Computation of minimum adjustment factors for sustainable groundwater management using data assimilation and Vensim dynamic model

Due to the growth of population and industrial advancements in Iran, especially Birjand, the use of groundwater makes the aquifer’s balance becomes negative. This negatively affects both quantity and quality conditions of groundwater. To prevent this, suitable water management is necessary for Birjand aquifer. In this study, to overcome negative groundwater balance, the concept of “adjustment factors” is presented. These factors are applied to all types of consumption and make the groundwater balance to be positive. For this aim, a dynamic model of groundwater resources in Birjand aquifer is created in Vensim software. This model helps to determine the groundwater balance. Then, with using dynamic model and particle filter approach in MATLAB software, minimum adjustment factors are achieved. All data and information of Birjand aquifer between 2004 and 2021 are entered into Vensim model; then, under three scenarios, the groundwater balance is computed for the next 5 years (2022–2026). Three scenarios are normal, dry, and wet conditions. In the next step, with the help of particle filter, the minimum adjustment factors for two types of consumptions including agricultural and industrial are computed. The results show that the adjustment factors for all consumptions in dry conditions are much higher than others. For instance, in 2026, the adjustment factor for agriculture in dry conditions is 0.081 while in normal and wet conditions is 0.75 and 0.031, respectively. Also, the findings indicate that applying these adjustment factors to groundwater model has successful results and make the groundwater balance to be positive.