Multi-level multi-object inter-basin water resources allocation model based on the evolution of coordination degree

With the development of social economy, water resources system is coupled with the systems of society and economy and environment, rather than an isolated system. The coupled system is called a water society economy environment compound system (WSEECS). To realize the sustainable development of WSEECS, each sub system of the system, namely the sub system of water resources, society, economy and environment, should be developed harmoniously. Because of serious water shortage, water volume plays an important role in the process of developing harmoniously each sub system, which can be quantitatively measured by an index called system coordination degree (SCD). The SCD fluctuates with the water volume allocated to each sub system varying. In the traditional water resources allocation model, SCD is made as a constraint. But for a complex huge WSEECS, such as inter-basin water resources system, the disposal manner has many defects and is not effective in the problem of inter-basin water resources allocation. In fact, the inter-basin WSEECS is a complex adaptive system (CAS). Therefore, according to CAS theory, based on the complexity and adaptability of system, through regarding water resources allocation as an evolutionary process and SCD as an evolution control factor, the paper puts forward a multi-level multi-object inter-basin water resources allocation model. Furthermore, the model is applied to the water resources allocation problem of the east-route of South-to-North Water Transfer Project and is verified through simulation.