COLLABORATIVE RESEARCH: Experimental Study of Downstream Fining in Coarse-Grained River Channels

这是一个为期2年的项目的更新，其总体目标是 通过沉积和选择性沉积来研究下游变细 在砾石中。 迄今为止的主要成果已经产生了下游 在50米长、0.3米宽的水道中， 圣安东尼福尔斯水力实验室（SAFHL）， 毫无疑问，选择性沉积是一种有效的澄清方法， 它可以在实验室实验中进行研究。 在约翰霍普金斯大学（JHU）的平行实验中， 彩色颗粒系统提供了部分传输数据 预测在SAFHL观察到的澄清所需的碱。 这个短语 现在涉及到一系列的运行与通道宽度为2.0的SAFHL 这将产生辫状地形，使调查 横向分选和地形对下游变细的影响。 JHU目前的部分运输计划将继续进行 添加组分对沉积物进料与 再循环和小尺度沉积的影响 功能. 最后，在麻省理工学院进行了一组并发运行， 在1.0米宽的通道中进行局部横向分选， 改变存款几何形状和提取百分比的影响， 计划好了 这项研究似乎是第一个真实的联系， 工程水力学与河流沉积学 泥沙输运力学相关基础研究。

This is a renewal of a 2-year project whose overall goal is to study downstream fining by aggradation and selective deposition in gravels. The main results so far have produced downstream fining by a factor of two in a channel 50 m long and 0.3 m wide at the St. Anthony Falls Hydraulic Laboratory (SAFHL), demonstrating unequivocally that selective deposition is an effective fining mechanism and that it can be studied in laboratory experiments. In parallel experiments at Johns Hopkins University (JHU), a novel colored-grain system is providing the fractional-transport data base needed to perdict the fining observed at SAFHL. This phrase now involves a series of runs a SAFHL with a channel width of 2.0 m; this will produce braided topography, enabling invesitgation of the effect of lateral sorting and topography on downstream fining. The present fractional-transport program at JHU, will continue adding components on the effect of sediment feed versus recirculation and the influence of small-scale sedimentary features. Finally, a concurrent set of runs at MIT to examine local lateral sorting in a 1.0 m wide channel as well as the effects of varying deposit geometry and percent extraction is planned. This research seems as the first real connection between engineering hydraulics and fluvial sedimentology and represents fundamental research related to sediment transport mechanics.