Forecasting of Groundwater Fluctuations Using Stochastic Models and GMS(Case Study: Rafsanjan Plain)

In this study, the prediction of fluctuations in groundwater level was influenced by stochastic models in Rafsanjan plain. Future precipitation was projected using the ARIMA model in EViews9 software for 2017-2023, then groundwater drainage was simulated using the groundwater model system (GMS) during the base period (2003-2016) and results from the ARIMA model for the upcoming period. The results of groundwater drainage simulation showed that in the whole region, groundwater abatement occurred in the upcoming period relative to the base period, and the most groundwater losses occurred in the southwest of the plain, and an annual increase of approximately 130 million cubic meters Groundwater resources are made. In general, groundwater has the highest level (upper level) at the beginning of the period and the lowest level (lowest level) at the end of the statistical period. After modeling the groundwater level for the base period, rainfall prediction from the ARIMA model was applied to the groundwater model with the assumption that the aquifer was operationally constant. The results showed that the aquifer volume deficit was 1021.09 million cubic meters in the final model year (2023). Also, the changes in the level of the aquifer in the Rafsanjan Plain from 2003 to 2023 indicate that, given the estimated rainfall from the ARIMA model, it can be admitted that an average of 1 meter annual waterfall will occur in this plain.