Abstract
Schistosomiasis is a parasitic disease mostly found in areas along the Changjiang River, Oncomelanias is the only intermediate host of schistosomiasis. Oncomelania entering into farmland or the residential zones through the flood discharge or irrigation system is the main reason of spreading schistosomiasis. Therefore it is most essential and effective way to control diffusion of oncomelanias along with flow for preventing epidemic of schistosomiasis disease. In order to simulate the flood discharge when the river dike break or the flow from main to branch channel, a side-weir flow system is set up in this paper, And furtherly the flow characteristic is studied by experiment and mathematical modeling, Finally the research on the diffusion law of oncomelania along with side-weir flow is carried out using the experimental test. The results show that oncomelanias do not equally distribute at floodplain areas, but place where flow velocity is small, i.e. in the vortex areas during oncomelanias moving along with side-weir flow. The settling positions of oncomelanias are obtained, Which lay a good foundation for eliminating oncomelanias.