The associations between river health and water resources management lead to the assessment of river state

Abstract

Abstract For social and economic development in China, the rivers are regulated, but its impact on river ecosystem has not evaluated yet. Maintaining a trade-off between social protection and ecological protection of the rivers is very crucial for a country where competition for water is severe. Thus, the main focus of this study is to carry out a comprehensive assessment of river health in relation to water resources management. In this paper, Guijiang, Nenjiang, and lower Yellow- three regulated river’s health statuses were drawn on the river-section scale using Fuzzy Matter Element (FME), Harmony Degree Evaluation (HDE), and Grey Relational Analysis (GRA) methods. The results indicated that the alteration of flow dynamics affected the ‘hydrology’ and ‘water ecology’ attributes of the rivers for which the River Health Index (RHI) of upstream sections of Nenjiang River was poor and downstream sections of lower Yellow River was critical respectively and the overall health statuses of the three rivers in that order, were good, fair to good, and fair. Particularly, Xiaolandi reservoir regulation at lower Yellow River impaired the habitat of benthic macroinvertebrate population that made the ecosystem health critical. We compared the evaluation methods and the results of FME and HDE were found consistent while GRA produced some discrepancies in the outcome. Finally, we proposed a framework for river health assessment for interpretation and communication of results to the managerial level. Our findings suggest that the water resources management of these regulated rivers should be rationalized and special care should be taken for ‘water ecology’ health restoration of the lower Yellow River.