Sedimentation patterns across a Coastal Plain floodplain: The importance of hydrogeomorphic influences and cross-floodplain connectivity
Sedimentation patterns across a Coastal Plain floodplain: The importance of hydrogeomorphic influences and cross-floodplain connectivity
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DOI：
10.1016/j.geomorph.2016.06.020
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发表时间：
2016-09
期刊：
影响因子：
3.9
通讯作者：
Christopher T. Kaase;J. Kupfer
中科院分区：
文献类型：
--
作者：
Christopher T. Kaase;J. Kupfer
美国东南部沿海平原河流的洪泛区是冲积沉积物和营养物质的重要长期储存场所。然而，相当大的不确定性围绕着许多大型河流洪泛区的沉积物动力学，特别是当地规模的因素，影响泥沙和营养物质从河流到洪泛区的通量和随后的沉积。本研究使用长石垫量化了2012年至2014年Congaree国家公园洪泛区沉积物沉积的短期速率。沉积物沉积速率范围为0.1至15.6厘米（中位数= 1.46厘米），并与洪水频率和地貌位置密切相关。跨洪泛区分流河道是将沉积物移到洪泛区的特别重要的通道。对土壤样本的物理和化学分析表明，大多数受洪水影响的地点的主要营养素和微量营养素（特别是磷）水平较高，营养成分也更多样化。本研究通过展示区域水文和当地洪泛区环境特征对沉积物和营养物供应的复杂影响，推进了当前对横向洪泛区连通性的理解。
The floodplains of large Coastal Plain rivers in the southeastern U.S. are important long-term storage sites for alluvial sediment and nutrients. Yet considerable uncertainty surrounds sediment dynamics on many large river floodplains and, in particular, the local scale factors that affect the flux of sediment and nutrients from rivers onto their floodplains and their subsequent deposition. This research quantifies short-term rates of sediment deposition from 2012 to 2014 on floodplain sites at Congaree National Park using feldspar pads. Sediment deposition rates ranged from 0.1 to 15.6 cm (median = 1.46 cm) and were closely associated with inundation frequency and geomorphic position. Cross-floodplain distributary channels served as particularly important conduits for moving sediment onto the floodplain. Physical and chemical analyses of soil samples demonstrated that the most flood-exposed sites had higher major nutrient and micronutrient levels (especially of phosphorus) and more diverse nutrient compositions. This research advances current understandings of lateral floodplain connectivity by demonstrating the complex effects of regional hydrology and local floodplain environmental characteristics on the supply of sediment and nutrients.