Morphodynamics and sedimentology of the tidally-influenced fluvial zone (TIFZ)

受潮汐影响的河流带（TIFZ）的形态动力学和沉积学

• 批准号: NE/H006524/1
• 负责人: Andrew Nicholas
• 金额: $ 22.9万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH006524%2F1
• 关键词: Morphodynamics; sedimentology; tidally; influenced; fluvial

All rivers across the globe that exit to the ocean contain a zone, which can be 100s of kilometres long, which is transitional between river and tidal environments (termed here the Tidally-Influenced Fluvial Zone, or TIFZ). This zone is one of the most complex environments on the surface of the Earth because it is an area where both river flow and tidal currents are significant, and these competing forces vary daily, seasonally and annually. These regions are important to mankind and form some of the areas of highest population density: they are strategically important in the present day because these zones are at the interface of competing demands for shipping, aquaculture, land reclamation and nature conservation. Thus in order to better maintain, manage and protect these fragile zones, we must understand how and why these regions change and what factors control such change. Additionally, the sediments of ancient TIFZ's may contain significant volumes of hydrocarbons which are increasingly the target for many energy companies. For example, the Athabasca oil sands form the largest petroleum deposit on Earth and these bitumen tars are locked up with ancient TIFZ sediments. Understanding the internal nature of such TIFZ sediments is thus of paramount importance when attempting to extract the maximum quantity of oil (or gas) from such ancient hydrocarbon reservoirs - we need to know what controls the geometry and internal characteristics of these reservoirs, and thus better plan efficient and maximal hydrocarbon extraction strategies. Thus all of these interests in both modern and ancient TIFZ environments depend on a detailed knowledge of the fluid flows in these areas, how such flows transport their sediment and critically how the form (or morphology) of these environments changes through time. However, due to the extraordinary challenges of working in such a complex and dynamic environment, few high-resolution, spatially-representative, field datasets exist and remarkably little work has been undertaken on the diagnostic internal sedimentary structure of such TIFZ deposits. Additionally, whilst there has been progress on the mathematical modelling of estuarine flow and sediment transport, these models remain largely untested. There is therefore a pressing need to link the processes and deposits of the TIFZ through an integrated study of their flow, morphology and sediment movement to quantify the key processes and how these are represented within the subsurface sedimentary record. This proposal outlines an integrated field and mathematical modelling study that seeks to achieve a step-change in our understanding of the TIFZ, using the very latest techniques in field survey and mathematical modelling. These techniques will yield unrivalled high-resolution datasets of bathymetry, flow, sediment transport and sedimentary structure that will then be used to construct and validate new numerical models of the TIFZ. This will ultimately allow evaluation of key unknowns with respect to the TIFZ, such as how such environments evolve under changing scenarios of tidal and fluvial contributions associated with sea-level change, and whether it is possible to differentiate between 'fluvial' and 'tidally' influenced deposits. Such results will transform our understanding of how such TIFZ zones behave in modern environments and critically how these changes may be recognized within ancient sedimentary successions.

所有穿过地球仪流入海洋的河流都包含一个区域，该区域可以长达数百公里，是河流和潮汐环境之间的过渡区（这里称为潮汐影响河流区，或TIFZ）。这个区域是地球表面最复杂的环境之一，因为它是一个河流和潮流都很重要的区域，这些相互竞争的力量每天、季节性和每年都在变化。这些地区对人类很重要，是人口密度最高的地区之一：它们在当今具有重要的战略意义，因为这些地区处于航运、水产养殖、土地开垦和自然保护等相互竞争的需求的交界处。因此，为了更好地维护、管理和保护这些脆弱地区，我们必须了解这些地区如何和为什么发生变化，以及哪些因素控制着这种变化。此外，古TIFZ的沉积物可能含有大量的碳氢化合物，这越来越成为许多能源公司的目标。例如，阿萨巴斯卡油砂形成了地球上最大的石油存款，这些沥青焦油与古老的TIFZ沉积物锁定在一起。因此，当试图从这种古老的油气藏中提取最大量的石油（或天然气）时，了解这种TIFZ沉积物的内部性质是至关重要的-我们需要知道是什么控制着这些油气藏的几何形状和内部特征，从而更好地规划有效和最大的油气开采策略。因此，对现代和古代TIFZ环境的所有这些兴趣都取决于对这些地区流体流动的详细了解，这些流动如何运输沉积物，以及这些环境的形式（或形态）如何随时间变化。然而，由于在这样一个复杂和动态的环境中工作的非凡的挑战，很少有高分辨率，空间代表性，现场数据集存在和显着很少的工作已经进行了诊断的内部沉积结构的TIFZ存款。此外，虽然在河口水流和泥沙输运的数学模型方面取得了进展，但这些模型在很大程度上仍未经检验。因此，迫切需要通过对TIFZ的流动、形态和沉积物运动进行综合研究，将TIFZ的过程和沉积物联系起来，以量化关键过程以及这些过程如何在地下沉积记录中表现出来。该提案概述了一项综合实地和数学建模研究，旨在利用实地调查和数学建模方面的最新技术，逐步改变我们对TIFZ的理解。这些技术将产生无与伦比的高分辨率测深、水流、沉积物输运和沉积结构数据集，然后将用于构建和验证TIFZ的新数值模型。这将最终允许对TIFZ的关键未知因素进行评估，例如在与海平面变化相关的潮汐和河流贡献的变化情况下，这些环境如何演变，以及是否有可能区分“河流”和“潮汐”影响的沉积物。这些结果将改变我们对TIFZ带在现代环境中如何表现的理解，以及如何在古代沉积序列中识别这些变化。

项目成果

Alluvial architecture of mid-channel fluvial-tidal barforms: The mesotidal Lower Columbia River, Oregon/Washington, USA

河道中部河流潮汐坝形的冲积建筑：美国俄勒冈州/华盛顿州哥伦比亚河下游中潮汐区

• DOI: 10.1111/sed.12754
• 发表时间: 2020
• 期刊: Sedimentology
• 影响因子: 3.5
• 作者: Prokocki E

Hydrodynamic modelling of tidal-fluvial flows in a large river estuary

大河口潮汐河流的水动力模拟

• DOI: 10.1016/j.ecss.2018.06.023
• 发表时间: 2018
• 期刊: Estuarine, Coastal and Shelf Science
• 作者: Sandbach S

Fluvial-Tidal Sedimentology

河流潮汐沉积学

• DOI: 10.1016/b978-0-444-63529-7.00022-5
• 发表时间: 2015
• 作者: Prokocki E