Abstract: In order to utilize rich hydropower resources in southwest mountain area of China and decrease flow with high sand proportion and debris flow disasters caused by flash flood, we should establish suitable two-dimensional bed load mathematical models for rivers in mountain area. On the basis of finite volumetric method, we dispersed common controlling equations in sediment numerical model of two-dimensional flow, dealt with dry land boundary by using frozen method, and established a general two-dimensional bed load mathematical model. Xintun section in Wangmo river located in Guizhou province was taken as an example. We carried out numerical calculation of flow field, exploring scouring and deposition of bed load. Test results showed that, as for water level calculation and verification of scouring and deposition in the river bed, simulated data was in consistent with data from empirical formula; after regulation project of the river, most of water levels along the flow direction decreased, except for slight increase in few sections; meanwhile, in the condition of given discharge,water level after the regulation was smaller than that before the regulation, and sediment deposition into the water flume decreased, which is in favor of river flood control.

Key words: river in mountain area, two-dimensional bed load, numerical model, scouring and deposition, river regulation project