A streamlined approach for sediment source fingerprinting in a Southern Piedmont watershed, USA

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• 作者：Robert Mckinley (1)
  David Radcliffe (1)
  Rajith Mukundan (2)
  
• 关键词：Carbon ; 13 ; Mixing model ; Nitrogen ; 15 ; Rapid geomorphic assessments ; Sediment fingerprinting ; TMDL
• 刊名：Journal of Soils and Sediments
• 出版年：2013
• 出版时间：December 2013
• 年：2013
• 卷：13
• 期：10
• 页码：1754-1769
• 全文大小：
• 作者单位：Robert Mckinley (1)
  David Radcliffe (1)
  Rajith Mukundan (2)
  
  1. Department of Crop and Soil Sciences, University of Georgia, 3111 Miller Plant Sciences Building, Athens, GA, 30605, USA
  2. Institute for Sustainable Cities, City University of New York, New York, NY, 10065, USA
  
• ISSN：1614-7480

文摘

Purpose Sediment fingerprinting is a relatively recent research technique, capable of determining the origin of suspended sediment. In this study, we investigated sub-basins within a larger watershed we examined previously. The objectives were to determine if there was spatial variation in the origin of the suspended sediments and to test a streamlined fingerprinting approach which would reduce the cost, thereby paving the way for adoption by government agencies. Materials and methods Samples were collected from three tributaries, the outlet of the main stem, and at the middle of the main stem. Two methods to collect suspended sediment samples were compared: a mobile continuous-flow centrifuge and automated samplers. A relatively small initial tracer suite consisting of stable isotopes of nitrogen (N) and carbon (C) (15N and 13C), total N (TN), and total C (TC) was tested. Tracer concentrations were obtained through a single mass spectrometry analysis requiring <1g of sediment. Results and discussion Multivariate discriminant analysis showed that three of the four tracers (15N, 13C, and TC) from the initial pool were capable of accurate classification of the source samples. A multivariate mixing model showed that banks contributed the majority of sediment throughout all locations sampled and that in tributaries it was an even more dominant source. Despite variations in land use and stream order, the legacy sediments comprising the banks and floodplains were the main factor in impairment for suspended sediment. We found a small but statistically significant difference in 15N and 13C concentrations collected using automated samplers vs. the mobile centrifuge, but the effect on analysis of sediment source proportions was minimal. Conclusions The results of this study indicate that, at least in the study watershed, the majority of sediment in suspension was of streambank origin. A cost-effective tracer suite was identified as well as an attempt to make a streamlined approach to the technique. The streamlined approach cost much less ($7,550 US) than the conventional approach ($46,600 US) and should be suitable for total maximum daily loads analysis by state government agencies in the Southern Piedmont region of the USA.