Estimated height and peak runoff rate in a stream erosion in Kojoor region of Noshahr - Northern Alborz

Flooding is a natural hazard events and Survey data from the annual losses due to flood in Iran and the world show the extent of the flood damage caused on natural and human resources. To estimate height of the runoff and discharge maximum in basins and stream erosion، there are various experimental methods and mathematical models that one of these models، SCS model is. Thus، the aim of this study was to estimate the Runoff coefficient and Maximum discharge by Curve Number method with different units forming the Fyruzkla Kojoor basin and zoning maps of potential runoff and stream erosion in the drainage basin is. After mapping the watershed CN and S، to calculate the volume of runoff produced in the region، short-term rainfall for different return periods were calculated using Pearson distribution of type III. According to the map of potential runoff in the basin، forest land has the lowest runoff potential and pasture lands have the greatest potential to generate runoff and erosion is occurring and also has the lowest penetration. The middle part of the basin، the most prone to runoff and erosion and gully formation in the region are. After determining the height of the basin surface runoff، peak discharge was calculated for various hydrological. The highest values of maximum flow rate are based on rangeland with hydrologic group D.