Health assessment of the current situation of rivers and discussion on ecological restoration strategies: A case study of the Gansu province section of the Bailong river.

• Bailong River's ecological health was evaluated by using a multi-indicator system. • An evaluation system covering natural attributes and functionality was established. • The Bailong River is in a sub-healthy condition, with weak spatial heterogeneity. • Restoration focuses on river habitat and fish species conservation. • To a certain extent, it fills the gap in the study of the health of the Bailong River. The health of watershed ecology is mutually constrained by the sustainable development of the regional economy and society, and health assessment helps to identify the ecological status quo. As one of the "ethnic corridors", the Bailong River has become a region of human solid interference. Therefore, this study constructed an indicator evaluation system to reflect rivers' natural attributes and functionality by analyzing candidate indicators' sensitivity, principal components, and independence. The weight of the indicators was determined using the Analytic Hierarchy Process combined with expert opinions. The ecological status of the Bailong River was evaluated through field monitoring data, and ecological restoration suggestions were proposed. The results show that Bailong River's comprehensive score is 58.27, indicating sub-health. The constructed evaluation system includes thirteen indicators, of which 53.84% are in an ideal state, 15.39% are healthy, 7.69% are sub-health, 15.39% are unhealthy, and 7.69% are pathological, with weak spatial heterogeneity. The evaluation results of the guidelines show that the state of "cleanliness" and "service" is ideal, "circulation" and "life" are healthy, and "physical structure" is worrying. Based on this, the ecological restoration and protection of the Bailong River in the future should focus on the following aspects: improving methods and theories, restoring the habitat environment of the river, ensuring water quantity, improving water quality, and conserving fish species. This study can provide necessary theoretical support for the ecological restoration of severely disturbed water-deficient rivers and lakes in northern China. [ABSTRACT FROM AUTHOR]