Water allocation using ecological and agricultural value of water

Abstract

Although wetlands are among the most diverse and productive ecosystems in the world, they are under threat due to human activities and agricultural developments. The economic value of ecosystem services, including provisioning, regulating, supporting, and cultural services, provides a quantitative basis for the sustainable management of water resources systems. Moreover, ignoring the economic value of ecosystem services in the management of water resources systems can lead to a critical degradation not only in the ecosystem health but also in the long-term agricultural production. In this study, the total economic value of the water resources system is calculated as the summation of the economic value of the wetland's ecosystem services and agricultural production. A simulation-optimization approach is developed for hydro-economic planning at basin scale and designing environmental flow based on wetland's ecosystem services. The objective function is the total economic value of the system and the design variables include the cultivation area of agricultural sectors and environmental flow for the wetland. The optimal water allocation solution would result in 2048 billion rials that is 67 % from agriculture and 33 % from wetland ecosystem services. The results show that considering the value of wetland ecosystem services along with economic water use such as agriculture, in addition to increasing the total economic value, can result in an effective water allocation that satisfies the wetland's environmental requirements and leads to healthy and optimal planning at the basin.