Analysis of Bearing Capacity of Water Resources Based on System Dynamics in Yiwu City of China

A risk assessment model for water shortage was constructed from the risk analysis method based on the information diffusion theory. The application of this model was demonstrated in the city of Yiwu in Zhejiang Province, China. The study indicates that the present model is more stable and effective when compared with the traditional model, based on analytical results from a small sample. The risk assessment result was used to analyze the carrying capacity of water resources from an ecological angle. The author advances that the carrying capacity of water resources should be defined as the maximum bearing capacity of water resources for human activity in certain stages of social development under the sound circle of the ecological system. Further study on Yiwu was also performed in the paper, and the result indicates that water shortage in this city is not of the relevant type of water source and can classified in terms of water quality type as well as water conservancy. In order to verify the result of the theoretical investigation in the present paper, the author also simulates the dynamic changing process of carrying capacity of water resources under the condition of enforcement of the future policy in the city. The simulation uses the model of system dynamics (SD), according to the historical data of the city over twenty years and the governmental standard for comprehensively building a comfortable society by 2020. The paper simultaneously indicates that the primary scheme of unilaterally pursuing the fast development of the economy at the expense of environment and the secondary scheme of taking environmental protection as the primary goal via slowing of development of the economy are undesirable for Yiwu. Furthermore, a scheme of simultaneously giving consideration to both economic development and environmental protection should be the preferred scheme. However, if the present amount of water supply is constantly maintained in the near future, the requirement for water supply will not be satisfied under the balanced considerations of economy and environment. The carrying capacity of water resources in this region can be effectively improved only under the situation of not only strengthening the investment in environmental protection but also increasing income and reducing expenditure year after year.