عنوان مقاله [English]
Watershed management planning and preference need variety of data like water yield and its fluctuation. Average water yield on different probabilities is needed for river discharge estimation and small and big dams utilization planning. On the other hand, annual water yield is needed for planning and management of downstream agricultural lands. In this research, 40 hydrologic stations with acceptable quantitative and qualitative data within a common base period. Watersheds homogeneity was analyzed based on water yield and influence of numeral parameters and segregated into two homogenous watersheds. The accuracy of homogeneity was tested by discriminant analysis and was 100 and 94 percent in clusters one and two, respectively. In addition to regional annual water yield analysis, the discharge probability was estimated and normal distribution was chosen as the best statistical distribution for discharges of two to 100 years return periods. Regional probable water yield equations with different return periods for homogenous regions were extracted using hydrological and numeral data such as annual discharge, area, slope and forest canopy cover. The results of present research were the probable annual water yield with different return periods which could be used in watershed management and water resources projects.