Modelling seawater intrusion in the Pingtung coastal aquifer in Taiwan, under the influence of sea-level rise and changi
- PDF / 3,583,208 Bytes
- 19 Pages / 595.276 x 790.866 pts Page_size
- 56 Downloads / 168 Views
REPORT
Modelling seawater intrusion in the Pingtung coastal aquifer in Taiwan, under the influence of sea-level rise and changing abstraction regime Mahdieh Dibaj 1 & Akbar A. Javadi 1 Yih-Chi Tan 2 & Albert S. Chen 1
&
Mohammad Akrami 1
&
Kai-Yuan Ke 2
&
Raziyeh Farmani 1
&
Received: 13 June 2019 / Accepted: 21 April 2020 # The Author(s) 2020
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. Keywords Groundwater modeling . Saltwater intrusion . Climate change . FEFLOW . Taiwan
Introduction Developing industrial, agricultural and tourism activities together with human settlements in coastal areas has led to overexploitation of aquifers, increasing seawater intrusion (SWI) and decreasing groundwater quality. The sea-level rise (SLR) due to climate change associated with global warming is expected to exacerbate the problem (Stocker 2014). The coastal plain of Pingtung in Taiwan currently suffers from SWI due to overexploitation of the aquifer system by a significant number
* Akbar A. Javadi [email protected] 1
Department of Engineering, College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, Devon EX4 4QF, UK
2
Department of Bioenvironmental Systems Engineering, Hydrotech Research Institute, National Taiwan University, Taipei 106, Taiwan
of pumping wells screened through the aquifers, at different pumping rates and depths, and using different well types. There are two different methods commonly used for analysing SWI: “sharp interface” and “variable density” methods (Sherif et al. 2012). In the sharp interface method, the saltwater and freshwater are considered as immiscible fluids with a sharp interface separating them in
Data Loading...
