High-frequency water quality monitoring in an urban catchment: hydrochemical dynamics, primary production and implications for the Water Framework Directive
High-frequency water quality monitoring in an urban catchment: hydrochemical dynamics, primary production and implications for the Water Framework Directive
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DOI：
10.1002/hyp.10453
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发表时间：
2015-07-15
影响因子：
3.2
通讯作者：
Jarvie, Helen P.
中科院分区：
文献类型：
--
作者：
Halliday, Sarah J.;Skeffington, Richard A.;Jarvie, Helen P.
本文介绍了水化学的一个低地，城市化的河流系统，在英格兰的削减，使用现场每日采样。截污渠接收来自四个主要污水处理厂的污水，为约19万人提供服务。这些排放物主要包括处理过的水，最初从泰晤士河抽取，并通过供水网络返回，大大增加了自然流量。每小时的水质数据通过每周人工采样进行补充，并进行实验室分析，以检查每小时的数据并测量进一步的决定因素。平均磷和硝酸盐浓度非常高，违反了欧盟立法规定的标准。虽然56%的集水区是农业，水化学动力学显着影响污水排放约占50%的年度P集水区输入负荷，平均59%的河流流量在监测点。昼夜溶解氧数据表明高流生产力。从高频和常规监测数据的比较中可以推断，初级生产主要是底栖藻类，主要是硅藻。尽管生产力和营养物浓度很高，但河水并没有缺氧，也没有观察到浮游植物大量繁殖。观察到的强烈的日变化和年变化表明，根据水框架指令（WFD）进行的水质评估对采样的时间和季节敏感。建议为每个被测定物指定特定的采样时间窗口，并且WFD目标应结合应用，以帮助确定最大生态风险的时期。(c)2015作者出版社：John Wiley & Sons Ltd
This paper describes the hydrochemistry of a lowland, urbanised river-system, The Cut in England, using in situ sub-daily sampling. The Cut receives effluent discharges from four major sewage treatment works serving around 190000 people. These discharges consist largely of treated water, originally abstracted from the River Thames and returned via the water supply network, substantially increasing the natural flow. The hourly water quality data were supplemented by weekly manual sampling with laboratory analysis to check the hourly data and measure further determinands. Mean phosphorus and nitrate concentrations were very high, breaching standards set by EU legislation. Although 56% of the catchment area is agricultural, the hydrochemical dynamics were significantly impacted by effluent discharges which accounted for approximately 50% of the annual P catchment input loads and, on average, 59% of river flow at the monitoring point. Diurnal dissolved oxygen data demonstrated high in-stream productivity. From a comparison of high frequency and conventional monitoring data, it is inferred that much of the primary production was dominated by benthic algae, largely diatoms. Despite the high productivity and nutrient concentrations, the river water did not become anoxic, and major phytoplankton blooms were not observed. The strong diurnal and annual variation observed showed that assessments of water quality made under the Water Framework Directive (WFD) are sensitive to the time and season of sampling. It is recommended that specific sampling time windows be specified for each determinand, and that WFD targets should be applied in combination to help identify periods of greatest ecological risk. (c) 2015 The Authors. Hydrological Processes published by John Wiley & Sons Ltd.