River health evaluation based on the fuzzy matter-element extension assessment model

Abstract

The measured values of river health indexes that are not necessarily in the same range of a certain health grade level cause the problem of how to classify the actual status of river health. To solve such incompatibility and evaluate the health condition of a river ecosystem objectively we can use the river health integrated index (RHI), which was determined by the fuzzy matter-element extension assessment model (FMEAM). FMEAM was established by combining the fuzzy matter-element extension assessment method with the proposed aggregative index system. By employing the model above, as well as data from the 1980s, 1990s, and 2000s, we evaluated the health state of the Luanhe River. The results showed that the Luanhe River was in a sub-healthy state in the 1980s and in an unhealthy state in the 1990s and 2000s. The reasons leading to the Luanhe River’s health degradation have been analyzed. Among them, water conservation projects’ building and operations are the major influence factors. Waste water emissions, the expansion of urban built-up areas, over exploitation of groundwater, and other unreasonable human activities also intensified the river ecosystem degradation. Finally, countermeasures for the ecological restoration and protection of the river were put forward.