Assessment of Changing Land-Use Practices on Basin Sediment Yields and Provenance in Western North Carolina using Multivariate Finger Printing Techniques.

摘要

Fairfield Lake, located approximately 16 km east of Cashier, NC, was constructed in 1890 and contains a 111-year record of upland erosion and reservoir sedimentation. During this investigation, multivariate fingerprinting techniques were used in conjunction with sediment mixing models to determine the proportion of lake bed sediment derived from the major bedrock formations and the predominant land-use types within the Fairfield Lake Watershed. Data collected from a total of 19 cores demonstrate that sedimentation within the lake has been limited since dam closure. However, lacustrine deposits dated using (sup 210)Pb, combined with cartographic information from aerial photographs obtained in 1963, 1975, 1988, and 2000, indicate that sedimentation rates have increased several fold during the past two decades in response to local development. The statistical treatment of geochemical data collected from delineated land-use categories, and the two underlying bedrock formations, suggests that the soils associated with these sediment sources can be geochemically fingerprinted. Moreover, the developed mixing models show change in sediment source coincident with the documented increase in sedimentation rates associated with development. Nonetheless, the utilized approach will require modification before it can be effectively applied on a large scale in western North Carolina.