Understanding the Decadal Variation of the Groundwater Resources along the Coastal Aquifers of Pondicherry – A Climate Change Perspective

Abstract

Groundwater and their regional variations are controlled by long-term climate conditions. Climate change will therefore have a great impact on groundwater resources. In this study, long term rainfall (1900 to 2016) and water level changes (1989 to 2009) from Pondicherry region were observed. The rainfall pattern shows cyclic changes of high and low rainfall over decadal period and in particular up to 2011 from 1998 and then decreases, whereas the groundwater level has decreased drastically from 1998 onwards until 2003 and subsequently there is an increasing trend. The changes in climate have resulted in deviation in amount of rainfall, shift in rainfall period, variation in water level and enrichment of stable isotopes in the region. Further the land use pattern has increased in the urban regions due to increase in population which has resulted in the excessive pumping of groundwater in Pondicherry coastal aquifer, thereby enhancing the salinity in major portion of the study area. The geochemical factors like EC and isotopes give an insight in understanding the variation in climate change and its effects on groundwater quantity and quality. Hence the careful land use planning only will help to conserve the groundwater resource which is precious and finite, and will help to protect recharge zones mechanisms.