Improving soil stability with alum sludge : an ai-enabled approach for accurate prediction of california bearing ratio
- Baghbani, Abolfazl, Nguyen, Minh, Alnedawi, Ali, Milne, Nick, Baumgartl, Thomas, Abuel-Naga, Hossam
- Authors: Baghbani, Abolfazl , Nguyen, Minh , Alnedawi, Ali , Milne, Nick , Baumgartl, Thomas , Abuel-Naga, Hossam
- Date: 2023
- Type: Text , Journal article
- Relation: Applied Sciences (Switzerland) Vol. 13, no. 8 (2023), p.
- Full Text:
- Reviewed:
- Description: Alum sludge is a byproduct of water treatment plants, and its use as a soil stabilizer has gained increasing attention due to its economic and environmental benefits. Its application has been shown to improve the strength and stability of soil, making it suitable for various engineering applications. However, to go beyond just measuring the effects of alum sludge as a soil stabilizer, this study investigates the potential of artificial intelligence (AI) methods for predicting the California bearing ratio (CBR) of soils stabilized with alum sludge. Three AI methods, including two black box methods (artificial neural network and support vector machines) and one grey box method (genetic programming), were used to predict CBR, based on a database with nine input parameters. The results demonstrate the effectiveness of AI methods in predicting CBR with good accuracy (R2 values ranging from 0.94 to 0.99 and MAE values ranging from 0.30 to 0.51). Moreover, a novel approach, using genetic programming, produced an equation that accurately estimated CBR, incorporating seven inputs. The analysis of parameter sensitivity and importance, revealed that the number of hammer blows for compaction was the most important parameter, while the parameters for maximum dry density of soil and mixture were the least important. This study highlights the potential of AI methods as a useful tool for predicting the performance of alum sludge as a soil stabilizer. © 2023 by the authors.
- Authors: Baghbani, Abolfazl , Nguyen, Minh , Alnedawi, Ali , Milne, Nick , Baumgartl, Thomas , Abuel-Naga, Hossam
- Date: 2023
- Type: Text , Journal article
- Relation: Applied Sciences (Switzerland) Vol. 13, no. 8 (2023), p.
- Full Text:
- Reviewed:
- Description: Alum sludge is a byproduct of water treatment plants, and its use as a soil stabilizer has gained increasing attention due to its economic and environmental benefits. Its application has been shown to improve the strength and stability of soil, making it suitable for various engineering applications. However, to go beyond just measuring the effects of alum sludge as a soil stabilizer, this study investigates the potential of artificial intelligence (AI) methods for predicting the California bearing ratio (CBR) of soils stabilized with alum sludge. Three AI methods, including two black box methods (artificial neural network and support vector machines) and one grey box method (genetic programming), were used to predict CBR, based on a database with nine input parameters. The results demonstrate the effectiveness of AI methods in predicting CBR with good accuracy (R2 values ranging from 0.94 to 0.99 and MAE values ranging from 0.30 to 0.51). Moreover, a novel approach, using genetic programming, produced an equation that accurately estimated CBR, incorporating seven inputs. The analysis of parameter sensitivity and importance, revealed that the number of hammer blows for compaction was the most important parameter, while the parameters for maximum dry density of soil and mixture were the least important. This study highlights the potential of AI methods as a useful tool for predicting the performance of alum sludge as a soil stabilizer. © 2023 by the authors.
