Data from: Comparison of sediment transport and bedforms from steady and unsteady flow hydrographs of similar flow rate

This is the dataset that was used to make the figures for the publication entitled "Comparison of sediment transport and bedforms from steady and unsteady flow hydrographs of similar flow rate"The citation for the publication is: Wren, D. G., McAlpin, T. O., and Langendoen, E. L. Comparison of sediment transport and bedforms for equilibrium flows to unsteady hydrograph flows at the same flow rates. Journal of Hydraulic Engineering. (In preparation).Flow rates and depths in natural rivers and streams can change rapidly with time due to runoff from rainfall and snowmelt. These changing conditions complicate the prediction of sediment transport, bed topography, and flow depth. Due to the difficulty in collecting field data during unsteady flow events, it is necessary to use laboratory flume experiments to study sediment transport and bedform properties during unsteady flows. The goal of the work described here was to isolate the effects of hydrograph flows on bedform dimensions, water surface slope, and sediment transport relative to the same flow rates in equilibrium conditions for steady flows while also comparing results across the various flowrates. For three repeated hydrographs of 1-, 3-, and 6-hour periods, quantities measured at four different flow rates during the hydrographs will be compared to equilibrium conditions for each flow rate. The development of bedforms during rising and peak flow rates competed with the destruction of bedforms during falling flow rates. When bedform growth was greater than decay, bedform sizes, water surface slopes, and transport rates during falling flow rates were typically greater than for equilibrium steady conditions at the same flow rate, while they were typically smaller than equilibrium bedforms for rising flow rates.

本数据集用于制作题为《相似流量下恒定流与非恒定流水文过程线的泥沙输移与床沙形态对比》的学术论文配图。该论文的引用信息为：Wren, D. G., McAlpin, T. O., 及 Langendoen, E. L. 《相同流量下平衡恒定流与非恒定水文过程流的泥沙输移与床沙形态对比》，《水利工程学报（Journal of Hydraulic Engineering）》（待刊）。
天然河流与溪流的流量及水深会因降雨与融雪产生的径流快速随时间变化，这类动态条件会增加泥沙输移（sediment transport）、床面地形与水深预测的难度。由于非恒定流（unsteady flow）事件期间难以获取野外实测数据，因此需借助实验室水槽实验（laboratory flume experiments）开展非恒定流条件下的泥沙输移与床沙形态（bedforms）特性研究。本研究的核心目标为：分离水文过程流相较于恒定流（steady flow）平衡状态下同等流量时，对床沙形态尺寸、水面坡度与泥沙输移的影响，并对比不同流量下的实验结果。针对1小时、3小时及6小时周期的三组重复水文过程线（hydrographs），将对比水文过程中四个不同流量测点的实测数据与各流量对应的恒定流平衡状态数据。在涨水与峰值流量阶段，床沙形态的发育过程会与退水阶段的床沙形态破坏过程相互竞争：当床沙形态的增长速率大于衰减速率时，退水阶段的床沙尺寸、水面坡度与输沙率通常高于同等流量下的恒定流平衡状态；而涨水阶段的床沙形态尺寸通常低于对应平衡状态。