Mechanism of sustainable water resources system

Based on the sustainability and system theory, the connotation and features of Sustainable Water Resources System (SWRS) were discussed and the SWRS evolution forcing mechanism was put forwarded, that is, the SWRS is controlled by the interactions among dynamical, resistant, and coordinate mechanism. A quadratic nonlinear differential equation was used to describe the evolution process of SWRS quantitatively on basis of generalizing the influencing factors for SWRS evolution. The SWRS evolution follows a four-stage (initiation, growth, mature and steady) evolution cycle before it goes to the new evolution cycle. Further, taking Shanghai city as an example, the SWRS evolution equation was established by fitting method, and the evaluation results and the causes were given.