Assessing the effectiveness of water sensitive urban design in Southeast Queensland

Water Sensitive Urban Design (WSUD) systems have the potential mitigate the hydrologic disturbance and water quality concerns associated with stormwater runoff from urban development. In the last few years WSUD has been strongly promoted in South East Queensland (SEQ) and new developments are now required to use WSUD systems to manage stormwater runoff. However, there has been limited field evaluation of WSUD systems in SEQ and consequently knowledge of their effectiveness in the field, under storm events, is limited. The objective of this research project was to assess the effectiveness of WSUD systems installed in a residential development, under real storm events. To achieve this objective, a constructed wetland, bioretention swale and a bioretention basin were evaluated for their ability to improve the hydrologic and water quality characteristics of stormwater runoff from urban development. The monitoring focused on storm events, with sophisticated event monitoring stations measuring the inflow and outflow from WSUD systems. Data analysis undertaken confirmed that the constructed wetland, bioretention basin and bioretention swale improved the hydrologic characteristics by reducing peak flow. The bioretention systems, particularly the bioretention basin also reduced the runoff volume and frequency of flow, meeting key objectives of current urban stormwater management. The pollutant loads were reduced by the WSUD systems to above or just below the regional guidelines, showing significant reductions to TSS (70-85%), TN (40-50%) and TP (50%). The load reduction of NOx and PO4 3- by the bioretention basin was poor (<20%), whilst the constructed wetland effectively reduced the load of these pollutants in the outflow by approximately 90%. The primary reason for the load reduction in the wetland was due to a reduction in concentration in the outflow, showing efficient treatment of stormwater by the system. In contrast, the concentration of key pollutants exiting the bioretention basin were higher than the inflow. However, as the volume of stormwater exiting the bioretention basin was significantly lower than the inflow, a load reduction was still achieved. Calibrated MUSIC modelling showed that the bioretention basin, and in particular, the constructed wetland were undersized, with 34% and 62% of stormwater bypassing the treatment zones in the devices. Over the long term, a large proportion of runoff would not receive treatment, considerably reducing the effectiveness of the WSUD systems.

Towards sustainable urban futures : evaluating urban sustainability performance of the Gold coast, Australia

Creating sustainable urban environments is one of the challenging issues that need a clear vision and implementation strategies involving changes in governmental values and decision making process for local governments. Particularly, internalisation of environmental externalities of daily urban activities (e.g. manufacturing, transportation and so on) has immense importance for which local policies are formulated to provide better living conditions for the people inhabiting urban areas. Even if environmental problems are defined succinctly by various stakeholders, complicated nature of sustainability issues demand a structured evaluation strategy and well-defined sustainability parameters for efficient and effective policy making. Following this reasoning, this study involves assessment of sustainability performance of urban settings mainly focusing on environmental problems caused by rapid urban expansion and transformation. By taking into account land-use and transportation interaction, it tries to reveal how future urban developments would alter daily urban travel behaviour of people and affect the urban and natural environments. The paper introduces a grid-based indexing method developed for this research and trailed as a GIS-based decision support tool to analyse and model selected spatial and aspatial indicators of sustainability in the Gold Coast. This process reveals parameters of site specific relationship among selected indicators that are used to evaluate index-based performance characteristics of the area. The evaluation is made through an embedded decision support module by assigning relative weights to indicators. Resolution of selected grid-based unit of analysis provides insights about service level of projected urban development proposals at a disaggregate level, such as accessibility to transportation and urban services, and pollution. The paper concludes by discussing the findings including the capacity of the decision support system to assist decision-makers in determining problematic areas and developing intervention policies for sustainable outcomes of future developments.

A decision support system for sustainable urban development : the integrated land use and transportation indexing model

Broad, early definitions of sustainable development have caused confusion and hesitation among local authorities and planning professionals. This confusion has arisen because loosely defined principles of sustainable development have been employed when setting policies and planning projects, and when gauging the efficiencies of these policies in the light of designated sustainability goals. The question of how this theory-rhetoric-practice gap can be filled is the main focus of this chapter. It examines the triple bottom line approach–one of the sustainability accounting approaches widely employed by governmental organisations–and the applicability of this approach to sustainable urban development. The chapter introduces the ‘Integrated Land Use and Transportation Indexing Model’ that incorporates triple bottom line considerations with environmental impact assessment techniques via a geographic, information systems-based decision support system. This model helps decision-makers in selecting policy options according to their economic, environmental and social impacts. Its main purpose is to provide valuable knowledge about the spatial dimensions of sustainable development, and to provide fine detail outputs on the possible impacts of urban development proposals on sustainability levels. In order to embrace sustainable urban development policy considerations, the model is sensitive to the relationship between urban form, travel patterns and socio-economic attributes. Finally, the model is useful in picturing the holistic state of urban settings in terms of their sustainability levels, and in assessing the degree of compatibility of selected scenarios with the desired sustainable urban future.

