Result-based management approach for aquifer restoration problems using a combined numerical simulation – parallel evolutionary optimization model

Abstract

Result-based management (RBM) has been used as a new management approach for groundwater resources planning. Based on this approach, three levels of results including outputs (aquifer stability), outcomes (positive balance), and impacts (aquifer restoration) have been considered in this study. To monitor these levels, three indicators based on sustainability, filling, and restoration definitions are given to describe the associated RBM aquifer restoration problems. In this study, a combined simulation–optimization model has been developed using a MODFLOW-based numerical simulation model and a parallel evolutionary algorithm of continuous ant colony optimization. The model has been applied to a real case study of Namdan aquifer located in Fars province, Iran, over a planning horizon of 10 years. Three levels of outputs, outcomes, and impacts have been achieved and the effectiveness of RBM approach in groundwater resources management has been assessed. The important observations are: (1) The planning based on the management problems of sustainability, filling, and restoration indicators leads to an increase in the groundwater elevation by 3, 9.47, and 10.61 m at the end of management period in comparison with the beginning of the period; (2) The planning based on the restoration indicator causes the highest level of rise in groundwater elevation and reaches the restoration target as highlighting the significance of a proper management setup to achieve the proposed target; (3) The investigations based on reliability, utility, and vulnerability indicators show the improvement of aquifer restoration status over the results chain. The methodology given in this study can be a novel approach to the realistic management of groundwater resources considering the proposed targets while it can be improved by the involvement of stakeholders and beneficiaries in RBM implementation.