Document Type : Research Paper
Author
department of civil engineering, Estahban branches, Islamic azad university
Abstract
Flood estimation of ungauged catchments is very important for designing hydraulic structures. In catchments with high permeability, the subsurface flow has an important role to the runoff. One of the methods of hydrograph prediction of surface and subsurface flow is to use the Geomorphological Instantaneous Unit Hydrograph (GIUH) method based on the geomorphological information of ungauged catchments. This method has the ability to separate surface and subsurface flow from the total flow. The GIUH model has been mostly used to estimate the surface flow in past researches, so the equations of this model have been expanded to be able to estimate the surface flow hydrograph of the basin. In this research, the GIUH model was used to estimate the surface and subsurface flow of two Kesilian basins in Iran and Gajas basin in India. Based on the results, the estimation error of the peak direct runoff in the Kesilian basin was between 3% and 16%, and in the Gajas basin, it was between 1.6% and 12%, which are suitable values. The Nash-Sutcliffe coefficient of efficiency in predicting the runoff hydrograph of the entire two basins in the top 8 events was 0.8.
Keywords
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