Flow and sediment dynamics in river channels

这项研究计划涉及冲积和基岩河道水流和沉积动力学的各个方面。重点将放在（一）河流形态的浅滩和池的粗粒通道的规模，（二）基于实地测量的流动特性，在一个砂床河的实地网站的涟漪沙丘过渡，及（三）侵蚀的岩床流在南部安大略。 需要进行有系统的浅滩-水池单元的现场研究，目的是更完整地描述这种单元上方的湍流场。还将进行沿沿着浅滩-水池单元的河床形态和水流特性的计算机模拟。一维河床高程序列将通过自回归模型进行模拟，而水流特性将沿着此类序列通过模拟程序（如HEC-RAS（美国陆军工程兵团））进行模拟。此外，进一步的问题，在砂床河流的底形过渡将在实地为基础的设置。特别是，重点将放在流动阻力和推移质输沙率的变化，从涟漪到沙丘的过渡发生。这将在位于加纳拉斯卡河（安大略南部）支流上的一个现场沿着实现。最后，安大略南部的一些河段是基岩河道（沉积岩）。这些基岩河道主要由相对平坦的沉积岩碎片构成。岩床溪流的演变部分地受到暴露的基岩表面的特征以及岩石碎片如何容易被侵蚀的控制。然而，对这些碎片的可侵蚀性知之甚少。现场和实验室实验将进行，以进一步提高我们的知识，水流和泥沙输运过程沿着约克控制的河流到达南部安大略。这项研究计划将大大有助于我们在冲积和基岩渠道的流动和沉积动力学的知识。在当地，拟议的研究计划将提高我们对侵蚀问题和沿着由克拉克控制的城市河流的河道演变的理解

This research proposal deals with various aspects of flow and sediment dynamics in alluvial and bedrock channels. Emphasis will be placed on (i) river morphology at the scale of riffles and pools in coarse-grained channels, (ii) field based measurements of flow characteristics across the ripple-dune transition at a field site in a sand-bed river, and (iii) erosion of rockbed streams in southern Ontario.  Systematic field studies of riffle-pool units need to be undertaken with a goal to achieve a more complete characterization of turbulent flow fields above such units. Computer simulations of both bed morphology and flow characteristics along riffle-pool units will also be undertaken. One-dimensional series of bed elevations will be simulated from autoregressive models and flow characteristics along such sequences from simulation programs such HEC-RAS (US Army Corps of Engineers). Moreover, further questions on bedform transitions in sand-bed rivers will be addressed in a field-based setting. In particular, emphasis will be placed on changes in flow resistance and bedload transport rates as the transition from ripples to dunes takes place. This will be achieved along a field site located on a tributary of the Ganaraska river (southern Ontario). Finally, some river reaches in southern Ontario are bedrock channels (sedimentary rocks). These bedrock channels are dominated by relatively flat sedimentary rock fragments. The evolution of rockbed streams is controlled in part by the characteristics of the exposed bedrock surfaces and how easily rock fragments can be eroded. Little is know, however, on the erodibility of these fragments. Both field and laboratory experiments will be conducted to further enhance our knowledge of flow and sediment transport processes along bedrock-controlled river reaches in southern Ontario. This program of research will contribute significantly to our knowledge of flow and sediment dynamics in both alluvial and bedrock channels. Locally, the proposed program of research will enhance our understanding of erosional problems and channel evolution along bedrock-controlled urban streams