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

Abstract

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.

Keywords:

• Assessment
• Decision support systems
• Multi criteria analysis (MCA)
• Triple-bottom-line (TBL)
• Urban stormwater

Acknowledgements

Brisbane City Council, Melbourne Water and the Victorian Government (through the Environmental Protection Authority as part of the Victorian Stormwater Action Program) are gratefully acknowledged for their role in helping to fund research in this area.

Notes

∗In this paper, ‘stakeholders’ refers to people and groups who are potentially affected by the outcome of the assessment process. These typically include local government councillors, community groups, environmental groups, professional associations, industry groups, technical staff from stormwater management agencies and/or directly affected residents. In some cases, the general public may also be consulted as ‘stakeholders’ to help determine the relative importance of the assessment criteria from the perspective of the broader community, rather than vested interests.

∗∗A cost or benefit that arises from an economic transaction (e.g., the construction of a stormwater quality improvement pond by a government agency) and falls on a person who doesn't participate in the transaction (e.g., a person living next to the pond). That is, there is no market feedback from the person who experiences the loss or gain to the person who created it (Young 2000).

∗In this paper, ‘traditional stakeholders’ refers to groups of people with a strong interest in the issue who are frequently consulted, such as community groups, environmental groups, local government councillors, industry groups and professional associations, rather than members of the general public.

∗Note that the business as usual option was retained in the assessment process for academic purposes. It would normally be screened out in Step 3, as it fails to address some of the project's key objectives (e.g., protection of water quality/ecosystem health).

∗A systematic process for continually improving management practices by learning from the outcomes of previously employed practices.