A Comparison of Hydrological Models Under Climate Change on the Water Resources of Megech River Catchment, Abbay Basin, Ethiopia

Abstract

This study was aimed to compare the uncertainty of two hydrological models in discharge modeling and their performance and catchment hydrological response to climate change in Megech river catchment. In this study, large scale regional climate model (REMO) output was downscaled statistically to metrological variables at a daily resolution using SDSM model version 5.11. The two hydrological models, HBV-Light and GR4J, were successfully calibrated (1991-1995) and validated (1998-2000) using current climatic inputs and observed river flows. The overall performances of the two models in reproducing historical records were good at daily and monthly time scale both on calibration and validation (NSE=0.91 for HBV and NSE=0.88 for GR4J). The models results in predicting hydrological response of changed climate (2015-2050) was simulated using statistically downscaled 20 ensembles climate scenario data for both A1B and B1 scenarios. Both model results showed a reduction of the peak discharge in August and September The total annual discharge for future period (2015-2050) showed a decreasing trend for HBV-Light simulation and an increasing trend for GR4J simulation. More studies using different hydrological models on different catchments need to be carried out in order to provide more general conclusions about the reliability of the model output.

Keywords: Gr4J, HBV-Light, Megech, REMO, SDSM

DOI: 10.7176/JNSR/9-1-03