Sediment delivery to the Fraser River Delta; sediment transport mechanisms and modeling framework

这项研究计划的目的是促进我们对沙层河道力学的了解，特别是开发基于物理的预测工具，以预测沉积物如何在海洋中的源头和最终下沉之间移动。该计划旨在将弗雷泽河下游的沙床河段作为一个天然实验室来调查和量化过程。弗雷泽还将作为SFU新的景观动力学实验室进行更详细观测的原型，最终将产生一个基于物理的沙层河流，特别是弗雷泽河的地貌动力学预测模型。目前，关于有多少泥沙进入弗雷泽河的砂层河段，有多少泥沙被沉积在弗雷泽三角洲和潮滩上，人们已经有了一些了解，但负责通过不列颠哥伦比亚省下大陆85公里河段的泥沙移动的机制仅在概念上被理解。河流中泥沙的动态控制对洪水的响应，以及河道、三角洲和潮滩环境中的栖息地质量。需要一个基于物理的泥沙输送模型，以可靠地预测沙层河道和三角洲环境将如何应对各种扰动(即气候变暖、水通量的变化、与土地利用做法有关的泥沙通量的变化以及海平面的当代变化)。迫切需要对流入大海的沙床河流(如弗雷泽河下游)的泥沙输送进行预测，因为这些河流往往是世界各地密集的城市发展地点，这些自然景观过程的动态对这种发展的社会经济可行性有重大影响。

The objective of this research program is to advance our knowledge of the mechanics of sand-bedded river channels and, in particular, to develop physically-based predictive tools for how sediments move between their source and ultimate sink in the ocean. The program is designed to use the sand-bedded reach of the lower Fraser River as a natural laboratory to investigate and quantify processes. The Fraser also will serve as a prototype for more detailed observations in SFU's new Landscape Dynamics Laboratory that will ultimately lead to a physically-based predictive model for the morphodynamics of sand-bedded river channels, and the Fraser River in particular. At present, there is some understanding of how much sediment is moving into the sand-bedded reach of the Fraser River and how much is being deposited on the Fraser's delta and tidal flats, yet the mechanisms responsible for moving sediment through the 85 km river reach that passes through British Columbia's Lower Mainland is understood only conceptually. The dynamics of sediment in the river control response to flood flows and the quality of habitat in the channel, delta, and tidal flat environments. A physically-based model for sediment routing is required to make reliable predictions of how the sand-bedded channel and the delta environments will respond to various perturbations (i.e. a warmer climate, changes in water flux, changes in sediment flux associated with land use practices, and contemporary variation in sea level). There is a pressing need to make predictions of sediment transport in sand-bedded rivers that empty into the sea, such as the lower Fraser River, because they are often sites of intense urban development world-wide and the dynamics of these natural landscape processes significantly affect the socio-economic viability of this development.