22. Response of Groundwater Level to Climate Variability: A Case Study of Mirzapur, Uttar Pradesh, India

This paper presents the trend analysis of two climatic variables: annual average rainfall and annual average temperature and fluctuating groundwater levels (GWL) for the pre-monsoon and post-monsoon season at ten different stations of Mirzapur district of Uttar Pradesh, India, using the decadal data ranging from 2011 to 2021 using nonparametric Mann–Kendall (MK) test. The trend magnitude for each of the parameter is studied using Sen’s slope estimate. The result of the decadal study showed that there has been a strong negative trend reflecting the general consistent decline in the annual average rainfall pattern temporally. On the other hand, a non-significant negative trend was witnessed in the case of annual average temperature showing the overall decline in temperature over the last ten years but with varying yearly fluctuations. The groundwater levels trend analysis shows an overall negative trend of falling groundwater level during the pre-monsoon period. However, a locally varied trend was observed in the post-monsoon season where certain stations showed the rise in GWL. Decline in the annual average rainfall and temperature were associated with the gradual impact of climate change on the northern Gangetic plains of India. Declining groundwater levels during pre-monsoon season was attributed to the delayed and declining rainfall pattern, resulting in groundwater extraction during the sowing season of kharif crops. On the other hand, variability in the groundwater level trends during post-monsoon was attributed to the possible role of concretisation in urban areas, increasing surface runoff and its extraction for household and agricultural activities during lean season. Since this area has been limited studied in the context of impact of climate change on climatic variables and groundwater levels, this study would further aid the future researches, policy making and agricultural management.