The importance of a triple bottom line approach for safeguarding urban water quality

Water environments are greatly valued in urban areas as ecological and aesthetic assets. However, it is the water environment that is most adversely affected by urbanisation. Urban land use coupled with anthropogenic activities alters the stream flow regime and degrade water quality with urban stormwater being a significant source of pollutants. Unfortunately, urban water pollution is difficult to evaluate in terms of conventional monetary measures. True costs extend beyond immediate human or the physical boundaries of the urban area and affect the function of surrounding ecosystems. Current approaches for handling stormwater pollution and water quality issues in urban landscapes are limited as these are primarily focused on ‘end-of-pipe’ solutions. The approaches are commonly based either on, insufficient design knowledge, faulty value judgements or inadequate consideration of full life cycle costs. It is in this context that the adoption of a triple bottom line approach is advocated to safeguard urban water quality. The problem of degradation of urban water environments can only be remedied through innovative planning, water sensitive engineering design and the foresight to implement sustainable practices. Sustainable urban landscapes must be designed to match the triple bottom line needs of the community, starting with ecosystem services first such as the water cycle, then addressing the social and immediate ecosystem health needs, and finally the economic performance of the catchment. This calls for a cultural change towards urban water resources rather than the current piecemeal and single issue focus approach. This paper discusses the challenges in safeguarding urban water environments and the limitations of current approaches. It then explores the opportunities offered by integrating innovative planning practices with water engineering concepts into a single cohesive framework to protect valuable urban ecosystem assets. Finally, a series of recommendations are proposed for protecting urban water resources within the context of a triple bottom line approach.

Urban rural water exchange : PRW in the Lockyer Valley

A significant amount (ca. 15-25 GL/a) of PRW (Purified Recycled Water) from urban areas is foreseen as augmentation of the depleted groundwater resources of the Lockyer Valley (approx. 80 km west of Brisbane). Theresearch project uses field investigations, lab trials and modelling techniques to address the key challenges: (i) how to determine benefits of individual users from the augmentation of a natural common pool resource; (ii) how to minimise impacts of applying different quality water on the Lockyer soils, to creeks and on aquifier materials; (iii) how to minimuse mobilisation of salts in the unsaturated and saturated zones as a result of increased deep drainage; (iv) determination of potential for direct aquifer recharge using injection wells?

An environmental assessment model for knowledge-based urban development

Purpose – In recent years, knowledge-based urban development (KBUD) has introduced as a new strategic development approach for the regeneration of industrial cities. It aims to create a knowledge city consists of planning strategies, IT networks and infrastructures that achieved through supporting the continuous creation, sharing, evaluation, renewal and update of knowledge. Improving urban amenities and ecosystem services by creating sustainable urban environment is one of the fundamental components for KBUD. In this context, environmental assessment plays an important role in adjusting urban environment and economic development towards a sustainable way. The purpose of this paper is to present the role of assessment tools for environmental decision making process of knowledge cities. Design/methodology/approach – The paper proposes a new assessment tool to figure a template of a decision support system which will enable to evaluate the possible environmental impacts in an existing and future urban context. The paper presents the methodology of the proposed model named ‘ASSURE’ which consists of four main phases. Originality/value –The proposed model provides a useful guidance to evaluate the urban development and its environmental impacts to achieve sustainable knowledge-based urban futures. Practical implications – The proposed model will be an innovative approach to provide the resilience and function of urban natural systems secure against the environmental changes while maintaining the economic development of cities.

Development of pollutant build-up parameters for MIKE URBAN for Southeast Queensland, Australia

Accurate estimation of input parameters is essential to ensure the accuracy and reliability of hydrologic and water quality modelling. Calibration is an approach to obtain accurate input parameters for comparing observed and simulated results. However, the calibration approach is limited as it is only applicable to catchments where monitoring data is available. Therefore, methodology to estimate appropriate model input parameters is critical, particularly for catchments where monitoring data is not available. In the research study discussed in the paper, pollutant build-up parameters derived from catchment field investigations and model calibration using MIKE URBAN are compared for three catchments in Southeast Queensland, Australia. Additionally, the sensitivity of MIKE URBAN input parameters was analysed. It was found that Reduction Factor is the most sensitive parameter for peak flow and total runoff volume estimation whilst Build-up rate is the most sensitive parameter for TSS load estimation. Consequently, these input parameters should be determined accurately in hydrologic and water quality simulations using MIKE URBAN. Furthermore, an empirical equation for Southeast Queensland, Australia for the conversion of build-up parameters derived from catchment field investigations as MIKE URBAN input build-up parameters was derived. This will provide guidance for allowing for regional variations in the estimation of input parameters for catchment modelling using MIKE URBAN where monitoring data is not available.

Complex Urban Systems

Presentation about research projects that build understanding of urban design and interactions and plan for future opportunities. What do we need to model?

Urban Informatics in Creative Industries

Presentation of research projects