Abstract:

Present researches on ecological water requirement mainly focus on the theoretical approaches and case applications in terms of water resources management and ecology protection, yet no study has been carried out on combining water resources management with ecology protection. In view of this, a model coupling the ecological water requirement coefficient and the hydrological index is established to calculate the ecological in-stream flow requirement and ecological in-stream water requirement in rivers. Two typical rivers (Lancang river and Honghe river) in southwest China are taken as case study. Comparison on the application results reveal that the minimum, appropriate and optimal ecological water requirement in the Honghe River respectively accounts for 21.55%, 34.51% and 54.62% of the natural run-off of Honghe River, while the minimum, appropriate and optimal ecological water requirement in the Lancang River respectively takes up 15.61%, 27.45% and 48.85% of the natural run-off of Lancang River. The ecological in-stream water requirement of Honghe River deduced from the ecological flow requirement occupies 42.27% of the natural run-off of Honghe River, and the ecological in-stream water requirement of Lancang River calculated by ecological flow requirement makes up 19.06% of the natural run-off of Lancang River. Owning to differences in application, the results of in-stream ecological water requirement and ecological flow requirement are slightly different. Multivariant correlation analysis verifies that the calculation results are strongly correlated, and the model presented in this paper is highly applicable. This comprehensive analysis provides scientific support for both water resources management and ecological protection.

Key words: ecological in-stream water requirement, ecological flow requirement, ecological characteristic index, Lancang river, Honghe river