Investigation of hillslope vineyard soil water dynamics using field measurements and numerical modeling
- Krevh, Vedran, Groh, Jannis, Weihermüller, Lutz, Filipović, Lana, Defterdarović, Jasmina, Kovač, Zoran, Magdić, Ivan, Lazarević, Boris, Baumgartl, Thomas, Filipović, Vilim
- Authors: Krevh, Vedran , Groh, Jannis , Weihermüller, Lutz , Filipović, Lana , Defterdarović, Jasmina , Kovač, Zoran , Magdić, Ivan , Lazarević, Boris , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: Soil heterogeneities can impact hillslope hydropedological processes (e.g., portioning between infiltration and runoff), creating a need for in-depth knowledge of processes governing water dynamics and redistribution. The presented study was conducted at the SUPREHILL Critical Zone Observatory (CZO) (hillslope vineyard) in 2021. A combination of field investigation (soil sampling and monitoring campaign) and numerical modeling with hydrological simulator HYDRUS-1D was used to explore the water dynamics in conjunction with data from a sensor network (soil water content (SWC) and soil-water potential (SWP) sensors), along the hillslope (hilltop, backslope, and footslope). Soil hydraulic properties (SHP) were estimated based on (i) pedotransfer functions (PTFs), (ii) undisturbed soil cores, and (iii) sensor network data, and tested in HYDRUS. Additionally, a model ensemble mean from HYDRUS simulations was calculated with PTFs. The highest agreement of simulated with observed SWC for 40 cm soil depth was found with the combination of laboratory and field data, with the lowest average MAE, RMSE and MAPE (0.02, 0.02, and 5.34%, respectively), and highest average R2 (0.93), while at 80 cm soil depth, PTF model ensemble performed better (MAE = 0.03, RMSE = 0.03, MAPE = 7.55%, R2 = 0.81) than other datasets. Field observations indicated that heterogeneity and spatial variability regarding soil parameters were present at the site. Over the hillslope, SWC acted in a heterogeneous manner, which was most pronounced during soil rewetting. Model results suggested that the incorporation of field data expands model performance and that the PTF model ensemble is a feasible option in the absence of laboratory data. © 2023 by the authors.
- Authors: Krevh, Vedran , Groh, Jannis , Weihermüller, Lutz , Filipović, Lana , Defterdarović, Jasmina , Kovač, Zoran , Magdić, Ivan , Lazarević, Boris , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: Soil heterogeneities can impact hillslope hydropedological processes (e.g., portioning between infiltration and runoff), creating a need for in-depth knowledge of processes governing water dynamics and redistribution. The presented study was conducted at the SUPREHILL Critical Zone Observatory (CZO) (hillslope vineyard) in 2021. A combination of field investigation (soil sampling and monitoring campaign) and numerical modeling with hydrological simulator HYDRUS-1D was used to explore the water dynamics in conjunction with data from a sensor network (soil water content (SWC) and soil-water potential (SWP) sensors), along the hillslope (hilltop, backslope, and footslope). Soil hydraulic properties (SHP) were estimated based on (i) pedotransfer functions (PTFs), (ii) undisturbed soil cores, and (iii) sensor network data, and tested in HYDRUS. Additionally, a model ensemble mean from HYDRUS simulations was calculated with PTFs. The highest agreement of simulated with observed SWC for 40 cm soil depth was found with the combination of laboratory and field data, with the lowest average MAE, RMSE and MAPE (0.02, 0.02, and 5.34%, respectively), and highest average R2 (0.93), while at 80 cm soil depth, PTF model ensemble performed better (MAE = 0.03, RMSE = 0.03, MAPE = 7.55%, R2 = 0.81) than other datasets. Field observations indicated that heterogeneity and spatial variability regarding soil parameters were present at the site. Over the hillslope, SWC acted in a heterogeneous manner, which was most pronounced during soil rewetting. Model results suggested that the incorporation of field data expands model performance and that the PTF model ensemble is a feasible option in the absence of laboratory data. © 2023 by the authors.
Leached copper correlation with dissolved organic carbon in sloped vineyard soil
- Filipovi, Lana, Defterdarović, Jasmina, Chen, Rui, Krevh, Vedran, Gerke, Horst, Baumgartl, Thomas, Kovač, Zoran, Ondrašek, Gabrijel, Ružičić, Stanko, He, Hailong, Dusek, Jaromir, Filipović, Vilim
- Authors: Filipovi, Lana , Defterdarović, Jasmina , Chen, Rui , Krevh, Vedran , Gerke, Horst , Baumgartl, Thomas , Kovač, Zoran , Ondrašek, Gabrijel , Ružičić, Stanko , He, Hailong , Dusek, Jaromir , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: The solubility and mobility of copper (Cu) in soil is strongly influenced by the presence of dissolved organic carbon (DOC); however, the interactions between Cu and DOC are complex and not yet fully understood. In this study, Cu and DOC concentrations were measured monthly for two years in leachates from self-constructed lysimeters installed at inter- and intra-row vineyard hilltop, backslope, and footslope areas at the SUPREHILL Critical Zone Observatory, Croatia. The aim was to quantify Cu and DOC leaching from the hilltop towards the backslope and the footslope. The assumed strong relationship between Cu and DOC in the leachates was statistically analyzed and explained using chemical equilibrium software. Leachates were analyzed for pH, EC, DOC, Cu, and major ion concentrations. The highest Cu concentrations found in leachates from the intra-row footslope suggested Cu downhill transport. Although not strong, a significant positive correlation between Cu and DOC in footslope leachates confirmed the relevance of Cu complexation by DOC. Speciation confirmed that more than 99.9% of total Cu in leachates was found as a Cu-DOC complex. Data implied the role of soil water flow pathways in explaining Cu downhill transport. Critical timing for applying Cu fungicides at sloped vineyards was highlighted. © 2023 by the authors.
