Post-fire water-quality response in the western United States
Post-fire water-quality response in the western United States
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DOI：
10.1071/wf17115
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发表时间：
2018-01-01
影响因子：
3.1
通讯作者：
McCray, John
中科院分区：
文献类型：
--
作者：
Rust, Ashley J.;Hogue, Terri S.;McCray, John
美国西部森林地区野火的规模和严重程度都在增加。火灾不仅会改变地表，还会影响下游系统的地表水质量。先前对单个火灾的研究已经观察到，在火灾后的不同时期，溪水中各种形式的营养物质、离子、沉积物和金属都有所增加。在这项研究中，收集了美国西部24,000多起火灾的数据，以评估火灾后的水质反应。该数据库包括这些火灾下游的数百万个水质数据点，并与每个被烧毁的流域的地球物理数据一起合成。153个被烧毁的流域的159起火灾的数据被用来确定火灾后头5年的常见水质反应。在这个庞大的数据集中，进一步研究了七个火灾的子集，以确定水质响应的趋势。变化点分析用于确定火灾后水质数据中分析物浓度发生显著变化的时刻。对单个火灾的评估显示，初始浓度的强烈增加或减少，取决于分析物，在5年的平均时间内被掩盖。该分析的证据表明，在火灾后的头5年内，营养物通量（不同形式的氮和磷）、主要离子通量和金属浓度的显著增加是溪流水质最常见的变化。火灾后5年，大气中离子和金属溶解组分浓度呈下降趋势，而颗粒物浓度继续升高。收集这个独特而广泛的数据集提供了确定美国西部大而多样的最常见的火灾后水质变化的机会。这项研究的结果可以为世界其他地区的研究提供信息，将有助于参数化和验证火灾后的水质模型，并帮助受野火影响的社区预测其水质的变化。
Wildfires are increasing in size and severity in forested landscapes across the Western United States. Not only do fires alter land surfaces, but they also affect the surface water quality in downstream systems. Previous studies of individual fires have observed an increase in various forms of nutrients, ions, sediments and metals in stream water for different post-fire time periods. In this research, data were compiled for over 24 000 fires across the western United States to evaluate post-fire water-quality response. The database included millions of water-quality data points downstream of these fires, and was synthesised along with geophysical data from each burned watershed. Data from 159 fires in 153 burned watersheds were used to identify common water-quality response during the first 5 years after a fire. Within this large dataset, a subset of seven fires was examined further to identify trends in water-quality response. Change-point analysis was used to identify moments in the post-fire water-quality data where significant shifts in analyte concentrations occurred. Evaluating individual fires revealed strong initial increases or decreases in concentrations, depending on the analyte, that are masked when averaged over 5 years. Evidence from this analysis shows significant increases in nutrient flux (different forms of nitrogen and phosphorus), major-ion flux and metal concentrations are the most common changes in stream water quality within the first 5 years after fire. Dissolved constituents of ions and metals tended to decrease in concentration 5 years after fire whereas particulate matter concentration continued to increase. Assembling this unique and extensive dataset provided the opportunity to determine the most common post-fire water-quality changes in the large and diverse Western USA. Results from this study could inform studies in other parts of the world, will help parameterise and validate post-fire water-quality models, and assist communities affected by wildfire to anticipate changes to their water quality.