Policy analysis on groundwater and agricultural dynamics in semi-arid regions with agent-based simulation

A significant part of the water withdrawals among surface water resources and groundwater resources is used in agricultural systems. In semi-arid regions where surface water is limited, agricultural activities are sustained depending on groundwater resources. However, increase in drought levels in these regions increases the gap between available groundwater resources and the required water for agricultural activities. Therefore, the future of groundwater resources and agricultural production are risky. Konya Closed Basin, one of the semi-arid region, has the highest total agricultural production value in Türkiye. In such an important region, groundwater resources have been declining rapidly in the last decades based on issues such as changes in crop patterns, uneducated farmer behaviors, climate issues, and lack of supervision and enforcement in control mechanisms. In this thesis, an agent-based model is established which is inspired by the Konya Closed Basin to examine groundwater and agricultural dynamics in semi-arid regions, and simulations are executed for 50-year periods. Various social, environmental, and economic scenarios are analyzed in the model and compared to the base run simulation to investigate which conditions would support groundwater resources without harming agricultural efficiency. Based on scenario analysis, various policies are developed and analyzed that limit crop planting patterns and groundwater usage in addition to the policy that supports the groundwater resources by transporting water from outside. Results of the analysis showed that as farmers become more educated and necessary control mechanisms are implemented in the semi-arid regions, groundwater usage can be reduced without losing agricultural production volume significantly through various policies.