Data for: Multiscale bedform reorganization at the onset of substantial suspended sediment transport

Sand-bedded rivers feature dunes and ripples, collectively referred to as
bedforms, that regulate flow resistance and sediment fluxes. Recent
research has demonstrated that in large lowland rivers, bedforms are
characterized by their multiscale organization; however, the flow and
sediment transport conditions under which these arrangements are stable
remain unknown. In this study, we analyzed twelve flume experiments of
bedform evolution to reveal a previously unrecognized transition in the
organization of multiscale bedforms. The data herein accompany the
manuscript “Multiscale bedform reorganization at the onset of substantial
suspended sediment transport ” by Debsmita Das, Vamsi Ganti, and Robert C.
Mahon. This dataset consists of bathymetric data from four flume
experiments of bedform evolution conducted in a 15m-long, 2-m-wide, and
1-m-deep flume at the Experimental Sedimentology Laboratory, University of
California, Santa Barbara. This includes a 20-hour-long step-discharge
experiment, systematically increasing the discharge from 0.28 m3/s to 0.41
m3/s in ten increments, then decreasing it back to 0.28 m3/s in ten steps.
The initial and peak discharges represented bedload-dominated and
suspension-dominated conditions, respectively. We also include three
steady-state experiments at 0.28 m3/s (baseflow; duration ~6.6 hrs), 0.41
m3/s (peak-flow; 3 hrs), and 0.37 m3/s (intermediate flow; ~8 hrs) to
characterize equilibrium bedform dynamics. The vertical and horizontal
resolution of all experimental data is 1 mm, and the temporal resolution
of scans is 4 minutes.

砂质河床河流发育沙丘与沙纹，二者统称为床形（bedforms），可调控水流阻力与泥沙通量。近期研究表明，大型低地河流中的床形具有多尺度组织特征，但维持该组织模式稳定的水流与泥沙输移条件仍未明确。本研究通过分析12组床形演化水槽实验，揭示了多尺度床形组织中此前未被发现的转变过程。本数据集配套于Debsmita Das、Vamsi Ganti及Robert C. Mahon撰写的论文《大规模悬移质输移起始阶段的多尺度床形重组》（Multiscale bedform reorganization at the onset of substantial suspended sediment transport）。本数据集包含美国加州大学圣巴巴拉分校实验沉积学实验室中，在长15m、宽2m、深1m的水槽内开展的4组床形演化实验的水深地形数据。其中包含1组时长20小时的分级流量实验：以10级增量将流量从0.28 m³/s逐步提升至0.41 m³/s，随后再以10级增量将流量回落至0.28 m³/s。实验初始与峰值流量分别对应推移质主导与悬移质主导的输移条件。此外还包含3组稳态实验，分别在0.28 m³/s（基流，时长约6.6小时）、0.41 m³/s（洪峰流量，时长3小时）与0.37 m³/s（中间流量，时长约8小时）下开展，用于表征平衡床形动力学特性。所有实验数据的垂直与水平分辨率均为1 mm，扫描的时间分辨率为4分钟。