**6. Conclusions**

USGS Diffusion Hydrodynamic Model is a legacy Fortran 77 that has been widely applied for multiple one and two-dimensional flow scenarios. The computational limitations in the model which prevent its application over large domains have been addressed in this paper. The enhanced model can accommodate 9999 cells and 99 inflow and outflow nodes. Based on the analysis that was carried out and the close agreement of the results between the two models gives confidence in the reliability of the extended model. Current findings encourage future development of parallel EDHM in order to reduce the computational time.
