08 Nov Wei Huang
Dr. Wei Huang from China Institute of Water Resources and Hydropower Research , works on environmental flows.
Assessment of Environmental Flow in a Dam-Regulated River Reach Based on Quantitative Flow-Ecology Relationship
In this study, the environmental flow of the middle reaches of the Jinsha River in the upper Yangtze River, which has been regulated by several dams, have been assessed. Fish abundance and riparian vegetation coverage were selected as key ecological factors. The key hydrological factors for fish abundance are Hi pulse L, May, and Reversals. The key hydrological factors for riparian vegetation coverage are 1-day max, 90-day min, and Lo pulse L. Several quantitative response relationship between the degree of change (percentage) in key hydrological factors and the change (percentage) in biological indicators (fish abundance or riparian vegetation coverage) is established. For example, the relationship between fish biomass and the hydrological factor May was fitted as △FR = -0.36*(△May)2-0.05 *△May-0.35. Meanwhile, the typical indicator threshold for river ecosystem health in environmental flow management is determined through the biological disturbance index. Combined with the quantitative relationship of the hydrological–ecological response, the threshold value of key environmental flow factors for the protection of fish or riparian vegetation is determined. Finally, the ecological flow of rivers in the middle reaches of the Jinsha River in 2016 was evaluated based on the threshold values of key ecological flow factors for different ecological factors protection. Moreover, key ecological flow control sections and management methods for the protection of fish and riparian vegetation were determined. The findings can help river managers to operate the key hydrological factors and propose watershed environmental flow for dam-regulated rivers.