Bugs in engineering? Understanding the transport of cohesive sediment in aquatic systems

计算机正越来越多地被用来帮助预测拟议中的基础设施项目对环境的影响，如拆除水坝或建造桥梁。 然而，计算机建模的有用性仍然受到我们对自然系统如何工作的理解以及我们如何用数字表示自然的知识和经验的限制。水动力和泥沙输运模型是更好地了解水动力环境（水流速度、方向等）以及河道物质的侵蚀和沉积。 拟议的研究旨在进一步了解Petitcodiac河口附近的Shepody湾生物丰富的泥滩的动态侵蚀特性。 这些泥滩被认为是国际上的重要地点，因为每年有超过200万只候鸟来到这里，享用丰富的泥虾。 Petitcodiac河堤道的拟议部分开放将增加河口内的潮汐能，并可能对泥滩产生影响;该网站将被用作案例研究，以支持研究。 以前尝试数值模拟堤道的开放没有考虑生物有机体的侵蚀或堤道下游的泥滩建设的存在。 因此，环境保护规划的作用有限。 拟议的研究有两个组成部分：1）调查大型生物的存在对粘性河口沉积物侵蚀速率的影响; 2）推进预测性输运模型的发展，以模拟细粘性沉积物的侵蚀和命运，特别是将生物有机体的存在的影响。 这项研究将增强我们对这些过程的理解，从而建立一个更全面、更准确的模型，更好地支持决策者和规划者。

More and more, computers are being used to help predict the environmental impacts of proposed infrastructure projects, such as the removal of dams or the building of bridges.  However, the usefulness of computer modelling is still limited by our understanding of how natural systems work and our knowledge and experience with how to represent nature with numbers. Hydrodynamic and sediment transport modelling is a powerful tool to better understand the relationship between the hydrodynamic environment (water velocity, direction, etc.) and the erosion and deposition of material from a river channel.       The proposed research seeks to further the understanding of the dynamic erosional properties of biologically-rich mudflats in Shepody Bay near the Petitcodiac River Estuary.  These mudflats are considered as important sites internationally, as they are visited every year by more than two million migratory birds that feast on the abundant mudshrimp.  The proposed partial opening of the Petitcodiac River causeway will increase the tidal energy within the estuary and may have impacts on the mudflats; this site will be used as a case study to support the research.  Previous attempts to numerically model the opening of the causeway have not considered the presence of biological organisms on the eroding or building-up of mudflats downstream of the causeway.  As a result, there is a limit to the usefulness for environmental protection planning.   The proposed research has two components: 1) to investigate the impact of the presence of macro-organisms on the erosion rate of cohesive estuarine sediments; 2) to advance the development of predictive transport models for simulating the erosion and fate of fine cohesive sediments, and in particular incorporate the impact of the presence of biological organisms.  The research will enhance our understanding of these processes, leading to a more comprehensive and accurate model that can better support decision makers and planners.