Evaluation of aquatic ecological health of sluice-controlled rivers in Huai River Basin (China) using evaluation index system

The aquatic ecological health status was focused on the Huai River Basin (HRB) from the aspects of water quantity, water quality, water ecology, river connectivity, and riparian habitat environment. Ten monitoring sections were set up in the middle and upper reaches of HRB, and 5 experiments of each section were conducted in July and December from 2012 to 2014. Thus, relevant data on the species, the density of phytoplankton, zooplankton and benthic animals, the concentration of water physicochemical variables, and riparian habitat quality were obtained. Eleven key impact factors were chosen using frequency statistics, theoretical analysis, and correlation analysis methods, forming the evaluation index system of aquatic ecological health. Then, the indicator weight value was determined by the combined weight method, and the health degree was evaluated by the comprehensive index method. On the whole, the aquatic ecological health degree of the upper sections (D1 similar to D3) of the Shaying River ranges from 0.334 to 0.927, which is generally in a sub-healthy state. The aquatic ecological health degree of the main section of the Huai River (D8 similar to D10) ranges from 0.362 to 0.777, which is in the critical or sub-healthy state. The Huaidian Sluice (D5) and Fuyang Sluice (D6) in the middle and lower reaches of the Shaying River had the worst aquatic ecological health. Its water ecological health range is 0.283-0.523, and most of them are under sub-pathologic. The research results have important theoretical and practical significance. They can enrich the evaluation theories and methods of river aquatic ecological health, help to grasp the aquatic ecological health status in HRB, and provide basic support for aquatic ecological protection and water pollution control in sluice-controlled rivers.

Automated summary

This study focused on the aquatic ecological health status of the Huai River Basin, examining various aspects such as water quantity, quality, ecology, river connectivity, and riparian habitat environment. Data on species, phytoplankton and zooplankton density, water physicochemical variables, and habitat quality were collected and analyzed. The results revealed that the upper sections of the Shaying River were in a sub-healthy state, while the main section of the Huai River was in a critical or sub-healthy state. The Huaidian Sluice and Fuyang Sluice had the worst aquatic ecological health. The research provides valuable theoretical and practical support for evaluating and protecting aquatic ecosystems in sluice-controlled rivers.