عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The prediction and determination of surface runoff in catchment areas is the most important process in hydrological studies. United state soil conservation servies Methodology - The SCS-CN curve number is used to estimate runoff. This method is one of the methods for investigating the spatial distribution of runoff in hydrology. In this method, the main factor used to calculate runoff is the number of the curve. The selection of the curve number (CN) is based on land use and soil hydrologic groups (HSGs) of the study area. As the spatial distribution of the curve number estimation is difficult and time consuming by conventional methods, the CN-GIS (Geographic Information System) method was used for the Shirvan, Bojnurd, Farouk, Safiabad and Meshkan catchment areas. Using the combination of land use maps and soil hydrological groups, the resulting curve number for the whole basin was about 45 to 93 with a mean of 78. The average annual runoff depth of the SCS-CN method was 2 to 19 inches for the average rainfall. The results were consistent with the runoff measured in the basin.