G Akbari - Assistant Professor, Department of Civil Engineering, University of Sistan and Baluchestan
B Firoozi - Post Graduate. Student, Department of Civil Engineering, University of Sistan and Baluchestan

River flow predictions are needed in many water resources management. The beginning of the modern study of unsteady flow in open channels can be traced to the latter half of the nineteenth century when the French engineer Saint-Venant introduced the partial differential equations of continuity and momentum governing free surface flow in open channels. These equations are highly nonlinear and therefore do not have analytical solutions. The computer revolution in twentieth century made a new era where numeric methods can be utilized effectively to solve nonlinear partial differential equations. This paper presents the results of two different numerical methods, namely; Preissmann and Lax diffusive schemes for numerical solution of Saint-Venant equations that govern the propagation of flood wave, in natural rivers, with the objective of the better understanding of this propagation process. The results have shown that the hydraulic parameters play important game in the flood wave propagation. The results of these numerical solutions are compared with the HEC-RAS commercial computer model.

numerical flood routing, Saint-Venant equations, Priessmann, Lax, HEC-RAS