Regional Model of Annual Runoff with the Emphasize on the Time Distribution ofRainfall and the Amount of Water Utilization in Ghezelozan Sub-Basins

Exact recognition of effective factors in hydrological processes such as conversion of rainfall to runoff in the annual scale can improve the accuracy of estimations. Investigations on 13 sub-basins in the Ghezelozan river basin show that the effective parameters of mean annual potential yield (mean annual runoff accompanied by water utilities in basins) are adjusted precipitation، curve number، mean annual temperature، area and basin slope. Meanwhile، this paper focused on adjusted precipitation which is related to the time distribution of water utilities in the basins. Validation processes using runoff data in basins for minimizing the differences between estimated and observed discharge values have been conducted. Those processes recognized two equations according to basin area for validation. Investigations in validation of two basins show that runoff result tolerances are about 5 than that observed discharges