The Effect of Drought Phenomenon on the Surface of Groundwater Aquifer in Qazvin Plain in Iran

Abstract

As one of the most catastrophic atmospheric events, drought affects various aspects of the environment. Groundwater resources are one the sectors that are influenced by long-term droughts and received insufficient attention compared to other aspects of the environment. Rainfall data collected by 23 metrological stations for 20 years (2005, 2010, 2015,2020) was used to investigate the drought event and its situation in Qazvin plain, the central plateau of Iran. Drought characteristics are evaluated using the 24-month standardized precipitation index (SPI). The results of SPI indicated that insufficient precipitation, excessive use of groundwater for irrigation, and utilization of uncontrolled wells caused a significant reduction in groundwater aquifers from 2015 to 2020. To assess the performance of the SPI, a five-year moving average of available precipitation data was calculated, and the result confirmed the outcomes of SPI. Appropriate geostatistical interpolation methods are used to generate maps of drought zoning. Based on the results of this investigation in the northeastern part of the study area, June and November had the highest and the lowest rate of drought, respectively. The linear regression between the annual average of precipitation and the changes of groundwater aquifer level exposed a significant correlation of R2 = 0.4253. Furthermore, linear regression between 24-month SPI and groundwater aquifer level indicated a correlation of R2 = 0.614. Considering the results of this study, the reduction of groundwater aquifer levels in Qazvin plain from 2015 to 2015 exposed a significant negative difference compared to previous years (2005 to 2010).