Sediment transport in the Luanhe River delta: grain size trend analysis

Sediment grain size in the deltaic environment of the Luanhe River (LR), Liaoning, China, contains sediment transport pathway information useful in elucidating the shoreline change and fluvial-marine interaction. In this study, we utilized numerical partitioning of the sedimentary components and geostatistical grain size trend analysis (GSTA) to define the sediment transport pattern in the Luanhe River delta (LRD) and interpolated the sediment transport pattern using content changes of end numbers (EM). EM1 (the mean grain size 7.12 Φ, fine silt), EM2 (2.37 Φ, fine sand), and EM3 (1.27 Φ, medium sand) components were identified by the numerical partitioning by GSTA. Kriging interpolation method was used to interpolate the parameters of the grain size for the regular grid, and the interpolation radius was 0.015 decimal degree. We chose 0.09 decimal degree as the characteristic distance for GSTA in the semi-variogram model using the geostatistical method. The FB(−) case (finer, better sorted and more negatively skewed) was adopted in GSTA for its satisfaction in the Global Moran’s I test. The result of the GSTA shows that the sediments in the south barriers (SBs) were transported to the southwest of the study area. The sediments in the north, in the SE direction of sediment transport trend from the river mouth, indicated that the sediments in the north of the study area were transported from the LR to the northern beaches, and to the south and east of the study area. The sediment transport trend that simplified by GSTA as the FB(−) case was approved by the content changes of sedimentary components (i.e. EM1, EM2, and EM3). In addition, the turbulent jet diffusion pattern indicated that the coarse sediments (EM3) were delivered by LR during the flood season, and the EM2 and EM1 were from wave and tide, respectively.