Evaluation of water resource management policies for achieving sustainable agricultural development using the distance-to-optimal solution index: Application of the WEFE Nexus and NSGA-II method

Abstract

The Water-Energy-Food-Environment (WEFE) nexus is a framework that plays a crucial role in addressing concerns related to sustainable agricultural development and food security. Therefore, evaluating and revising policies and management approaches from the perspective of achieving WEFE nexus goals can operationalize sustainable agricultural development. Despite the highlighted importance of this connection, there is no comprehensive framework and method for its implementation considering various environmental criteria along with the evaluation of water resource management policies. This study aims to first extract the optimal sustainable solution by considering all Water-Energy-Food (WEF) nexus goals combined with environmental objectives such as minimizing the use of fertilizers, pesticides, and CO2 emissions, and maximizing wetland conservation scores using the NSGA-II method. Then, it estimates the effects of water resource management policies, including policies for reducing available water resources (P1), improving irrigation efficiency (P2), and crop pattern modification (P3), using the PMP model and evaluates them by calculating the Distance-to-Optimal Solution Index (DOSI). For this purpose, the Jiroft plain in Kerman province, Iran, was selected as the study area. The results showed that the optimal sustainable cropping pattern, with a reduction of 3988 ha from the current cultivated area, significantly improves environmental criteria such as reducing the use of fertilizers and pesticides, CO2 emissions, and increasing the conservation of the Jazmourian wetland. Additionally, it was found that the DOSI for the current pattern is −2.70, and for the patterns with the implementation of policies P1, P2, and P3, it is −2.89, −3.22, and − 1.19, respectively. Therefore, the policy of modifying the cropping pattern towards crops with lower water requirements (P3) can improve the sustainability of the region's agriculture. In contrast, policies for reducing available water resources (P1) and improving irrigation efficiency (P2) not only do not improve the sustainability compared to the current conditions but also worsen it. Overall, the framework used to identify the best water resource management policies by leveraging the comprehensive WEFE nexus approach will be a strategy to ensure sustainable agricultural development.