## 1 Introduction  
Water resources are a vital and irreplaceable natural asset for human survival and development. With the rapid progress of national economic construction and the improvement of living standards, the demand for groundwater resources continues to increase, leading to an increasingly prominent imbalance between supply and demand. Simultaneously, the issue of water pollution has become more pronounced due to the continuous development of industry and agriculture, posing a serious threat to human development. Shallow groundwater systems are highly susceptible to changes in precipitation levels since their recharge primarily comes from surface sources [1]. Groundwater, as a crucial water source, has garnered significant attention. Under recent climate change, groundwater resources have been increasingly exploited and utilized worldwide, resulting in pollutant issues, particularly in highly vulnerable areas [2]. Groundwater extraction, which serves as a widespread and accessible method for obtaining high-quality freshwater, accounts for up to 30% of total global freshwaterutilization [3,4]. However, excessive groundwater exploitation often leads to a continuous decline in the water table [5, 6, 7], posing risks of land subsidence and collapse, especially in densely populated urban areas such as Tianjin, Jakarta, Konya, Mashhad, and Hanoi [8, 9, 10, 11, 12]. Moreover, groundwater exploitation significantly contributes to vulnerability associated with high levels of human activity [13, 14]. The exploitation of groundwater and its impact on ecological systems pose challenges to global economic and social development [15, 16]. Groundwater vulnerability reflects both the extent of contamination and the ability of groundwater to self-repair and maintain sustainability. As a complex black box system, groundwater vulnerability factors are diverse, and various research methods are available. For example, [PERSON] et al. [17], [PERSON] et al. [18], and [PERSON] et al. [19] employed Mann-Kendall's Test, Poisson Distribution, End-member mixing analysis, and other relevant models based on land use change and soil infiltration. These studies revealed that groundwater responses to precipitation weaken or even disappear due to the thickened vadose zone and reduced permeability caused by declining groundwater levels and the conversion of natural grasslands to artificial farmland [20]. In a recent study in Nigeria, GLSI and LC models were used to conduct a case study of the ljero mining site, examining the comparative effect of lateritic shield on groundwater vulnerability [21, 22]. Groundwater vulnerability assessment provides significant scientific support for implementing measures to prevent groundwater pollution [23, 24]. [PERSON] and [PERSON] [25] and [PERSON] et al. [26] selected environmental parameters such as vadose zone impact, hydraulic conductivity, population density, and river recharge, utilizing the DRASTIC model to evaluate aquifer vulnerability. The DRASTIC model aims to use seven factors such as \"Depth to water, Net recharge, Aquier media, Soil media, Topography, Impact of vadose zone, and Hydraulic Conductivity\", and allocates the ratings to all factors according to the range of factors [27], which is simple and widely used in evaluating groundwater contamination vulnerability. However, previous studies tend to assess groundwater vulnerability subjectively and refer only to a small number of factors, or have reported only a weak correlation between water pollutant concentrations (commonly nitrate) and the calculated DRASTIC index [28, 29], which provided difficulties in obtaining conclusion accurately. This research integrated DRASTIC with additional methods like the GIS techniques, PCA (Principal Component Analysis), and other statistical approaches, which improve the evaluation systems to be modified to obtain more accurate results based on local hydrogeological conditions [30, 31, 32].