-

Among the main objectives in hydrology are to quantitively forecast the process of
rainfall-runoff, and to determine flood discharge at the outlet of a watershed. Flood
I
discharge can be estimated using rainfall-runoff models: which explain hydrological phenomena for ungaged watersheds. If the dimensions 01 flood hydrograph (which is the result of the watershed response to rainfall) are known, then the importance of models which are based on geomorphology of a basin will be very clear. The purpose
of this study is to investigate the consistency, accuracy and reliability of
geomorphological and geomorphoclimatical models in estimating the shape and discharge of flood resulting from a rainfall with certain intensity and duration. The results of these two models were compared with Nash, Rosso and SCS models. The results showed that the efficiency of geomorphologic model ratio to
geomorphoclimatic, Nash, Roso and SCS are 106.56, 171.12, 106.79 and 112.64
I
percent respectively, and that geomorphoclimatic model ratio to Nash, Rosso and SCS
is 106.57, 100,21 and 105.69 percent, respectively. Therefore, the result of geomorphologic model compared to other models (based on this study) is the most efficient model to estimate flood discharge.