Fuzzy Comprehensive Evaluation For Flow Distribution Of River Network

As the hydrodynamic environment of river network becomes complicated,variable and increasing deteriorated,the treatment for the hydrodynamic environment of river network is imperative.The hydrodynamic environmental improvement in river network can be realized by water replacement.As for the river network with constant flow,the optimization of flow distribution proves to be capable of exchanging the water in each river.Flow distribution of river network has close river facies relations with geometrical characteristics.When the variations in discharge occur and reach the equilibria or quasi-equilibria state automatically,a master-slave relationship develops between the balanced cross section and the discharge.Therefore,geometrical characteristics such as the river length l,slope bottom i,bifurcation angle a are considered as slave variables in this paper.By using the fuzzy comprehensive evaluation(FCE)based on the multi-attribute fuzzy clustering method and information attributes reduction algorithm,considering the effect about the distribution of river network with different slave variables comprehensively,the unidirectional flow distribution model of the river network is establishing.When the tidal occur in the river network,the flow movement features of reciprocating flow exist in the branch,which is considered in the paper as to establish the flow distribution model for river.This paper import the graph theoretic approach to ascertain the incidence matrix for the steady flow in river network so that the topological relationship equation can be built;import Bernoulli equation as basic output equation of water level,which can be dispersed with polynomial interpolating function,and then the flow direction factor can be obtained,which can realize the transformation from the unidirectional flow distribution model of the river network to the flow distribution model for the river network.The model has become true with Matlab.To verify the reasonability,the flow distribution model for the river network is applied to the hydrodynamic environmental research of river diversion engineering in Fuzhou.The results indicate that this model can provide important reference value for the comparison and selection about the flow distribution plans or regular operating scheme in the river network,and also provide a new idea for such reasearch.