Groundwater Research Group, The Queen's University of Belfast, David Keir Building, Stranmillis, Road, Belfast, Northern Ireland, United Kingdom.
Sci Total Environ. 2014 Jan 15;468-469:345-57. doi: 10.1016/j.scitotenv.2013.08.069. Epub 2013 Sep 14.
Prediction of the impact of suspended sediment on aquatic ecosystems requires adequate knowledge of sediment dynamics in surface waters. Often, studies reporting the response of aquatic biota to suspended sediment are concerned with concentrations, while catchment erosion studies often report sediment delivery as annual loads and yields, making the comparison to documented ecological impacts difficult. Similarly, the European Union Freshwater Fish Directive (FFD) (78/659/EC) stipulates a guideline value of 25 mg l(-1) which should not be exceeded, with the exception of floods and droughts. In this respect, the significance of suspended sediment in two Irish rivers was assessed using turbidity sensors calibrated for suspended sediment. Sediment yields of 0.07 tonnes (t) ha(-1) year(-1) and 0.44 t ha(-1) year(-1) and annual FFD exceedance frequency of 8.3% and 17.8% were estimated for the two catchments. Contrasts in the frequency of exceedance events between both catchments was observed, yet duration was typically short (<5h). Additionally, this study evaluated different sampling resolutions to assess the impact on estimated loads and exceedance frequency. Increasing resolution improved accuracy and reduced uncertainty, with the 24-7 'Plynlimon' sampling method (sampling every 7h) providing the best solution to estimating both loads and exceedance. This study documents some of the first data on sediment dynamics in Ireland and indicates that periods of elevated suspended sediment concentration in the two study catchments may be significant.
预测悬浮泥沙对水生生态系统的影响需要充分了解地表水的泥沙动力学。通常，报告水生生物群对悬浮泥沙的响应的研究关注浓度，而集水区侵蚀研究通常以年负荷和产量报告泥沙输送，这使得难以将其与记录的生态影响进行比较。同样，欧盟淡水鱼类指令 (FFD) (78/659/EC) 规定了 25mg l(-1) 的指导值，除非发生洪水和干旱，否则不应超过该值。在这方面，使用校准用于悬浮泥沙的浊度传感器评估了两条爱尔兰河流中悬浮泥沙的重要性。两个集水区的泥沙产量分别估计为 0.07 吨/公顷/年和 0.44 吨/公顷/年，FFD 年超标频率分别为 8.3%和 17.8%。观察到两个集水区之间超标事件的频率存在差异，但持续时间通常较短(<5h)。此外，本研究评估了不同的采样分辨率，以评估对估计负荷和超标频率的影响。增加分辨率可提高精度并降低不确定性，24-7 'Plynlimon' 采样方法（每 7h 采样一次）提供了估计负荷和超标最有效的解决方案。本研究记录了爱尔兰泥沙动力学的一些首批数据，并表明两个研究集水区中悬浮泥沙浓度升高的时期可能很重要。
