Predictions of groundwater vulnerability and sustainability by an integrated index-overlay method and physical-based numerical model

Vu, Tien Duc; Ni, Chuen-Fa; Li, Wei Ci; Truong, Mandy; Hsu, Shaohua Marko

doi:10.1016/j.jhydrol.2021.126082

Cited by 39 publications

(22 citation statements)

References 43 publications

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“…To investigate the unknown coefficients, approximations are applied to satisfy (1) with the boundary conditions, as shown in (2), at each point. The following linear system is acquired:…”

Section: The Fictitious Sourcesmentioning

confidence: 99%

“…A large number of multidisciplinary problems may require solutions involving complicated mathematical models and numerical techniques [1,2]. Among these approaches, the meshfree method has gained the attention of researchers from different scientific fields due to its capability of dealing with partial differential equations (PDEs) with complicated and irregular geometry [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Infinitely Smooth Polyharmonic RBF Collocation Method for Numerical Solution of Elliptic PDEs

Liu

Hong

et al. 2021

Mathematics

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In this article, a novel infinitely smooth polyharmonic radial basis function (PRBF) collocation method for solving elliptic partial differential equations (PDEs) is presented. The PRBF with natural logarithm is a piecewise smooth function in the conventional radial basis function collocation method for solving governing equations. We converted the piecewise smooth PRBF into an infinitely smooth PRBF using source points collocated outside the domain to ensure that the radial distance was always greater than zero to avoid the singularity of the conventional PRBF. Accordingly, the PRBF and its derivatives in the governing PDEs were always continuous. The seismic wave propagation problem, groundwater flow problem, unsaturated flow problem, and groundwater contamination problem were investigated to reveal the robustness of the proposed PRBF. Comparisons of the conventional PRBF with the proposed method were carried out as well. The results illustrate that the proposed approach could provide more accurate solutions for solving PDEs than the conventional PRBF, even with the optimal order. Furthermore, we also demonstrated that techniques designed to deal with the singularity in the original piecewise smooth PRBF are no longer required.

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“…To investigate the unknown coefficients, approximations are applied to satisfy (1) with the boundary conditions, as shown in (2), at each point. The following linear system is acquired:…”

Section: The Fictitious Sourcesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Infinitely Smooth Polyharmonic RBF Collocation Method for Numerical Solution of Elliptic PDEs

Liu

Hong

et al. 2021

Mathematics

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“…The concept of index-overlay models to create different types of potential or vulnerability maps has been widely used for many implementations. Such potential or vulnerability maps are critical references to decision-making for land-use planning, groundwater management, monitoring, and remediation [8][9][10][11]. Previous investigations have shown that the advantages of the index-overlay models are their ease of use, minimal data demand, and precise definition of parameters for site-specific problems.…”

Section: Introductionmentioning

confidence: 99%

“…The study aims to develop a workflow that uses the physical-based numerical model to validate the indexoverlay model and quantify the interflow in the downstream area along the Kaoping River. The study uses the analytic hierarchy process (AHP) to modify the weightings and ratings in the index-overlay model [10,11]. The quantification of the interflow potential relies on the integrated GSFLOW model to account for groundwater and surface water interactions.…”

Section: Introductionmentioning

confidence: 99%

Mapping Interflow Potential and the Validation of Index-Overlay Weightings by Using Coupled Surface Water and Groundwater Flow Model

Tran

Lee

et al. 2021

Water

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Interflow is an important water source contributing to river flow. It directly influences the near-surface water cycles for water resource management. This study focuses on assessing the interflow potential and quantifying the interflow in the downstream area along the Kaoping River in southern Taiwan. The interflow potential is first determined based on the modified index-overlay model, which employs the analytical hierarchy process (AHP) to calculate the ratings and weightings of the selected factors. The groundwater and surface water flow (GSFLOW) numerical model is then used to link the index-overlay model to quantify the interflow potential for practical applications. This study uses the Monte Carlo simulations to assess the influence of rainfall-induced variations on the interflow uncertainty in the study area. Results show that the high potential interflow zones are located in the high to middle elevation regions along the Kaoping River. Numerical simulations of the GSFLOW model show an interflow variation pattern that is similar to the interflow potential results obtained from the index-overlay model. The average interflow rates are approximately 3.5 × 104 (m3/d) in the high elevation zones and 2.0 x 104 (m3/d) near the coastal zones. The rainfall uncertainty strongly influences interflow rates in the wet seasons, especially the peaks of the storms or heavy rainfall events. Interflow rates are relatively stable in the dry seasons, indicating that interflow is a reliable water resource in the study area.

