While streambank legacy sediment has been increasingly recognized as an important contributor of fine sediment to watersheds, little is known about its contributions to suspended sediment‐bound nutrients. This uncertainty is exacerbated by the ubiquitous presence of legacy sediments in valley‐bottoms of the Mid‐Atlantic region of the United States. Using a sediment fingerprinting model, we quantified suspended sediment and sediment‐bound nutrient sources for a 114 km² agricultural, Piedmont watershed. Sediment sources included agricultural, developed, and forested soils as well as streambanks legacy sediments. Suspended sediment and sediment‐bound nitrogen (N) and phosphorus (P) concentrations were determined for 10 storms over the study period of August 1, 2017 to July 31, 2018. Streambanks contributed 50% of the annual suspended sediment yield of 1,348 kg/ha followed by agricultural (49%) and forested (1%) soils. Streambanks amounted to 26% and 32% of the suspended sediment‐bound N and P exports, respectively, whereas the corresponding loads from agricultural sources were 73 and 67%, respectively. Bank contributions varied with storm magnitude and seasonality, with the highest exports associated with the largest peak flows. These results highlight that streambank sediments constitute a significant fraction of suspended sediment‐bound nutrient exports and must be considered in watershed models, regulatory assessments, and management practices.

中文翻译：

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大西洋中部皮埃蒙特流域的河岸遗留沉积物对悬浮泥沙养分产量的贡献

尽管河岸遗留沉积物已被越来越多地认为是流域中细沙的重要贡献者，但对于其对悬浮泥沙养分的贡献却知之甚少。在美国中大西洋地区谷底普遍存在的传统沉积物加剧了这种不确定性。使用沉积物指纹模型，我们对114 km ^2的悬浮沉积物和沉积物结合的营养源进行了量化农业，皮埃蒙特流域。沉积物来源包括农业土壤，发达土壤和森林土壤以及河床遗留的沉积物。在2017年8月1日至2018年7月31日的研究期间，确定了10次暴风雨的悬浮泥沙和泥沙结合态氮（N）和磷（P）的浓度。水库贡献了1348千克/年的年度悬浮泥沙产量的50％ ha其次是农业土壤（49％）和森林土壤（1％）。河床分别占悬浮泥沙中氮和磷出口的26％和32％，而来自农业的相应负荷分别为73％和67％。银行的捐款随风暴的大小和季节而变化，最高的出口额与最大的高峰流量有关。