A quantitative approach to assessing the effectiveness of catchment management for the improvement of drinking water quality

Access to safe water is essential to maintain life. An understanding of all the potential contamination risks and an ability to manage those risks is imperative in the supply of water for human consumption. Having multiple scientifically validated barriers to contamination is the most widely accepted management technique for drinking water protection. Catchment management is a barrier that aims to control contamination at the source thereby reducing the reliance of removal of contamination by treatment. Buffer strips are one such measure. They are known to be effective at minimising waterway pollution by reducing the momentum and magnitude of surface and sub-surface runoff thereby aiding infiltration into the soil column and promoting entrapment of pollutants. This process has been well researched in terms of constituents such as sediments and nutrients. In a drinking water catchment, however, the ability of these buffer strips to trap or remove human infectious pathogens is of most interest as they are the greatest risk to consumers. <br><br>The aim of this research is to determine a way of predicting the decrease in risk to public health due to the implementation of buffer strips in an agricultural catchment and to validate their effectiveness. A drinking water catchment with an extensive amount of water quality data and an active catchment management program was chosen as the study catchment. Detailed statistical analysis was performed to evaluate the spatial and temporal changes in water quality and to determine trends. Additionally the processes most affecting water quality were established. <br><br>To enable prediction of any changes a model that specifically simulated pathogen fate and transport through a catchment was necessary. A simple lumped conceptual model, EG, was chosen. EG was not, however, specifically developed to determine the effectiveness of buffer strips and therefore modifications to the pathogen transport processes were required. Calibration, validation and uncertainty analyses were undertaken. <br><br>This research shows that it is possible to quantify the benefits of buffer strip implementation to final drinking water quality. Validation of the barrier’s effectiveness will allow the comparison of investing in catchment management to treatment costs and an assessment of the risk reduction benefits of both.