Hydrogeological assessment of the groundwater aquifers for sustainability state and development planning

Abstract

Integrated water resource planning is vital to develop the groundwater resources in a sustainable manner. The main focus of the present research work is to assess the healthy condition of aquifers for sustainable groundwater planning in Uppar Odai sub-basin in western part of Tamil Nadu. The sustainable groundwater aquifer zone should be sustainable in terms of potential, quality and water table conditions. Initially, the geology, geomorphology, slope, drainage density, soil thickness, electrical resistivity, lineament density and rainfall pattern were integrated to create sustainable groundwater potential theme. In the next stage, the layers of eight major ions were integrated for groundwater quality for drinking. The irrigation parameters like salinity, SAR, Na %, RSC, specific ion toxicity and miscellaneous effects due to Cl− and NO3− were integrated for derive irrigation water quality index. Finally, the groundwater table conditions in the basin were assessed in terms of shallow, moderate and deep aquifer zones. All the four thematic maps were integrated to assess the sustainability state of aquifers. In this spatial integration, the themes were ranked as per importance in terms of sustainable contributions. The final integrated outputs have revealed that only 11% of the basin area is in the sustainable zone and remaining 89% of area is in slightly unsustainable–highly unsustainable zone which requires immediate restriction of the current rate of groundwater exploitation and protects the aquifer through artificial recharge to maintain the aquifer in sustainable environment. Based on the sustainable category, further groundwater developmental planning is suggested. The current state of groundwater development is recommended for sustainable zone. However, the groundwater development reduced for 10–50% for marginally unsustainable–unsustainable category. In the highly unsustainable zone, further groundwater development should be restricted and the quality-tolerant cropping pattern can be adopted.