Appraisal of Groundwater Vulnerability Pollution Mapping Using GIS Based GOD Index in Tiruchendur, Thoothukudi District, India

Abstract

Recently, groundwater resources have become the main freshwater supply for human activities worldwide, especially in semi-arid regions, and groundwater pollution from anthropological events is one of the chief environmental problems in built-up and industrial coastal areas. Many researchers around the world have conducted studies to evaluate the impact of groundwater management. For this study, GIS based GOD vulnerability models were used to assess the intrinsic impact and risk of pollution of coastal and irrigated areas in Tiruchendur Taluk, Thoothukudi district in Tamil Nadu. Here, GOD stands for G—Groundwater hydraulic confinement, O—Overlying aquifer strata, and D—Depth to groundwater. The parameters of G, O, and D show that 70% of the study area consists of an unconfined aquifer whose central part often consists of sandstone and fine to medium clay with sand along the coast that acts as an aquifer. The recorded value was 1–28 mbgl. The map of vulnerability using the GOD method shows that 32% of the medium vulnerabilities are located in the almost northern part of the study area, where the main source of pollution is from agricultural land and anthropological activities. A total of 39 groundwater samples were collected from different types of aquifers and used to validate the pollution map, using the EC concentration (230 to 15,480 µs/cm with an average of 2758 µs/cm) and NO3− concentration (2 to 120 mg/L with an average of 46 mg/L) in groundwater as indicators of pollution. Finally, we measured how the EC and NO3− parameters represent the medium vulnerability zone of the GOD model based on the pattern of their concentrations in groundwater. Therefore, the GIS with GOD model is the best model among these models for predicting groundwater vulnerability in Tiruchendur Taluk.

Intrinsic Vulnerability Assessment of the Qingduo Karst System, Henan Province

“…The vulnerability values in the maps are computed by spatially aggregating weighted indices according to certain criteria. The commonly used index-based methods, such as the DRASTIC [22][23][24][25], GOD [26,27], and AVI [28,29], often compose indices, such as the topographic slope, medium of the vadose zone, groundwater level, soil type, and aquifer recharge, which are suitable for the porous aquifers (Table 1). On the contrary, vulnerability assessment indices must undergo adjustments in karst aquifers due to the typically heterogeneous nature of rock dissolvability and the prevalent presence of geological structures in karst regions.…”

Drought and Groundwater Development

“…This Special Issue focuses on various technologies to resolve water scarcity and contamination caused by abnormal droughts in Asia and Africa. It includes research on the utilization of groundwater level and precipitation data; drought prediction and diagnosis; and evaluation technologies for securing water resources [3,9,10]. In general, in an upstream watershed, water is quickly discharged, so drought damage appears there first.…”