PARTICLE SIZE CHARACTERISTICS OF RIVERBED SEDIMENTS TRANSPORTED BY TIDAL BORE ‘BONO’ IN KAMPAR ESTUARY, RIAU-INDONESIA

Kampar River is one of the biggest rivers in Riau Province, which well known for the natural phenomenon namely Bono. Bono is a tidal wave which propagates within the river, resulting a destructive force. Bono’s wave crest triggers a turbulence of bed sediment, where it is the major factor inducing sediment transport along Kampar River. This study aims to determine the particle characteristics of bed sediment and the oceanographical aspects during the propagation of Bono. The employed methods were stratified purposive sampling, sieve, and granulometry as well as statistical analysis, which were applied to determine the sediment characteristics. Current and tide measurements were conducted at the same time field survey. River depth ranged randomly from 0 - 12 m. It is shallow in the upstream and gradually shallower in the downstream. Sediment texture is divided into 5 types, such as sand, silty sand, sandy silt, silt, and clayey silt. Tidal range during Bono’s propagation ranged from 0-3.5 m. Current speed ranged from 0.2-0.95 m/s. Bono occurrence impacts to lead bed erosion/scour precisely beneath the first wave crest. It also Induces sediment deposition when the propagation speed was decreased, affecting the unstable sedimentation and erosion along Kampar River.