensors are needed and where to install them to capture the overall water distribution under drip irrigation. For example, better agreement with the "exact" solution occurs with increasing the number of observation points from 6 to 9 and no significant improvement when increasing from 9 to 16. The method can also be applied to parameter estimation of soil hydraulic properties, which we uniquely reproduced for generated data.

@article{937741e5048840e8aa93011243cffc4f,
title = "Subsurface water distribution from drip irrigation described by moment analyses",
abstract = "Moment analysis techniques are used to describe spatial and temporal subsurface wetting patterns resulting from drip emitters. The water added is considered a {"}plume{"} with the zeroth moment representing the total volume of water applied. The first moments lead to the location of the center of the plume, and the second moments relate to the amount of spreading about the mean position. We tested this approach with numerically generated data for infiltration from surface and buried line and point sources in three contrasting soils. Ellipses (in two dimensions) or ellipsoids (in three dimensions) can be depicted about the center of the plume. Any fraction of water added can be related to a {"}probability{"} curve relating the size of the ellipse (or ellipsoid) that contains that amount of water. Remarkably, the probability curves are identical for all times and all of the contrasting soils. The consistency of the probability relationships can be exploited to pinpoint the extent of subsurface water for any fraction of the volume added. The new method can be immediately applied to the vital question of how many sensors are needed and where to install them to capture the overall water distribution under drip irrigation. For example, better agreement with the {"}exact{"} solution occurs with increasing the number of observation points from 6 to 9 and no significant improvement when increasing from 9 to 16. The method can also be applied to parameter estimation of soil hydraulic properties, which we uniquely reproduced for generated data.",
author = "N. Lazarovitch and Warrick, {A. W.} and A. Furman and J. {\v S}imůnek",
year = "2007",
month = feb,
doi = "10.2136/vzj2006.0052",
language = "אנגלית",
volume = "6",
pages = "116--123",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "1",

}

Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering

Furman A, Ferré TPA, Heath GL. Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering. Geophysics. 2007;72(2):F65-F73. https://doi.org/10.1190/1.2433737
 

Electrical resistivity tomography (ERT) has shown great promise for monitoring transient hydrologic processes. One advantage of ERT under those conditions is the ability of a user to tailor the spatial sensitivity of an ERT survey through selection of electrode locations and electrode combinations. Recent research has shown that quadripoles can be selected in a manner that improves the independent inversion of ERT data. Our ultimate interest lies in using ERT data along with measurements from other sensors, which typically can provide high-quality data from shallow regions of the subsurface, in a joint inversion. As a result, we do not consider the selection of quadripoles specifically for inde-pendent ERT inversion. Rather, we present an approach to focusthe spatial sensitivity of ERT surveys in specificsubsurface regions with the assumption that those data, when interpreted along with other measurements that are sensitive to those regions, will lead to more complete hydrologic characterization. Because we are interested in monitoring rapid processes, our approach is designed to efficiently identify optimal quadripoles. This is achieved by separating the optimization from the inversion grid, significantly reducing computational effort. We extend our previous work to consider the use of both surface and borehole ERT electrodes and to consider the impacts of horizontally layered electrical conductivity conditions. Results confirm the ability of the method to focus survey sensitivity while showing the importance of incorporation of prior knowledge of the subsurface electric conductivity structure in designing optimal ERT surveys.

@article{715cf375cd25478c8d6d7f1ce4c01e2b,
title = "Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering",
abstract = "Electrical resistivity tomography (ERT) has shown great promise for monitoring transient hydrologic processes. One advantage of ERT under those conditions is the ability of a user to tailor the spatial sensitivity of an ERT survey through selection of electrode locations and electrode combinations. Recent research has shown that quadripoles can be selected in a manner that improves the independent inversion of ERT data. Our ultimate interest lies in using ERT data along with measurements from other sensors, which typically can provide high-quality data from shallow regions of the subsurface, in a joint inversion. As a result, we do not consider the selection of quadripoles specifically for inde-pendent ERT inversion. Rather, we present an approach to focusthe spatial sensitivity of ERT surveys in specificsubsurface regions with the assumption that those data, when interpreted along with other measurements that are sensitive to those regions, will lead to more complete hydrologic characterization. Because we are interested in monitoring rapid processes, our approach is designed to efficiently identify optimal quadripoles. This is achieved by separating the optimization from the inversion grid, significantly reducing computational effort. We extend our previous work to consider the use of both surface and borehole ERT electrodes and to consider the impacts of horizontally layered electrical conductivity conditions. Results confirm the ability of the method to focus survey sensitivity while showing the importance of incorporation of prior knowledge of the subsurface electric conductivity structure in designing optimal ERT surveys.",
keywords = "Electrical conductivity, Hydrology, Terrestrial electricity",
author = "Alex Furman and Ferr{\'e}, {Ty P.A.} and Heath, {Gail L.}",
year = "2007",
doi = "10.1190/1.2433737",
language = "אנגלית",
volume = "72",
pages = "F65--F73",
journal = "Geophysics",
issn = "0016-8033",
publisher = "Society of Exploration Geophysicists",
number = "2",

}

לאן הולך הגשם?

