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The increasing use of internet surveys for stated preference studies raises questions about the effect of the survey mode on welfare estimates. A number of studies have conducted convergent validity investigations that compare the use of the internet with other survey implementation modes such as mail, telephone and in-person. All, but one, of these comparison studies is confounded different sample frames for the different modes of survey implementation. In this study we investigate differences in internet and mail survey modes holding the sample frame constant. This is done in the context of a choice-modelling study of improvements in the River Murray in Australia. We also investigate sample frame holding the survey mode (mail) constant. We find that survey mode (internet vs. mail) influences welfare estimates, and the internet welfare estimates are about 78 % of the mail welfare estimates on average. There is not a significant effect of sample frame (internet panel vs. postal addresses) on welfare estimates for implementation of a mail survey.

In an effort to increase the livability of its cities, public agencies in Australia are investing in green infrastructure to improve public health, reduce heat island effects and transition toward water sensitive urban design. In this paper, we present a simple and replicable approach to building a business case for green infrastructure. This approach requires much less time and resources compared to other methods for estimating the social and economic returns to society from such investments. It is a pragmatic, reasonably comprehensive approach that includes socio-demographic profile of potential users and catchment analysis to assess the economic value of community benefits of the investment. The approach has been applied to a case study area in the City of Brimbank, a western suburb of Greater Melbourne. We find that subject to a set of assumptions, a reasonable business case can be made. We estimate potential public benefits of avoided health costs of about AU$75,049 per annum and potential private benefits of AU$3.9 million. The project area is one of the most poorly serviced areas in the municipality in terms of quality open spaces and the potential beneficiaries are from relatively low income households with less than average health status and education levels. The values of cultural (recreational benefits, avoided health costs, and increased property values) and regulating (reduction in heat island effect and carbon sequestration) ecosystem services were quantified that can potentially offset annual maintenance costs.

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Abstract. Investment in and operation of flow control infrastructure such as dams, weirs, and regulators can help increase both the health of regulated river ecosystems and the social values derived from them. This requires high-quality and high-resolution spatiotemporal ecohydrological and socioeconomic information. We developed such an information base for integrated environmental flow management in the River Murray in South Australia (SA). A hydrological model was used to identify spatiotemporal inundation dynamics. River ecosystems were classified and mapped as ecohydrological units. Ecological response models were developed to link three aspects of environmental flows (flood duration, timing, and interflood period) to the health responses of 16 ecological components at various life stages. Potential infrastructure investments (flow control regulators and irrigation pump relocation) were located by interpreting LiDAR elevation data, digital orthophotography, and wetland mapping information; and infrastructure costs were quantified using engineering cost models. Social values were quantified at a coarse scale as total economic value based on a national survey of willingness-to-pay for four key ecological assets; and at a local scale using mapped ecosystem service values. This information was integrated using a constrained, nonlinear, mixed-integer, compromise programming optimization model and solved using a stochastic Tabu search algorithm. We tested the model uncertainty and sensitivity using 390 Monte Carlo model runs at varying weights of ecological health vs. social values. Integrating ecohydrological and socioeconomic information identified environmental flow management regimes that efficiently achieved both ecological and social objectives. Using an ecologically weighted efficient and socially weighted efficient scenario, we illustrated model outputs including a suite of cost-effective infrastructure investments and an operational plan for new and existing flow control structures including dam releases, weir height manipulation, and regulator operation on a monthly time step. Both the investments and management regimes differed substantially between the two scenarios, suggesting that the choice of weightings on ecological and social objectives is important. This demonstrates the benefit of integrating highquality and high-resolution spatiotemporal ecohydrological and socioeconomic information for guiding the investment in and operational management of environmental flows.