Geochemical Fingerprinting - Application of Geochemical Tracers to Fluvial Sediment - page 41

Mukundan et al. ( 2012 ) shows, however, that the transformation of geochemical
fingerprinting from the research to themanagement/regulatory realm is not as straight
forward as one might think, and has been slowed by several factors.
1. Many land-use managers and regulatory personal are unfamiliar with the specifics
of the approach .
In comparison with many traditional approaches, land-use managers/regulators
may have a relatively poor understanding of geochemical fingerprinting tech-
niques, and therefore do not necessarily understand the benefits of incorporating
the methods into their management framework. As Mukundan et al. ( 2012 ) point
out, they are likely to question the practicality of applying the approach, especially
with regards to the cost and time required for the analysis, the spatial scale towhich
it can be applied, the type of geochemical analyses that must be carried out, and
the likelihood of obtaining meaningful results. Moreover, the benefits of applying
geochemical fingerprinting methods as part of a larger management strategy may
be unclear. Sediment budgeting, for example, is a relatively well known method
of conceptualizing the sediment dispersal system. However, defining the terms
within a sediment budget by monitoring sediment loads, quantifying upland ero-
sion rates, or through the use of empirically or physically based models have
proven problematic. In contrast, fingerprinting has been shown to be an effective
approach to estimate the relative contributions of sediment from defined sources
at the catchment scale, and can be applied within a relatively short time frame.
It allows, then, for the targeting of the primary source areas or types to reduce
sediments loads within the catchment. In addition, mixing model results may be
combined with upland erosion and downstream sediment load data to determine:
(1) the fraction of the sediment load generated from each sediment source that
exists within the basin, and (2) the fraction of sediment eroded from upland areas
that is deposited and stored within channels and floodplains (Mukundan et al.
2012 ). Similarly, geochemical fingerprinting can be linked to the results obtained
from watershed models to determine the export and storage of sediment from
individual sources. Thus, fingerprinting can be incorporated into the traditional
budgeting or modeling approach to refine and greatly improve upon its overall
results, a fact that is not always recognized. It is also important to note that the
conversion of relative source contributions to estimates of mass sediment trans-
port may allow for a comparison with the more traditional methods of measuring
sediment inputs to rivers from the defined sources. For example, rates of bank
erosion determined through repeated channel surveys may be compared to esti-
mates of bank erosion influx made by fingerprinting techniques. In doing so,
fingerprinting serves as a way to assess the uncertainty inherent in the outcomes
of the traditional methods (Mukundan et al. 2012 ).
2. Currently, a well-defined set of procedures are lacking .
Most analyses performed within a regulatory framework are governed by a well-
defined set of operating procedures that are accepted by the 'scientific commu-
nity' and that lead to accurate and reproducible results. The intent is to produce
results that can withstand the rigors of both scientific and legal review. At the