Headwater stream quality for Britain

Data consist of modelled estimates of observed/expected Biological Monitoring Working Party (an index for measuring the biological quality of rivers using selected families of macroinvertebrates as biological indicators) scores for freshwater streams across Great Britain (GB). The BMWP scores (1-10) are based on the principle that macroinvertebrates differ in their perceived sensitivity or tolerance to organic pollution (i.e. nutrient enrichment). Values greater than 1 indicate high water quality. Data pooled across two survey years (1998 and 2007) was used to model the relationships between headwater stream quality and catchment/stream characteristics for headwater streams across GB based on known relationships for headwater streams in Countryside Survey squares. Modelled estimates of stream water quality were based on a Boosted Regression Tree modelling approach .

本数据集包含英国（Great Britain，GB）全境淡水溪流的观测/预期生物监测工作组(Biological Monitoring Working Party，BMWP)评分的模型估算值。该指数以特定类群的大型无脊椎动物作为生物指示物，用于评估河流的生物质量。BMWP评分区间为1至10分，其构建原理基于大型无脊椎动物对有机污染（即营养物富集）的感知敏感性与耐受性存在差异这一原则，评分高于1分代表水体质量较高。研究团队整合了1998年与2007年两次调查的汇总数据，依托英国乡村调查样方内源头溪流的已知关联规律，针对英国全境的源头溪流构建了其水质与集水区/溪流特征之间的关联模型。本数据集的溪流水质模型估算值采用提升回归树(Boosted Regression Tree，BRT)建模方法生成。