INTER- COMPARISONS OF THE PERFORMANCE OF DIFFERENT RAINFALL-RUNOFF HYDROLOGICAL MODELS IN ABAYA-CHAMO RIVER BASIN A CASE STUDY OF BILATE AND KULFO CATCHMENTS

Abstract

In river flow simulation and forecasting where there is insufficient data and minimum gauging stations, hydrological models are appropriate operational tools to simulate and extend the time series. The aim of this study was to inter- compare the performance of four deterministic- Lumped rainfall-runoff models in the Abaya Chamo River Basin. In this River Basin the meteorological & hydrological data from Bilate and Kulfo catchtnents were considered for the analysis. The Simple Linear Model (SLM), The Linear Perturbation Model (LPM), the Soil Moisture Accounting and Routing Model (SMAR) and HBV models were used for the study. The selected mpdeis performance was evaluated and compared for the two catchments. Visual comparison of the simulated and observed runoff response, Nash efficiency criterion (R^), the index of volumetric fit (IVF) and the relative error of peak (RE) criteria were used to compare the models outputs. The optimum parameters which give better simulation result were determined for the calibration periods of each model. The verification have been made for the optimum parameters obtained during the calibration period. The SMAR, HBV and LPM gave better model performance in Bilate compared to the result in Kulfo catchment. Out of the four models the SMAR model result was better in both the catchments. Therefore, the SMAR model can be used to estimate discharge in the two catchments. Further investigation has to be made to generalize the applicability of this model to all Abaya Chamo River Basins.