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The focus of this study is on the development of a novel approach to evaluate the impact of the R4D Alliance at project and program level, including practical guidance to support more effective project design and impact for future R4D investment. A significant limitation amongst many current impact evaluation methodologies is that a narrow set of approaches is often used to evaluate complex development issues. This means that impacts may be only partially described and this is compounded by a lack of clarity around the validation and attribution of impacts to particular interventions - in some cases uncertainties may be larger than claimed benefits! Our mixed methods approach to impact evaluation overcomes many of these challenges, allowing us to evaluate and quantify the impact of the Alliance at program level and at the individual project level in a timely manner, and to the best of our knowledge is the only product of this type currently in use. Our approach demonstrates that with a small additional investment impacts can be successfully tested for at project completion and greater confidence levels for impact pathways can be achieved. These are essential if confidence in the value of R4D investment is to be maintained, and will contribute to the ongoing quality and effectiveness of Australian aid. We anticipate that this approach will raise the bar for future impact evaluations.

Climate variability can induce uncertainty in yields, and threaten long term economic viability of rainfed agricultural enterprises in the absence of effective adaptation strategies. Enterprise mix diversification has been found to be an effective adaptation strategy for mitigating multiple sources of farm business risk in some contexts. The extent to which enterprise mix diversification can mitigate climate induced variability in long term net returns from rainfed agriculture is assessed in this paper. Building on APSIM modelling, the assessment applies Monte Carlo simulation, probability theory, and finance techniques, to assess the potential for enterprise mix diversification to mitigate climate-induced variability in long term economic returns from rainfed agriculture. Five alternative farm enterprise types comprising three non-diversified farm enterprises and two diversified farm enterprises consisting of a correlated mix of rainfed agricultural activities were considered. The decision to switch from a non-diversified agricultural enterprise with the highest expected return to a diversified agricultural enterprise consisting of a mix of agricultural enterprises was analysed. Correlation analysis showed that yields were not perfectly correlated (i.e. are less than 1) indicating that changes in climate variables cause non-proportional impacts on yields. Results show that whilst diversification can reduce the standard deviation of net returns by up to A$122ha-1 and increase the worst probable net loss by A$99ha-1, diversification can reduce the expected net returns by up to A$96ha-1 and reduce the maximum probable net gain by up to A$602ha-1. Further, under non-diversified enterprises, the likelihood of realising net losses higher than the maximum probable net loss under the diversified enterprise was estimated at up to 6%. Conversely, under the non-diversified enterprise, the likelihood of realising net gains higher than the maximum probable net gain under diversified enterprises was estimated at up to 16%.

Climate change and climate variability induce uncertainty in yields, and thus threaten long term economic viability of rain-fed agricultural enterprises. Enterprise mix diversification is the most common, and is widely regarded as the most effective, strategy for mitigating multiple sources of farm business risk. We assess the potential for enterprise mix diversification in mitigating climate induced variability in long term net returns from rain-fed agriculture. We build on APSIM modelling and apply Monte Carlo simulation, probability theory, and finance techniques, to assess the potential for enterprise mix diversification to mitigate climate-induced variability in long term economic returns from rain-fed agriculture. We consider four alternative farm enterprise types consisting of three non-diversified farm enterprises and one diversified farm enterprise consisting of a correlated mix of rain-fed agricultural activities. We analyse a decision to switch from a non-diversified agricultural enterprise with the highest expected return to a diversified agricultural enterprise consisting of a mix of agricultural enterprises. Correlation analysis showed that yields were not perfectly correlated (i.e. are less than 1) indicating that changes in climate variables cause non-proportional impacts on yield production. We conclude that at best, diversification can reduce the standard deviation of net returns by up to about A$110 Ha-1, or 52% of mean net returns; increase the probability of below-average net returns by up to about 4% and increase the mean of 10% of worst probable annual net returns by up to A$54/ha. At worst, diversification can reduce the mean of net returns by up to about A$95 Ha-1, or 46%.

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.

This article presents an econometric analysis of irrigation commodity area and revenue responses to varying commodity prices, water availability and climate conditions for the second half of a decade long drought in the Murray Darling Basin, Australia. We find statistically significant evidence of irrigation area decline with reductions in water allocations and irrigation revenue shrinking with area irrigated. Results also indicate hotter drier weather conditions experienced in the drought effected crops differently: some crop revenues suffered, while higher evapotranspiration and yield potential appeared to support higher revenue outcomes for other crops. Comparison revealed that marginal revenue changes in response to water allocations estimated are much less than those implicit in other economic assessments of water scarcity impacts for the same basin that used different methods. We find that triangulation of results between methods provides confidence in consistent results and reveals possible avenues for future research and methodological development. Refereed/Peer-reviewed

Increasingly, water agencies and utilities have an obligation to consider the broad environmental impacts associated with investments. To aid in understanding water cycle interdependencies when making urban water supply investment decisions, an ecosystem services typology was augmented with the concept of integrated water resources management. This framework is applied to stormwater harvesting in a case study catchment in Adelaide, South Australia. Results show that this methodological framework can effectively facilitate systematic consideration and quantitative assessment of broad environmental impacts of water supply investments. Five ecosystem service impacts were quantified including provision of 1) urban recreational amenity, 2) regulation of coastal water quality, 3) salinity, 4) greenhouse gas emissions, and 5) support of estuarine habitats. This study shows that ignoring broad environmental impacts can underestimate ecosystem service benefits of water supply investments by a value of up to A$1.36/kL, or three times the cost of operating and maintenance of stormwater harvesting. Rigorous assessment of the public welfare impacts of water infrastructure investments is required to guide long-term optimal water supply investment decisions. Numerous challenges remain in the quantification of broad environmental impacts of a water supply investment including a lack of peer-reviewed studies of environmental impacts, aggregation of incommensurable impacts, potential for double-counting errors, uncertainties in available impact estimates, and how to determine the most suitable quantification technique. Refereed/Peer-reviewed