Study on river health assessment based on a fuzzy matter-element extension model

In order to facilitate watershed management, we developed an expansive river health assessment method based on a fuzzy matter-element extension model in this study that developed based on the transitive hierarchies and degree of membership from improved fuzzy optimization theory. Eight characteristics of river flow, namely, the morphology, flow, water quality, river habitat, aquatic organisms, riparian zone, flood control safety, and level of the water supply, were investigated in this study to establish a system of indices to assess river health. We apply the above method to a river health assessment in the Luanhe River as sub-healthy. The results show that the method is accurate for the river health assessment compared with the actual conditions in Luanhe river. Moreover, the river health assessment method described in this study covers the different health states of river ecosystems, including the natural function and the social service function of a river. It is a reasonable river health assessment method that can evaluate river health status systematically, comprehensively and accurately. Therefore, this method is reasonable and effective and can be used to assess the ecological health of rivers in other regions.