אסולין ש, פורמן א. לאן הולך הגשם? מים וסביבה. 2007;72:6-11.
 
שינויים במאפייני הגשם במספר תחנות בישראל בשני העשורים האחרונים - היבטים חקלאיים.
@article{3d4a890a6a894940a83b83a91141c053,
title = "לאן הולך הגשם?",
abstract = "שינויים במאפייני הגשם במספר תחנות בישראל בשני העשורים האחרונים - היבטים חקלאיים.",
author = "שמואל אסולין and אלכס פורמן",
year = "2007",
language = "עברית",
volume = "72",
pages = "6--11",
journal = "מים וסביבה",

}

2006

Modified kostiakov infiltration function: Accounting for initial and boundary conditions

Furman A, Warrick AW, Zerihun D, Sanchez CA. Modified kostiakov infiltration function: Accounting for initial and boundary conditions. Journal of Irrigation and Drainage Engineering. 2006 Nov;132(6):587-596. https://doi.org/10.1061/(ASCE)0733-9437(2006)132:6(587)
 

The effect of specific initial and boundary conditions is generally not considered when applying the Kostiakov infiltration functions. A methodology is developed to account for changes in water levels and initial soil moisture. First, Richards' equation is solved numerically to generate a database of one-dimensional infiltration values, with varying initial (water content or pressure head) and boundary (ponding depth) conditions for three contrasting soils. These are then used to calibrate corresponding coefficients for modified Kostiakov models and, by considering linear regressions, to obtain simple correction factors. Results show that the correction factors are not universally valid, and only the correction to the Kostiakov k parameter shows statistically consistent applicability. However, examples demonstrate potentially significant improvement in the accuracy of irrigation models by correcting the Kostiakov equation to account for initial and boundary conditions.

@article{8a8f70668aa64d2695d906e2774d3ecc,
title = "Modified kostiakov infiltration function: Accounting for initial and boundary conditions",
abstract = "The effect of specific initial and boundary conditions is generally not considered when applying the Kostiakov infiltration functions. A methodology is developed to account for changes in water levels and initial soil moisture. First, Richards' equation is solved numerically to generate a database of one-dimensional infiltration values, with varying initial (water content or pressure head) and boundary (ponding depth) conditions for three contrasting soils. These are then used to calibrate corresponding coefficients for modified Kostiakov models and, by considering linear regressions, to obtain simple correction factors. Results show that the correction factors are not universally valid, and only the correction to the Kostiakov k parameter shows statistically consistent applicability. However, examples demonstrate potentially significant improvement in the accuracy of irrigation models by correcting the Kostiakov equation to account for initial and boundary conditions.",
keywords = "Boundaries, Hydrologic models, Infiltration, Moisture content, Surface irrigation, Water flow",
author = "Alex Furman and Warrick, {A. W.} and Dawit Zerihun and Sanchez, {C. A.}",
year = "2006",
month = nov,
doi = "10.1061/(ASCE)0733-9437(2006)132:6(587)",
language = "אנגלית",
volume = "132",
pages = "587--596",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "6",

}

2005

Coupled surface-subsurface solute transport model for irrigation borders and basins. II. Model evaluation

Zerihun D, Sanchez CA, Furman A, Warrick AW. Coupled surface-subsurface solute transport model for irrigation borders and basins. II. Model evaluation. Journal of Irrigation and Drainage Engineering. 2005 Sep;131(5):407-419. https://doi.org/10.1061/(ASCE)0733-9437(2005)131:5(407)
 

The development of a coupled surface-subsurface solute transport model for surface fertigation management is presented in a companion paper (Part I). This paper discusses an evaluation of the coupled model. The numerical solution for pure advection of solute in the surface stream was evaluated using test problems with steep concentration gradients. The result shows that the model can simulate advection without numerical diffusion and oscillations, an important problem in the solution of the advection-dispersion equation in advection dominated solute transport. In addition, a close match was obtained between the numerical solution of the one-dimensional advection-dispersion equation and a simplified analytical solution. A comparison of field data and model output show that the overall mean relative residual between field observed and model predicted solute breakthrough curves in the surface stream is 16.0%. Excluding only two outlier (in the graded basin data) reduces the over all mean relative residual between field observed and model predicted breakthrough curves to 5.2%. Finally, potential applications of the model in surface fertigation and salinity management are highlighted. Journal of Irrigation and Drainage Engineering

