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A MEASURE-CENTRIC APPROACH TO DIFFUSE
POLLUTION MODELLING AND COST-CURVE ANALYSIS
OF MITIGATION MEASURES
DR Chadwick 1 , BJ Chambers 2 , S Anthony 3 , S Granger 1 , PM Haygarth 1 , D Harris 3
and K Smith 3
1
IGER, North Wyke Research Station, Okehampton, Devon, EX20 2SB, UK, E-mail:
david.chadwick@bbsrc.ac.uk; 2 ADAS, Gleadthorpe, Meden Vale, Mansfield, Notts,
NG20 9PF, UK; 3 ADAS, Wolverhampton, Woodthorne, Wolverhampton, WV6 8TQ,
UK
SUMMARY
A new model framework has been developed that explicitly represents the mode
of action of individual mitigation measures for reducing diffuse water pollution. This
measure centric framework is termed the ‘Cost-Cube’. The model represents the
functional behaviour of pollutants and the associated processes and pathways
that can be affected by remediation measures. It is based on an export coefficient
approach but extended to provide explicit fractions of the total pollutant loss by
unique aspects of the source, mobilisation and transport dimensions. This framework
was used to explore mitigation options for ammonium, nitrite, biological oxygen
demand, and pathogens in terms of their economics and applicability for a number
of model farm systems. A cost benefit analysis was used to prioritise measures that
work within the bounds of current agricultural practice.
INTRODUCTION
Protection of water quality requires implementation of land management options that
reduce the totality of contributors to diffuse pollution including transfers of nutrients,
sediment, organic matter, agrochemicals and potentially pathogenic organisms. To
do this effectively, we require an understanding of the key behavioural characteristics
of diffuse pollutant groups and the potential for targeting of measures. We have
developed a new conceptual modelling framework that represents the mode of
action of mitigation measures for reducing diffuse pollution, and we have coupled
this to a cost-curve analysis. In this paper, we present the parameterisation and
application of this ‘measure-centric’ framework, as well as the ultimate deliverable, a
cost-curve analysis of mitigation measures.
MATERIALS AND METHODS
Model Framework
A new conceptual modelling framework was developed to explicitly represent the
mode of action of individual measures. This measure centric framework was centred
on the ‘Cost-Cube’, an enhanced export coefficient model with three dimensions
of pollutant source, mobilisation and transport (see, for example, RPA, 2003). The
Cost-Cube explicitly represents the proportions of pollutant loss due each type of
source, process of mobilisation and path of transport (Figure 1). These are referred
to as the aspects of each dimension. For example, the mobilisation dimension is
separated into the processes of solubilisation, detachment and contingent losses
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