Document Type : پژوهشی
Authors
1 M. Sc. in Climatology, Geography Dept., Razi University
2 Associate Professor of Climatology, Geography Dept., Razi University
Abstract
A major part of the fresh water demand in the world is provided through groundwater. Droughts and wet periods are among the most important factors that have a significant effect on the fluctuation of the groundwater level. The purpose of this study is to investigate the relationship between SPI and GRI indexes in the Eslamabad-e Gharb plain (Kermanshah Province) in a 20-year period and predict the future state of the groundwater level. The values of both indexes were calculated in different time scales. To obtain the relationship between two indices, the correlation coefficient was used once in different time scales and again with time delays of 1 to 12 months. Then, the future precipitation data of the plain in a 20-year period were extracted with four CMIP6 models under three scenarios, and then were downscaled with the SDSM model. Finally, the CanSM5-CanOE model was selected and its downscaled data were entered into the regression model of the relationship between precipitation and water level to predict the future state of the groundwater level. The results showed that the highest significant correlation between 48-month SPI and 48-month GRI values is observed at a time delay of 12 months, which indicates the effect of precipitation on changes in the groundwater level in medium and long-term scales. The forecast results of the groundwater level for the coming period indicate a water level drop of 5.17, 6.02 and 8.08 meters respectively under the three scenarios SSP1-2.6, SSP2-4.5, and SSP5-8.5.
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