Models for optimum distribution of water resources at three hierarchies and their applications

In this paper, models for optimum distribution of water resources (ODWR) are divided into three hierarchies. The first hierarchy is the model for optimum distribution of water resources based on considering sustainable development (SDO), the second is the model for optimum distribution of water resources based on considering the carrying capacity of water resources (CCO), and the third is a general optimum distribution model with no consideration of the carrying capacity of water resources (GOD). In the first and highest hierarchy, the model is developed based on considering the objective of sustainable development. In the model at the second hierarchy, the carrying capacity of water resources is considered and regarded as a constraint to be put into the optimum model. In the model at the third hierarchy, the carrying capacity of water resources is not considered, and the model is a general optimum model only. A study was carried out in Zhengzhou City to demonstrate the applicability of the models at all hierarchies. It is concluded that these models at three hierarchies could be applied in water resources studies and the corresponding models should be developed based on different conditions.