Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory
Abstract Saturated hydraulic conductivity (Ks) is a crucial parameter that influences water flow in saturated soils, with applications in various fields such as surface water runoff, soil erosion, drainage, and solute transport. However, accurate determination of Ks is challenging due to temporal an...
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Wiley
2024-10-01
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| Series: | Water Resources Research |
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| Online Access: | https://doi.org/10.1029/2023WR036164 |
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| author | Saeed Nikghalb Ashouri Adrian Pittari Vicki Moon Ali Shokri |
| author_facet | Saeed Nikghalb Ashouri Adrian Pittari Vicki Moon Ali Shokri |
| author_sort | Saeed Nikghalb Ashouri |
| collection | DOAJ |
| description | Abstract Saturated hydraulic conductivity (Ks) is a crucial parameter that influences water flow in saturated soils, with applications in various fields such as surface water runoff, soil erosion, drainage, and solute transport. However, accurate determination of Ks is challenging due to temporal and spatial uncertainties. This study addresses the knowledge gap regarding the long‐term behavior of Ks in sandy soils with less than 10% fine particles. The research investigates the changes in Ks over a long period of constant head tests and examines the factors influencing its variation. Two sandy samples were tested using a hydraulic conductivity cell, and the hydraulic head and discharge were recorded for over 50 days. The results show a general decline in Ks throughout the test, except for brief periods of increase. At the end of both tests, there are noticeable reductions in the saturated hydraulic conductivities of the samples, with one sample being 96% and the other sample 91% less than the maximum recorded saturated hydraulic conductivity during the tests. Furthermore, the relationship between flow rate and hydraulic head gradient does not follow the expected linear correlation from Darcy's law, highlighting the complex nature of sandy soil saturated hydraulic conductivity. The investigation of soil properties in three different sections of the samples before and after the tests revealed a decrease in the percentage of fine particles and a shift in specific gravity from the bottom to the top of the sample, suggesting particle migration along the flow direction. Factors such as clogging by fine particles and pore pressure variation contribute to the changes in Ks. The findings of this research show the importance of considering changes of saturated hydraulic conductivity during constant‐head laboratory tests. Therefore, this study provides evidence for the requirement to further assess the laboratory methods for measurement of the saturated hydraulic conductivity in sandy soil mixtures. |
| format | Article |
| id | doaj-art-c44e1483643e4106a962f254c7c21078 |
| institution | OA Journals |
| issn | 0043-1397 1944-7973 |
| language | English |
| publishDate | 2024-10-01 |
| publisher | Wiley |
| record_format | Article |
| series | Water Resources Research |
| spelling | doaj-art-c44e1483643e4106a962f254c7c210782025-08-20T02:09:24ZengWileyWater Resources Research0043-13971944-79732024-10-016010n/an/a10.1029/2023WR036164Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the LaboratorySaeed Nikghalb Ashouri0Adrian Pittari1Vicki Moon2Ali Shokri3School of Engineering University of Waikato Hamilton New ZealandSchool of Science University of Waikato Hamilton New ZealandSchool of Science University of Waikato Hamilton New ZealandSchool of Engineering University of Waikato Hamilton New ZealandAbstract Saturated hydraulic conductivity (Ks) is a crucial parameter that influences water flow in saturated soils, with applications in various fields such as surface water runoff, soil erosion, drainage, and solute transport. However, accurate determination of Ks is challenging due to temporal and spatial uncertainties. This study addresses the knowledge gap regarding the long‐term behavior of Ks in sandy soils with less than 10% fine particles. The research investigates the changes in Ks over a long period of constant head tests and examines the factors influencing its variation. Two sandy samples were tested using a hydraulic conductivity cell, and the hydraulic head and discharge were recorded for over 50 days. The results show a general decline in Ks throughout the test, except for brief periods of increase. At the end of both tests, there are noticeable reductions in the saturated hydraulic conductivities of the samples, with one sample being 96% and the other sample 91% less than the maximum recorded saturated hydraulic conductivity during the tests. Furthermore, the relationship between flow rate and hydraulic head gradient does not follow the expected linear correlation from Darcy's law, highlighting the complex nature of sandy soil saturated hydraulic conductivity. The investigation of soil properties in three different sections of the samples before and after the tests revealed a decrease in the percentage of fine particles and a shift in specific gravity from the bottom to the top of the sample, suggesting particle migration along the flow direction. Factors such as clogging by fine particles and pore pressure variation contribute to the changes in Ks. The findings of this research show the importance of considering changes of saturated hydraulic conductivity during constant‐head laboratory tests. Therefore, this study provides evidence for the requirement to further assess the laboratory methods for measurement of the saturated hydraulic conductivity in sandy soil mixtures.https://doi.org/10.1029/2023WR036164saturated hydraulic conductivityconstant head testcloggingsandy soildrainable poresconnectivity |
| spellingShingle | Saeed Nikghalb Ashouri Adrian Pittari Vicki Moon Ali Shokri Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory Water Resources Research saturated hydraulic conductivity constant head test clogging sandy soil drainable pores connectivity |
| title | Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory |
| title_full | Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory |
| title_fullStr | Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory |
| title_full_unstemmed | Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory |
| title_short | Examining the Mid to Long‐Term Variability in Saturated Hydraulic Conductivity of Sandy Soils and Its Influencing Factors Under Constant Head Test in the Laboratory |
| title_sort | examining the mid to long term variability in saturated hydraulic conductivity of sandy soils and its influencing factors under constant head test in the laboratory |
| topic | saturated hydraulic conductivity constant head test clogging sandy soil drainable pores connectivity |
| url | https://doi.org/10.1029/2023WR036164 |
| work_keys_str_mv | AT saeednikghalbashouri examiningthemidtolongtermvariabilityinsaturatedhydraulicconductivityofsandysoilsanditsinfluencingfactorsunderconstantheadtestinthelaboratory AT adrianpittari examiningthemidtolongtermvariabilityinsaturatedhydraulicconductivityofsandysoilsanditsinfluencingfactorsunderconstantheadtestinthelaboratory AT vickimoon examiningthemidtolongtermvariabilityinsaturatedhydraulicconductivityofsandysoilsanditsinfluencingfactorsunderconstantheadtestinthelaboratory AT alishokri examiningthemidtolongtermvariabilityinsaturatedhydraulicconductivityofsandysoilsanditsinfluencingfactorsunderconstantheadtestinthelaboratory |