During a winter of storms in a small UK catchment, hydrology and water quality responses follow a clear rural-urban gradient
During a winter of storms in a small UK catchment, hydrology and water quality responses follow a clear rural-urban gradient
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DOI：
10.1016/j.jhydrol.2016.12.037
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发表时间：
2017-02
影响因子：
6.4
通讯作者：
S. McGrane;M. Hutchins;James Miller;G. Bussi;T. Kjeldsen;M. Loewenthal
中科院分区：
文献类型：
--
作者：
S. McGrane;M. Hutchins;James Miller;G. Bussi;T. Kjeldsen;M. Loewenthal
本文介绍了水文和水质响应，从一系列的极端风暴事件，通过整个英国在冬季的2013/2014年，在一个实验集水区，在四个嵌套的子集水区具有很强的城乡梯度。在英国泰晤士河流域上游的射线集水区，广泛监测使用原位，高分辨率（15分钟）流量和水质仪器。采用溶解氧、氨氮、浊度和电导率等指标来表征水质动态。斯温登污水处理厂对集水区出口水质化学的影响相当大。水文和水质响应在事件期间变化很大，农村集水区表现出比城市地区慢得多的水文响应。一个简单的水文模型（TETIS）的开发，以提供深入了解嵌套子集水区的水源，突出对比的土地利用在事件期间的水文动态的差异。雨水径流源的变化影响水质信号与城市站点的稀释动态铵，而更多的农村网站的经验在同一事件中的铵的峰值。溶解氧浓度随城乡梯度变化，在事件发生期间，在Water Eaton出口（4.4 mg/l）出现明显下降，如果在夏季温度较高的情况下发生，将导致重大的生态危害。在水文年的更广泛背景下，这些风暴的水质影响可以忽略不计，2014年夏季观测到的水质信号明显较差。虽然铵浓度在事件期间升高（高于“良好”状态阈值下的WFD），较高的值在春季和夏季观察到。高流量实际上似乎冲洗污染物的射线及其子集水区，虽然城市网站表现出再补给动态在临时干旱期间。数据表明，冬季风暴后，在城市集水区干旱造成一些短暂的和空间广泛的水质恶化。更多的慢性影响，虽然延长，只看到下游的污水处理厂。这些都表明基础设施的能力正在达到，从数据来看，似乎没有严重到足以造成生态损害。
This paper presents the hydrological and water quality response from a series of extreme storm events that passed across the UK during the winter of 2013/2014, in an experimental catchment with a strong rural-urban gradient across four nested sub-catchment areas. The Ray catchment in the upper Thames basin, UK, was extensively monitored using in-situ, high-resolution (15 min) flow and water quality instrumentation. Dissolved oxygen, ammonium, turbidity and specific conductivity are used to characterise the water quality dynamics. The impact of the Swindon sewage treatment works (SSTW) on water chemistry at the catchment outlet is considerable. Hydrological and water-quality response varies considerably during the events, with the rural catchments exhibiting a much slower hydrological response compared to urban areas. A simple hydrological model (TETIS) was developed to provide insight into water sources in nested subcatchments, highlighting the disparity of the hydrological dynamics across contrasting land-uses during events. The variation in stormwater runoff sources impacts water quality signals with urban sites contributing to dilution dynamics in ammonium, whereas the more rural site experiences a peak in ammonium during the same event. Dissolved oxygen concentrations vary on a rural-urban gradient and experience a notable sag at the Water Eaton outlet (4.4 mg/l) during the events, that would have resulted in significant ecological harm had they occurred during the summer in warmer temperatures. The water-quality legacy of these storms in the wider context of the hydrological year is somewhat negligible, with markedly poorer water quality signals being observed during the summer months of 2014. Although ammonium concentrations during the events are elevated (above the ‘good’ status threshold under the WFD), higher values are observed during spring and summer months. The high flows actually appear to flush contaminants out of the Ray and its subcatchments, though the urban sites demonstrate a resupply dynamic during interim dry periods. Data suggest winter storms following dry spells in urban catchments cause some short-lived and spatially extensive deteriorations in water quality. More chronic effects, although prolonged, are only seen downstream of SSTW. These are indicative of capacity of infrastructure being reached, and from the data do not appear to be severe enough to cause ecological harm.