Impact of an extreme rainfall event on solute and sediment dynamics in a mineralised river system

极端降雨事件对矿化河流系统中溶质和沉积物动态的影响

• 批准号: NE/P000053/1
• 负责人: Adam Jarvis
• 金额: $ 5.28万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP000053%2F1
• 关键词: Impact; extreme; rainfall; event; solute

Over the weekend of 5 - 6 December 2015 the most intense rainfall ever recorded in the UK fell over parts of Cumbria, peaking at 341.4 mm over a 24 hour period at Honister Pass, resulting in widespread flooding. It is now widely acknowledged (e.g. statement to the media in December 2015 by Rory Stewart MP) that such 'flash flooding from intense rainfall' (FFIR) events are likely to become more frequent in the UK due to the effects of climate change. Prior to the floods of 5-6 December 2015, Newcastle University researchers spent several years measuring the effects of varying flow conditions on the amount of polluting metal and sediment discharged from the Coledale Beck, some 10 km due north of Honister Pass. These metals include zinc which is toxic to fish along with cadmium and lead that are toxic to most flora and fauna. At the head of the Coledale Beck lies the abandoned Force Crag metal mine (a rain gauge at the mine showed that 223.8 mm of rain fell in a 24 hour period during the weekend of 5-6 December 2015). A novel treatment system, completed in April 2014, treats some of the polluted water that emerges from the mine. Nevertheless, although the treatment system works efficiently, we know that some pollution of the Coledale Beck persists, mainly as a result of metals discharged to the river from other locations around the mine site. These sources arise primarily from sediments in the abandoned spoil heaps and in the river itself. The flash flooding of 5-6 December resulted in wholesale changes to the geomorphology of the Coledale Beck. Large volumes of sediment were carried down the river, whilst new sediments were exposed due to landslides and erosion. Because we already hold baseline data relating to the export of metals and sediments under different hydrological conditions from the Coledale Beck, we are uniquely positioned to now investigate how such extreme rainfall events change the whole-system dynamics of metal and sediment cycling in such upland river catchments. In particular, due to the geomorphic impacts of the December 2015 floods on the Coledale Beck system it will be possible to evaluate how exposure of new sediments influences the behaviour of metals. This is important because the form of metals in rivers (their 'partitioning') determines the readiness with which they may be carried downstream, and also influences their toxicity to the ecology of such rivers. These issues in turn have implications for users of water further downstream (e.g. fisheries, utility companies). Because hydrological extremes are likely to increase in the future as a result of climate change, we need to understand how these events change the physical and chemical characteristics of rivers, so that it is possible to plan adaptive strategies to better deal with such events. The research will be undertaken by collecting samples of waters and sediment along the length of the Coledale Beck on 10 separate occasions, thereby ensuring that samples are collected across a range of flow conditions. The results will be compared with baseline data previously collected, to determine what changes in patterns of metal and sediment movement are caused by extreme events. These results will be complemented by laboratory tests and geochemical modelling to help us assess the likely toxicity of the sediments and metals in the river to aquatic life. The intended outcome of this research will allow transfer of the results of the work to other river systems. There are 450 such rivers in England and Wales negatively impacted by abandoned mine pollution. The research is urgent because rivers are dynamic systems with key changes being driven by high magnitude events. However to properly understand the effects of flash flooding events such as that of 5-6 December 2015, it is critical to undertake sampling and analysis as soon as possible after the event itself.

在2015年12月5日至6日的周末，英国有史以来最强烈的降雨落在坎布里亚郡的部分地区，在24小时内在霍尼斯特山口达到341.4毫米的峰值，导致大范围的洪水。现在人们广泛承认（例如，2015年12月Rory Stewart MP向媒体发表的声明），由于气候变化的影响，这种“强降雨引发的山洪”（FFIR）事件可能会在英国变得更加频繁。在2015年12月5日至6日的洪水之前，纽卡斯尔大学的研究人员花了几年时间测量不同水流条件对从霍尼斯特山口以北约10公里处的Coledale Beck排放的污染金属和沉积物数量的影响。这些金属包括对鱼类有毒的锌，以及对大多数植物群有毒的镉和铅。在Coledale Beck的顶部是废弃的Force Crag金属矿（矿场的雨量计显示，2015年12月5日至6日周末期间，24小时内降雨量为223.8毫米）。2014年4月完成的一个新的处理系统处理了矿井中的部分污水。然而，尽管处理系统有效运作，但我们知道Coledale Beck的一些污染仍然存在，主要是由于矿场周围其他地点向河流排放的金属。这些来源主要来自废弃弃土堆和河流本身的沉积物。12月5日至6日的暴洪导致科莱代尔贝克的地貌发生大规模变化。大量的沉积物顺流而下，而新的沉积物由于滑坡和侵蚀而暴露出来。由于我们已经掌握了与Coledale Beck不同水文条件下金属和沉积物出口相关的基线数据，因此我们现在处于独特的位置，可以调查这种极端降雨事件如何改变这种高地河流流域中金属和沉积物循环的整个系统动态。特别是，由于2015年12月洪水对Coledale Beck系统的地貌影响，将有可能评估新沉积物的暴露如何影响金属的行为。这一点很重要，因为金属在河流中的形式（它们的“分区”）决定了它们可能被带到下游的准备程度，也影响了它们对这些河流生态的毒性。这些问题反过来又影响到下游的用水者（例如渔业、公用事业公司）。由于气候变化，水文极端事件在未来可能会增加，我们需要了解这些事件如何改变河流的物理和化学特性，以便能够规划适应性战略，更好地应对此类事件。这项研究将通过在10个不同的场合沿着Coledale Beck的长度收集沃茨和沉积物样本来进行，从而确保在各种水流条件下收集样本。这些结果将与以前收集的基线数据进行比较，以确定极端事件造成金属和沉积物移动模式的哪些变化。这些结果将得到实验室测试和地球化学建模的补充，以帮助我们评估河流中沉积物和金属对水生生物的可能毒性。这项研究的预期成果将允许将工作成果转移到其他河流系统。英格兰和威尔士有450条河流受到废弃矿山污染的负面影响。这项研究是紧迫的，因为河流是动态系统，其关键变化是由高级别事件驱动的。然而，为了正确理解2015年12月5日至6日山洪暴发事件的影响，在事件发生后尽快进行采样和分析至关重要。

项目成果

Mine water outbreak and stability risks: examples and challenges

矿井水爆发和稳定风险：实例与挑战

• 发表时间: 2016
• 作者: Mayes WM

Predicting the Benefits of Mine Water Treatment under Varying Hydrological Conditions using a Synoptic Mass Balance Approach

使用天气质量平衡方法预测不同水文条件下矿井水处理的效益

• DOI: 10.1021/acs.est.8b06047
• 发表时间: 2018
• 期刊: Environmental Science & Technology
• 影响因子: 11.4
• 作者: Jarvis A

Effect of an extreme flood event on solute transport and resilience of a mine water treatment system in a mineralised catchment.

极端洪水事件对矿化流域矿井水处理系统溶质输送和恢复能力的影响。

• DOI: 10.1016/j.scitotenv.2020.141693
• 发表时间: 2021
• 期刊: The Science of the total environment
• 作者: Mayes WM