It is observed the gravel river sediment discharge with existing empirical regime relationships.The aim of the research is to give a mathematical model about the stable cross-section geometry and to determine a model for the stable slope of an alluvial channel which is in nature seldom stable.In an alluvial channel to reach an equilibrium condition,it changes its plane geometry until to have a stable condition in plane configuration.There are three different parameters in plan configuration about river behavior:width,depth and slope.