Characterisation of channel morphological pattern changes and flood corridor dynamics of the tropical Tana River fluvial systems, Kenya

Abstract

Historical morphological changes are useful tools for understanding river evolutionary trends and condition. This study characterised planform changes and floodplain dynamics of the Tana River fluvial systems, Kenya, between 1975 and 2017 using an integrated remote sensing and geographical information system (GIS) methodological framework. The river has witnessed significant alterations in channel morphology over a period of 42 years, indicating a highly active and meandering nature with a generally rising sinuosity in the downstream direction. The annual lateral river movement rate reduced significantly after the river regulation, which occurred between 1981 and 1988. Land cover change detection of the study reaches revealed tremendous spatial and temporal progressive disappearance of the riparian vegetation and dynamic channel morphological characteristics, trends that may continue in the coming years. The approach adopted in this study can be applied to other river reaches within study area with similar protocols or modifications according channel type and reach condition to provide water managers with evidence on the dynamic fluvial channel plan morphology for sustainable planning management and restoration activities.