Impact of Climate Change on Groundwater Heads Using Predicted Land Use and Projected Population in Numerical Modelling for Chennai Basin

ABSTRACT Groundwater, a crucial resource in humanity’s development and sustainability, is studied, focusing on the impact of climate change and changing land use patterns. It is carried out through numerical modelling, and it predicts future groundwater heads with precipitation from the climate model, as well as predicted decadal land use and projected population. The recharge is estimated based on precipitation and land use. Extraction is estimated based on population and land use. The model was calibrated, and a good match was found for steady (1995) and transient states from 1996 to 2020. The prediction was carried out using a calibrated model from 2021 to 2050. Groundwater head was impacted by fluctuation based on the intensity of rainfall and drought years. Similarly, the increasing population will be the dominant factor in reducing the groundwater head in the future. Due to increased extraction, groundwater declined by 1.25 to 2.00 m in all assessing wells between 2021 and 2050. Proper governance on extraction and recharge is required for future resource sustainability. Restriction on the built-up expansion should be moved apart to restrict the extraction.