- Authors: Filipovi, Lana , Defterdarović, Jasmina , Chen, Rui , Krevh, Vedran , Gerke, Horst , Baumgartl, Thomas , Kovač, Zoran , Ondrašek, Gabrijel , Ružičić, Stanko , He, Hailong , Dusek, Jaromir , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: The solubility and mobility of copper (Cu) in soil is strongly influenced by the presence of dissolved organic carbon (DOC); however, the interactions between Cu and DOC are complex and not yet fully understood. In this study, Cu and DOC concentrations were measured monthly for two years in leachates from self-constructed lysimeters installed at inter- and intra-row vineyard hilltop, backslope, and footslope areas at the SUPREHILL Critical Zone Observatory, Croatia. The aim was to quantify Cu and DOC leaching from the hilltop towards the backslope and the footslope. The assumed strong relationship between Cu and DOC in the leachates was statistically analyzed and explained using chemical equilibrium software. Leachates were analyzed for pH, EC, DOC, Cu, and major ion concentrations. The highest Cu concentrations found in leachates from the intra-row footslope suggested Cu downhill transport. Although not strong, a significant positive correlation between Cu and DOC in footslope leachates confirmed the relevance of Cu complexation by DOC. Speciation confirmed that more than 99.9% of total Cu in leachates was found as a Cu-DOC complex. Data implied the role of soil water flow pathways in explaining Cu downhill transport. Critical timing for applying Cu fungicides at sloped vineyards was highlighted. © 2023 by the authors.
Quantification of intra- vs. inter-row leaching of major plant nutrients in sloping vineyard soils
- Filipović, Lana, Krevh, Vedran, Chen, Rui, Defterdarović, Jasmina, Kovač, Zoran, Mustać, Ivan, Bogunović, Igor, He, Hailong, Baumgartl, Thomas, Gerke, Horst, Toor, Gurpal, Filipović, Vilim
- Authors: Filipović, Lana , Krevh, Vedran , Chen, Rui , Defterdarović, Jasmina , Kovač, Zoran , Mustać, Ivan , Bogunović, Igor , He, Hailong , Baumgartl, Thomas , Gerke, Horst , Toor, Gurpal , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: Nutrient leaching from agricultural soils presents an economic loss for farmers and can degrade the quality of the surrounding environment. Thus, leachates from 18 in situ wick lysimeters, installed at 40 cm soil depth at the vineyard hilltop, backslope, and footslope intra- and inter-row area (SUPREHILL Critical Zone Observatory, Croatia) were collected monthly over two years and analyzed for major plant nutrient ions. Our objectives were to quantify nutrient losses via leaching from the hilltop towards the backslope and to the footslope, and to compare leaching from vine plant rows (intra-row) with grassed areas between vine rows (inter-row). We found that the concentrations of nitrate, orthophosphate, and potassium were significantly higher in leachates collected at the footslope as compared to the hilltop and backslope only at intra- and not at inter-row positions, while ammonium was independent of the slope and row positions. The vineyard intra-row is identified as the probable spatial origin of nutrient leaching along the slope, thus confirming spatially different contributions of overall hillslope to major plant nutrients leaching. The experimental field scheme used in this study, which separately analyses vineyard intra- and inter-row, was confirmed to be an adequate approach for optimizing vineyard management practices. © 2023 by the authors.
