Historical Trends in Sedimentation Rates and Sediment Provenance, Fairfield Lake, Western North Carolina

Abstract

Sedimentation rates and sediment provenance were examined for lacustrine sediments deposited in Fairfield Lake, western North Carolina, during the past 111 years. Stratigraphic, radionuclide, and cartographic data indicate that sedimentation rates have increased several fold during the past three decades in response to localized development. The magnitude of increased sedimentation was surprising given limited development within the basin: 0.12 to 0.68 buildings/ha in 2000 in those parts directly delivering sediment to the dated cores. Thus, the analysis illustrates the potential sensitivity of watersheds in the southern Appalachians to changes in land cover. An approach that combined geochemical fingerprinting with sediment mixing models was subsequently evaluated to determine its ability to accurately estimate the contribution of sediment from (1) major bedrock formations that underlie the watershed and (2) potential sources associated with four land cover categories. Sediment sources in both analyses proved difficult to geochemically fingerprint to greater than 90 percent accuracy using data on acid‐soluble metals and selected isotopes of lead (Pb). The relative contributions of sediment from delineated sources, estimated by the mixing models, generally corresponded with known temporal and spatial patterns of land cover. However, the models were plagued by two significant problems — the chemical alteration of sediments as they were transported through upland streams to depositional sites within the lake and the loss of elemental mass. Thus, future investigations using the fingerprinting approach in this area of intense weathering, and presumably others, will need to modify the existing methods to more accurately elucidate changes in sediment provenance related to development.

Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa

“…The use of geochemical fingerprinting methods to elucidate sediment provenance from non-point sources has increased significantly during the past two decades (Slattery et al, 1995;Collins, 1995;Collins et al, 1997aCollins et al, ,b, 1998Walling et al, 1999;Bottrill et al, 2000;Russell et al, 2001;Douglas et al, 2003Douglas et al, , 2005Douglas et al, , 2010Miller et al, 2005;Foster et al, 2007Foster et al, , 2012. Geochemical fingerprinting methods were used here to determine the predominant source of sediments found in three wetland and one reservoir sediment cores collected from along the drainage network.…”

“…It is then possible to characterize the sediments within the source areas and the downstream alluvial/lacustrine deposits for a suite of parameters and statistically compare their parameter characteristics to unravel the relative proportion of sediment that was derived from each source type (Miller and Orbock Miller, 2007). During this investigation, the original model used by Miller et al (2005) was modified using the approach provided by Rowen et al (2000) to estimate sediment source contributions from the hillslopes to the cored deposits.…”

Forensic Assessment of Metal Contaminated Rivers in the 21st Century Using Geochemical and Isotopic Tracers

“…It is therefore possible to characterize the suspected contaminant sources, the background materials within the basin, and sediments obtained from along the channel for selected geochemical tracers and statistically compare their tracer characteristics to unravel the relative proportion of sediment that was derived from each source [4,40,64]. In most non-point source studies, multiple tracers are utilized to effectively fingerprint the contaminated materials; thus, the approach represents a multivariate statistical method for source identification.…”

“…As a result, trace metal concentration data may prove to be ineffective as a tracer, particularly when the elemental concentrations are near background values. To address the problem, investigators have combined the analysis of multiple elements with multivariate statistical methods (e.g., principle component analysis, cluster analysis, or discriminate analysis) to fingerprint the source [36], an approach widely utilized to determine sediment and nutrient provenance from non-point sources of pollution [37][38][39][40][41]. A significant shortcoming of the approach is that it requires a large number of samples, and its effectiveness depends on the variability inherent within the source materials.…”

Ascribing soil erosion types for sediment yield using composite fingerprinting technique

“…However, using single property or component signatures is likely to prove unrealistic and result in spurious linkages between source materials and sediment (Collins and Walling 2002), so most fingerprinting studies now employ composite fingerprints, which comprise a range of different diagnostic properties influenced by contrasting environmental controls, and thereby greatly improve the reliability of sediment source discrimination (Walling et al 2006). Today composite fingerprints have been successfully employed by mixing models for source tracing and determining the relative importance of individual sediment source types in a number of different contexts (Walling and Woodward 1995, Russell et al 2001, Motha 2003, Miller et al 2005, Walling et al 2006, Collins and Walling 2007, Minella et al 2008, Collins et al 2010a, 2010b.…”