Morphology Changes Affected by Sediment Concentration and River Flow in
Meandering Channels of the Bengawan Solo River
Abstract
Increases in critical land in the Bengawan Solo River Basin contribute
to floods and severe damage to infrastructures along the river channel.
Additionally, the occurrence of excessive erosion is a source of
sediment materials, especially at meandering sections. Riverbank erosion
destabilises dykes and sediment deposition decrease capacity, thereby
resulting in floods (especially during rainy seasons). Although both
phenomena can be evaluated by observing flow velocity and sediment
concentration, there is a paucity of field investigations on parameters
that affect erosion under dry and rainy seasons. This study investigates
the aforementioned parameters and contrasts circumstances during dry and
rainy seasons by presenting relevant information on sediment quantity
and flow velocity. The results indicate that sediment concentration at
the outer banks of the flow path significantly exceeds that at the inner
banks, thereby indicating significant occurrence of erosion. Further
examination of riverbed material suggests that the interaction between
sediment concentration and flow velocity, especially in meandering
segments, can provide an estimate of the erosion rate and the change in
the morphology of the alluvial river. Sediment concentration is
correlated with seasonal conditions such that sediment concentration
during the rainy season is approximately five times that in the dry
season. This clarifies that more significant river morphology changes
occur during peak seasons. Further, the results of the study can be used
in river dynamic process prediction, especially in alluvial streams or
in soft soil with properties similar to that of alluvial streams.