Land Use and Land Cover Change Detection in the Upper Dijo River Catchment, Silte Zone, Southern Ethiopia

Remote sensing and gis-based Land use and land cover change detection in the upper Dijo river catchment, Silte zone, southern Ethiopia Working papers on population and land use change in central Ethiopia, nr. 17 ABSTRACT Land use and land cover (LULC) change is one of the challenges which strongly influence the process of agricultural development and the food security situation in Ethiopia in general and in the Upper Dijo River catchment in particular. Remote sensing and geographic information systems (GIS) are important for the monitoring, modelling and mapping of land use and land cover changes across a range of spatial and temporal scales, in order to assess the extent, direction, causes, and effects of the changes. The changes in land use and land cover which occurred between 1972 and 2004 in the Upper Dijo River catchment, located in the middle Rift Valley system of Ethiopia, were monitored using such advanced spatial technologies, supplemented by field verification. The study area covered 55.7 km 2 , and had previously undergone substantial land use and land cover changes, mainly due to high population pressure. The main objective of the study was to assess and evaluate the extent and direction of changes in LULC in the Upper Dijo River catchment, to explain the changes and identify some of their effects on both the livelihoods of the local people and the local environment, and also to explore some of the conservation measures designed to overcome problems associated with land use and land cover changes. Aerial photographs taken in 1972, an EROS-1 satellite image from late 2004 and also geographic information system (GIS) techniques were used to monitor the changes and to generate maps of the LULC of the area in these periods. Information on the socioeconomic conditions of 120 selected households and the results of tests on soil samples taken from a depth of 30 cm at four different land use sites were used to identify the underlying factors and explain the effects of LULC changes. Observations showed that in the 32-year period between 1972 and 2004 shrub-grassland and riverine trees covers had decreased at a rate of 21.5 and 16.3 ha per year respectively. Riverine trees suffered the greatest devastation and by 2004 had been reduced to only 16% of their cover in 1972. In contrast, eucalyptus tree plantations, annual crops and bare land/open grassland cover increased at a rate of 2.8, 12.5 and …