A partial area model for storm flow synthesis

The storm Hydrograph model described is based on the partial contributing area concept. It utilizes a physically based infiltration capacity distribution for computation of rainfall excess, and it incorporates two stages of kinematic routing. In the first stage the rainfall excess is routed over a flow plane to become the lateral inflow hydrograph for the second or channel phase. The overland flow plane expands upslope as the infiltration capacity is exceeded, the size of contributing area and the length of the flow plane being calculated from infiltration curves. The model attempts to account for the natural watershed variability in terms of necessary input data and boundary and initial conditions. The data requirements are three: they include two Manning's n values, one for the channel and one for the overland flow plane, and the initial soil water content.