Evaluating Watershed Hydrological Responses to Climate Changes at Hangar
Watershed, Ethiopia.
Abstract
The aim of this study is to model the responses of Hangar watershed
Hydrology to future climate changes under the two Representative
concentration pathway (RCP) scenarios. Future changes in precipitation
and temperature were produced using output of dynamically downscaled
data of Regional Climate Model (RCM) 50 Km resolution under RCP 4.5 and
RCP 8.5 scenarios for 2025-2055 and 2056-2086. The future projection of
the RCM model of climate parameters showed an increasing trend relative
to the base period (1987-2017). At 2025-2055 an annual average
precipitation increment of +15.7% and +19.8% expected for RCP 4.5 and
RCP 8.5 respectively. For 2056-2086 of RCP 4.5 and RCP 8.5, also similar
trend showed in which change in average annual precipitation may
increase by +20.1% and +23.4% respectively. The changes of climate
parameters used as input in to SWAT hydrological model to simulate the
future runoff at the out let of gauging station. The increment in
precipitation projection resulted in positive magnitude impact on
average runoff flow. The average annual change in runoff at 2025-2055 of
both RCP 4.5 and RCP 8.5 may by +260.01m3/s and +733.18m3/s
respectively. At 2056-2086, change in average annual runoff of
+257.08m3/s and +732.26m3/s for RCP 4.5 and RCP 8.5 may expected
respectively. This increment may create an opportunity for community of
the area to harness enough amount of water during most increased season
for later use.