| dc.description.abstract | This study presents the development of an integrated surface and subsurface model for transient analysis of groundwater flow, salinity intrusion, river flow and river inundation, to aid decision-making and management of water resources. A coupled framework, linking subsurface flow and surface hydrodynamics, was developed and applied to a real-world case study of Pingtung coastal aquifer in southwest of Taiwan. FEFLOW was adopted to develop a three-dimensional variable-density finite element model to study the combined effects of overabstraction and seawater intrusion. 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 different time periods while hydraulic head, soil permeability, and precipitation were assigned as input data together with the pumping records in different layers of the aquifer system. The developed groundwater model was coupled with a 1-D river network model, comprised of the main river and its two tributaries, using MIKE 11. The developed model was calibrated and validated based on observed data. The model was used to analyse the interaction between the surface water and groundwater and the effects on seawater intrusion. Also, the relationship between rainfall, surface water and groundwater recharge lag time was studied. The numerical simulation results showed that all aquifer layers are affected by seawater intrusion, however, the length of inland encroachment in the top and bottom aquifers are greater compared with the middle layer. The effects of pumping rate, sea-level rise, and relocation of wells on seawater intrusion were examined. 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 option to mitigate the effect of seawater intrusion (SWI). 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. | en_GB |
