[A-HW21] Surface and subsurface hydrologic models: Technical advances and applications for water management

[AHW21-P09] Integration of GemPy and FloPy packages for modeling seawater and freshwater interactions in coastal aquifers

*Hsin-Po Wang¹, Chuen-Fa Ni¹, Yu-Huan Chang¹, Chi-Ping Lin², Yi-Jing Chen¹, Chia-Yu Hsu¹, An-Yi Hsu¹ (1.Graduate Institute of Applied Geology, National Central University, 2.Center for Environmental Studies, National Central University)

Keywords:Coastal aquifer, Uncertainty, Open-source, Seawater and freshwater interaction, Geological model

Coastal groundwater resource is a potential alternative water resource to bridge the gap of increasing water demands. An accurate hydrogeological model could reduce the uncertainty of the flow and transport estimations in coastal aquifers. The study aims to develop a framework that integrates the open-source GemPy and FloPy for modeling seawater and freshwater interactions in the coastal aquifer in Taoyuan, Taiwan. The GemPy is a geological modeling suite based on implicit interpolation algorithms and is employed to build the 3D geological model for the coastal aquifer. The FloPy allows the users to simulate MODFLOW and the relevant modeling packages for aquifer systems. In the study, a series of field works were conducted to acquire site-specific information, including core drilling and identification of geological materials, groundwater level observation, and hydraulic tests. The geological model uses data obtained from the core samples to map the stratigraphic distribution of the coastal aquifer. The groundwater flow model was then calibrated and validated based on long-term observation at the site. The submarine groundwater discharge at the site was systematically assessed and the parameter heterogeneous induced uncertainty was evaluated.