Comparison of reservoir-based GUHR, NASH and Hybrid models in derivation of unit hydrograph (case study: Kamanaj Olia watershed)

Document Type : Research Paper

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Abstract

Runoff estimation is almost one of the main concerns of hydrologists, water resources managers and planners. Unit hydrograph models are the most popular and widely used tools to model the rainfall-runoff process. Ralating Synthetic Unit Hydrograph models to watershed geomorphologic properties can provide a reasonable representation of runoff estimation by considering both rainfall and watershed characteristics and extend the usage of SUH models in ungauged catchments. This study evaluates three conceptual reservoir based rainfall-runoff models including Geomorphologic unit hydrograph reservoir (GUHR), NASH and HYBRID models for four rainfall-runoff events in Kamanaj Olia watershed located in eastern Azerbayjan province. Comparison of resulted and observed unit hydrographs using five error criteria;( coefficient of determination, Nash- Sutcliffe, error in volume of  hydrograph, error  in  peak flow  and time to peak) indicated desirable accuracy estimation  through all three models. All three models computed peak flows smaller than those of observed, but generally GUHR model simulated peak flows and time to peaks better than others.

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