38-5 An Efficient Surrogate-based Multi-Objective Optimisation Framework Using Sequential Sampling Strategy and Evolutionary Algorithm for Sustainable Island Groundwater Management under Recharge Change and Sea-level Rise

Session: Geoscience and Hydrogeology in the AI Era: From Predictive Models to Real-Time Applications

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Abstract:

To efficiently and effectively obtain optimal pumping schemes (OPS) in coastal regions, striking a balance between sustainability, economic costs, and seawater intrusion (SWI) control under recharge change and sea-level rise (SLR), this study develops an efficient offline surrogate-based multi-objective optimisation framework (OFSMOOF). In this framework, SEAWAT is employed to simulate aquifer response under pumping to produce training data. Gaussian Process (GP) emulation is applied to construct model surrogates, predicting management objective and constraint values. A sequential sampling strategy within the iterative process is proposed to select training points, where new sampling locations are found by selecting from a large network of candidate points, the one that has the maximum distance from the closest available training point. Evolutionary algorithm, continuous ant colony optimisation, is employed to search OPS across the input space according to the GP model predictions instead of calling SEAWAT simulations. This study focuses on a two-objective groundwater pumping optimisation considering recharge change and SLR, formulated on a simplified three-dimensional island aquifer, using hydrogeological conditions of the San Salvador Island (Bahamas). GP models can provide associated uncertainties in predictions by conducting repeated Monte Carlo simulations using these GP models, so it is possible to ascertain the probability of Pareto optimality for each pumping scheme. OPS given by OFSMOOF are characterised by the Pareto-optimal probabilities and validated by SEAWAT simulations. Results reveal that the proposed OFSMOOF can efficiently produce trustworthy OPS for sustainable island groundwater management under recharge change and SLR.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8379

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