University of Tabriz Journal of Hydrogeomorphology 2383-3254 9 32 2022 11 16 Comparison of Effective Rainfall Conversion Methods to Surface Runoff in Flood Hydrographic Simulation of Nanehkaran Watershed, Ardabil Province Comparison of Effective Rainfall Conversion Methods to Surface Runoff in Flood Hydrographic Simulation of Nanehkaran Watershed, Ardabil Province 86 63 14861 10.22034/hyd.2022.50000.1624 FA Fariba Esfandyari Darabad Professor, Department of Natural Geography, Faculty of Social Sciences, , University of Mohaghegh Ardabili, Ardabil, Iran. Zeinab Pourganji M.Sc Student of Geomorphology-Environmental Management, Faculty of Social Sciences, Mohaghegh Ardabili University, Ardabil, Iran Raoof Mostafazadeh Associate Professor, Department of Natural Resources, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili Maryam Aghaie M.Sc. Graduated in Remote Sensing and GIS, Department of Literature and Humanities, Faculty of Natural Geography, Mohaghegh Ardabili University, Ardabil, Iran Journal Article 2022 01 21 <br /><br />Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior of the watershed. In this study, various rainfall-runoff transformation methods have been evaluated, including triangular, broken triangular, variable triangular and SCS-curvilinear unit hydrograph methods in Nenekaran watershed, Ardabil province. In this regard, the Wildcat5 hydrological model have been used to this purpose. The precipitation amount at the 25-year return period was calculated using Cumfreq software. After preparing the land use map of the study area using satellite images, the area of each land use in the area has been calculated using ArcGIS software. The precipitation value and the time of concentration were considered constant during the simulation procedure. The results showed that the SCS method had the highest runoff of 44.50 cubic meters per second. The minimum time to the peak was 2.19 hours and the variable triangular method had the lowest peak flow rate. The simple triangular method has a maximum time to peak of 4.51 hours, which shows the great difference between the hydrograph of the SCS method and the other three methods. The difference in the nature of the methods, the watershed condition, and the suitability of estimating tc and CN parameters should be considered in rainfall-runoff transformation methods. <br /><br /><br /> <br /><br />Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior of the watershed. In this study, various rainfall-runoff transformation methods have been evaluated, including triangular, broken triangular, variable triangular and SCS-curvilinear unit hydrograph methods in Nenekaran watershed, Ardabil province. In this regard, the Wildcat5 hydrological model have been used to this purpose. The precipitation amount at the 25-year return period was calculated using Cumfreq software. After preparing the land use map of the study area using satellite images, the area of each land use in the area has been calculated using ArcGIS software. The precipitation value and the time of concentration were considered constant during the simulation procedure. The results showed that the SCS method had the highest runoff of 44.50 cubic meters per second. The minimum time to the peak was 2.19 hours and the variable triangular method had the lowest peak flow rate. The simple triangular method has a maximum time to peak of 4.51 hours, which shows the great difference between the hydrograph of the SCS method and the other three methods. The difference in the nature of the methods, the watershed condition, and the suitability of estimating tc and CN parameters should be considered in rainfall-runoff transformation methods. <br /><br /><br /> https://hyd.tabrizu.ac.ir/article_14861_95bb6681f10d9586f11e19d14f17ae95.pdf