Tracing spatial sources of suspended sediment in the Ohio River basin, USA, using water quality data from the NASQAN programme

摘要

Documenting catchment suspended sediment sources remains critical for guiding the design of sediment management strategies and for abating the numerous environmental issues associated with enhanced loadings. Sediment fingerprinting techniques have received increasing attention in this respect since, at the catchment scale, they avoid many of the problems and uncertainties experienced with using more traditional measurement methods. As part of the US Geological Survey's revised NASQAN (National Stream Quality Accounting Network) programme, routine water quality samples are collected in selected large river basins in the United States. The geochemical data generated from these samples over a period of 10 years (1996-2006), were used as the basis of a fingerprinting exercise to assess the key tributary sub-catchment spatial sources of suspended sediment transported by the Ohio River. A Monte Carlo approach was used during the fingerprinting mass balance modelling to quantify uncertainty in the spatial source estimates. The results should be interpreted with respect to the routine but infrequent nature of the suspended sediment samples used as the basis for the sourcing exercise, but nonetheless, demonstrate how routine monitoring samples can be used to provide some preliminary information on sediment provenance in large drainage basins.