- Authors: Filipović, Lana , Krevh, Vedran , Chen, Rui , Defterdarović, Jasmina , Kovač, Zoran , Mustać, Ivan , Bogunović, Igor , He, Hailong , Baumgartl, Thomas , Gerke, Horst , Toor, Gurpal , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: Nutrient leaching from agricultural soils presents an economic loss for farmers and can degrade the quality of the surrounding environment. Thus, leachates from 18 in situ wick lysimeters, installed at 40 cm soil depth at the vineyard hilltop, backslope, and footslope intra- and inter-row area (SUPREHILL Critical Zone Observatory, Croatia) were collected monthly over two years and analyzed for major plant nutrient ions. Our objectives were to quantify nutrient losses via leaching from the hilltop towards the backslope and to the footslope, and to compare leaching from vine plant rows (intra-row) with grassed areas between vine rows (inter-row). We found that the concentrations of nitrate, orthophosphate, and potassium were significantly higher in leachates collected at the footslope as compared to the hilltop and backslope only at intra- and not at inter-row positions, while ammonium was independent of the slope and row positions. The vineyard intra-row is identified as the probable spatial origin of nutrient leaching along the slope, thus confirming spatially different contributions of overall hillslope to major plant nutrients leaching. The experimental field scheme used in this study, which separately analyses vineyard intra- and inter-row, was confirmed to be an adequate approach for optimizing vineyard management practices. © 2023 by the authors.
Soil–water dynamics investigation at agricultural hillslope with high-precision weighing lysimeters and soil–water collection systems
- Krevh, Vedran, Groh, Jannis, Filipović, Lana, Gerke, Horst, Defterdarović, Jasmina, Thompson, Sally, Sraka, Mario, Bogunović, Igor, Kovač, Zoran, Robinson, Nathan, Baumgartl, Thomas, Filipović, Vilim
- Authors: Krevh, Vedran , Groh, Jannis , Filipović, Lana , Gerke, Horst , Defterdarović, Jasmina , Thompson, Sally , Sraka, Mario , Bogunović, Igor , Kovač, Zoran , Robinson, Nathan , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 13 (2023), p.
- Full Text:
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- Description: A quantitative understanding of actual evapotranspiration (ETa) and soil–water dynamics in a hillslope agroecosystem is vital for sustainable water resource management and soil conservation; however, the complexity of processes and conditions involving lateral subsurface flow (LSF) can be a limiting factor in the full comprehension of hillslope soil–water dynamics. The research was carried out at SUPREHILL CZO located on a hillslope agroecosystem (vineyard) over a period of two years (2021–2022) by combining soil characterization and field hydrological measurements, including weighing lysimeters, sensor measurements, and LSF collection system measurements. Lysimeters were placed on the hilltop and the footslope, both having a dynamic controlled bottom boundary, which corresponded to field pressure head measurements, to mimic field soil–water dynamics. Water balance components between the two positions on the slope were compared with the goal of identifying differences that might reveal hydrologically driven differences due to LSF paths across the hillslope. The usually considered limitations of these lysimeters, or the borders preventing LSF through the domain, acted as an aid within this installation setup, as the lack of LSF was compensated for through the pumping system at the footslope. The findings from lysimeters were compared with LSF collection system measurements. Weighing lysimeter data indicated that LSF controlled ETa rates. The results suggest that the onset of LSF contributes to the spatial crop productivity distribution in hillslopes. The present approach may be useful for investigating the impact of LSF on water balance components for similar hillslope sites and crops or other soil surface covers. © 2023 by the authors.
- Authors: Krevh, Vedran , Groh, Jannis , Filipović, Lana , Gerke, Horst , Defterdarović, Jasmina , Thompson, Sally , Sraka, Mario , Bogunović, Igor , Kovač, Zoran , Robinson, Nathan , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 13 (2023), p.
- Full Text:
- Reviewed:
- Description: A quantitative understanding of actual evapotranspiration (ETa) and soil–water dynamics in a hillslope agroecosystem is vital for sustainable water resource management and soil conservation; however, the complexity of processes and conditions involving lateral subsurface flow (LSF) can be a limiting factor in the full comprehension of hillslope soil–water dynamics. The research was carried out at SUPREHILL CZO located on a hillslope agroecosystem (vineyard) over a period of two years (2021–2022) by combining soil characterization and field hydrological measurements, including weighing lysimeters, sensor measurements, and LSF collection system measurements. Lysimeters were placed on the hilltop and the footslope, both having a dynamic controlled bottom boundary, which corresponded to field pressure head measurements, to mimic field soil–water dynamics. Water balance components between the two positions on the slope were compared with the goal of identifying differences that might reveal hydrologically driven differences due to LSF paths across the hillslope. The usually considered limitations of these lysimeters, or the borders preventing LSF through the domain, acted as an aid within this installation setup, as the lack of LSF was compensated for through the pumping system at the footslope. The findings from lysimeters were compared with LSF collection system measurements. Weighing lysimeter data indicated that LSF controlled ETa rates. The results suggest that the onset of LSF contributes to the spatial crop productivity distribution in hillslopes. The present approach may be useful for investigating the impact of LSF on water balance components for similar hillslope sites and crops or other soil surface covers. © 2023 by the authors.
