Assessing 30 Years of Land Use Dynamics in Usangu Catchment, Tanzania

Abstract

This paper assesses land use dynamics in the Usangu catchment from 1986 to 2017. It employs historical data search, which include Landsat 5 Thematic Mapper and Landsat 8 Operational Land Imager collected from the United States Geological Survey. Additional data were generated from field observation in specific GPS points for classification accuracy assessment. Visual analysis of land use was carried out with the aid of Google Earth navigation. In-depth interview with key informants served as a useful means of collecting land use information. Landsat images of 1986, 1996, 2006 and 2017 were classified in ArcMap 10.3 under supervised classification technique to produce land use and land cover maps of the particular years. Land use and land cover changes were assessed based on the classified maps for change detection analysis. The results suggest that land use and land cover had a remarkable transformation during the 30 years of the study period. Open bush land gained 4.34% of land from mixed forest in 2006-2017. Water bodies area decreased by 2.4% between 1986 and 1996 due to an increase in bare land by 1.2% in the catchment. Land for agriculture rose by 2.6% in 1996-2006, but declined by 4.5% in 2006-2017. The revealed negative changes in mixed forests, water bodies and open bush land in Usangu catchment result into serious stress on environmental resources. Therefore, this calls up for more conservation efforts by authorities and stakeholders concerned with environmental management issues in the Usangu catchment.

Keywords: land use change, land cover change, water catchment, remote sensing, change detection