Modelling the Sediment Load in the Bird Feather-Type Watersheds along the Main Rivers of Banyuwangi Regency

Abstract

A sediment transportation process may lead to a river overflow. This was the case with 4 major rivers in Banyuwangi Regency, namely Baru, Setail, Bomo, and Tambong rivers. The watersheds in Banyuwangi are shaped alike to bird feathers, belonging to the dendritic drainage type with an elongated drainage form, relatively small discharge, and flooding that occurs for a relatively long time. The use of downstream areas by residents for sand mining indicates a high amount of sediment in the watersheds. The purpose of this study was to model the sediment load in the bird feather-type watersheds along the main rivers of Banyuwangi Regency. Data from water level, flow velocity, and discharge measurements were correlated with the results of suspended load and bedload analyses to create rating curves. Equations for the modeling of the sediment load in the bird feather-type watersheds were generated by regression methods. The results of the modeling of the sediment load in the bird feather-type watersheds in Banyuwangi Regency using the equations above were obtained by the suspended load model qs (tons/day) = 27.0 - 39.0.h (m) – 122.V (m/s) + 71.1.q (m3/s), with R-Sq = 59.4%, and by the bedload model qb (tons/day) = - 0.0758 + 0.0853.h (m) + 0.0585.V (m/s) + 0.165.q (m3/s), with R-Sq = 73.6%. Sediment load modeling can be used as a projection of sediment transport in studies on type C excavations along the major rivers in Banyuwangi Regency.