| The reservoir is a artificially constructed link between humans and rivers,which maintain the development and stability of human society.It is of great significance to build reservoirs in the sediment-laden river where located in arid and semi-arid areas to store water and regulate sediment,so as to rationally allocate water resources,cover the shortage of water resources and the imbalance between supply and demand,and efficiently utilize river resources.At present,the number of reservoirs on the rivers in China is enormous and the distance between them is different.Only the research on the health and function recovery of individual reservoir can not match the actual situation of the reservoir at the current stage.Therefore,this paper studies the cascade reservoirs of the Fenhe River,which are only 80 km away from the upper reaches of the Fenhe River,and the Fenhe Reservoir and the second Fenhe Reservoir.The main research contents include:(1)To construct a health evaluation index system for sandy river reservoirsThis article summarizes the characteristics and current situation of the sediment-laden river reservoirs.According to the function and influence of the sediment-laden river reservoir and the connection between the reservoir and the river upstream and downstream,the new definition of the health of the sediment-laden river reservoir is proposed,and the connotation of the health of the sediment-laden reservoir is expounded.On the basis of the new definition of the health of sediment-laden river reservoirs,the main factors affecting the health of sediment-laden river reservoirs are summarized,and then constructed the health assessment index system of the reservoir,which includes four aspects: reservoir structure safety,upstream and downstream river health,social service benefits and regional ecosystem health.Besides the health status is divided into five levels of ideal state,health,sub-health,unhealthy,and pathological.(2)Method of endow with weightThis paper applies subjective weighting method(AHP),objective weighting method(EWM)and subjective and objective comprehensive weighting method(AHP-EWM,AHP-Cloud,AHP-EWM-Cloud)to weight analyze the sediment-laden river reservoir.The index weights obtained by the objective weighting method are significantly different from those of other weighting methods,indicating that the subjective characteristics and fuzzy characteristics of the reservoir health assessment are strong.Based on the fuzzy verification method of fuzzy rough sets,the Minkowski Distance of the five weighting methods are determined.The results show that the AHP-EWM-Cloud method considers both the objective existence of measured data and the subjective consciousness of decision makers,and is the optimal weighting method for reservoir health assessment.(3)Health evaluation of cascade reservoirAccording to the health assessment model of the sediment-laden river reservoir,the multi-year measured datum of the Fenhe Reservoir and the second Fenhe Reservoir,and applies the fuzzy synthetic evaluation method and cloud model evaluation method to assess the health of the Fenhe Reservoir and the second Fenhe Reservoir.The assessment results obtained by the two methods are more consistent.(4)Analysis of reservoir health evaluation resultsThe Fenhe Reservoir is in a healthy state at the present stage,but its health value is low,and the decline of health status cannot be ignored,and the main cause of the decrement is sedimentation problems.The influence of siltation should be eliminated under the situation of decreasing inflow water and sediment.Because of the short running time,the second Fenhe Reservoir still in good health.Meanwhile the artificial regulation of the upper reservoir has become the main factor affecting its health.Focused on a variety of affecting the health of Fenhe Reservoir and the second Fenhe Reservoir,this article raises some thoughts and approaches,providing the theoretical base and secientific foundation for the sustainable development of the reservoir. |
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