Research On Ecological Restoration Technology Of Upper Stream Of Xiaoqing River

Xiaoqing river is an important flood channel. Its functions contains flood protection,waterlogging elimination.irrigation and so on. In recent years,water environment of Xiaoqing river is worsing more and more because of the discharge of industry and living sewage. There is not only theory but also realistic meaning to chose the upper stream of Xiaoqing river(Jinan reach of Xiaoqing river) as the ecological restoration study area. It can improve the water environment quality, protect and renew the function of sight riverway.By several methods such as data collection, reference inquiry and site survey and so on, the thesis analyzed the historical evolution of river configuration and eco-environment of Xiaoqing river over the past 100 years, and the results show that:the river meandering coefficient of 1996 is 1.087, compared with 1917, it has not changed much, yet the channel only turns wide at estuary region; difference of river bed elevation ranges between 0.13-4.13m, with an average of 2.05m; cross-section profile has artificially turned into trapezoid; water quality has seriously degraded, with that of all river segment rated as V degree except for the upper reaches satisfyingⅢstandard; hydro-bios has died out in over 80% of the channel. Impact index analysis reveals that main factors of water pollution in Xiaoqing River includes DO, COD, BOD, ammonia nitrogen, fluorine ion. Take cross-section of 9+300 for example, ecological restoration schemes by river regulation, water supplement, pollution control and comprehensive control are proposed and simulated, and results show that:①in supplement water of 6.4m3/s scheme, COD,NH3-N improves by 34.1%,56.7%, respectively;②by systematic treatment of artificial wetland, concentrate of BOD, COD, NH3-N are reduced by 38.6%,32%,68.1%, respectively;③by river configuration maintenance, river dynamic is changed, flow rate is reduced, which are all helpful for degradation of pollution; Construction of bank vegetation and buffer zone increases self-clean capacity of water body and degradation capacity of bios to pollutions. In this scheme, average concentrate of BOD, COD, NH3-N are reduced by 4.7%,7.4%,4.3%, respectively;④combined with river regulation, water supplement schemes, average concentrate of BOD, COD, NH3-N are reduced by 42%,38%, 72%, respectively, and this scheme achieves thorough ecological restoration of Xiaoqing river.