@article{b22d2b64806747c0aa87aa648b41269e,
title = "Coupled surface-subsurface solute transport model for irrigation borders and basins. II. Model evaluation",
abstract = "The development of a coupled surface-subsurface solute transport model for surface fertigation management is presented in a companion paper (Part I). This paper discusses an evaluation of the coupled model. The numerical solution for pure advection of solute in the surface stream was evaluated using test problems with steep concentration gradients. The result shows that the model can simulate advection without numerical diffusion and oscillations, an important problem in the solution of the advection-dispersion equation in advection dominated solute transport. In addition, a close match was obtained between the numerical solution of the one-dimensional advection-dispersion equation and a simplified analytical solution. A comparison of field data and model output show that the overall mean relative residual between field observed and model predicted solute breakthrough curves in the surface stream is 16.0%. Excluding only two outlier (in the graded basin data) reduces the over all mean relative residual between field observed and model predicted breakthrough curves to 5.2%. Finally, potential applications of the model in surface fertigation and salinity management are highlighted. Journal of Irrigation and Drainage Engineering",
keywords = "Coupling, Models, Salinity, Solutes, Surface irrigation, Unsaturated flow",
author = "D. Zerihun and Sanchez, {C. A.} and A. Furman and Warrick, {A. W.}",
year = "2005",
month = sep,
doi = "10.1061/(ASCE)0733-9437(2005)131:5(407)",
language = "אנגלית",
volume = "131",
pages = "407--419",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "5",

}

Coupled surface-subsurface solute transport model for irrigation borders and basins. I. Model development

Zerihun D, Furman A, Warrick AW, Sanchez CA. Coupled surface-subsurface solute transport model for irrigation borders and basins. I. Model development. Journal of Irrigation and Drainage Engineering. 2005 Sep;131(5):396-406. https://doi.org/10.1061/(ASCE)0733-9437(2005)131:5(396)
 

Surface fertigation is widely practiced in irrigated crop production systems. Lack of design and management tools limits the effectiveness of surface fertigation practices. The availability of a process-based coupled surface-subsurface hydraulic and solute transport model can lead to improved surface fertigation management. This paper presents the development of a coupled surface-subsurface solute transport model. A hydraulic model described in a previous paper by the writers provided the hydrodynamic basis for the solute transport model presented here. A numerical solution of the area averaged advection-dispersion equation, based on the split-operator approach, forms the surface solute transport component of the coupled model. The subsurface transport process is simulated using HYDRUS-1D, which also solves the one-dimensional advection-dispersion equation. A driver program is used for the internal coupling of the surface and subsurface transport models. Solute fluxes calculated using the surface transport model are used as upper boundary conditions for the subsurface model. Evaluation of the model is presented in a companion paper. Journal of Irrigation and Drainage Engineering

@article{1ec0d257e99f4c30a378640f7aecbc8b,
title = "Coupled surface-subsurface solute transport model for irrigation borders and basins. I. Model development",
abstract = "Surface fertigation is widely practiced in irrigated crop production systems. Lack of design and management tools limits the effectiveness of surface fertigation practices. The availability of a process-based coupled surface-subsurface hydraulic and solute transport model can lead to improved surface fertigation management. This paper presents the development of a coupled surface-subsurface solute transport model. A hydraulic model described in a previous paper by the writers provided the hydrodynamic basis for the solute transport model presented here. A numerical solution of the area averaged advection-dispersion equation, based on the split-operator approach, forms the surface solute transport component of the coupled model. The subsurface transport process is simulated using HYDRUS-1D, which also solves the one-dimensional advection-dispersion equation. A driver program is used for the internal coupling of the surface and subsurface transport models. Solute fluxes calculated using the surface transport model are used as upper boundary conditions for the subsurface model. Evaluation of the model is presented in a companion paper. Journal of Irrigation and Drainage Engineering",
keywords = "Coupling, Models, Salinity, Solutes, Surface irrigation, Unsaturated flow",
author = "D. Zerihun and A. Furman and Warrick, {A. W.} and Sanchez, {C. A.}",
year = "2005",
month = sep,
doi = "10.1061/(ASCE)0733-9437(2005)131:5(396)",
language = "אנגלית",
volume = "131",
pages = "396--406",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "5",

}

Infiltration under variable ponding depths of water

Warrick AW, Zerihun D, Sanchez CA, Furman A. Infiltration under variable ponding depths of water. Journal of Irrigation and Drainage Engineering. 2005 Jul;131(4):358-363. https://doi.org/10.1061/(ASCE)0733-9437(2005)131:4(358)
 

Cumulative infiltration was computed as a function of time-varying ponded water depths using a Green and Ampt analysis. The input water depths were field-measured values from two irrigation events on Superstition sand, one from a basin and one from a border. For both types of irrigation, the computed cumulative infiltration at a given measuring station was nearly the same whether using a variable head input or a constant (average) head during the time of opportunity. As an example, at the first measurement station for the basin event, the ponded depth went from a 0 to 9 cm depth over the 2-12 min. from the time water was introduced into the basin; this was followed by a decrease to a depth of 4 cm at 60 min. The computed infiltration using the depth hydrograph was 14.3 cm compared to 14.1 cm when using an average depth. A smaller value of 13.7 cm is found using the appropriate time of opportunity with a field averaged depth and a considerably smaller value of 12.4 cm was found when a zero-depth boundary is considered. Basin and border uniformities were also computed based on variable and different constant depths and the results were found to be reasonably robust whether infiltration is computed using a variable or an appropriate constant ponded depth.

