Abstract:There are significant differences between the classical theory of sediment movement mechanics and natural mountain river system bed load movement.Considering this status,based on the analysis of mountainous watered sediment supply conditions,the responses of mountain river channel adjustment and mutation mechanism were studied.The influence of the recharge conditions of sediment on non uniform gravel starting and the transport characteristics,and the relationship among the sand pebbles recharge, mountain river formation and hindering navigation was revealed.At the same time,the variation of water and sediment movement characteristics in the singular and width and floodplain compound navigation channels in response to the bed mutations phenomenon was provided.The study showed that using the water and sediment load shifting,separation of water and sediment build degree reduction technology means to control the peak period of the disaster pebble river sediment supply conditions is the core of flash floods and sediment disaster hazard prevention and control of risk reduced order.