Study On The Evolution Of River Bed Scour And Siltation In The Reservoirs Of Rubber Dams In Chan-Ba Ecological District

Chan-ba River flow along through the Chan-ba River Ecological District. To promote the standard of prevention and control flood of Chan-ba River, and improve the ecological environment and landscape, high-standard embankment and 21 rubber dams are implementing.After finishing constructions of embankment and 21 rubber dams, because the Chan-ba River is filled up by inflowed sediment heavily, the changes of the river bed due to the erosion and siltation along the river are rapidly, and the elevation of the River bed declines seriously at present, as a result the evolution due to the scour and siltation occurred in the reservoirs (rubber dams) will impact on the water-surface sight, and the safety of bridges and related buildings. Therefore, it is very important and necessary to research and analyze on the changes of the Chan-ba River bed after the completion of embankment and 21 rubber dams.In this study, firstly, by collecting and analysis a great deal of hydrologic and sedimental data of Maduwang station in the Ba River, three of representative run-off and sediment series were worked out with the help of a new method of translation gliding. Secondly, the reaches located in the central area of Chan-ba River Ecological District were chosen as a representative river reaches, and a distorted river model with movable bed and total loads was designed by using a set of suitable similarity laws. Furthermore, in order to simulate the changes of the river bed due to scour and siltation and the impacts to the project, several experiments were carried out by adopting both of the rich-runoff & rich sediment of 10 years ~ par-runoff & par sediment and the par-runoff & par sediment of 10 years ~ rich-runoff & rich sediment series. .The results have indicated that after the construction of dams in the Chan-ba River , the reservoir areas tend to fill up from the up-stream to the down- stream. Dams from up-stream to the down- stream along the Ba river will achieve a balance status after 6～17 years and 17～18 years, and there are two dams on Chan river have no storage capacity. All the reservoirs will show a slightly siltation after they achieved the balance statuses, and will possibly impact on the water landscape and the safety of related buildings.Consequently, in order to keep stable water landscape, some artificial measures like desilting and dredging up is suggested to be planed and carried out near the futrue.