Modelling flow and inorganic nitrogen dynamics on the Hampshire Avon: Linking upstream processes to downstream water quality.
Modelling flow and inorganic nitrogen dynamics on the Hampshire Avon: Linking upstream processes to downstream water quality.
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DOI：
10.1016/j.scitotenv.2016.02.156
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发表时间：
2016-12
期刊：
影响因子：
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通讯作者：
Li Jin;P. Whitehead;C. Heppell;K. Lansdown;D. Purdie;M. Trimmer
中科院分区：
文献类型：
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作者：
Li Jin;P. Whitehead;C. Heppell;K. Lansdown;D. Purdie;M. Trimmer
管理集水区的扩散污染是环境管理人员计划达到水质标准和遵守欧盟水框架指令的一个主要问题。扩散污染的一个主要来源是氮，高硝酸盐浓度影响供水和河流生态。一个动态的，基于过程的流量，硝酸盐和铵（INCA-N）模型已被应用到汉普郡埃文作为NERC宏量营养素循环计划的一部分，连接上游和下游的水化学测量。该模型已被校准和验证对环境署的排放和溶质化学数据，以及从河流站点的河口潮限上游收集的数据集。在六个站点的反硝化上游测量已被用来评估在植被和非植被条件下的硝酸盐去除率。结果表明，植被下的沉积物与显着更高的硝酸盐去除率比无植被的沉积物（平均增加245%）。这些数据已被用于扩大硝酸盐损失率到整个流域规模，并已通过模型实施。河床地质和水生植物覆盖对流域尺度氮动态的影响进行了探讨，并评估了进入河口的营养盐通量。该模型是用来测试的战略，氮减少使用硝酸盐脆弱区（NVZ）的方法进行评估。这表明，硝酸盐和铵浓度可以在10年内降低10%，氮水平可以达到更低的水平，但需要很长一段时间。
Managing diffuse pollution in catchments is a major issue for environmental managers planning to meet water quality standards and comply with the EU Water Framework Directive. A major source of diffuse pollution is from nitrogen, with high nitrate concentrations affecting water supplies and in-stream ecology. A dynamic, process based model of flow, nitrate and ammonium (INCA-N) has been applied to the Hampshire Avon as part of the NERC Macronutrient Cycles Programme to link upstream and downstream measurements of water chemistry. The model has been calibrated and validated against Environment Agency discharge and solute chemistry data, as well as a data set collected from a river site immediately upstream of the estuary tidal limit. Upstream measurements of denitrification at six sites have been used to evaluate nitrate removal rates in vegetated and non-vegetated conditions. Results show that sediments underlying vegetation were associated with significantly higher rates of nitrate removal than un-vegetated sediments (with an average increase of 245%). These data have been used to scale up rates of nitrate loss to the whole catchment scale and have been implemented via the model. The effects of streambed geology and macrophyte cover on catchment-scale nitrogen dynamics are explored and nutrient fluxes entering the estuary are evaluated. The model is used to test a strategy for nitrogen reduction assessed using a nitrate vulnerable zone (NVZ) methodology. It suggests that nitrate and ammonium concentrations could be reduced by 10% in 10 years and much lower nitrogen level can be achieved but only over a long time period.