A morphometric analysis for investigation climate impact on settlement in Lengkiti, Ogan Komering Ulu Regency, Indonesia

The change in morphological patterns upstream of Ogan River were investigated to analyze land-use and climate change impact on the river meandering. This study aimed to investigate morphological changes of Ogan River in Lengkiti area between 1996 and 2019. Two sets of Landsat areal (1990 and 2016) were used to identify the morphological changes during flood periods. Data analysis used the maximum likelihood approach, t-test and Spearman correlation analysis. The morphometric indicators such as river width (W), meander neck length (L), axis length (A), curvature radius (R), water flow and sinuosity of meander (C) were extracted to identify the morphological pattern of river meandering. Analysis of land-use change used Support Vector Machine (SVM) and kernel function method to interpret the meander parameter change. Ogan River in Lengkiti, such as Batu Kuning and Marga Jaya segments, which have rice field and settlement cover from 1996 to 2019, had been cut off. Cut-off occurred due to landslides that entered river’s body and narrowed riverbed. This fasted river flow even though river discharge was same, caused intensive erosion and sedimentation. The increase in water velocity increased flow power, shortened flow distance and cut-off caused reduced meander’s sinuosity (C).