Analysis of Drivers of Trends in Groundwater Levels Under Rice–Wheat Ecosystem in Haryana, India

Abstract

In India, especially in the state of Haryana in the northwestern parts, groundwater is the key source of water supply for domestic, industrial and agricultural uses. In recent years, the dependence on groundwater has increased drastically over the state due to speedy expansion of area under rice–wheat cultivation and therefore the states’ aquifers have started experiencing over-exploitation. The aim of this study was to compute the magnitudes of groundwater level trends and abrupt change point detections spatially and temporally based on secondary data obtained from the Groundwater Cell, Department of Agriculture, Government of Haryana with respect to 118 community development blocks for pre- and post-monsoon seasons during 1990–2013. Three statistical models, namely Mann–Kendall test, Sen’s slope estimator and simple linear regression, were applied to understand the trend and rate of change in groundwater level, whereas the abrupt change point detection analysis was carried out using Pettitt’s test, standard normal homogeneity test, Buishand’s range test and von Neumann ratio test. The results indicate that the average depth to groundwater level during pre-monsoon season in the state has ranged from 3.42 to 43.90 m below ground level (mbgl), whereas the average depth to groundwater level during post-monsoon season has ranged from 2.48 to 43.68 mbgl. The mean of groundwater level fluctuations during pre- and post-monsoon seasons was found to be − 6.0 and − 6.7 mbgl, respectively. The study highlights that the negative (falling) trends are much more pronounced (significant at 0.01% probability level) than positive (rising) ones, which corroborate the unsustainable groundwater development in the state. The abrupt change point detection analysis of groundwater levels indicates toward different change points, with maximum change points between the years 2000–2006 during pre- and post-monsoon seasons. This can be attributed to the advanced transplanting of rice crop by farmers much before the start of rainy season. In addition, both anthropogenic and climatic factors have led to groundwater depletion in the study area. These findings may be helpful for the planners and policy makers toward judicious utilization of groundwater resources in the state.