Ecological And Environmental Risk Analysis On The Upper Reaches Cascade Development Of The Yellow River

It is one of the most important subjects that urgently need to be resolved in the field of development and utilization of water resources and eco-environmental protection in today's international arena, which is of great significance to ensure the sustainable development of ecology and environment under cascade development.To the development and utilization of water resources of the upper reaches of the Yellow River as the engineering background, the project conducted a systematic study on eco-environmental risk under cascade development of the river basin. Based on effective eco-environmental risk identification, particularly on water pollution, eco-environmental water requirements, sand sedimentation, reservoir water temperature variations and other risk issues, reasonably practicable modeling analysis and risk evaluation methods were researched, and the corresponding eco-environmental risk management mechanisms and risk prevention and mitigation measures were also done. Specific research contents and the results obtained are as follows:The eco-environmental risk under cascade development of the river basin were conducted a systematic study for the first time. A basic frame system for eco-environmental risk management was set up, the practicable analysis and evaluation model of the different types of risk were built, the corresponding risk management and coping mechanisms as well as specific risk prevention and mitigation measures were proposed, which provide the scientific decision-making basis for the risk management.An analysis method of grey-stochastic compound uncertainty of water quality risk under cascade development was advanced. Regarding respectively the many uncertainties affected the water quality risk and the complex uncertainty relationship among the various factors as random effect and grey relationship, thus establishing the risk analysis method of water quality based on grey-stochastic uncertainty, which achieve compound uncertainty analysis of the water quality risk under cascade development of the river basin.An FNN(fuzzy neural network) model based on AHP(analytical hierarchy process) of eco-environmental water requirements under cascade development was put forward. AHP was used to analyse the interaction of risk factors of eco-environmental water requirements, to establish quantitative indicators' compound weight on various factors, the weight sets were input as initial weight values of the impact factors of FNN model, thus effectively eliminating the impact randomly assigned initial values on the model results.Based on the systematic analysis of sand sedimentation risk under cascade development of the river basin, PLSR(partial least squares regression)model for transporting sand sediment water requirements was advanced and established, which effectively solve the accuracy of conventional PLSR model affected by multi-correlation interference among independent variable factors.The water temperature risk and its spatial and temporal distribution under cascade development was studied, and the two-dimensional mathematical model of reservoir water temperature distribution and sediment density water temperature model under cascade development was established.Related project instances application show that the model and analysis methods of eco-environmental risk are reasonable and feasible, and worthy of popularization.The research project was supported by the national natural science fund (50779051) and the state key laboratory open fund of water resource&.hydropower engineering science (2007B037).