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<p>In this study, we developed a methodology that integrates field observations with geological, hydrogeological, and hydrological data pertaining to the Minab aquifer to elucidate subsidence behavior and identify its underlying mechanisms. This approach involved the preparation of longitudinal and transverse sections of alluvial layers utilizing Rockworks software, which facilitated a comprehensive analysis of the alluvial aquifer layers and sediments within the Minab plain. To assess the groundwater table level (GWTL) behavior and its relationship with aquifer recharge conditions and the resultant subsidence at the surface of the Minab plain, we analyzed variations in aquifer static volume alongside a 37-year time series of rainfall data. The results indicate that excessive overexploitation of groundwater has resulted in a significant decline of the GWTL by 16.92&#xa0;m. These uncontrolled withdrawals have not only induced extensive subsidence in the eastern regions of the plain but have also facilitated saline seawater intrusion in the western areas, thereby establishing hydraulic gradients that direct flow from the sea into the aquifer. To further elucidate the mechanisms underlying subsidence across the entire aquifer, exploratory boreholes were strategically positioned at the locations of existing piezometers. Three boreholes were drilled at the beginning, middle, and end of the aquifer, and chemical analyses of the collected samples were conducted to enhance our understanding of the subsidence phenomena. Geotechnical assessments of the sedimentary conditions in the region reveal that, in addition to the observed drawdown in GWTL, the presence of swellable and soluble sediments has exacerbated the severity of subsidence effects across the plain. Consequently, by integrating the findings from soil studies with the quantitative and qualitative evaluation of the aquifer, Minab plain has been categorized into three distinct zones based on subsidence risk. In the upstream section of the aquifer, subsidence predominantly manifests as compaction of the alluvial layers, which is significantly influenced by extensive groundwater withdrawals. In contrast, the central region of the plain exhibits subsidence characterized primarily by pit and crack formation, attributed to the presence of problematic soils. At the downstream end of the aquifer, however, subsidence is less pronounced, owing to saline seawater intrusion and elevated GWTL. Overall, the assessment indicates that Minab plain is concurrently grappling with both subsidence and seawater intrusion, underscoring the urgent need for the implementation of optimal management strategies for surface and groundwater resources to foster sustainable conditions within the aquifer.</p>

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Evaluating and determining the mechanism of land subsidence susceptibility under excessive overexploitation of groundwater and problematic sediments

  • 期刊论文

  • 发表日期：

    2025年12月5日

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  • Mahmoud Mohammad Rezapour Tabari,
  • Mehdi Eilbeigi

摘要

In this study, we developed a methodology that integrates field observations with geological, hydrogeological, and hydrological data pertaining to the Minab aquifer to elucidate subsidence behavior and identify its underlying mechanisms. This approach involved the preparation of longitudinal and transverse sections of alluvial layers utilizing Rockworks software, which facilitated a comprehensive analysis of the alluvial aquifer layers and sediments within the Minab plain. To assess the groundwater table level (GWTL) behavior and its relationship with aquifer recharge conditions and the resultant subsidence at the surface of the Minab plain, we analyzed variations in aquifer static volume alongside a 37-year time series of rainfall data. The results indicate that excessive overexploitation of groundwater has resulted in a significant decline of the GWTL by 16.92 m. These uncontrolled withdrawals have not only induced extensive subsidence in the eastern regions of the plain but have also facilitated saline seawater intrusion in the western areas, thereby establishing hydraulic gradients that direct flow from the sea into the aquifer. To further elucidate the mechanisms underlying subsidence across the entire aquifer, exploratory boreholes were strategically positioned at the locations of existing piezometers. Three boreholes were drilled at the beginning, middle, and end of the aquifer, and chemical analyses of the collected samples were conducted to enhance our understanding of the subsidence phenomena. Geotechnical assessments of the sedimentary conditions in the region reveal that, in addition to the observed drawdown in GWTL, the presence of swellable and soluble sediments has exacerbated the severity of subsidence effects across the plain. Consequently, by integrating the findings from soil studies with the quantitative and qualitative evaluation of the aquifer, Minab plain has been categorized into three distinct zones based on subsidence risk. In the upstream section of the aquifer, subsidence predominantly manifests as compaction of the alluvial layers, which is significantly influenced by extensive groundwater withdrawals. In contrast, the central region of the plain exhibits subsidence characterized primarily by pit and crack formation, attributed to the presence of problematic soils. At the downstream end of the aquifer, however, subsidence is less pronounced, owing to saline seawater intrusion and elevated GWTL. Overall, the assessment indicates that Minab plain is concurrently grappling with both subsidence and seawater intrusion, underscoring the urgent need for the implementation of optimal management strategies for surface and groundwater resources to foster sustainable conditions within the aquifer.