Sediment and contaminant delivery to upland reservoirs following severe wildfire

2018年6月和7月毁灭性的沼泽野火肆虐了英格兰北部的大部分地区，这是自1976年以来最严重的泥炭地野火。与有管理的焚烧不同，严重的野火可以起到催化剂的作用，导致地表植被、土壤和径流系统发生灾难性变化。通过火灾清除植被，再加上土壤物理和化学性质的变化，增加了径流，增加了沉积物和其他污染物向排水系统的输送。尽管火灾是沼地栖息地变化的重要驱动因素，但其下游影响在很大程度上仍然未知。鉴于随着气候变化，这类野火的发生频率可能会增加，最近的2018年火灾提供了一个难得的机会，可以在事件发生后立即获取有关这些被烧毁的沼地集水区的影响和反应的新数据。在这个项目中，我们将量化燃烧后的集水区向高地水库输送的沉积物和污染物。我们将与当地土地所有者和主管当局合作，通过积极促进研究人员和土地管理者之间的知识交流，促进这些敏感流域的恢复。该项目的总体目标是量化2018年7月影响英格兰北部的严重野火后高地集水区的沉积物和污染物输送。一般的方法考虑火灾产生的“沉积物”的命运，从源头到汇，沿着高地沉积物级联，从侵蚀的沼地山坡，通过高地河道网络沉积到下游水库。我们将描述集水区内的沉积物来源，以便沉积物指纹可以用于追踪燃烧的沉积物，因为它向下游移动。绘制集水区的地图将使我们能够确定侵蚀沉积物从山坡、通过河道和进入水库的路径。通过在水库和水系中捕获沉积物的综合方法，我们将量化下游集水区侵蚀沉积物的通量（例如总量、污染物、有机、无机）。通过分析维多利亚水库中沉积的木炭层沉积物岩心，我们将重建当地火灾事件的历史。这些信息对于解决几个基本问题将是非常有价值的，这些问题包括：在严重的沼地火灾之后，集水区的侵蚀率是否会显著增加，哪些地区的风险特别大？与该地区的历史火灾记录相比，当前的火灾有多严重？通过在研究人员、当地土地所有者和修复团队之间建立明确的知识交流途径，我们将直接协助集水区从火灾的影响中恢复过来。

The devastating moorland wildfires of June and July 2018 which ravaged large parts of Northern England were the worst peatland wildfires since 1976. Severe wildfires, as distinct from managed burning, can act as a catalyst, resulting in catastrophic change in surface vegetation, soil and water runoff systems. Removal of vegetation by fire, coupled with changes to soil physical and chemical properties, enhances runoff and increases delivery of sediment and other contaminants to drainage systems. Although fire is a significant driver of change in moorland habitats the downstream impacts remain largely unknown. Given that such wildfires are likely to increase in frequency as the climate changes, the recent 2018 fires provide a rare opportunity to capture new data on the impact and response of these burnt moorland catchments in the immediate aftermath of the event. In this project we will quantify sediment and contaminant delivery to upland reservoirs from burnt catchments. We will work with local landowners and responsible authorities to promote recovery of these sensitive catchments by actively facilitating knowledge exchange between researchers and land managers. The overall objective of the project is to quantify sediment and contaminant delivery from upland catchments in the immediate aftermath of a severe wildfire which affected Northern England in July 2018. The general approach considers the fate of fire-generated 'sediment' from source-to-sink along the upland sediment cascade from eroding moorland hillslopes, through the upland channel network to deposition in downstream reservoirs. We will characterise sediment sources within the catchment so that sediment fingerprinting can be used to trace burnt sediment as it moves downstream. Mapping of the catchment will allow us to determine the pathways eroded sediment takes from the hillslopes, through the stream channels and into the reservoirs. Using a combined approach of trapping sediment in the reservoir and the stream network we will quantify the fluxes of eroded sediment (e.g. total, contaminant, organic, inorganic) from the catchment downstream. By analysing sediment cores for charcoal layers deposited in the Victorian reservoirs we will reconstruct a history of fire events in the local region. This information will be extremely valuable in addressing several fundamental questions including whether catchment erosion rates significantly increased after severe moorland fires and which areas are particularly at risk?; and how significant are the current fires in comparison to the historical record of fires in the area?. By establishing clear pathways of knowledge exchange between researchers, local landowners and restoration teams we will directly assist in the recovery of the catchments from the impacts of the fire.