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: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567594
• 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.

该计划的目标是了解冲积河道（即在其自身沉积物中自行形成的河道）发育的控制因素，其中泥沙运输是最重要的。四种工作方式提供了互补的结果，并允许学生自由选择他们的工作方式：(i)关于泥沙运输和沉积的水槽实验；沉积物输运和河道几何形状的实地测量；（iii）长期研究河道对泥沙运移的响应；（四）河流与景观演化理论。我们已经开始进行河床输运中的谷物分选实验（与法国IRSTEA研究所合作）和谢尔兹泥沙夹带标准实验。前者需要一种新的观点，认为泥沙输运是一种颗粒状现象。后者是泥沙输运理论的基础，但80年来一直没有受到挑战。我们认为希尔兹数是一个床态参数，而不仅仅是一个颗粒迁移率数，这需要研究沉积物在河床上的结构排列的影响，而希尔兹没有考虑到这一点。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状态理论来预测通道正在演变的新的平衡形式。我们还将通过在2014年重新调查我们的纪念性横截面，延长我们已有40多年历史的渠道调整现场记录。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19世纪砂矿开采的遗留问题。特别是，我们正在研究覆盖沙输运对估计的总体泥沙收支的影响。此外，我们还利用新颖的声学技术研究了不列颠哥伦比亚省米森市弗雷泽河的悬浮泥沙输运，以及河口远端河道的泥沙输运。我们将利用弗雷泽河和奇利瓦克河的数据，继续进行长时间和长距离的沉积物运输模型的关键研究。弗雷泽的研究代表了进一步证实砂矿开采遗产的尝试。Chilliwack的研究试图将土地管理结果的物理分析方法扩展到小型流域之外，该研究主要局限于小型流域。这些研究也有助于理解在现代过程和构造演化的时间尺度之间的中间阶段的景观演变，以及在中间景观区域（以千平方公里为单位）的重要尺度，这些尺度在很大程度上被忽视了。其中大部分工作，特别是关于和平河和弗雷泽河的工作，对河流管理具有直接意义，前者与计划中的进一步水电开发有关，后者与洪水保护有关。事实上，有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推动的。