Effect of Meteorological Drought on Groundwater Resources of Varamin Plain Using SPI, NISTOR and GRI index

The purpose of this study is to investigate the effect of meteorological drought on groundwater resources in Varamin plain. For this purpose, the effect of meteorological drought was investigated through standard precipitation index (SPI), NISTOR index and groundwater source index (GRI). Therefore, in order to evaluate the effect of climatic parameters such as temperature and precipitation on the groundwater status of Varamin plain, time statistics (1367-1397) of the parameters of the plain were used. The results showed that according to the SPI index, this plain is approaching weak drought conditions during the last 10 years of the study period. Therefore, due to the lack of natural food sources of the aquifer in recent years (since 1388), accidental falls have occurred in this aquifer, which has led to the GRI index from normal drought conditions to relatively severe drought conditions. Finally, the results of SPI and GRI index were compared with NISTOR index, which is obtained from the inferential matrix of the combination of Di-Marton climate index and effective precipitation. This index also assessed the effect of drought and rainfall nutrition index on groundwater resources in the desired period as very severe.