Analyzing Impact of Climate and Land Use Land Cover Changes on the Hydrologic Regime: The Case of Tekeze River Basin, Ethiopia
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Date
2020-06
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Addis Ababa University
Abstract
Investigating the impacts of land-use and climate change on hydrologic regimes are essential
in understanding the patterns and movement of hydrologic processes. The changes in land use
land cover and climate change were experienced in the Upper Tekeze River basin in the last
three decades (the 1990s, 2000s, and 2010s) and climate changes is likely to occur under near
future projections (2020-2040). The paper provides potential implications of land use/ land
cover and climate change on streamflow, surface runoff, baseflow, evapotranspiration and
water yield of Upper Tekeze River basin using soil and water assessment tool (SWAT) model.
The analysis of this study includes an investigation of changes in historical land-use patterns,
individual and combined impacts of land use and climate change on hydrology and the factor
playing a dominant role in modifying the hydrology of the area. The analysis of three land
use/land cover reveals that the decline in forest and grassland and the increment in agricultural
land where the predominant land use/land cover change over the past three decades. The
hydrologic simulations indicate the influence of climate changes on the hydrologic regime was
dominant than land-use change. The variation in evapotranspiration was more pronounced in
land use/land cover change. However, the monthly variation in streamflow was mainly related
to the seasonal changes in precipitation. The reduction in baseflow was mainly attributed to
land-use change. The increment in surface runoff caused by climate change was enhanced by
land-use change, while, the decline in evapotranspiration was enhanced by deforestation.
Furthermore, the combined action of climate and land use follow the trends similar to the
impact of climate change. Under future projection the result reveals that except
evapotranspiration all other hydrological components (stream flow, surface runoff, base flow
and water yield) show the decline under RCP8.5 while the increment under RCP4.5 except
water yield which shows the decline. The finding from this thesis could provide information for
local administration, and policymakers to better understand the changes in the hydrology of
this region.
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Keywords
Land use/land cover, Hydrologic regime, Upper Tekeze River Basin, SWAT model,