Environmental flow assessment in the Lower Yellow River using habitat simulation and hydrological reference system

The accuracy of the habitat simulation method is often questioned due to limited simulated elements and indicator species. This study established an environmental flow assessment method by coupling fish habitat simulation with hydrological reference system. The environmental flow obtained through the habitat simulation method was corrected by the statistical characteristics of natural flow regime. The environmental flow of the Huayuankou section in the Lower Yellow River was assessed. The results show that the environmental flow demand of the Huayuankou section is 7.9 - 15.4 billion m 3 /y without consideration of sediment transport. An environmental baseflow of 220 - 400 m 3 /s is required throughout the year. One to two high flow pulses are needed in the rising-water season to trigger spawning, followed by flow events of 350 - 500 m 3 /s with more than 1 week duration to create the spawning grounds.