Research On The Riverbed Evolution And Renovation Measurements Of Dawen River In Tai'an, Shandong Province

This research mainly deals with a main stream with a length of 58 km from Dawen Wenkou Dam to Daicun Dam. The hydrologic characteristics of the silts and sands and the riverway characteristics were analyzed by field-measured data. The changes of the riverbed's plane section and transect were analyzed through a comparison of the riverbed's transects in 1972,1982,1992 and 2002. The factors that influence the evolvement of the riverbed were analyzed and concluded. As an emphasis, the effect of irrational sand excavation on riverbed evolvement was intensively discussed. The analyses led to the conclusion that the riverbed should be comprehensively fathered and sand excavation must be effectively integrated with riverbed control. By using the basic rule of silt and sand transportation and the basic principle of riverbed change as the directional theory, and using the optimized calculation results of the riverbed's width as the theoretical foundation to determine the range of sand excavation prohibition, the range of sand excavation prohibition at different river section was presented. On the other hand, the renovation principle, the renovation schemes and the renovation measurements were thoroughly and systemically researched according to the riverbed's characteristics and the current project status. By the calculation of renovation flow rate, renovation river width and renovation radius, concrete renovation measurements and project layouts were presented. Additionally, engineering measurements were taken to improve the riverbed's boundary conditions, control some disadvantageous change of the riverbed and try to lead the riverbed evolve in favor of flood control. Consequently, benefits from the river were maximized and harms were minimized in the interest of people living near to the bank of the river.