Trend Analysis of Rainfall and Groundwater Level in Jaisalmer District of the Thar Desert, Rajasthan, India

Abstract

In this paper, the trend analysis of groundwater level with reference to rainfall for a period from 1979 to 2022 has been carried out for the Thar district of Jaisalmer where the annual rainfall is the minimum in the state of Rajasthan. This area has not been researched for this kind of study earlier. Rainfall data have been collected from IMD (Indian Metrological Department) Pune whereas the groundwater data have been collected from CGWB (Central Ground Water Board, Govt. of India), GWD (Ground Water Department, Govt. of Rajasthan) and India-WRIS portal, Govt. of India. The collected data have been analysed in terms of fluctuations in groundwater level. Being located in the Thar Desert, Jaisalmer is the third largest and one of the hot districts in India where water availability plays a critical role. The statistical analysis has been performed by using Microsoft excel and XLSTAT statistical software in which Innovative trend analysis (ITA), Mann-Kendall Trend analysis Test (MK test) and Sen’s slope estimator have been used. It has been observed that the yearly rainfall shows significantly upward trend (p < 0.05) during the study period whereas the groundwater level has significantly decreasing trend (p = 0.044) which indicates that groundwater level is rising. ITA support the results of MK test. The climatic and geological factors including unauthorized extraction of groundwater for irrigation purposes are also responsible for groundwater level fluctuation. In order to get the optimum out of the incident rainfall in the district, it is necessary to carry out a comprehensive study considering all relevant variables using advanced technology of assessment, measurement and extraction of groundwater, consumptive use of water, artificial recharge and regular monitoring at the level of local authorities in the field.