@article{86a6158c11f146ae93a9fa9d732aa1c0,
title = "Infiltration under variable ponding depths of water",
abstract = "Cumulative infiltration was computed as a function of time-varying ponded water depths using a Green and Ampt analysis. The input water depths were field-measured values from two irrigation events on Superstition sand, one from a basin and one from a border. For both types of irrigation, the computed cumulative infiltration at a given measuring station was nearly the same whether using a variable head input or a constant (average) head during the time of opportunity. As an example, at the first measurement station for the basin event, the ponded depth went from a 0 to 9 cm depth over the 2-12 min. from the time water was introduced into the basin; this was followed by a decrease to a depth of 4 cm at 60 min. The computed infiltration using the depth hydrograph was 14.3 cm compared to 14.1 cm when using an average depth. A smaller value of 13.7 cm is found using the appropriate time of opportunity with a field averaged depth and a considerably smaller value of 12.4 cm was found when a zero-depth boundary is considered. Basin and border uniformities were also computed based on variable and different constant depths and the results were found to be reasonably robust whether infiltration is computed using a variable or an appropriate constant ponded depth.",
keywords = "Border irrigation, Infiltration rate, Soil water, Surface irrigation",
author = "Warrick, {A. W.} and Dawit Zerihun and Sanchez, {C. A.} and Alex Furman",
year = "2005",
month = jul,
doi = "10.1061/(ASCE)0733-9437(2005)131:4(358)",
language = "אנגלית",
volume = "131",
pages = "358--363",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "4",

}

Unsaturated flow through spherical inclusions with contrasting sorptive numbers

Furman A, Warrick AW. Unsaturated flow through spherical inclusions with contrasting sorptive numbers. Vadose Zone Journal. 2005 May;4(2):255-263. https://doi.org/10.2136/vzj2004.0076
 

The analytic element method (AEM) is used to model unsaturated flow through a spherical inclusion of contrasting hydraulic properties. The steady state Richards' equation is combined with the Gardner model for unsaturated hydraulic conductivity to form the Helmholtz equation. The later is solved by means of the AEM. The background and inclusion materials are assumed to have different saturated hydraulic conductivities and different sorptive numbers; hence, the conditions are more general than treatments of spherical inclusions. Continuity of the interfacial head boundary condition leads to a nonlinear system of equations, whose solution requires an iterative solution. Analysis includes the effect of the hydraulic properties and of the background flux and evaluation of computational efficiency for contrasting hydraulic properties. To examine water contents, a methodology is presented for matching Gardner and van Genuchten parameters. The new solution is more realistic than the previous solution for a spherical inclusion with a sorptive number the same as the background but is computationally more tedious.

@article{fcf51292b79e44aebb3c5cc0ca71b4df,
title = "Unsaturated flow through spherical inclusions with contrasting sorptive numbers",
abstract = "The analytic element method (AEM) is used to model unsaturated flow through a spherical inclusion of contrasting hydraulic properties. The steady state Richards' equation is combined with the Gardner model for unsaturated hydraulic conductivity to form the Helmholtz equation. The later is solved by means of the AEM. The background and inclusion materials are assumed to have different saturated hydraulic conductivities and different sorptive numbers; hence, the conditions are more general than treatments of spherical inclusions. Continuity of the interfacial head boundary condition leads to a nonlinear system of equations, whose solution requires an iterative solution. Analysis includes the effect of the hydraulic properties and of the background flux and evaluation of computational efficiency for contrasting hydraulic properties. To examine water contents, a methodology is presented for matching Gardner and van Genuchten parameters. The new solution is more realistic than the previous solution for a spherical inclusion with a sorptive number the same as the background but is computationally more tedious.",
author = "Alex Furman and Warrick, {A. W.}",
year = "2005",
month = may,
doi = "10.2136/vzj2004.0076",
language = "אנגלית",
volume = "4",
pages = "255--263",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "2",

}

Coupled surface-subsurface flow model for improved basin irrigation management

Zerihun D, Furman A, Warrick AW, Sanchez CA. Coupled surface-subsurface flow model for improved basin irrigation management. Journal of Irrigation and Drainage Engineering. 2005 Mar;131(2):111-128. https://doi.org/10.1061/(ASCE)0733-9437(2005)131:2(111)
 

The availability of a process-based coupled surface-subsurface model can lead to improved surface irrigation/fertigation management practices. In this study, a one-dimensional zero-inertia model is coupled with a one-dimensional unsaturated zone water-flow model: HYDRUS-1D. A driver program is used to effect internal iterative coupling of the surface and subsurface flow models. Flow depths calculated using the surface-flow model are used as Dirichlet boundary conditions for the subsurface-flow model, and infiltration amounts calculated by the subsurface model are in turn used in surface-flow mass balance calculations. The model was tested by using field data collected at the University of Arizona, Yuma Mesa, research farm. The maximum mean absolute difference between field-observed and model-predicted advance is 2 min. Applications of the coupled model in improved irrigation management are highlighted. In addition, the significance of the effects of soil moisture redistribution on irrigation water availability to crops and the capability of the coupled model in tracking those changes in soil water status over time are discussed using examples.

