Abstract: In view of the ecological restoration problem of dehydrated river reaches in the downstream of diversion-type hydropower station in medium and small watersheds, five methods of calculating ecological flow are summarized. A model which couples Matter Element(ME) Analysis and Tennant method to evaluate river ecological flow process is proposed. Liujiaping Hydropower Station in Hunan Province is taken as a case study. The proposed ME-Tennant model is adopted to evaluate the ecological flow process calculated by different methods. The minimum ecological flow process is determined by the NGPRP (Northern Great Plains Resource Program) method and the dynamic calculation method, while the appropriate ecological flow process is determined by the monthly frequency method with two different guarantee rates. Both results are in accordance with the hydrological ecological characteristics of the watershed. The study intends to provide a new idea for determining the ecological flow process, and offer reference for the ecological restoration of dehydrated river reaches.

Key words: dehydrated river reaches, ecological flow process, matter element analysis method, ME-Tennant method, Liujiaping Hydropower Station