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This paper presents a comprehensive analysis on the ecological benefit and loss of Xiaolangdi reservoir from its completion in 2000 to 2012. We firstly propose a three-step framework of the ecological benefit–loss evaluation for hydropower projects, in accordance with which an index system of riverine wetland ecosystem services valuation was established originally. Then we make a quantitative valuation on the change of riverine wetland ecosystem services caused by this project. Finally, the ecological benefit and loss of the project in the riverine wetland were evaluated in two aspects of positive impacts and negative impacts. The results showed that (1) the positive impacts of Xiaolangdi reservoir mainly included 9 categories of ecosystem services: flood control, ice prevention, sedimentation reduction, energy substitution, emission reduction benefit, water supply, afforestation, shipping and entertainment; the total ecological benefit of the project in the riverine wetland was 26.2058 billion yuan. (2) The negative impacts of Xiaolangdi reservoir mainly included 5 categories: loss due to land submergence, heritage submergence, water and soil erosion, reservoir sedimentation and immigration; the total ecological loss of the project in the riverine wetland was 24.2167 billion yuan. (3) From 2000 to 2012, the net value of ecological benefit–loss for the project was 1.9891 billion yuan. [ABSTRACT FROM AUTHOR]

Abstract: This paper studies relations between bankfull discharge, lateral cross section variation and the incoming flow and sediment condition in the Lower Yellow River using measured data from 1950 to 2003. Since 1950 the bankfull discharge has obviously decreased and the ratio of channel width to flow depth has increased. The critical annual average incoming sediment coefficient (defined as the ratio of sediment concentration to discharge) and discharge at the Huayuankou station are approximately 0.012 and 1,850 m3 s−1, respectively, for no accumulative deposition occurring in the reach from Huayuankou to Lijin. On this basis, a mathematical model is used to study the scale of the main channel in the Lower Yellow River and its corresponding bankfull discharge under possible incoming flow and sediment conditions in the near future. The main factors influencing the scale of the main channel are analyzed, and measures to shape and maintain a medium-sized channel are discussed. The results show the effect of various water and sediment combinations released from the Xiaolangdi Reservoir on the shaping of the main channel and suggest that under recent incoming flow and sediment conditions, it is possible to shape and maintain a medium-sized channel with a bankfull discharge of approximate 4,000 m3 s−1. [Copyright &y& Elsevier]