In order to investigate propriety of computed peak flow using rainfall distribution of 50% exceedance probability of Huff's method which is widely applied in Korean water resources practice, those applied 10~90% exceedance probability rainfall distribution of 1st~4th quatile and mean values of each quatiles were computed and compared. Peak flow variation characteristics which follow in quatiles and specific peak flow proprieties were investigated too.
Firstly, It is examined that peak flows of 50% exceedance probability are less than mean peak flow of 10~90% exceedance probability, and It will be desirable to apply the peak flow value which is more than mean peak flow.
Secondly, The trend that peak discharges of 2nd~4th quatiles are more than that of 1st quatile as 11~16%, 21%~26%, 25%~30%, respectively was investigated. And the trend that the extent of peak flow changes in quatiles are more sensitive according as watershed area decreases are grisped.
Lastly, It was examined that empirical specific flood flow formulae such as MOC(1993) and Jung(1993) have relatively low application possibility to basins with small scale watershed area and the specific flood flow scale were changed rapidly on the order of watershed area 15km².