| River plays an important role in production and lives of human, however, irrational activities from human always bring negative influences to river in the last centuries,such as channel shrinkage and ecological imbalance etc.With the promotion and deepening of environmental protection,the concept of river health emerges.River health assessment,in which describes the status of river,aims at providing reliable basis and guidance for river management.As the most commonly used method for RHA,fuzzy comprehensive assessment remains to be accurately and appropriately confirmed.Taking the lower Yellow River as a case,standing on the river structure,the paper testifies the traditional model and also makes upgrade that on the basis of actual measured data.According to the above exploring,the thesis completes the following tasks:Firstly,by reviewing the development history and connotation of river healt h and assessment methods,intrinsic attributes,evaluating indexes,valuing standards and measuring methods are discussed in detail.Secondly,after analyzing the advantages and disadvantages of traditional assessment model,the most appropriate membership-function and weighting method get selected together, triangular-membership- function and AHP-Entr opy weighting method should be regard as optimized choices in their own domain.Thirdly,according to the 2 results above,principle and procedure for index-selecting are effectively fixed,and finally the assessment indexes system about river structure health in the lower Yellow River is scientifically set up.Fourthly,the 3 key indicators that profound affecting River Structure Health were selected,sufficient water quantity and coordinated water-sediment relationship are the decisive factors to maintain RSH in the lower Yellow River.Fifthly and the last, the upgraded model is applied to the river structure health of the lower Yellow River,it is concluded that the health status floating trend between 1986 and 2005. |
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