Animal Waste, Water Quality and Human Health

180Animal Waste, Water Quality and Human Healthfor which high- and low-flow FIO data were available for the summer bathingseason and 11 sites for which parallel winter data were available.Satellite-derived land use data were used to characterise the catchment land useupstream of these monitoring sites. These data have been used to deriverelationships between land use and water quality during both high- and low-flowconditions and to quantify the effects of seasonality on FIO transport. This isimportant with respect to non-seasonal water uses such as abstraction fordrinking-water, particularly private supplies, and where receiving waters areused for shellfish harvesting. Table 5.8 presents the observed transport rates ofFIOs from these catchments expressed as faecal indicator concentrationobserved at catchment outlets with different land uses in the UK summer andcomparative winter data for 11 catchments. Table 5.9 expresses these data asexport coefficients which are the more common requirement of catchmenttransport models.The information in Tables 5.8 and 5.9 represent an attempt to provide themodelling community with a peer-reviewed accessible data resource to drivecatchment microbial transport models. They are, of course, regionally specific,highly biased to the developed nations and narrowly restricted to FIOs, that isnot having pathogen transport data and certainly not having specific informationdescribing zoonotic pathogen transport. The current status of transport data forthe FIO microbial parameters could compare with that available for the nutrientparameters some 25 years ago in North America (see e.g. PLUARG, 1983).5.5 CONCLUSIONS(1) Nutrient transport, as quantified by the export coefficient approach withina GIS, is exemplified for nitrogen by Mattikalli and Richards (1996). Inmany respects, this parallels the drivers of microbial transport outlinedin Kay et al. (2005, 2008b) in the United Kingdom. Other literaturesources of export coefficient for the FIOs are not, at present, available.However, it should be noted that FIO transport is highly episodic innature and highly seasonal. Thus, coefficients for high and low flow andfor winter and summer are likely to be needed in addition to coefficientsfor different land use types. For large-scale catchment appraisal, thisapproach is likely to provide sufficient detail for the policy communitywishing to prioritise “measures” designed to reduce FIO concentrationsand where the key questions relate to the balance between point anddiffuse inputs and the likely impact of specific interventions e.g.enhanced attenuation and storage to prevent sewerage system spills