Evaluation of GIS Efficiency in Estimating Runoff Depth by SCS-CN Method Case Study: Baghan Basin (Jam and Riz)

Natural and human factors have caused the level of groundwater aquifers to decline in recent decades, so the management of groundwater resources is very important. In groundwater resources management, rainfall storage in the basin and its infiltration into the aquifer and consequently the relationship between precipitation and runoff can be considered a very important factor in hydrological studies. In this study, the height of runoff in Baghan basin (Jam and Riz) was calculated using the method of the US Soil Protection Organization (curve number method). The main factor in this method is the appropriate estimation of the curve number, which is based on land use and hydrological groups of soil in the study area. After selecting the best statistical distribution of daily rainfall using the Hyfran hydrological model and also determining the curve number, finally the runoff height was calculated by calculating the surface retention. The results of this study show that due to the mountainous and low permeability, the area is prone to severe floods, so it is necessary to identify areas for artificial feeding and flood storage projects as well as reduce flood damage. The results of this study showed the efficiency of GIS in estimating runoff height, as well as increasing runoff height by increasing the return period and reducing the probability of occurrence.