Using dye and bromide tracers to identify preferential water flow in agricultural hillslope soil under controlled conditions
- Defterdarović, Jasmina, Krevh, Vedran, Filipović, Lana, Kovač, Zoran, Phogat, Vinod, He, Hailong, Baumgartl, Thomas, Filipović, Vilim
- Authors: Defterdarović, Jasmina , Krevh, Vedran , Filipović, Lana , Kovač, Zoran , Phogat, Vinod , He, Hailong , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 12 (2023), p.
- Full Text:
- Reviewed:
- Description: Processes in hillslope soils present a particular challenge for agricultural production and soil management due to their hydropedological specifics and high soil erosion risk. Soil heterogeneities can cause preferential and/or lateral flow on the entire hillslope resulting in the off-site movement of water, fertilizers and chemicals used in crop production. A study was conducted under controlled conditions in a laboratory with undisturbed soil cores (250 cm3), which were used to estimate the soil hydraulic properties (SHP) using HYPROP and WP4C devices, while undisturbed soil columns (diameter = 16 cm, length = 25 cm) were used for the evaluation of preferential flow pathways using potassium bromide and Brilliant Blue. Samples were excavated in triplicate from the hilltop, backslope and footslope regions within the inter-rows of a vineyard from a critical zone observatory, SUPREHILL, in Croatia in Dystric Luvic Stagnosol. The aim of this study was to determine if the erosion-affected hillslope position affected the physical, chemical and hydraulic properties of soil and to identify water flow and possible preferential flow using dye and bromide tracers. The results of the sensor measurements and estimated SHPs were in agreement, showing a faster leaching of the irrigated rainwater in the footslope column. The tracer experiments showed variability even in the columns taken from the same position on the hillslope, which can be linked to plant roots and soil fauna activity. Altogether, the results showed a deeper loose layer at the footslope as a consequence of the soil erosion, which then resulted in higher hydraulic conductivity and the leached mass of the bromide due to better soil structure and pore connectivity. Thus, due to significant differences in the leached mass of bromide, this research should be later expanded in field experiments to reveal the impact of surface runoff, subsurface preferential and lateral flow on a larger scale. © 2023 by the authors.
- Authors: Defterdarović, Jasmina , Krevh, Vedran , Filipović, Lana , Kovač, Zoran , Phogat, Vinod , He, Hailong , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 12 (2023), p.
- Full Text:
- Reviewed:
- Description: Processes in hillslope soils present a particular challenge for agricultural production and soil management due to their hydropedological specifics and high soil erosion risk. Soil heterogeneities can cause preferential and/or lateral flow on the entire hillslope resulting in the off-site movement of water, fertilizers and chemicals used in crop production. A study was conducted under controlled conditions in a laboratory with undisturbed soil cores (250 cm3), which were used to estimate the soil hydraulic properties (SHP) using HYPROP and WP4C devices, while undisturbed soil columns (diameter = 16 cm, length = 25 cm) were used for the evaluation of preferential flow pathways using potassium bromide and Brilliant Blue. Samples were excavated in triplicate from the hilltop, backslope and footslope regions within the inter-rows of a vineyard from a critical zone observatory, SUPREHILL, in Croatia in Dystric Luvic Stagnosol. The aim of this study was to determine if the erosion-affected hillslope position affected the physical, chemical and hydraulic properties of soil and to identify water flow and possible preferential flow using dye and bromide tracers. The results of the sensor measurements and estimated SHPs were in agreement, showing a faster leaching of the irrigated rainwater in the footslope column. The tracer experiments showed variability even in the columns taken from the same position on the hillslope, which can be linked to plant roots and soil fauna activity. Altogether, the results showed a deeper loose layer at the footslope as a consequence of the soil erosion, which then resulted in higher hydraulic conductivity and the leached mass of the bromide due to better soil structure and pore connectivity. Thus, due to significant differences in the leached mass of bromide, this research should be later expanded in field experiments to reveal the impact of surface runoff, subsurface preferential and lateral flow on a larger scale. © 2023 by the authors.
