Effect of Water Level Fluctuation on Riverbank Stability at the Estuary Area of Muaro Kualo Segment, Muara Bangkahulu River in Bengkulu, Indonesia

Abstract

The paper presents an investigation of riverbank stability at the estuary area of Muaro Kualo Segment, Muara Bangkahulu River in Bengkulu, Indonesia. This area had experienced slope failures along the riverbank during the Bengkulu flood in 2019. This study is initiated by conducting a geotechnical survey to observe site condition. During the survey, slope geometry measurement and soil sampling are performed. The laboratory tests are performed to collect physical and engineering soils properties. The rainfall intensity during period of 2011-2020 is also collected to observe normal and critical river water level. The finite element method is employed to analyse the slope stability analysis under the normal and critical river water level conditions. The results showed that the slope failure is generally initiated at the slope toe. Because of the river water level, factor of safety of slope along the estuary is less than the minimum criteria for the stable slope. It indicates that slope failure is very possible to occur. Implementation of sheet pile is conducted to reduce the slope failure potential.  The results showed that the use of sheet pile is relevant to improve slope stability in the study area.