@article{31d77a3daad74ace9f438f172653a6e4,
title = "Coupled surface-subsurface flow model for improved basin irrigation management",
abstract = "The availability of a process-based coupled surface-subsurface model can lead to improved surface irrigation/fertigation management practices. In this study, a one-dimensional zero-inertia model is coupled with a one-dimensional unsaturated zone water-flow model: HYDRUS-1D. A driver program is used to effect internal iterative coupling of the surface and subsurface flow models. Flow depths calculated using the surface-flow model are used as Dirichlet boundary conditions for the subsurface-flow model, and infiltration amounts calculated by the subsurface model are in turn used in surface-flow mass balance calculations. The model was tested by using field data collected at the University of Arizona, Yuma Mesa, research farm. The maximum mean absolute difference between field-observed and model-predicted advance is 2 min. Applications of the coupled model in improved irrigation management are highlighted. In addition, the significance of the effects of soil moisture redistribution on irrigation water availability to crops and the capability of the coupled model in tracking those changes in soil water status over time are discussed using examples.",
keywords = "Coupling, Hydrologic models, Irrigation practices, Surface irrigation, Unsaturated flow",
author = "D. Zerihun and A. Furman and Warrick, {A. W.} and Sanchez, {C. A.}",
year = "2005",
month = mar,
doi = "10.1061/(ASCE)0733-9437(2005)131:2(111)",
language = "אנגלית",
volume = "131",
pages = "111--128",
journal = "Journal of Irrigation and Drainage Engineering",
issn = "0733-9437",
publisher = "American Society of Civil Engineers (ASCE)",
number = "2",

}

2004

Optimization of ERT surveys for monitoring transient hydrological events using perturbation sensitivity and genetic algorithms

Furman A, Ferré TPA, Warrick AW. Optimization of ERT surveys for monitoring transient hydrological events using perturbation sensitivity and genetic algorithms. Vadose Zone Journal. 2004 Nov;3(4):1230-1239. https://doi.org/10.2113/3.4.1230
 

A simple yet powerful algorithm is presented for the optimal allocation of electrical resistivity tomography (ERT) electrodes to maximize measurement quality. The algorithm makes use of a definition of the sensitivity of an ERT array to a series of subsurface perturbations. An objective function that maximizes the average sensitivity of a survey comprised of a large number of arrays is defined. A simple genetic algorithm is used to find the optimal ERT survey if there is a limited time allowed for survey. We further show that this approach allows for user definition of the sensitivity distribution within the targeted area. Results show clear improvement in the sensitivity distribution. The total sensitivity of the optimized survey compared with typically used surveys composed of one array type. This improved sensitivity will allow for more accurate monitoring of static and transient vadose zone processes. Furthermore, the algorithm presented may be fast enough to allow for real-time optimization during time- lapse surveys.

@article{3f6efbeaca4a4002bcdf5efd4eabcdac,
title = "Optimization of ERT surveys for monitoring transient hydrological events using perturbation sensitivity and genetic algorithms",
abstract = "A simple yet powerful algorithm is presented for the optimal allocation of electrical resistivity tomography (ERT) electrodes to maximize measurement quality. The algorithm makes use of a definition of the sensitivity of an ERT array to a series of subsurface perturbations. An objective function that maximizes the average sensitivity of a survey comprised of a large number of arrays is defined. A simple genetic algorithm is used to find the optimal ERT survey if there is a limited time allowed for survey. We further show that this approach allows for user definition of the sensitivity distribution within the targeted area. Results show clear improvement in the sensitivity distribution. The total sensitivity of the optimized survey compared with typically used surveys composed of one array type. This improved sensitivity will allow for more accurate monitoring of static and transient vadose zone processes. Furthermore, the algorithm presented may be fast enough to allow for real-time optimization during time- lapse surveys.",
author = "Alex Furman and Ferr{\'e}, {Ty P.A.} and Warrick, {Art W.}",
year = "2004",
month = nov,
doi = "10.2113/3.4.1230",
language = "אנגלית",
volume = "3",
pages = "1230--1239",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "4",

}

Laplace transform analytic element method for transient flow problems

Furman A, Neuman SP. Laplace transform analytic element method for transient flow problems. Developments in Water Science. 2004;55(PART 1):371-379. https://doi.org/10.1016/S0167-5648(04)80065-0
 

