hydrogeology
Fariba Esfandyari Darabad; Zeinab Pourganji; Raoof Mostafazadeh; Maryam Aghaie
Abstract
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 ...
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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.
Abstract
Abstract
In recent years geomorphological instantaneous unit hydrograph approach has gained wide acceptability in estimating the runoff from a watershed due to different storm patterns and watersheds with scanty data. Using geomorphologic features is a suitable criterion for derivation of hydrograph ...
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Abstract
In recent years geomorphological instantaneous unit hydrograph approach has gained wide acceptability in estimating the runoff from a watershed due to different storm patterns and watersheds with scanty data. Using geomorphologic features is a suitable criterion for derivation of hydrograph and watershed management in ungagged watersheds. In this study, using morphometric characteristics of Daryan Chay basin, such as bifurcation ratio and longest flow path, geomorphological instantaneous unit hydrographs which were derived for 5 events and by using criterion such as determination coefficient, percentage error in peak discharge and time to peak discharge, Nash-Sutcliffe efficiency and percentage error in runoff volume were compared with observed hydrographs. The findings showed that the most important components of the hydrograph were time to peak and peak discharge. A slight difference was observed between simulated time to peak using geomorphological instantaneous unit hydrograph and observed hydrograph. In other words, geomorphologic instantaneous unit hydrograph predicted the geomorphological instantaneous unit hydrograph accordingly.
