The role of water quality modelling in decision-making

  • Leslie McNamara

Western Sydney University thesis: Doctoral thesis

Abstract

Catchment management organisations often use computer-based water quality models to support their decision-making needs. However, literature suggests that model use by catchment managers can be highly problematical. Commonly reported issues that negatively impact upon the effectiveness of modelling for decision-making are data quality and availability, miscommunication between analysts and decision-makers, inappropriate treatment of uncertainty, excessive model complexity ('sophistication') or simplicity and poor modelling practice. The challenges that beset catchment managers are usually framed as technical problems that can be overcome by using or communicating the science that underlies the models more effectively. As a result, many of the problems associated with the use of models by catchment managers have not been adequately elucidated from the standpoint of a manager. This thesis examines the problem of modelling for decision-making from a fresh perspective. Systemic approaches to research are commonly used where the research problem is ill-defined, as it is here. 'Action research' is one qualitative, systemic methodology, and was used here as the guiding methodology to explore the model related problems faced by catchment managers. Action research involves recurrent cycles of planning, action, observation and reflection. The research was undertaken with the Sydney Catchment Authority (SCA), a New South Wales government agency responsible for water quality and catchment health in the drinking water catchments of Sydney, Australia. The SCA had expressed a particular need for tools to support the assessment of development applications with respect to potential impacts on water quality, and to prioritise rural land for remedial action to improve water quality in the drinking water catchments. The research had two broad aims that were:1.to develop two models differing in sophistication, and to use them to prioritise nutrient pollution sources and calculate nutrient loads; And, through the participatory development of the models, 2.to learn methodological lessons that catchment managers can apply to choose and use models more effectively. In this research, action was in the form of five planned activities, including: i. a review of relevant literature from diverse disciplines; ii. the holding of two workshops; the first exclusively involving SCA managers to identify their modelling needs, and the second involving water quality scientists and modelers to discuss methods for meeting the modelling needs; iii. the development and use of two export coefficient nutrient models; iv. a focus group discussion involving key staff in the SCA; and v. a review of published guidelines for good modelling practice in environmental management. Note was also taken of statements or behaviour at numerous meetings and seminars, mostly with SCA staff, that were relevant to the research questions.
Date of Award2007
Original languageEnglish

Keywords

  • water quality management
  • drinking water
  • catchment management
  • Australia
  • New South Wales

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