An empirical analysis of sediment export dynamics from a constructed landform in the wet tropics
- Yavari, Shahla, McIntyre, Neil, Baumgartl, Thomas
- Authors: Yavari, Shahla , McIntyre, Neil , Baumgartl, Thomas
- Date: 2021
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 13, no. 8 (2021), p.
- Full Text:
- Reviewed:
- Description: Although plot-scale erosion experiments are numerous, there are few studies on constructed landforms. This limits the understanding of their long-term stability, which is especially important for planning mined land rehabilitation. The objective of this study was to gain insight into the erosion processes in a 30 × 30 m trial plot on a mine waste rock dump in tropical northern Australia. The relationships between rainfall, runoff and suspended and bedload sediment export were assessed at annual, seasonal, inter-event and intra-event timescales. During a five-year study period, 231 rainfall– runoff–sediment export events were examined. The measured bedload and suspended sediments (mainly represented in nephelometric turbidity units (NTU)) showed the dominance of the wet season and heavy rainfall events. The bedload dominated the total mass, although the annual bedload diminished by approximately 75% over the five years, with greater flow energy required over time to mobilise the same bedload. The suspended load was more sustained, though it also exhibited an exhaustion process, with equal rainfall and runoff volumes and intensities, leading to lower NTU values over time. Intra-event NTU dynamics, including runoff-NTU time lags and hysteretic behaviours, were somewhat random from one event to the next, indicating the influence of the antecedent distribution of mobilisable sediments. The value of the results for supporting predictive modelling is discussed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Authors: Yavari, Shahla , McIntyre, Neil , Baumgartl, Thomas
- Date: 2021
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 13, no. 8 (2021), p.
- Full Text:
- Reviewed:
- Description: Although plot-scale erosion experiments are numerous, there are few studies on constructed landforms. This limits the understanding of their long-term stability, which is especially important for planning mined land rehabilitation. The objective of this study was to gain insight into the erosion processes in a 30 × 30 m trial plot on a mine waste rock dump in tropical northern Australia. The relationships between rainfall, runoff and suspended and bedload sediment export were assessed at annual, seasonal, inter-event and intra-event timescales. During a five-year study period, 231 rainfall– runoff–sediment export events were examined. The measured bedload and suspended sediments (mainly represented in nephelometric turbidity units (NTU)) showed the dominance of the wet season and heavy rainfall events. The bedload dominated the total mass, although the annual bedload diminished by approximately 75% over the five years, with greater flow energy required over time to mobilise the same bedload. The suspended load was more sustained, though it also exhibited an exhaustion process, with equal rainfall and runoff volumes and intensities, leading to lower NTU values over time. Intra-event NTU dynamics, including runoff-NTU time lags and hysteretic behaviours, were somewhat random from one event to the next, indicating the influence of the antecedent distribution of mobilisable sediments. The value of the results for supporting predictive modelling is discussed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Modelling hydrological performance of a bauxite residue profile for deposition management of a storage facility
- Shaygan, Mandana, Usher, Brent, Baumgartl, Thomas
- Authors: Shaygan, Mandana , Usher, Brent , Baumgartl, Thomas
- Date: 2020
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 12, no. 7 (2020), p.
- Full Text:
- Reviewed:
- Description: Accurate scheduling of bauxite residue (red mud) deposition time is required in order to prevent the risk of storage facility failure. This study was conducted to precisely determine the hydraulic parameters of bauxite residue and investigate the capability of HYDRUS to accurately estimate the residue moisture profile and the timing for its deposition. The hydraulic properties of the bauxite residue profile were determined by solving an inverse problem. A one-dimensional hydrological model (HYDRUS-1D) was validated using a 300 mm long column filled with bauxite residue and exposed to a dynamic lower boundary condition. After numerical validation, the model was used to simulate the moisture profile of bauxite residue under the climatic conditions of an alumina refinery site in Queensland, Australia, as well as other scenarios (i.e., high (300 mm) and small (1.7 mm) rainfall events of the site). This study showed that the HYDRUS model can be used as a predictive tool to precisely estimate the moisture profile of the bauxite residue and that the timing for the re-deposition of the bauxite residue can be estimated by understanding the moisture profile and desired shear strength of the residue. This study revealed that the examined bauxite residue approaches field capacity (water potential-10 kPa) after three days from a low rainfall event (<1.7 mm) and after eight days from an intense rainfall event (300 mm) at the time of disposal. This suggests that the bauxite residue can be deposited every four days after low rainfall events (as low as 1.7 mm) and every nine days after high rainfall events (as high as 300 mm) at the time of deposition, if bauxite residue experiences an initial drying period following deposition. © 2020 by the authors.
