Ecological Flow Regime and its Satisfactory DegreeAssessment Based on an Integrated Method

Abstract

Ecological flow regime (EFR) evaluation is essential in river ecosystem protection. To evaluate and maintain EFR under a changing environment reasonably, an integrated method based on both the monthly 7Q10 method and biological analysis method was put forward for its simple modelling and small data requirement, and then reasonable EFR was obtained after a reasonable check by the Tennant method. Meanwhile, the concept and quantitative formula of the ecological flow regime satisfactory degree (EFRSD) were recommended and successfully applied in the Luanhe River. The results showed that the flow regime of the Luanhe was significantly interrupted by human activities after 1979, and EFRSD has been distinctly damaged since 1998; after 1979, from good to bad, the EFRSD of the Luanhe was the upstream, midstream and downstream. Then the driving forces leading to the Luanhe’s EFRSD deterioration that included reduction in the natural rainfall, construction and operating of water conservation projects, and overexploitation of groundwater were discussed and analyzed. Finally, countermeasures for the ecological rehabilitation of the river were pertinently put forward.