Sediment and Nutrient Retention in Ponds on an Agricultural Stream: Evaluating Effectiveness for Diffuse Pollution Mitigation
Sediment and Nutrient Retention in Ponds on an Agricultural Stream: Evaluating Effectiveness for Diffuse Pollution Mitigation
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DOI：
10.3390/w13121640
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发表时间：
2021-06-01
期刊：
影响因子：
3.4
通讯作者：
McKnight, David
中科院分区：
文献类型：
--
作者：
Robotham, John;Old, Gareth;McKnight, David
池塘和湿地的建立有可能减轻受扩散性农业污染影响的集水区的溪流水质损害。了解这些特征的水文和地球化学功能对于确定其减轻污染的有效性非常重要。本研究调查了沉积物和营养物质的保留在三个连接（在线）池塘的低地源头流采样流入和流出的浓度在基准流和暴雨流。沉积物捕集装置被用来量化沉积物和磷积累池塘内约每月一次。同时测定了沉积物有机质含量和颗粒组成。池塘保留溶解硝酸盐，可溶性活性磷和悬浮固体在基流。在小到中度风暴事件，一些池塘能够减少悬浮固体和磷的峰值浓度和负荷，但是，在大规模的事件，沉积物的再悬浮导致净损失。池塘最有效地过滤掉较大的颗粒。在2019年8月至2020年3月期间，池塘从30公顷的贡献区域积累了0.306吨公顷（-1）沉积物。在此期间，池塘中的沉积物累积总量估计等于离开下游340公顷集水区的悬浮通量的7.6%。这项研究表明，污染物保留动态的复杂性，在网上池塘，并强调其有效性可以影响事件的时间和规模。
The creation of ponds and wetlands has the potential to alleviate stream water quality impairment in catchments affected by diffuse agricultural pollution. Understanding the hydrological and biogeochemical functioning of these features is important in determining their effectiveness at mitigating pollution. This study investigated sediment and nutrient retention in three connected (on-line) ponds on a lowland headwater stream by sampling inflowing and outflowing concentrations during base and storm flows. Sediment trapping devices were used to quantify sediment and phosphorus accumulations within ponds over approximately monthly periods. The organic matter content and particle size composition of accumulated sediment were also measured. The ponds retained dissolved nitrate, soluble reactive phosphorus and suspended solids during baseflows. During small to moderate storm events, some ponds were able to reduce peak concentrations and loads of suspended solids and phosphorus; however, during large magnitude events, resuspension of deposited sediment resulted in net loss. Ponds filtered out larger particles most effectively. Between August 2019 and March 2020, the ponds accumulated 0.306 t ha(-1) sediment from the 30 ha contributing area. During this period, total sediment accumulations in ponds were estimated to equal 7.6% of the suspended flux leaving the 340 ha catchment downstream. This study demonstrates the complexity of pollutant retention dynamics in on-line ponds and highlights how their effectiveness can be influenced by the timing and magnitude of events.