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

Abstract

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.

Multi-Annual Dynamics of a Coastal Groundwater System with Soil-Aquifer Treatment and Its Impact on the Fate of Trace Organic Compounds

“…Both assumptions mainly refer to the transition zone (freshwater-saltwater interface), where the fluid density varies in time and space as a function of temperature and salt concentration. When these mechanisms are essential, variable density flow modelling helps explaining saltwater intrusion observations [38][39][40]. Considering such processes in the model applied to the Agon-Coutainville SAT would modify the simulated results, such as: (1) decreased flow velocities of saline groundwater relative to fresh groundwater; (2) vertical stratification of more dense saline groundwater relative to fresh groundwater; and (3) increased velocity of the infiltrating STWW freshwater plume due to the existence of this stratification.…”

Assessment of Hydrogeochemical Characteristics and Seawater Intrusion in Coastal Aquifers by Integrating Statistical and Graphical Techniques: Quaternary Aquifer, West Nile Delta, Egypt

“…The dissolution of Fe and Mn oxides in the aquifer is at the cost of the oxidation of organic matter [70,71], and the bicarbonate will increase. The reaction Equations (7) and (8) The encountered dissolved silicate minerals are albite, anorthite, K-feldspar, kaolinite, and quartz. Groundwater samples are undersaturated with albite and anorthite.…”

“…Due to extreme use of the groundwater in coastal aquifers for industrial, agricultural, and urban expansion, seawater intrusion has come to be a global problem [8][9][10][11]. Climate change has raised atmospheric surface temperatures and melted ice caps, mountain glaciers, and polar ice sheets, which raises ocean and sea water levels, compounding the problem [12].…”

Status of seawater intrusion in coastal aquifer of Gujarat, India: a review

“…The model was thoroughly calibrated with monitored data of water level, current velocity and salinity. Similarly, a FEFLOW model was created to scrutinize the collective paraphernalia of over-abstraction and SWI in the Pingtung Plain coastal aquifer system, Taiwan [64]. The model was created in distinctive layers to signify the three aquifers and two aquitards.…”