Evaluation of Land Degradation and Landsude Using Integrated Remote Sensing and Gis Approach Around Wolayita Sodo-Shone Area, Southern Ethiopia
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Date
2005-06
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Addis Ababa University
Abstract
In this study two major environmental hazards, namely land degradation and landslide have been
investigated. These hazards have clear dynamic relationships given that both are chaotic phenomena
that can be trigg~le e9..uilibrium situation occurring drastically and abruptly to the
enVironment. ,.
Southern Nation's National Peoples Region is one of the most populated regions in the country. The
area is situated in the western margin of the Ethiopian Main Rift system and it is structurally
controlled and tectonically active. Therefore, the study area is an excellent site where natural and
human induced or anthropogenic factors work jointly to result in such a staggering environmental
damage. Generally, it is a place where most favorable factors of land degradation and landslide
coincide in space.
An integrated GIS and remote sensing approach was very helpful to study the intensity and extent of
the two environmental hazards. The degradation rate that was calculated in areal base using cross
classification of temporal data shows the degradation rate is becoming severe with time. The
degradation rate that was 1.8 sq. km/year between 1984 and 1995 has increased in to 3.1 sq. km/year
in recent times (till 2001). These figures show that the rate of degradation is increasing at an alarming
rate.
The amount of soil lost from the study area is estimated using cut and fill technique applied on 5
representative sites. Profiling was done using GPS reading taken at every 5-10m interval and
organized in a database. The volume loss calculated shows that 2,485,818 mS amount of soil is lost
from 291,241 m'area; with the net lose per area being about 8.53 m~.
~i1 Factors that are found to be significant in triggering the Land degradation in the study area include
structure, lithology, landusc/ landcover, slope, soil, drainage, and climate. Similarly these factors with
addition of slope aspect play an important roll in aggravating the frequently occurring landslide.
The presence of all the factors that are responsible for the staggering environmental hazard and their
coincidence in space and time indicate that the area is highly prone to these hazards. Factors that are
considered to be responsible for the two environmental hazards were weighted in hierarchical order
using the MCE approach to produce susceptibility maps that express the likelihood occurrences of
the hazards in the area on the bases of the local terrain condition.
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Keywords
Evaluation of Land Degradation