Recently we [12] proposed a new Laplace transform analytic element method (LT-AEM) for the solution of transient groundwater flow problems. Laplace transformation of the transient flow equations leads to a time-independent modified Helmholtz equation and associated conditions at discontinuities. The latter are solved by AEM and the results transformed numerically back into the time domain. Though neither continuity of potential nor continuity of flux are satisfied automatically at internal discontinuities, both are satisfied approximately via least squares at an overdetermined system of control points in a manner similar to that of Janković [17] and Barnes and Janković [5]. LT-AEM preserves all advantages of the AEM in Laplace space, most importantly its mathematical elegance and grid-free nature. Solution in Laplace space and numerical back transformation into the time domain are done independently for any given time and are thus amenable to parallel computation on multiple processors. This renders the method particularly well suited for cases where a high-accuracy solution is required at a relatively small number of discrete space-time locations. LT-AEM requires a new family of analytic elements associated transformation of known analytic solutions in the time domain, or developed directly in the Laplace domain. We use both methods to develop a number of analytic elements for LT-AEM. We then illustrate the method on transient flow in a two-dimensional confined aquifer containing various inhomogeneities and time-dependent sources.

@article{ceed5b2e2d8345d08dd5ab721f5df98c,
title = "Laplace transform analytic element method for transient flow problems",
abstract = "Recently we [12] proposed a new Laplace transform analytic element method (LT-AEM) for the solution of transient groundwater flow problems. Laplace transformation of the transient flow equations leads to a time-independent modified Helmholtz equation and associated conditions at discontinuities. The latter are solved by AEM and the results transformed numerically back into the time domain. Though neither continuity of potential nor continuity of flux are satisfied automatically at internal discontinuities, both are satisfied approximately via least squares at an overdetermined system of control points in a manner similar to that of Jankovi{\'c} [17] and Barnes and Jankovi{\'c} [5]. LT-AEM preserves all advantages of the AEM in Laplace space, most importantly its mathematical elegance and grid-free nature. Solution in Laplace space and numerical back transformation into the time domain are done independently for any given time and are thus amenable to parallel computation on multiple processors. This renders the method particularly well suited for cases where a high-accuracy solution is required at a relatively small number of discrete space-time locations. LT-AEM requires a new family of analytic elements associated transformation of known analytic solutions in the time domain, or developed directly in the Laplace domain. We use both methods to develop a number of analytic elements for LT-AEM. We then illustrate the method on transient flow in a two-dimensional confined aquifer containing various inhomogeneities and time-dependent sources.",
author = "Alex Furman and Neuman, {Shlomo P.}",
year = "2004",
doi = "10.1016/S0167-5648(04)80065-0",
language = "אנגלית",
volume = "55",
pages = "371--379",
journal = "Developments in Water Science",
issn = "0167-5648",
publisher = "Elsevier",
number = "PART 1",

}

2003

Laplace-transform analytic element solution of transient flow in porous media

Furman A, Neuman SP. Laplace-transform analytic element solution of transient flow in porous media. Advances in Water Resources. 2003 Dec;26(12):1229-1237. https://doi.org/10.1016/j.advwatres.2003.09.003
 

A Laplace-transform analytic element method (LT-AEM) is described for the solution of transient flow problems in porous media. Following Laplace transformation of the original flow problem, the analytic element method (AEM) is used to solve the resultant time-independent modified Helmholtz equation, and the solution is inverted numerically back into the time domain. The solution is entirely general, retaining the mathematical elegance and computational efficiency of the AEM while being amenable to parallel computation. It is especially well suited for problems in which a solution is required at a limited number of points in space-time, and for problems involving materials with sharply contrasting hydraulic properties. We illustrate the LT-AEM on transient flow through a uniform confined aquifer with a circular inclusion of contrasting hydraulic conductivity and specific storage. Our results compare well with published analytical solutions in the special case of radial flow.

@article{1849263b1eb04a89b0b0794b782e9c27,
title = "Laplace-transform analytic element solution of transient flow in porous media",
abstract = "A Laplace-transform analytic element method (LT-AEM) is described for the solution of transient flow problems in porous media. Following Laplace transformation of the original flow problem, the analytic element method (AEM) is used to solve the resultant time-independent modified Helmholtz equation, and the solution is inverted numerically back into the time domain. The solution is entirely general, retaining the mathematical elegance and computational efficiency of the AEM while being amenable to parallel computation. It is especially well suited for problems in which a solution is required at a limited number of points in space-time, and for problems involving materials with sharply contrasting hydraulic properties. We illustrate the LT-AEM on transient flow through a uniform confined aquifer with a circular inclusion of contrasting hydraulic conductivity and specific storage. Our results compare well with published analytical solutions in the special case of radial flow.",
keywords = "Analytic element, Laplace transform, Transient flow",
author = "Alex Furman and Neuman, {Shlomo P.}",
year = "2003",
month = dec,
doi = "10.1016/j.advwatres.2003.09.003",
language = "אנגלית",
volume = "26",
pages = "1229--1237",
journal = "Advances in Water Resources",
issn = "0309-1708",
publisher = "Elsevier Ltd.",
number = "12",

