Delineating the decadal expansion of Lake Basaka (Ethiopia) using various image interpretation techniques

Lake Basaka is expanding at a significant rate. Before the establishment of Matahara Sugar Plantation, the lake was like a small surface pond created during rainy season and used as grazing area. The lake expansion has certain negative consequences to the region. Thus, appropriate method of quantification of the Lake expansion is extremely important. In this particular study, the areal expansion of the Lake Basaka and sugarcane plantation was analysed. Four LandSat images (1973, 1986, 2000 and 2008) were taken for the cloud-free period and processed in ERDAS Imagine and ArcGIS softwares. Three techniques were employed in the delineation of the areas of the lake and plantation: visual interpretation of FCC in GIS, enhancements and advanced classification in ERDAS Imagine. The study result shows that Lake Basaka expansion is very significant and the increment is geometric rather than linear. Overall, the finding indicates that visual image interpretation gives a fast and accurate indication of the Lake Basaka expansion compared to image enhancement and classification techniques.