The Effect of Land Use Land Cover Change on Hydrologic Response of Wukro-Genfel Catchment, Tekeze Basin, Ethiopia
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Date
2010-06
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Addis Ababa University
Abstract
The environment of the northern Ethiopia highlands are seriously affected by land
degradation, mainly caused by the combined effects of deforestation, overgrazing, expansion
of cropland and unsustainable use of naturaJ resources. These have also a potential effect on
the runoff, infiltration, sedimentation and other hydrologic parameters. The main objectives
of the current study are to assess land use land cover change that occurred during 1986-2007
and its effect on the hydrologic response of Wukro-Genfel catchment, in Tekeze river basin.
The widely used Soil Conservation Service - Curve Number (SCS-CN) method was integrated
with Remote Sensing and Geographical Information Systems (GIS) techniques. The analysis
revealed an overall decrement of woodland, scrub and grassland by 2.9%, 2.2% and 4.7%
respectively and increment of farmland, shrub and bareland by 8.6%, 3.1% and 2.3%
respectively over the past twenty one years (1986-2007). Considering Antecedent Moisture
Condition (AMC) II which is moderate soil moisture condition and taking 36mm of rainfall
event, there was a decrement of runoff depth by 37. 6% for shrub to woodland change, 6.1%
for scrub to shrub change and 2.1% for scrub to farmland change with Hydrologic Soil
Group (HSG) A, A and B respectively. On the other hand, there was an increment of runoff
depth by 30.4% for woodland to farmland and by 3.7% for farmland to bareland with HSG B
and C respectively. Out of the whole land uselcover classes, woodland plays significant role
on runoff generation and its spatial distribution. Thus, Special attention should be given to
sloppy river banks where high nmoff is generated. The total volumetric runoff was decreased
on average by 17.6% during the period 1986-2000 mainly due to the increment of woodland.
An average increment in the total volumetric runoff was also observed by 13.5% for the
period 2000-2007 caused by the depletion of woodland in the area.
Key Words: Land use land cover, Runoff, SCS-CN, Hydrologic Soil Group (HSG),
Remote Sensing, GIS
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Keywords
Land use land cover, Runoff, SCS-CN, Hydrologic Soil Group (HSG)Remote Sensing, GIS