Evaluating water ecological health in dam-impacted river: A new approach framework

Abstract

In multi-dam river systems, human disturbances can significantly disrupt river connectivity, fragment habitats, and harm aquatic ecosystems. Aiming at the comprehensive assessment of the spatial distribution of water ecological health, as well as the investigation of the impacts of human activities on river health, Shaying River in China between 2011 and 2015 was taken as a case study. Data on water environment, ecology, and habitat quality were collected by field investigations and then investigated by correlation analysis and principal component analysis. The SMI-P method was adopted to estimate the water ecological health condition. It was found that oxygen-consuming organic pollutants and nutrient salts were predominantly concentrated in the midstream and downstream sections, leading to severe pollution and degraded aquatic biodiversity. All monitored river sections were classified as the sub-healthy state or worse, while the Huaidian section exhibited the poorest conditions, with 100% of ratings falling into medium and sub-morbid categories. It was concluded that dam regulation, tributary water quality, and seasonal drivers like fertilizer use and river flow discharge, were the primary factors affecting the spatial variability of river ecological health. Furthermore, this paper has proposed a well-suited framework for the assessment of the water ecological health of dam-controlled rivers. This framework can be widely applied to similar river systems, providing valuable insights for effective management and conservation efforts.

Keywords

• Water ecological health
• SMI-P method
• Human activities impact
• Shaying River