- Authors: Shaygan, Mandana , Usher, Brent , Baumgartl, Thomas
- Date: 2020
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 12, no. 7 (2020), p.
- Full Text:
- Reviewed:
- Description: Accurate scheduling of bauxite residue (red mud) deposition time is required in order to prevent the risk of storage facility failure. This study was conducted to precisely determine the hydraulic parameters of bauxite residue and investigate the capability of HYDRUS to accurately estimate the residue moisture profile and the timing for its deposition. The hydraulic properties of the bauxite residue profile were determined by solving an inverse problem. A one-dimensional hydrological model (HYDRUS-1D) was validated using a 300 mm long column filled with bauxite residue and exposed to a dynamic lower boundary condition. After numerical validation, the model was used to simulate the moisture profile of bauxite residue under the climatic conditions of an alumina refinery site in Queensland, Australia, as well as other scenarios (i.e., high (300 mm) and small (1.7 mm) rainfall events of the site). This study showed that the HYDRUS model can be used as a predictive tool to precisely estimate the moisture profile of the bauxite residue and that the timing for the re-deposition of the bauxite residue can be estimated by understanding the moisture profile and desired shear strength of the residue. This study revealed that the examined bauxite residue approaches field capacity (water potential-10 kPa) after three days from a low rainfall event (<1.7 mm) and after eight days from an intense rainfall event (300 mm) at the time of disposal. This suggests that the bauxite residue can be deposited every four days after low rainfall events (as low as 1.7 mm) and every nine days after high rainfall events (as high as 300 mm) at the time of deposition, if bauxite residue experiences an initial drying period following deposition. © 2020 by the authors.
The effect of soil physical amendments on reclamation of a saline-sodic soil : Simulation of salt leaching using HYDRUS-1D
- Shaygan, Mandana, Baumgartl, Thomas, Arnold, Sven, Reading, Lucy
- Authors: Shaygan, Mandana , Baumgartl, Thomas , Arnold, Sven , Reading, Lucy
- Date: 2018
- Type: Text , Journal article
- Relation: Soil Research Vol. 56, no. 8 (2018), p. 829-845
- Full Text:
- Reviewed:
- Description: Poor soil physical conditions such as low hydraulic conductivity can limit salt depletion from surface soil. Altering the pore system by addition of organic and inorganic amendments may improve salt leaching as a reclamation strategy. Column studies were conducted to investigate salt leaching in amended and non-amended soil profiles. A one-dimensional water and solute transport model (HYDRUS-1D) was also assessed for its applicability to simulate salt leaching for amendment strategy. Columns of length 300 mm were filled with saline-sodic soil at the lower end (100-300 mm) and then covered with soil amended with 40% (wt/wt) fine sand and 20% (wt/wt) wood chips, separately. A control column was filled with saline-sodic soil only. One rainfall scenario typical for a location in south-west Queensland (Australia) was applied to the columns. Water potentials were monitored using tensiometers installed at three depths: 35, 120 and 250 mm. The concentrations of individual cations (Na
- Authors: Shaygan, Mandana , Baumgartl, Thomas , Arnold, Sven , Reading, Lucy
- Date: 2018
- Type: Text , Journal article
- Relation: Soil Research Vol. 56, no. 8 (2018), p. 829-845
- Full Text:
- Reviewed:
- Description: Poor soil physical conditions such as low hydraulic conductivity can limit salt depletion from surface soil. Altering the pore system by addition of organic and inorganic amendments may improve salt leaching as a reclamation strategy. Column studies were conducted to investigate salt leaching in amended and non-amended soil profiles. A one-dimensional water and solute transport model (HYDRUS-1D) was also assessed for its applicability to simulate salt leaching for amendment strategy. Columns of length 300 mm were filled with saline-sodic soil at the lower end (100-300 mm) and then covered with soil amended with 40% (wt/wt) fine sand and 20% (wt/wt) wood chips, separately. A control column was filled with saline-sodic soil only. One rainfall scenario typical for a location in south-west Queensland (Australia) was applied to the columns. Water potentials were monitored using tensiometers installed at three depths: 35, 120 and 250 mm. The concentrations of individual cations (Na
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