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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Evaluation of Land Degradation

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