MODELING THE IMPACT OF CLIMATE CHANGE ON THE HYDROLOGICAL REGIMES OF GUMARA WATERSHED

Abstract

One of the most momentous potential concerns of climate change is to understand changes in hydrological components. Climate change and its impact is revealing on different natural and manmade systems, in one or other ways. Accordingly, this impact is significant on the water resource system. The main aim of this study is to evaluate potential future impacts of climate change on hydrological regime at Gumara watershed. In order to estimate the level of climate change impact on the hydrological regimes of the watershed, climate change scenarios of precipitation and temperature were developed for Gumara watershed level for RCP scenarios, in which the watershed is situated for three future climate periods of 10 years from 2021 until 2090. The performance of the model was assessed through calibration and validation process and resulted R 2 =0.85 and NS=0.84 during calibration and R 2 =0.85 and NS=0.83 during validation. The bias correction in the RCP8.5 scenario for precipitation, maximum and minimum temperature was done before using it for water balance analysis. This analysis is based on projection of three different scenarios of climate change for future time horizons: 2020s (2021-2030), 2050s (2047- 2056) and 2080s (2081-2090). Surface inflows are simulated by using SWAT model. The result revealed that the maximum and minimum temperatures increase for all the three scenarios in all future time horizons, the precipitation shows decrease trend in all future time horizons. RCP8.5 were used as input to the calibrated SWAT model to investigate the possible impacts of potential climate change on the hydrology of the Gumara watershed. The period from 1994-2005 was used as baseline and has been used to determine the changes and the effect of the future climate changes. A simulation study of climate change effects on the basin demonstrates that the hydrology of the basin is very sensitive to climate change.