摘要：Evaluations of pathogen management options have focussed on assessing relative removal effectiveness as a basis for prioritising alternative management investment decisions. Using a case study of the Myponga catchment, South Australia, this paper presents results of a cost-effectiveness risk analysis of 13 catchment- and treatment-based water quality management alternatives for mitigating Cryptosporidium risk. A range of costs and benefits including set-up and operating costs, farm business costs and benefits, and environmental service benefits are considered in comparing the net cost associated with each management alternative. Considering the broader range of costs and benefits changes the relative cost-effectiveness of water quality management alternatives significantly. Combinations of catchment- and treatment-based management alternatives proved to be relatively more cost-effective at mitigating Cryptosporidium risk. Specifically, the combination of spatially targeted water course management upstream of the catchment with reservoir treatment by ultra-violet radiation provides a cost-effective Cryptosporidium risk mitigation strategy especially when the adoption of dung beetles and treatment by enhanced coagulation are included as complementary low cost alternatives. Considering the broader range of costs and benefits enhances the potential to increase the cost-effectiveness of investment in Cryptosporidium risk mitigation as well as produce a range of significant secondary benefits for water quality, biodiversity, and carbon sequestration.
