Water surface Changes of Lakes in the Central Rift Valley of Ethiopia

Abstract

Lakes are one of the most important biologically diverse ecosystems. However, extensive human and natural factors contributed to the loss of this ecosystem. Until recently, knowledge on the recent status of rift valley l,akes was lacking. The aim of this study was, therefore, to estimate the current extent of selected lakes in the central Rift Valley of Ethiopia using Landsat image. Satellite images of Landsat OLI_TIRS for the year 2018 were used for this study. Selected bands (green, near infrared, shortwave infrared and middle infrared) were selected in calculating automated water extraction index to distinguish water surface from non-water. The result revealed that the extent of water surface was reduced between 2015 and 2018 with an amount of 47.6, 2.4 and 0.9 % for lake Abjata, Shala and Langano, respectively. Such rapid conversions of aquatic ecosystem need urgent management and policy intervention. Furthermore, applied researches are needed to reduce the magnitude of change.