River dynamics and resilience of fluvial systems in perturbed environments

扰动环境中河流动力学和河流系统的恢复力

• 批准号: RGPIN-2016-05466
• 负责人: Biron, Pascale
• 金额: $ 2.91万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=688005
• 关键词: River; dynamics; resilience; fluvial; systems

River systems are under considerable pressure due to human impacts and global environmental changes. It is increasingly recognized that river management approaches must move away from hard-engineering structures that maintain rivers in a fixed position. Instead, an approach based on freedom space for rivers, which integrates more natural processes such as meander dynamics and floodplain connectivity, should lead to more resilient systems, particularly in a climate change context. The long-term objective of the research program is to test how freedom space for rivers may or may not modify the long-term condition of fluvial systems under various environmental perturbations. Environmental perturbations that are specifically examined are reduced lateral mobility of streams resulting from heavy bank stabilization associated with protection of infrastructure, river straightening and dredging in agricultural streams, and climate change resulting in more frequent flash floods in tributary watersheds. The long-term objective will be reached through the combination of and interactions between numerical modelling and field experimentation. The short-term objectives are to 1) develop tools to characterize river reaches that are more vulnerable to discharge variability in order to estimate where it is most effective to provide more space for natural river processes to operate in fluvial systems; 2) examine the applicability of management approaches which incorporate hydrogeomorphological concepts for straightened and dredged streams in agricultural watersheds in the Quebec context; and 3) assess the role of increased flash floods in small tributary watersheds on the confluence zone and on the mobility of the main channel. The scientific approach of this research program is based on the collection of field data at several river reaches that are affected by human perturbations. Field measurements include detailed bed topography, surface and sub-surface grain size, bedload transport, velocity, turbidity, stage and discharge. The field component is combined with Geographical Information System (GIS) analysis and numerical modelling experiments. Hydrogeomorphological GIS tools recently developed in my research laboratory, making use of the increased availability of fine-resolution LiDAR Digital Elevation Models (DEMs), will be further developed to help characterize both main branches and tributary channels in specific watersheds in terms of stream power and vulnerability to the anticipated increase in discharge variability in future climate. This program will allow significant progress in establishing an expertise in river management based on hydrogeomorphological concepts to tackle major environmental problems in a range of rivers, and on developing GIS and modelling tools to better inform river managers about vulnerable river reaches in a climate change context.

由于人类影响和全球环境变化，河流系统承受着相当大的压力。人们越来越认识到，河流管理方法必须摆脱将河流维持在固定位置的硬工程结构。相反，基于河流自由空间的方法整合了更多的自然过程，例如曲流动力学和洪泛区连通性，应该会带来更具弹性的系统，特别是在气候变化的背景下。该研究计划的长期目标是测试河流的自由空间可能或可能不会改变各种环境扰动下河流系统的长期状况。特别检查的环境扰动包括河流横向流动性的降低，这是由于与基础设施保护、河流矫直和疏浚农业溪流相关的严重河岸稳定性以及气候变化导致支流流域发生更频繁的山洪而导致的。长期目标将通过数值模拟和现场实验的结合和相互作用来实现。短期目标是 1) 开发工具来描述更容易受到流量变化影响的河流河段，以估计在河流系统中为自然河流过程提供更多空间最有效的地方； 2) 审查魁北克省农业流域中纳入水文地貌概念的管理方法的适用性； 3) 评估小支流流域山洪暴发增加对汇流区和主河道流动性的影响。该研究计划的科学方法基于在受人类干扰影响的几个河流河段收集现场数据。现场测量包括详细的河床地形、地表和地下颗粒尺寸、河床输送、速度、浊度、阶段和流量。现场组件与地理信息系统（GIS）分析和数值建模实验相结合。我的研究实验室最近开发了水文地貌 GIS 工具，利用高分辨率 LiDAR 数字高程模型 (DEM) 的可用性不断提高，将得到进一步开发，以帮助描述特定流域的主要支流和支流河道的河流功率和支流特征。未来气候中排放量变化预期增加的脆弱性。该计划将在建立基于水文地貌概念的河流管理专业知识方面取得重大进展，以解决一系列河流的主要环境问题，并在开发地理信息系统和建模工具方面取得重大进展，以便更好地向河流管理者通报气候变化背景下脆弱的河段。