Evaluation of Land Degradation Around Deber Zeyit Area Using Rs and Gis Techniques
No Thumbnail Available
Date
2005-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa Universty
Abstract
Gully development dynamics that occurred from 1971 to 2002 around the Debre Zeyit
area were evaluated using remote sensing and GIS in addition to field verification. The
study was conducted in about 694-km2 area with in the East Showa Zone of the Oromia
Region.
The main objective of this study is to understand the rate, cause and extent of gully
erosion around Debre Zeyit area in terms of change in landcover, development of
infrastructure, soil type and geology of the area. Four sets of remotely sensed images,
MSS-1973, TM-1986 & 1995 and ETM+ 2002 are used in evaluation of the change in
landuse and landcover of the area with in of 13, 9 and 7 years gaps and Aerial
photographs of 1971 as well as the 2002 ETM+ image are used in gully development rate
mapping. In addition to this field measurement of gullies width and depth volume
calculation is done to quantify the amount of soil lost by all gullies and rate of soil loss by
new gullies with in 31 years gap.
Results of landcover change analysis show cultivated land increased from 50% in 1971 to
55% in 1986 and to 67 and 69% in 1995 and 2002 respectively. The overall increase in
cultivated land is about 19%, which was mainly at the expense of grasslands and dense
shrub covers. The area which was mainly covered by the dense shrubs is changed to open
woodland and cropland. The size of urban and water bodies increased from 1.04% to
1.7% and 0.73% to 1.02% percent due to population increase and construction of dams
respectively. The area covered by wetland also show minor differences in size due to
evaporation.
New gullies are developing in areas where the original landcover is removed and where
slopes are between 2 and 10 percent. In addition to this on the southern part of the study
area construction of roads are important causes of gulling where the soil type and
lithology are favoring erosion processes.
Description
Keywords
Rs and Gis Techniques