I tried to simulate the transport of a sand dune in a rectangular channel by the equation of Hansen England through HECRAS I did all the steps, but I can not find how to bring the geomtrique of sand dune ; i find in the geomtrique data (fixed sediment elevation) so I introduie geometry of the dune when I made the simulation I can not find the results; the dune remained stable by time no transport . I think there is a mistake since I use fixed sediment are there any other steps that the sediment for mobile knowing that I introduced sediment data