Studies of fluvial sediment transport, sedimentation and river morphology

河流泥沙输送、沉积和河流形态研究

• 批准号: RGPIN-2014-06100
• 负责人: Church, Michael
• 金额: $ 2.7万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633925
• 关键词: Studies; fluvial; sediment; transport; sedimentation

The objective of the program is to understand the factors governing the development of alluvial river channels (i.e., channels self-formed in their own sediment deposits), amongst which sediment transport is paramount. Four styles of work provide complementary results and allow students freedom to select their style of work: (i) flume experiments on sediment transport and sedimentation; (ii) field measurements of sediment transport and channel geometry; (iii) long-term studies of channel response to sediment transport; and (iv) theory about river and landscape evolution. We have initiated experiments on grain sorting in bedload transport (in cooperation with the French institute IRSTEA) and on Shields’ entrainment criterion for sediment. The former entails a novel view of sediment transport as a granular phenomenon. The latter is the foundation for sediment transport theory but has remained unchallenged for 80 years. We consider the Shields number to be a bed-state parameter, not simply a grain mobility number, which entails investigating the effect of structural arrangements of sediment on the stream bed, not considered by Shields.We continue to study the response of Peace River to flow regulation in the 1960s for hydropower production, in particular to apply our developed rational regime theory to predict the new equilibrium form toward which the channel is evolving. We will also extend our field record of channel adjustment, which is now more than 40 years long, by resurveying our monumented cross sections in 2014. We will continue to study the problems of gravel influx and channel bed aggradation in lower Fraser River, which appears to be a legacy of 19th century placer mining. In particular, we are investigating the effect of cover sand transport on the estimated overall sediment budget. We have also initiated studies of suspended sediment transport in Fraser River at Mission, BC, using novel acoustic techniques and of sand transport in the distal estuarine channel. We will continue critical studies of sediment transport modelling over extended periods and distances using data from Fraser and Chilliwack rivers. The Fraser study represents an attempt to further substantiate the placer mining legacy. The Chilliwack study seeks to expand methods for physical analysis of land management outcomes beyond the scale of small drainage basins, to which it has mainly been limited. These studies are also a contribution toward understanding landscape evolution in the intermediate term between time scales of contemporary process and those of tectonic evolution, and over intermediate landscape areas (order thousands of square kilometres), important scales that have largely been neglected.Much of this work, especially on Peace and Fraser rivers, has immediate significance for river management, in the former case in relation to projected further hydropower development and in the latter in relation to flood protection. Indeed, some of the science is motivated by practical questions we have been asked to resolve in relation to these issues.

该计划的目的是了解冲积河道发展的控制因素（即，水道是在其沉积物中自行形成的），其中沉积物搬运是最重要的。四种工作方式提供了互补的结果，并允许学生自由选择自己的工作方式：（一）水槽实验泥沙输运和沉积;（二）泥沙输运和渠道几何形状的实地测量;（三）长期研究渠道对泥沙输运的响应;和（四）关于河流和景观演变的理论。我们已经开始进行推移质输运中颗粒分选的实验（与法国IRSTEA研究所合作）和希尔兹泥沙夹带标准的实验。前者需要一个新的观点，泥沙输运作为一个颗粒现象。后者是泥沙输运理论的基础，但80年来一直没有受到挑战。我们认为Shields数是一个床态参数，而不仅仅是一个颗粒流动性数，这需要调查沉积物在河床上的结构安排的影响，而不是Shields考虑的。我们继续研究和平河在20世纪60年代对水力发电流量调节的响应，特别是应用我们发展的理性政体理论来预测新的平衡形式，该渠道正在朝着这个方向发展。我们还将通过在2014年重新调查我们的纪念性横截面来延长我们的河道调整现场记录，该记录现已长达40多年。我们将继续研究弗雷泽河下游的砾石流入和河床淤积问题，这似乎是世纪砂矿开采的遗留问题。特别是，我们正在调查的影响，覆盖沙运输的估计总沉积物预算。我们还开始了在弗雷泽河的悬浮泥沙输运研究在使命，不列颠哥伦比亚省，使用新的声学技术和泥沙输运在远端河口通道。我们将继续使用弗雷泽河和奇利瓦克河的数据，对长时间和长距离的泥沙输运模型进行关键性研究。弗雷泽的研究代表了进一步证实砂矿开采遗产的一种尝试。奇利瓦克研究试图扩大对土地管理结果进行物理分析的方法，使其超越主要限于小流域的范围。这些研究也有助于理解现代过程时间尺度与构造演化时间尺度之间的过渡时期的景观演化，以及过渡景观区的景观演化（数千平方公里），重要的规模，在很大程度上被忽视。这项工作，特别是和平和弗雷泽河，对河流管理有直接的意义，在前一种情况下，与预计的进一步水电开发有关，在后一种情况下，与防洪有关。事实上，一些科学是由我们被要求解决与这些问题有关的实际问题所驱动的。