Fire and water: predicting and mitigating water pollution risk from wildfire ash

每年植被火灾（野火和管理烧伤）都会影响全球约4%的植被地表。这包括森林、草地或泥炭地，它们为世界上最大的100个城市提供了60%的供水，为英国70%的人口提供了供水。在英格兰，114平方公里的高地仅受到管理烧伤的影响，英国消防和救援服务每年处理70，000多起植被火灾。植被火灾可能对水质产生严重影响，再加上世界许多地区目前和预计未来淡水供应进一步减少和火灾风险增加，人们越来越关注火灾造成的水污染风险。主要的威胁是火灾留下的灰烬，这些灰烬很容易通过水侵蚀进入水体。火山灰通常富含污染物，近年来，火山灰转移到供水集水区导致了许多饮用水限制和大量处理费用（例如，贝尔法斯特、堪培拉、丹佛、麦克默里堡、悉尼）。在英国，植被火灾给水务行业造成的损失估计为1600万英镑。每一年。科学家和土地管理者广泛使用模型来预测诸如收割或野火等干扰事件后的土壤侵蚀或洪水风险，然而，目前还没有模型可以预测火灾后的灰烬运输和相关的水污染风险。知识和资源方面的这一差距严重损害了土地管理人员的能力，使他们无法预测火灾造成的水污染风险，也无法实施有效的缓解措施，以减少火灾风险，防止火灾后的侵蚀，并调整水处理能力。这个及时的项目汇集了来自英国，美国和澳大利亚的国际专家组成的跨学科团队，旨在解决这一关键知识和工具的差距。基于这一领域的最新进展和概念验证工作，我们现在能够（i）获得关于野火灰烬传输过程及其污染潜力的关键基础知识，并利用这些知识（B）开发第一个最终用户概率模型，该模型可以预测灰烬传输和相关的水文网络水污染风险。该模型将验证关键的火灾易发和火灾管理的土地覆盖类型，遭受了严重的灰引起的水污染事件在过去（包括英国高地，美国针叶林和澳大利亚桉树林）使用的第一个现场数据集灰运输参数水蚀和广泛的数据集灰通过本项目获得的潜在污染这些关键地区。为了最大限度地发挥该项目的影响，将与土地和集水管理部门的用户合作开发网络模型，并将其提供给这些用户，以支持有效保护水生生态系统和饮用水供应，使其免受火山灰污染。

Every year vegetation fires (wildfires and management burns) affect ~4% of the global vegetated land surface. This includes forests, grasslands or peatlands, which provide 60% of the water supply for the world's largest 100 cities and for 70% of for the UK's population. In England 114 km2 of uplands are affected by management burns alone and the UK Fire and Rescue Services attend to over 70,000 vegetation fires per year. Vegetation fires can have serious impacts on water quality, which, combined with the current and projected future further decline in fresh water availability and increase in fire risk in many regions around the world, has given rise to increased attention to water contamination risks from fire. The primary threat is ash left behind by fire, which can be transported very easily into water bodies by water erosion. Ash is typically rich in contaminants and its transfer into water supply catchments has led to numerous drinking-water restrictions and substantial treatments costs in recent years (e.g. for Belfast, Canberra, Denver, Fort McMurray, Sydney). In the UK, losses to the water industry from vegetation fires are estimated at £16 Mill. per year. Models are widely used by scientists and land managers to predict soil erosion or flood risks after disturbance events such as harvesting or wildfire, however, no models currently exist that allow predicting of ash transport and associated water contamination risk following fire. This gap in knowledge and resource seriously compromises the ability of land managers to anticipate water contamination risks from fire and to implement effective mitigation treatments to reduce fire risk, prevent erosion after fire and, adjust water treatment capabilities. This timely project brings together an interdisciplinary team of international experts from the UK, USA and Australia with the aim to address this critical knowledge and tools gap. Building on recent advances and proof-of-concept work in this field, we are now able to (i) obtain critical fundamental knowledge on wildfire ash transport processes and its contamination potential and, using this knowledge, to (b) develop the first end-user probabilistic model that allows predicting ash delivery and associated water contamination risk to the hydrological network. The model will be validated for key fire-prone and fire-managed land cover types that have suffered critical ash-induced water pollution events in the past (including UK uplands, US conifer forest and Australian eucalyptus forest) using the first field dataset on ash transport parameters by water erosion and an extensive dataset on potential contamination by ash obtained through this project for these key regions. To maximize the impact of the project, the web-based model will developed in collaboration with, and be made available to, users from land and catchment management sectors to support effective protection of aquatic ecosystems and drinking water supply from contamination by ash.