Catchment process affecting drinking water quality, including the significance of rainfall events, using factor analysis and event mean concentrations

摘要

To ensure the protection of drinking water an understanding of the catchment processes whichncan affect water quality is important as it enables targeted catchment management actions to benimplemented. In this study factor analysis (FA) and comparing event mean concentrations (EMCs)nwith baseline values were techniques used to asses the relationships between water qualitynparameters and linking those parameters to processes within an agricultural drinking waterncatchment. FA found that 55% of the variance in the water quality data could be explained by thenfirst factor, which was dominated by parameters usually associated with erosion. Inclusion ofnpathogenic indicators in an additional FA showed that Enterococcus and Clostridium perfringensn(C. perfringens) were also related to the erosion factor. Analysis of the EMCs found that mostnparameters were significantly higher during periods of rainfall runoff. This study shows that thenmost dominant processes in an agricultural catchment are surface runoff and erosion. It alsonshows that it is these processes which mobilise pathogenic indicators and are therefore mostnlikely to influence the transport of pathogens. Catchment management efforts need to focus onnreducing the effect of these processes on water quality.