The effects of hydrodynamic process and mangrove ecosystem on sedimentation rate in Kendal coastal area, Indonesia

Abstract

The Coastal Area of Kendal Regency is subjected to continually changing morphodynamic processes. The density of mangroves contributes to the extent of accretion, sediment distribution, and high surface elevation. The study aimed to identify the effects of hydrodynamics on sedimentation, calculate the sedimentation rate, and analyze the significance of mangrove ecosystems in shaping this rate. Located on the west side of Bodri River, the research area includes a mangrove ecosystem directly facing the open water. This quantitative research involved analysis and validation of hydrodynamic parameters, quantification of sedimentation rate, identification of mangrove species, and calculation of the Importance Value Index (IVI) of mangrove at each growth stage. Parameters in November-February represented intensive hydrodynamic processes with the highest monthly average detected in February, meaning that sediment movement is also the most intensive in this month. The lowest sedimentation rate was 0.1501 mg/cm²/day, while the highest was 23.4938 mg/cm²/day. Rhizophora apiculata and Avicennia alba were the two mangrove species growing in the area. A. alba had the highest relative dominance score in the community, as indicated by its IVI. Mangrove density and sedimentation rate showed a directly proportional relationship in Plot 3 at two growth stages, namely, sapling and seedling.