| dc.description.abstract | To address the recent drought phenomenon in Taiwan, groundwater has emerged as a crucial water resource for drought resilience. The depic-tion and assessment of the groundwater flow field are among the key issues in the field of water resource development. The primary objective of this study is to evaluate site-scale hydrogeological parameter analysis, consid-ering the significant influence of tidal fluctuations. This is achieved through the utilization of various in-situ hydraulic tests, innovative observation methods, hydrogeological tests, forward and inverse numerical modeling techniques, aiming to estimate the spatial distribution of hydrogeological parameters and construct the spatiotemporal dynamic characteristics of the groundwater flow field. The ultimate goal is to reduce the costs associated with traditional site assessment processes. The study focuses on the groundwater observation well site at the TaiCOAST Coastal Research Sta-tion, National Central University, comprising 6five monitoring wells. The conducted hydraulic profiling tests include slug tests, stratified quantified pumping and monitoring, and tracer tests. Additionally, the distribution of in-situ rock core materials is considered in conjunction with the VSAFT2 inverse modeling approach to estimate the two-dimensional spatial distri-bution of horizontal hydraulic conductivity. The study incorporates the spatial distribution of hydrogeological parameter characteristics obtained from hydraulic tests into numerical models and performs uncertainty analysis of parameter spatial distribution for each test, taking into account spatial representativeness and the results of inverse estimation. This model is then employed to analyze the response characteristics of groundwa-ter-seawater interaction at the study site and investigate the representative-ness of different test scales, thereby assessing the impact of the hydraulic profiling scale effects on the uncertainty of inversion results.
In this study, cross-hole stratified quantified pumping coupled with layered observations was employed at the field site to create multiple ob-servation points within a limited number of wells. By combining the results of quantified pumping tests in multiple wells and cross-hole quantified layered pumping tests, it was found that excluding or including tidal in-fluences would result in an order of magnitude difference in the estimation of hydraulic parameters. Integrating preliminary core interpretations, the site was observed to exhibit a general sequence from shallow to deep, charac-terized by gravel interbedded with sand and sandy mud layers. Excluding tidal influences and combining K values derived from tests of different scales, the results indicated minimal variation in K values at the field site. The K values obtained from various tests ranged from 0.188 to 4.23 m/day, falling within a reasonable range and consistent with core drilling data. The study results demonstrate that with an acceptable number of data points, integrating pumping test results and utilizing inverse estimation of hydraulic conductivity can effectively depict the distribution of aquifer heterogenei-ty. | en_US |