Seite - 1017 - in Book of Full Papers - Symposium Hydro Engineering

Engineering & the Ninth Annual Meeting of the Hydraulic Structure Specialized Committee of the China Hydraulic Engineering Society, 2010. SUMMARY The Yangtze River flows for 6,300 kilometers. It is the third longest river in the world. The Yangtze River Basin is a world hot spot of biodiversity, inhabited by over 400 fish species, of which some 350 are freshwater fish and up to 156 are endemic fish. Increasing human activity in the Yangtze River Basin has led to changes in the habitats that aquatic organisms inhabit, which then affect the reproduction and multiplication of aquatic organisms; the destruction of aquatic communities in turn affects the environment that humans depend on for survival. The major hydroecological problems and risks facing the Yangtze River Basin today include decline in aquatic biodiversity, partial loss of environmental conditions in biological habitats, aggravation of water pollution, and reduction in river connectivity. The decline in biodiversity is reflected mainly in decrease in species number, shrinking of population, miniaturization and high mortality rate among individuals, and degeneration of germplasm resources. The main reasons leading to the decline in biodiversity include reclamations, sluices, or embankments that reduce the connectivity of rivers and lakes; the construction of reservoirs across rivers lowers upstream-downstream connectivity; embankments turn rivers into channels, resulting in loss of vertical connectivity. In the face of the hydroecological problems and risks prevalent in the Yangtze River Basin, China has, over the years, enacted 9 laws concerning ecological improvement and environmental protection, 15 laws for the protection of natural resources, and over 660 regulations at all levels of government. In addition, efforts at natural conservation have been redoubled, such as promoting the development of protected areas and taking measures like artificial fecundation, release of fish, restricting fishing, and construction of fish pass facilities. However, as development projects in the Yangtze River Basin continue to grow, existing measures may not be able to delay or reverse ecological recession and more time is needed to test them. KEY WORDS Yangtze River Basin, water conservancy projects, ecological risks, ecological problems, protection measures 1017