Impacts of extreme flooding on physical habitats and flood risk management

极端洪水对自然栖息地和洪水风险管理的影响

• 批准号: NE/I002219/1
• 负责人: David Sear
• 金额: $ 6.16万
• 依托单位: University of Southampton
• 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%2FI002219%2F1
• 关键词: Impacts; extreme; flooding; physical; habitats

Destructive river floods, like the ones in Cumbria in late 2009, are important to forecast because of their economic and social impacts, but are also important to understand from the viewpoint of how they create new physical habitats and river channels. Whilst recent reports rightly concentrate on the immediate damaging impacts of extreme flooding, less information is available about the long term impacts of changes in river channel. The latter is important for two reasons. First, large economic costs can often result from changes in flood channel maintenance necessitated by post-flood channel adjustments. Second, and in contrast, there may actually be benefits arising from changes to physical habitats and river channels which may lessen subsequent flood risk. This is accepted within a raft of legislation whereby European (and US) river managers are required to restore and enhance river channels to meet stringent ecological standards. In this sense, our current knowledge of the benefits resulting from extreme flooding is poor. Thus one strand of our proposed research will analyse the changes in habitat and channels that were caused by the extreme floods in Cumbria in late 2009. Current river restoration methods are both spatially limited and expensive, but we aim to demonstrate that extreme floods can provide substantial changes in physical habitats and have the potential to deliver channel-scale restoration as demanded by regulators. Extreme floods are forecast to become more frequent under a range of climate and land use scenarios in the UK and elsewhere. But there is a lack of knowledge about the frequency, or return time, of extreme floods because monitored records of river flooding are often relatively short. A second strand of our research therefore takes the opportunity to find the signal of the recent extreme Cumbrian floods in the recent lake sediments accumulating at the bed of lake Bassenthwaite. If the recent flood signal can be clearly established, earlier 20th/21st century floods can be identified in lower sediments and confirmed by flood records. Deeper sediments can then be analysed to provide a regional record of flood frequencies and their sizes over several centuries. From these data, we can then say more about how common extreme floods are when viewed over centuries and whether the floods are becoming more or less common during the major periods of climate chnage and human activitiessince the early 20th century. Our project will collect field data from sites in and downstream of lake Bassenthwaite that were seriously affected by recent flooding in Cumbria. The research will impact directly on assessing appropriate post-flood management of floodplains and channel, and on the strategic assessment of the likelihood of future extreme flooding - both to the benefit of many stakeholders including local residents and farmers, the Environment Agency, DEFRA and a large international academic community.

破坏性的河流洪水，如2009年底坎布里亚郡的洪水，由于其经济和社会影响，预测很重要，但从它们如何创造新的物理栖息地和河道的角度来理解也很重要。虽然最近的报告正确地集中在极端洪水的直接破坏性影响，但有关河道变化的长期影响的信息较少。后者之所以重要，有两个原因。首先，大的经济成本往往会导致洪水后的渠道调整所必需的洪水渠道维护的变化。第二，与此相反，改变自然生境和河道实际上可能带来好处，这可能会减少随后的洪水风险。这是在一系列立法中被接受的，欧洲（和美国）的河流管理者被要求恢复和改善河道，以满足严格的生态标准。从这个意义上说，我们目前对极端洪水带来的好处的了解是贫乏的。因此，我们提出的研究的一个环节将分析2009年底坎布里亚郡极端洪水造成的栖息地和渠道的变化。目前的河流恢复方法在空间上是有限的和昂贵的，但我们的目标是证明，极端洪水可以提供物理栖息地的实质性变化，并有可能提供通道规模的恢复监管机构的要求。据预测，在英国和其他地方的一系列气候和土地利用情景下，极端洪水将变得更加频繁。但人们对极端洪水的频率或重现时间缺乏了解，因为河流洪水的监测记录往往相对较短。因此，我们研究的第二部分抓住机会，在巴森斯韦特湖床最近积累的湖泊沉积物中找到最近坎布里亚特大洪水的信号。如果能够清楚地确定最近的洪水信号，则可以在较低的沉积物中识别出20/21世纪世纪早期的洪水，并通过洪水记录加以证实。然后可以分析更深的沉积物，以提供几个世纪以来洪水频率及其规模的区域记录。从这些数据中，我们可以更多地了解几个世纪以来极端洪水的普遍程度，以及自世纪以来，洪水在气候变化和人类活动的主要时期是否变得越来越普遍。我们的项目将收集现场数据和下游的巴森斯韦特湖受到严重影响，最近在坎布里亚郡的洪水。该研究将直接影响评估洪泛区和渠道的适当洪水后管理，以及对未来极端洪水可能性的战略评估-这两个利益相关者包括当地居民和农民，环境局，DEFRA和大型国际学术界。

项目成果

Assessing the reliability of probabilistic flood inundation model predictions Reliability of Probabilistic Flood Inundation Predictions

评估概率洪水淹没模型预测的可靠性 概率洪水淹没预测的可靠性

• DOI: 10.1002/hyp.10451
• 发表时间: 2015
• 期刊: Hydrological Processes
• 影响因子: 3.2
• 作者: Stephens E

Sensitivity of a hydraulic model to channel erosion uncertainty during extreme flooding SENSITIVITY OF A HYDRAULIC MODEL TO CHANNEL EROSION UNCERTAINTY

极端洪水期间水力模型对河道侵蚀不确定性的敏感性 水力模型对河道侵蚀不确定性的敏感性

• DOI: 10.1002/hyp.10148
• 发表时间: 2015
• 期刊: Hydrological Processes
• 影响因子: 3.2
• 作者: Wong J

Using lake sediment archives to improve understanding of flood magnitude and frequency: Recent extreme flooding in northwest UK

• DOI: 10.1002/esp.4650
• 发表时间: 2019-06
• 期刊: Earth Surface Processes and Landforms
• 影响因子: 3.3
• 作者: R. Chiverrell;D. Sear;J. Warburton;N. Macdonald;D. Schillereff;J. Dearing;I. Croudace;J. Brown;J. Bradley