}

A sensitivity analysis of electrical resistivity tomography array types using analytical element modeling

Furman A, Ferré TPA, Warrick AW. A sensitivity analysis of electrical resistivity tomography array types using analytical element modeling. Vadose Zone Journal. 2003 Aug;2(3):416-423. https://doi.org/10.2113/2.3.416
 

The analytic element method is used to investigate the spatial sensitivity of different electrical resistivity tomography (ERT) arrays. By defining the sensitivity of an array to a subsurface location we were able to generate maps showing the distribution of the sensitivity throughout the subsurface. This allows us to define regions of the subsurface where different ERT arrays are most and least sensitive. We compared the different arrays using the absolute value of the sensitivity and using its spatial distribution. Comparison is presented for three commonly used arrays (Wenner, Schlumberger, and double dipole) and for one atypical array (partially overlapping). Most common monitoring techniques use a single measurement to measure a property at a single location. The spatial distribution of the property is determined by interpolation of these measurements. In contrast, ERT is unique in that multiple measurements are interpreted simultaneously to create maps of spatially distributed soil properties. We define the spatial sensitivity of an ERT survey to each location on the basis of the sum of the sensitivities of the single arrays composing the survey to that location. With the goal of applying ERT for time-lapse measurements, we compared the spatial sensitivities of different surveys on a per measurement basis. Compared are three surveys based on the typical Wenner, Schlumberger, and double dipole arrays, one atypical survey based on the partially overlapping array, and one mixed survey built of arrays that have been shown to be optimal for a series of single perturbations. Results show the inferiority of the double dipole survey compared with other surveys. On a per measurement basis, there was almost no difference between the Wenner and the Schlumberger surveys. The atypical partially overlapping survey is superior to the typical arrays. Finally, we show that a survey composed of a mixture of array types is superior to all of the single array type surveys. By analyzing the spatial sensitivity of the single array, and most significantly the sensitivity of the ERT survey, we set the basis for quantitative measurement of subsurface properties using ERT, with applications to both static and transient hydrologic processes.

@article{20e89684558b434ea097f30ef8b31a77,
title = "A sensitivity analysis of electrical resistivity tomography array types using analytical element modeling",
abstract = "The analytic element method is used to investigate the spatial sensitivity of different electrical resistivity tomography (ERT) arrays. By defining the sensitivity of an array to a subsurface location we were able to generate maps showing the distribution of the sensitivity throughout the subsurface. This allows us to define regions of the subsurface where different ERT arrays are most and least sensitive. We compared the different arrays using the absolute value of the sensitivity and using its spatial distribution. Comparison is presented for three commonly used arrays (Wenner, Schlumberger, and double dipole) and for one atypical array (partially overlapping). Most common monitoring techniques use a single measurement to measure a property at a single location. The spatial distribution of the property is determined by interpolation of these measurements. In contrast, ERT is unique in that multiple measurements are interpreted simultaneously to create maps of spatially distributed soil properties. We define the spatial sensitivity of an ERT survey to each location on the basis of the sum of the sensitivities of the single arrays composing the survey to that location. With the goal of applying ERT for time-lapse measurements, we compared the spatial sensitivities of different surveys on a per measurement basis. Compared are three surveys based on the typical Wenner, Schlumberger, and double dipole arrays, one atypical survey based on the partially overlapping array, and one mixed survey built of arrays that have been shown to be optimal for a series of single perturbations. Results show the inferiority of the double dipole survey compared with other surveys. On a per measurement basis, there was almost no difference between the Wenner and the Schlumberger surveys. The atypical partially overlapping survey is superior to the typical arrays. Finally, we show that a survey composed of a mixture of array types is superior to all of the single array type surveys. By analyzing the spatial sensitivity of the single array, and most significantly the sensitivity of the ERT survey, we set the basis for quantitative measurement of subsurface properties using ERT, with applications to both static and transient hydrologic processes.",
author = "Alex Furman and Ferr{\'e}, {Ty P.A.} and Warrick, {A. W.}",
year = "2003",
month = aug,
doi = "10.2113/2.3.416",
language = "אנגלית",
volume = "2",
pages = "416--423",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "3",

}

2002

Electrical potential distributions in a heterogeneous subsurface in response to applied current: Solution for circular inclusions

Furman A, Warrick AW, Ferré TPA. Electrical potential distributions in a heterogeneous subsurface in response to applied current: Solution for circular inclusions. Vadose Zone Journal. 2002 Nov;1(2):273-280. https://doi.org/10.2113/1.2.273
 

An analytic solution to the Laplace equation for potential distribution in response to current flow in a heterogeneous, two-dimensional semi-infinite domain is studied. Circular heterogeneities of varying sizes and electrical conductivities are considered. We investigate the response of the stream function, the potential field, and, in particular, the potential at the top boundary relative to the background as a function of the size, location, and electrical conductivity of circular inclusions taken singly or multiply. The analytic solution sets the basis for the application of sensitivity analysis to the electrical resistance tomography (ERT) method, as an initial step toward improving the application of the method to tracking rapid hydrological processes.

