Multi-objective groundwater management strategy under uncertainties for sustainable control of saltwater intrusion: Solution for an island country in the South Pacific

Lal, Alvin; Datta, Bithin

doi:10.1016/j.jenvman.2018.12.054

Cited by 54 publications

(16 citation statements)

References 48 publications

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“…Nogueira (2017) showed that the fossil saltwater entrapped within geological formations in the northern and western part of the aquifer is the most probable source of saline groundwater, but this hypothesis has not been assessed through numerical modelling. Several studies applied numerical saltwater transport models for the simulation of saltwater intrusion and assessment of climatic and human impacts, including those presented for the Pioneer Valley in Australia (Werner and Gallagher 2006), for the coastal area in the Danish-German border adjacent to the Wadden Sea (Meyer et al 2019), for the Neogene aquifer in Flanders, Belgium (Coetsiers et al 2004), for Kiribati (Lal and Datta 2019) and Kish (Ataie-Ashtiani et al 2013) Islands in the Pacific, and for Paleo-modelling of coastal saltwater, the Netherlands (Delsman et al 2014). Variable density groundwater flow modelling can be used to assess the current state of the freshwater/saltwater distributions and to predict effects of future management decisions (Oude Essink et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Application of numerical models to assess multi-source saltwater intrusion under natural and pumping conditions in the Great Maputo aquifer, Mozambique

et al. 2019

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Regional three-dimensional groundwater-flow and saltwater transport models were built to analyse saltwater intrusion in the Great Maputo area, southern Mozambique. Increased water demand has led to many private groundwater abstractions, as the local public water supply network has already reached maximum capacity. Pushing for new strategies to tackle the water-supply shortages exposes the aquifer system to saltwater intrusion from entrapped fossil saline groundwater and seawater. Previous attempts at modelling have been frustrated by data limitations. This study compiled all the available data to build the models, which were subsequently calibrated with observed heads, discharges and salt concentrations. The transport models were used to test hypotheses of potential sources of saltwater resulting in the current salinity distribution. Furthermore, scenarios were simulated to assess the impacts of sea-level rise and projected groundwater abstractions. Results show that saline groundwater is widely distributed in the aquifer's western sector, where it is a limiting factor for groundwater development, and seawater intrusion is a risk along the coastline. Newly constructed wells (46) along the Infulene River can be operated with some impacts of saltwater upconing and must be closely monitored. Although current groundwater abstractions (60,340 m 3 /day) are still small compared with groundwater recharge (980,823 m 3 /day), larger volumes of abstraction are feasible only when using a high number of production wells further away from the city with relatively low yields to avoid saltwater upconing. Capture of fresh groundwater upstream of discharge areas by wells for water supply is possible while maintaining groundwater discharges for groundwater dependent ecosystems.

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Section: Introductionmentioning

confidence: 99%

Application of numerical models to assess multi-source saltwater intrusion under natural and pumping conditions in the Great Maputo aquifer, Mozambique

et al. 2019

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“…Previous work on optimized saltwater intrusion management has been mainly dedicated to deterministic problems (Ketabchi & Ataie‐Ashtiani, 2015). Predictive uncertainty due to insufficient knowledge of recharge, hydraulic or transport parameters was included by training surrogate or metamodels (e.g., Lal & Datta, 2019; Rajabi & Ketabchi, 2017). While surrogate models are a popular choice to replace computationally demanding physically based models, in practice they are limited because of the considerable effort needed for training surrogates, the need to verify optimized solutions with physically based models and the significant expertise that is needed for their robust application.…”

Section: Introductionmentioning

confidence: 99%

Pumping Optimization Under Uncertainty in an Island Freshwater Lens Using a Sharp‐Interface Seawater Intrusion Model

Coulon

Lemieux

Pryet

et al. 2022

Water Resources Research

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Island groundwater resources often form freshwater lenses overlying saline groundwater. When water is withdrawn from a freshwater lens by a pumping well, saline groundwater migrates upwards toward the well. This vertical seawater intrusion process, also called saltwater upconing, is a major concern when managing well fields. Freshwater lenses of island aquifers have been described as being more vulnerable than continental coastal aquifers, since vertical migration distances associated with upconing are shorter than horizontal ones (Jiao &

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“…The analytics developed in machine learning techniques (MLT) continue to evolve and are now established as an efficient tool for predicting trends within experimental data. In the field of groundwater saline intrusion, their implementation has been mostly focused on the prediction of the amount of intruding saltwater [49,50] as well as the efficient management of vulnerable aquifers [51][52][53]. Robinson et al [54] utilised the Random Forests ensemble learning method to shorten the experimental procedure in sandbox investigations.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Laboratory Investigations of Saline Intrusion by Incorporating Machine Learning Techniques

Etsias

Hamill

Benner

et al. 2020

Water

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Deriving saltwater concentrations from the light intensity values of dyed saline solutions is a long-established image processing practice in laboratory scale investigations of saline intrusion. The current paper presents a novel methodology that employs the predictive ability of machine learning algorithms in order to determine saltwater concentration fields. The proposed approach consists of three distinct parts, image pre-processing, porous medium classification (glass bead structure recognition) and saltwater field generation (regression). It minimizes the need for aquifer-specific calibrations, significantly shortening the experimental procedure by up to 50% of the time required. A series of typical saline intrusion experiments were conducted in homogeneous and heterogeneous aquifers, consisting of glass beads of varying sizes, to recreate the necessary laboratory data. An innovative method of distinguishing and filtering out the common experimental error introduced by both backlighting and the optical irregularities of the glass bead medium was formulated. This enabled the acquisition of quality predictions by classical, easy-to-use machine learning techniques, such as feedforward Artificial Neural Networks, using a limited amount of training data, proving the applicability of the procedure. The new process was benchmarked against a traditional regression algorithm. A series of variables were utilized to quantify the variance between the results generated by the two procedures. No compromise was found to the quality of the derived concentration fields and it was established that the proposed image processing technique is robust when applied to homogeneous and heterogeneous domains alike, outperforming the classical approach in all test cases. Moreover, the method minimized the impact of experimental errors introduced by small movements of the camera and the presence air bubbles trapped in the porous medium.

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Multi-objective groundwater management strategy under uncertainties for sustainable control of saltwater intrusion: Solution for an island country in the South Pacific

Cited by 54 publications

References 48 publications

Application of numerical models to assess multi-source saltwater intrusion under natural and pumping conditions in the Great Maputo aquifer, Mozambique

Application of numerical models to assess multi-source saltwater intrusion under natural and pumping conditions in the Great Maputo aquifer, Mozambique

Pumping Optimization Under Uncertainty in an Island Freshwater Lens Using a Sharp‐Interface Seawater Intrusion Model

Optimizing Laboratory Investigations of Saline Intrusion by Incorporating Machine Learning Techniques

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