Evaluation of river ecological flow based on baseflow separation in Xiangjiang River, China

ABSTRACT Research on ecological flows has received much attention. Few studies, meanwhile, have looked into rivers’ ecological flow safety from the standpoint of flow warning. Thus, using the base flow separation technique and the Tennant method, the ecological flow thresholds of rivers were determined in this research and applied to the Xiangjiang River. Additionally, the Soil and Water Assessment Tool–long short-term memory (SWAT–LSTM) coupled model was utilized to simulate hydrological processes to establish an early warning system of river ecological flow, and the separative framework was used to separate the impacts of climate change and human activity on the Ecological Flow Assurance Degree (EFAD). The ecological flow thresholds for the Fish Spawning and Fattening Period and the General Water Use Period were found based on the Base Flow Relative Duration Curve. Five Early Warning Levels could be categorized based on ecological flow thresholds. The warning system developed in this research has an accuracy rate of over 84.58% monthly and over 84.07% daily. Furthermore, the study discovered that the effects of both climate change and human activities on EFAD alterations varied across time. The research provides scientific support for other watershed management and water resource planning.