The SD Modelling And The Forecast Of The Water Resource-economy-social Harmonious Development In Shiyanghe Vally

The serious ecological and environmental problem caused by water shortage has affected the sustainable development in Shiyanghe Vally. It's also threateningthe environment in Northwest China and North China. To enforce the Scientific Development Strategy ,it's urgent to further research the problem of harmonious development of the Shiyanghe Vally. The System Dynamic(SD) modelling is an effective economic method. It can simulate the inner mechanism and dynamic change rule of the vally's water resource-economy-social system. The theories of Sustainable development,Regional Economics,Water Resource Bearing Capacity and System Dynamics are the foundation of the disertation. The water resource shortage,the nonreasonable economic structure and population pressure are the main reasons which lead to the ecological and environmental problem in Shiyanghe Vally. It's necessary to adopt SD method to caculate the total amount of water resource and exploitable water resource for the complex hydraulic relationship between the ground water and underground water. According to the Cause-result Relationship Figure,a large model is compiled in DYNAMO language which consists of about 300 variables and 900 dynamic equations. Water resource demond-supply margin and ecological water demond are selected as parameters. By changing these parameters,4 different simulation schemes are planned. After running these schemes,some important results are obtained which includes:the amount of exploitable water resource,the areas of farmland and the areas proportion of various farmlands,the amount of water demond for agriculture,industry,population and ecological system in 3 districts and the long-term trend of the above data from 1990 to 2020. Finally,according to the results of SD modelling,6 policy suggestions are put forward: reconsider the sustainable development problem in Shiyanghe Vally to guarantee the enforcement of the Scientific Development Strategy;to increase the central government investment to harness the vally's environment;to take three strategy steps to enforce the Scientific Development Strategy;resonable water property right needs to be established and present water price needs to be increased; "virtual water"concept should be carried out;the basic research of water resource should be enhanced.