Coupled three-dimensional modelling of groundwater-surface water interactions for management of seawater intrusion in Pingtung Plain, Taiwan

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

doi:10.1016/j.ejrh.2021.100850

Mahdieh Dibaj, Akbar A Javadi + Show 5 more

Open Access

https://doi.org/10.1016/j.ejrh.2021.100850

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Abstract

Study regionA coupled framework, linking subsurface flow and surface hydrodynamics, is developed and applied to a real-world case study of Pingtung coastal aquifer in southwest of Taiwan, in East Asia. Study focusFEFLOW is adopted to develop a 3-D variable density and transient groundwater model of the Pingtung shallow aquifer lying 250 m below mean sea level (MSL). This model is coupled with a 1-D river network model, comprised of the main river and its two tributaries, using MIKE 11 through the IFM MIKE 11 coupling interface. The model is capable of analysing the relationship between rainfall, surface water and groundwater recharge lag time. Also, the analysis of potential river inundation and maximum river discharge enable the model to choose the best location to apply artificial recharge as a management scenario to mitigate the effect of seawater intrusion (SWI). To the authors’ knowledge, the developed coupled model is the first detailed integrated framework analysing the interaction of surface and subsurface water, with the capability to contribute to the restoration, rehabilitation, and management of the river network. New hydrological insights for the regionThe rainfall ratio in the wet season to dry season is significant in this plain comparing with the rest of Taiwan. Also, southern Taiwan experiences the largest sea and river interaction, while Kaoping River playing as a pathway role for inland lead of seawater intrusion.

Highlights

In recent decades, there has been significant spatial and temporal instability in hydrological conditions due to climate change (Simonovic and Li, 2003) increasing the vulnerability of water resources (Chang et al, 2011)
The main focus of this study is to investigate the interaction between river network and underlying groundwater under influence of the rainfall
The developed model was coupled with a 1-D river network model for integrated simulation of groundwater flow, surface water flow and seawater intrusion in Pingtung plain

Summary

Introduction

There has been significant spatial and temporal instability in hydrological conditions due to climate change (Simonovic and Li, 2003) increasing the vulnerability of water resources (Chang et al, 2011). Groundwater plays a vital role in providing stable regional water resources (Tsur, 1990). Fresh groundwater in coastal aquifers is vulnerable to salinization by upconing and seawater intrusion (Post, 2005). An integrated framework considering surface and subsurface water as a single resource is essential for improving the reliability of water supply (Sophocleous, 2002; Montazar et al, 2010). Numerical models can be used to investigate the behaviour of surface-subsurface water systems in coastal areas for different climate change scenarios (Yang et al, 2015).

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