Research On Fuzzy And Stochastic Methods And Their Applications In Water Resources Management System

First, this paper interprets the concept and connotations of sustainable development of water resources. Then, it expounds the dialectical relationship between sustainability and development and analyzes subjective and objective identity of water resources bearing capacity and role of science and technology and management in water resources development. Next, it presents the principal and major research contents of sustainable development of water resources. However, due to the wide-range and complex of its research contents, this paper will mainly deal with the stochastic uncertainty and fuzziness of water resources system. The major contents and research results are as follows:1. Considering the importance and complexity of prediction of hydraulic elements in the field of water resources management, this article applies the neural network with fuzzy pattern recognition model for prediction by combining fuzzy mathematics with neural network, and presents two new methods of Max-Speed Descending-Conjugate Grade and Evolution Simplex. With the case study of mid-long runoff forecasting, the new methods are reasonable. Due to the evolution simplex method features with parallel searching iteration in most points and stochastic production of simplex, to some extent, this method solves the problem of so called local minimum of neural network model-learning. This method is also an attempt of solving non-convex problem in non-linear programming.2. In accordance with the dynamic characteristic of decision-making→feedback→re-decision-rnaking in the process of optimal selection of schemes, this article discusses the method of dialog between man and computer to solve the relations of weight-adjust in the model of fuzzy optimum selection and optimal results. A case study shows how it works to deal with management research of corresponding development of economy and water resources in Dalian.3. Based on the traditional concept of accident probability and the concept of acute degree and probability of unfavorable results, two models are developed respectively. One is risk analysis of flood level in reservoir, the other is fuzzy risk analysis of flood level in reservoir. With the example of hydro-power stations and reservoirs of Fengman and Baishan, this paper proposes a structural model of system simulation by use of Monte Carlo Method. Finally, the simulation results of designed flood level in these two reservoirs are reached in terms of risk analysis.4. To solve the problems in present method of hydraulic engineering economy profit calculation, the paper presents a new formula that calculates engineering profits based on considering stochastic element and time-related value of fund. And this method is thus further applied to profits calculation of flood control engineering with consideration of economic growth. With the projects of different designed warranted efficiency, the reasonability and suitability ofthe formula are further analyzed. By comparing this method with present method, the economic evaluation results obtained by this method are more reasonable than those of the later one.5. This thesis also gives the- principle of sustainable development for regional water resources, pedigree structure and successive structure of water resources coordinate management according to administrative region. Coordinative management model of regional water resources sustainable development is developed and it can be used as following:5.1 To convey the experience and decision idea of decision-maker by means of adjusting the weights among sub-regions and different sections.5.2 To reach regional development level by means of maximizing total profit under the constraints of resources.5.3 To balance profit relationships of sub-regions and different sections by use of coordinating model.5.4 To develop optimal model of cultivating structure for main water-consumer of agriculture.5.5 To balance the profits among generations and guarantee the linking-up and orderly development of productive structure by means of analysis of different planning years. With an example, the proposed model is verified and analyzed.6. Based on the analysis of effect and reason of frequent dry up of Yellow River, synthesizing the thoughts of, different experts in China, the sustainable development view, centering on giving full play water resources of Yellow River under present condition and further developing Yellow River and importing water resources from outside water sheds, this paper develops a short, middle and long term measure for sustainable development of Yellow River. Considering of the key role of reservoir group in the regional water resources control and management, taking Sanmenxia Reservoir as an example, the article presents a new dynamic programming model of long-term optimal control for sediment river. An improved method is proposed based on characteristics of multi-dimensions of state variables and enormous calculation of considering calculation of sediment.7. Finally, a summary is given and some problems to be further studied are discussed.