Analyzing groundwater level trend by hybrid approach in 37 districts of Bihar State, India

Abstract

In the eastern Indian state of Bihar, the majority of the people depends on groundwater for irrigation. Bihar is mainly an agricultural area; over time, groundwater levels have been dropping due to rising water demands from different industries. Therefore, analyzing groundwater levels and their trends is essential for ensuring the safe use of groundwater resources. This study determines the groundwater level trend by a novel hybrid approach of Mann‐Kendall–Sen's innovative trend analysis in 37 districts of Bihar State, India. In May 2019, August 2019, November 2019, and January 2020, the normalized test statistics (P) were determined using Mann‐Kendall‐trend analysis for 37 districts. According to the results, in May 2019, there was a decrease in the groundwater depth level observed in 28 districts, an increase in seven districts, and no noticeable trend in two districts. The trend of groundwater depth level decreased in 29 districts, increased in five districts, and had no trend in three districts in August 2019. In November 2019, the groundwater depth level showed a decreasing trend in 30 districts, an increasing trend in five districts, and no discernible trend in two districts. Similarly, in January 2020, the groundwater depth level decreased in 29 districts, with an increasing trend in five districts and no trend in three districts. The study's findings are significant for the sustainable management of groundwater resources in Bihar State, India.