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“…Vulnerability assessment is holistically an essential stride in evaluating groundwater contaminations (Agoubi et al 2018;Rizka, 2018;George, 2021a). This challenge calls for concerns and the need to scientifically delineate the frequently and economically exploitable hydrogeological units, mostly those that are liable to susceptibility and vulnerability from surface infiltrations in the habitable areas (Vu et al 2021). As opined by Piver et al (1997), much pecuniary loss perpetrated by abandonment of well and grave health-related threats would have been obviated if scientific approach that considers wellplanned aquifer vulnerability assessment mappings has been opted for as alternative to wildly embraced wildcat drilling.…”

Section: Introductionmentioning

confidence: 99%

Integrating hydrogeological and second-order geo-electric indices in groundwater vulnerability mapping: A case study of alluvial environments

George

2021

Appl Water Sci

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AVI (Aquifer vulnerability index), GOD (groundwater occurrence, overlying lithology and depth to the aquifer), GLSI (geo-electric layer susceptibility indexing) and S (longitudinal unit conductance) models were used to assess economically exploitable groundwater resource in the coastal environment of Akwa Ibom State, southern Nigeria. The models were employed in order to delineate groundwater into its category of vulnerability to contamination sources using the first- and second-order geo-electric indices as well as hydrogeological inputs. Vertical electrical sounding technique employing Schlumberger electrode configuration was carried out in 16 locations, close to logged boreholes with known aquifer core samples. Primary or first-order geo-electric indices (resistivity, thickness and depth) measured were used to determine S. The estimated aquifer hydraulic conductivity, K, calculated from grain size diameter and water resistivity values were used to calculate hydraulic resistance (C) used to estimate AVI. With the indices assigned to geo-electric parameters on the basis of their influences, GOD and FSLI were calculated using appropriate equations. The geologic sequence in the study area consists of geo-electric layers ranging from motley topsoil, argillites (clayey to fine sands) and arenites (medium to gravelly sands). Geo-electric parametric indices of aquifer overlying layers across the survey area were utilized to weigh the vulnerability of the underlying water-bearing resource to the contaminations from surface and near-surface, using vulnerability maps created. Geo-electrically derived model maps reflecting AVI, BOD, FLSI and S were compared to assess their conformity to the degree of predictability of groundwater vulnerability. The AVI model map shows range of values of log C ( −3.46—0.07) generally less than unity and hence indicating high vulnerability. GOD model tomographic map displays a range of 0.1–0.3, indicating that the aquifer with depth range of 20.5 to 113.1 m or mean depth of 72. 3 m is lowly susceptible to surface and near-surface impurities. Again, the FLSI map displays a range of FLSI index of 1.25 to 2.75, alluding that the aquifer underlying the protective layer has a low to moderate vulnerability. The S model has values ranging from 0.013 to 0.991S. As the map indicates, a fractional portion of the aquifer at the western (Ikot Abasi) part of the study area has moderate to good protection (moderate vulnerability) while weak to poor aquifer protection (high vulnerability) has poor protection. The S model in this analysis seems to overstate the degree of susceptibility to contamination than the AVI, GOD and GLSI models. From the models, the categorization of severity of aquifer vulnerability to contaminations is relatively location-dependent and can be assessed through the model tomographic maps generated.

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Predictions of groundwater vulnerability and sustainability by an integrated index-overlay method and physical-based numerical model

Cited by 39 publications

References 43 publications

Infinitely Smooth Polyharmonic RBF Collocation Method for Numerical Solution of Elliptic PDEs

Infinitely Smooth Polyharmonic RBF Collocation Method for Numerical Solution of Elliptic PDEs

Mapping Interflow Potential and the Validation of Index-Overlay Weightings by Using Coupled Surface Water and Groundwater Flow Model

Integrating hydrogeological and second-order geo-electric indices in groundwater vulnerability mapping: A case study of alluvial environments

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