Triple-bottom-line assessment of stormwater quality projects: advances in practicality, flexibility and rigour

Decision-support frameworks that help users to consider financial, social and ecological costs and benefits (i.e., ‘triple-bottom-line’ decision frameworks) are increasingly being used by water managers. This paper describes the outcomes of a project that was undertaken to assist stormwater managers to complete triple-bottom-line assessments of proposed urban stormwater quality management measures. The primary outcomes have been: a set of guidelines that clearly define a twelve step assessment process; and the results of a trial that was used to test and refine the guidelines in Brisbane, Australia. A brief overview of the twelve step assessment process is provided. The strengths and weaknesses of typical triple-bottom-line assessment processes are highlighted through the trial, where seven alternative stormwater treatment and reuse options for new, medium density, residential estates were assessed and ranked to help inform broad policy and local design decisions. For managers of urban stormwater quality, we conclude that the guidelines are more tailored, practical and flexible than existing decision support frameworks, whilst maintaining a high degree of assessment rigour. The trial confirmed their value in building the capacity of local stakeholders and making more informed and carefully considered decisions.