Tracking sediment waves through Himalayan fluvial cascades following extreme mass flows

跟踪极端质量流后穿过喜马拉雅河流瀑布的沉积物波

• 批准号: NE/Y002911/1
• 负责人: Matthew Westoby
• 金额: $ 10.87万
• 依托单位: Plymouth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FY002911%2F1
• 关键词: Tracking; sediment; waves; through; Himalayan

Mountain landscapes experience sudden and violent geohazards, such as landslides, lake outburst floods, and debris flows. The size and frequency of such events is anticipated to increase due to climate change, enhancing landscape instability. These landscapes are also experiencing rapid population growth, directly exposing people and assets to geohazards, but also exposing them to legacy impacts which manifest after an event and are commonly overlooked and unquantified. A legacy impact of many mountain geohazards is enhanced coarse sediment transport in rivers. This is a problem because sediment travelling as 'bedload' is the primary driver of river channel adjustment. These adjustments affect: 1) flood hazard, by modifying channel bed elevation; 2) the integrity of riparian infrastructure, e.g. hydropower, by blocking intakes and rapidly filling reservoirs, and 3) fluvial ecology, by reorganising channel substrate. It is therefore vital to generate well-constrained knowledge of the pace and manner in which the bedload transport regime evolves in mountain rivers after extreme disturbances. However, due to technical limitations and challenges associated with working in unstable, post-flood landscapes, we have little first-hand information on the behaviour of such systems, which this project aims to address.This new project will consolidate a new international partnership of leading researchers from the UK and India. The team is led by the University of Plymouth, working in close collaboration with the Indian Institute of Technology Roorkee (IITR) and the Wadia Institute of Himalayan Geology (WIHG), the University of Exeter, and Newcastle University. The diverse team bring complementary expertise in geomorphology, hydrology, and environmental sensor networks, and the work would not be possible without the regional knowledge, technical competencies, and field experience of the international partners. The project also features prominent early- and early-to-mid-career researchers in leading roles. Working together we will apply a suite of innovative environmental monitoring and modelling tools to characterise the hydrological and bedload transport regime of the Alaknanda river, Uttarakhand, India, which experienced an extreme debris flow in February 2021 which killed >200 people and triggered enhanced sediment transport as a legacy impact, evidenced through pilot work.To achieve our aim, we will: 1) Develop a new hydrological model of the Alaknanda catchment, enabling us to identify and disentangle the key components of flow (e.g. snowmelt, rainfall). This information will be used to better understand the hydrological drivers of sediment transport; 2) Quantify the grain size characteristics of channel bars using drone- and satellite-based observations and modelling. This information will allow us to explore downstream transitions in grain size through time and examine the influence of the Chamoli event; 3) Deploy innovative, low-cost 'smart' tags to track the motion of cobbles and boulders travelling as bedload. We will supplement these data with measurements of the timing and relative magnitude of bedload transport using low-cost passive seismics. We will effect skills and knowledge transfer in-person via joint fieldwork and discussions at IITR and WIHG), and a regular series of virtual project meetings and seminars. We will publish results in peer-reviewed open-access journals and will produce a technical summary report which we will disseminate to local stakeholders. Project success will lead to future joint funding bids which will appraise the role of hydropower as a disruptor to coarse sediment transport in mountain rivers and explore operational practices that can mitigate the immediate and legacy impacts of extreme floods. In doing so we will further consolidate a wider research network involving regional academics and practitioners, whilst supporting the development of early career researchers in both countries.

山地景观经历了突然而剧烈的地灾，例如滑坡，湖爆发洪水和碎屑流。由于气候变化，预计此类事件的大小和频率将增加，从而增强了景观的不稳定。这些景观也正在经历人口的迅速增长，直接使人们和资产暴露于地球扎下，但也将它们暴露于遗产影响下，这些影响在事件发生后体现出来，并且通常被忽视和未经量化。许多山地地球岩的遗产影响是河流中的粗糙沉积物运输增强。这是一个问题，因为作为“床上”的沉积物是河道调整的主要驱动力。这些调整会影响：1）通过修改通道床高程，洪水危害； 2）河岸基础设施的完整性，例如水力发电，通过阻止摄入量并快速填充储层，以及3）河流生态学，通过重组通道基板。因此，至关重要的是，对床负载运输方式在极端干扰后在山河中演变的步伐和方式有充分约束的知识至关重要。但是，由于与在不稳定的洪水后景观中工作相关的技术局限性和挑战，我们几乎没有有关此类系统行为的第一手信息，该项目旨在解决这些行为。该新项目将巩固来自英国和印度的主要领先研究人员的新国际伙伴关系。该团队由普利茅斯大学（University of Plymouth）领导，与印度理工学院Roorkee（IITR）和瓦迪亚喜马拉雅地质学院（WIHG），埃克塞特大学和纽卡斯尔大学密切合作。多元化的团队带来了地貌，水文学和环境传感器网络方面的互补专业知识，如果没有国际合作伙伴的区域知识，技术能力和现场经验，这项工作将是不可能的。该项目还以领导角色的早期和早期研究人员为特色。我们将共同努力，我们将应用一套创新的环境监控和建模工具来表征印度北阿坎德邦阿拉克南达河的水文和床负载运输方式，这些机构在2021年2月在2021年2月经历了极端的碎屑流动，杀死了200人> 200人，并触发了增强的沉积物运输，这是一种遗产的影响，通过飞行员的发展，我们将为我们的AIL AIL AIN提供了成功。使我们能够识别并解开流量的关键组成部分（例如，融雪，降雨）。这些信息将用于更好地了解沉积物传输的水文驱动因素； 2）使用基于卫星和卫星的观测值和建模来量化通道条的晶粒尺寸特性。这些信息将使我们能够通过时间探索晶粒大小的下游过渡，并检查Chamoli事件的影响； 3）部署创新的低成本“智能”标签，以跟踪鹅卵石和巨石作为卧床的运动。我们将使用低成本的被动地震学来测量床载运输的时机和相对幅度。我们将通过IITR和WIHG的联合现场工作和讨论以及定期的一系列虚拟项目会议和研讨会来实现技能和知识转移。我们将在经过同行评审的开放访问期刊中发布结果，并将制定一份技术摘要报告，我们将向当地利益相关者传播。项目成功将导致未来的共同资助投标，这将评估水力发电作为山河中粗泥沙运输的破坏者的作用，并探索可以减轻极端洪水的直接和遗产影响的运营实践。通过这样做，我们将进一步巩固涉及区域学者和从业人员的更广泛的研究网络，同时支持两国早期职业研究人员的发展。