Modelling seawater intrusion in the Pingtung coastal aquifer in Taiwan, under the influence of sea-level rise and changing abstraction regime

Dibaj, Mahdieh; Javadi, Akbar A.; Akrami, Mohammad; Ke, Kai-Yuan; Farmani, Raziyeh; Tan, Yih-Chi; Chen, Albert S.

Modelling seawater intrusion in the Pingtung coastal aquifer in Taiwan, under the influence of sea-level rise and changing abstraction regime | Modélisation de l’intrusion d’eau de mer dans l’aquifère côtier de Pingtung à Taiwan, sous l’influence de l’élévation du niveau de la mer et du changement du régime de prélèvement Modelado de la intrusión de agua de mar en el acuífero costero de Pingtung en Taiwán, debido a la influencia de la elevación del nivel del mar y el cambio del régimen de explotación 海平面上升和改变开采方案影响下的台湾屏东沿海含水层海水入侵的模拟研究 Modelagem da intrusão de água do mar no aquífero costeiro de Pingtung, em Taiwan, sob a influência do aumento do nível do mar e da mudança do regime de abstração

2020

A three-dimensional variable-density finite element model was developed to study the combined effects of overabstraction and seawater intrusion in the Pingtung Plain coastal aquifer system in Taiwan. The model was generated in different layers to represent the three aquifers and two aquitards. Twenty-five multilayer pumping wells were assigned to abstract the groundwater, in addition to 95 observation wells to monitor the groundwater level. The analysis was carried out for a period of 8 years (2008–2015 inclusive). Hydraulic head, soil permeability, and precipitation were assigned as input data together with the pumping records in different layers of the aquifer. The developed numerical model was calibrated against the observed head archives and the calibrated model was used to predict the inland encroachment of seawater in different layers of the aquifer. The effects of pumping rate, sea-level rise, and relocation of wells on seawater intrusion were examined. The results show that all layers of the aquifer system are affected by seawater intrusion; however, the lengths of inland encroachment in the top and bottom aquifers are greater compared with the middle layer. This is the first large-scale finite-element model of the Pingtung Plain, which can be used by decision-makers for sustainable management of groundwater resources and cognizance of seawater intrusion in coastal aquifers.

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