Status of urban hydrogeology research with emphasis on India

Urban areas have witnessed an inexorable expansion in population density, urban sprawl, industrialization and agricultural activities in the past few decades. Withdrawal of groundwater to meet water demand has resulted in over-drafting of aquifers and, commonly, lowered water tables in many urban centres of India, like Delhi, Lucknow, Patna, Kolkata and others. Overdraft has also deteriorated the chemical and biogeochemical quality of surface water and groundwater. This paper highlights some of the research approaches, namely hydrogeochemical investigation, groundwater modeling, and use of geographic information systems and remote sensing, used worldwide to resolve issues specific to urban groundwater. The paper also highlights approaches that are practiced internationally (combined hydrogeologic and multi-isotopic studies, integrated modeling techniques, etc.) but still need to be developed on a large scale in India. A detailed overview of the literature indicates the need for a more holistic approach incorporating various types of conceptual and management models to strengthen the research level in India and elsewhere. For instance, a computational tool that can incorporate different models, such as for urban water and contaminant balance and pipeline leakage, should be developed to generate predefined scenarios of potential groundwater contamination and help in the socio-economic analysis of different scenarios. In hydrogeochemical approaches, multi-isotope ratios should be coupled with hydrogeologic approaches for better understanding of water quality problems.