@article{db468f887d8640f78d7f463f8849cfb8,
title = "Electrical potential distributions in a heterogeneous subsurface in response to applied current: Solution for circular inclusions",
abstract = "An analytic solution to the Laplace equation for potential distribution in response to current flow in a heterogeneous, two-dimensional semi-infinite domain is studied. Circular heterogeneities of varying sizes and electrical conductivities are considered. We investigate the response of the stream function, the potential field, and, in particular, the potential at the top boundary relative to the background as a function of the size, location, and electrical conductivity of circular inclusions taken singly or multiply. The analytic solution sets the basis for the application of sensitivity analysis to the electrical resistance tomography (ERT) method, as an initial step toward improving the application of the method to tracking rapid hydrological processes.",
author = "Alex Furman and Warrick, {A. W.} and Ferr{\'e}, {Ty P.A.}",
year = "2002",
month = nov,
doi = "10.2113/1.2.273",
language = "אנגלית",
volume = "1",
pages = "273--280",
journal = "Vadose Zone Journal",
issn = "1539-1663",
publisher = "Soil Science Society of America",
number = "2",

}

2001

The location of deep salinity sources in the Israeli Coastal aquifer

Shavit U, Furman A. The location of deep salinity sources in the Israeli Coastal aquifer. Journal of Hydrology. 2001 Sep 1;250(1-4):63-77. https://doi.org/10.1016/S0022-1694(01)00406-1
 

The salinization process of the Israeli Coastal aquifer has led to an average concentration of about 200 mgCl/l with a significant number of discrete salinity plumes in the middle and southern regions. The salinity of these plumes is high (500-1000 mgCl/l) and is increasing rapidly. Geochemical evidence has suggested that the salinity source in the Be'er Tuvia plume (in the south part of the aquifer) is at the bottom of the aquifer. This paper describes a solution of the source inverse problem and its application in the Be'er Tuvia plume. A transient two-dimensional finite element model was solved and the source terms were computed at each node in a 14 × 14 km2 area. An error analysis has shown that when no errors are introduced in the input data the reconstruction is perfect. The results of a sensitivity analysis are presented and the actual reconstruction errors are estimated. Applying the model in the Be'er Tuvia region indicates that a salinity source exists about 1 km to the west and 1.5 km to the north of the center of the salinity plume. This source is believed to be the plume source.

@article{516ccaa685bd4815b3d71d79cf4af383,
title = "The location of deep salinity sources in the Israeli Coastal aquifer",
abstract = "The salinization process of the Israeli Coastal aquifer has led to an average concentration of about 200 mgCl/l with a significant number of discrete salinity plumes in the middle and southern regions. The salinity of these plumes is high (500-1000 mgCl/l) and is increasing rapidly. Geochemical evidence has suggested that the salinity source in the Be'er Tuvia plume (in the south part of the aquifer) is at the bottom of the aquifer. This paper describes a solution of the source inverse problem and its application in the Be'er Tuvia plume. A transient two-dimensional finite element model was solved and the source terms were computed at each node in a 14 × 14 km2 area. An error analysis has shown that when no errors are introduced in the input data the reconstruction is perfect. The results of a sensitivity analysis are presented and the actual reconstruction errors are estimated. Applying the model in the Be'er Tuvia region indicates that a salinity source exists about 1 km to the west and 1.5 km to the north of the center of the salinity plume. This source is believed to be the plume source.",
keywords = "Finite elements, Groundwater, Inverse problem, Israeli Coastal aquifer, Salinity sources",
author = "Uri Shavit and Alex Furman",
year = "2001",
month = sep,
day = "1",
doi = "10.1016/S0022-1694(01)00406-1",
language = "אנגלית",
volume = "250",
pages = "63--77",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",
number = "1-4",

}

1998

הכתמים המלוחים: פיתוח שיטה חישובית לשם זיהוי מקורות המלחה באקוויפר החוף

שביט א, פורמן א. הכתמים המלוחים: פיתוח שיטה חישובית לשם זיהוי מקורות המלחה באקוויפר החוף. טכנולוגיות מים. 1998;39:47-52.
@article{c080d5103e36484facf0f40a528a757f,
title = "הכתמים המלוחים: פיתוח שיטה חישובית לשם זיהוי מקורות המלחה באקוויפר החוף",
author = "אורי שביט and אלכס פורמן",
year = "1998",
language = "עברית",
volume = "39",
pages = "47--52",
journal = "טכנולוגיות מים",
issn = "0793-9137",

}

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