Population growth in Australian cities is predominantly being absorbed by infill development in older middle suburbs that have large blocks of land and housing at the end of its life. Infill development is anticipated to continue over the coming decades as city populations grow.
Infill development lacks a strategic planning framework and is resulting in piecemeal, ad hoc developments that are reducing the liveability and amenity of our cities.
Water sensitive infill design can support both higher density living at the same time as preserving or improving liveability. It can improve city water performance and reduce urban heat.
Research findings and reports
- The Water sensitive outcomes for infill development: final report summarises the outcomes from Integrated Research Project 4 and explains the project's three main outputs: the Infill Performance Evaluation Framework, the Site-scale Urban Water Mass Balance Assessment (SUWMBA) Tool and the Infill Typologies Catalogue.
- The Infill Development Evaluation Framework demonstrated that, compared with business as usual development, water sensitive urban design can support denser development without increasing the impact on hydrological flows. (Quantifying the hydrological performance of infill development)
- The Urban Metabolism Evaluation Framework for Water (UMEF4Water) is useful for understanding current water metabolism performance and the influence of water sensitive interventions. Assessing metabolic performance at a smaller scale can inform decisions on water sensitive interventions for infill development. (Urban metabolism for planning water sensitive city-regions Proof of concept for an urban water metabolism evaluation framework)
- In 2016, there was no targeted water sensitive urban design (WSUD) policy for urban infill and lot scale development in Queensland, New South Wales, Victoria, South Australia or Western Australia. (Policy framework for water sensitive urban design in 5 Australian cities)
- Road space in urban infill development is important for locating WSUD interventions. (Analysing water sensitive urban design options)
The CRCWSC’s urban infill research has been applied to:
- The Townsville, Brisbane, Knutsford and Salisbury integrated case studies demonstrate how to use the suite of CRCWSC tools to assess water sensitive options for infill developments.
- The Scenario Tool worked example: Highett Gasworks demonstrates how the tool was used to assess how various development options will impact urban heat and the water cycle in a hypothetical development at the Highett Gasworks.
- The Knutsford and Salisbury case studies demonstrate the potential for coordinated architectural and water services design for mitigating adverse impacts of infill development and the value of interdisciplinary collaboration in urban water, planning, modelling, engineering and design.
- Ideas for Bentley identifies best practice water sensitive initiatives for a major infill development project in metropolitan Perth. The proposed ideas include:
- enhancing the central green spine
- implementing a precinct-scale water grid
- establishing additional local water sources
- incorporating water sensitive buildings.
- The Central Park recycled water scheme services a mixed-use high density infill development in Sydney. Wastewater is collected from buildings within the development and an adjacent public sewer. Recycled water is distributed within the precinct to supply water from cooling towers, irrigation, toilet flushing and washing machines.
Tools and guidelines
We have developed industry tools and guidelines informed by our urban infill research, for example:
- The Infill Typologies Catalogue provides evidence-based design guidance to enable better informed residential infill practice. A range of housing typologies are provided, at densities and configurations relevant to Australian cities and applicable to different contemporary infill development scenarios. The water sensitive performance of each typology is evaluated.
- The Infill Performance Evaluation Framework is a guide for assessing design of small-scale infill development to support water sensitive cities outcomes. The framework includes three groups of performance criteria: (i) water performance (which includes hydrology, water demand and supply, greening), (ii) urban heat, and (iii) architectural and urban spaces quality.
- The Site-scale Urban Water Mass Balance (SUWMBA) Tool provides a comprehensive account of water flows in the natural and anthropogenic water cycles (including rainfall, evapotranspiration, stormwater runoff, imported water, decentralised water and wastewater).
The following infographics can be useful for demonstrating urban heat concepts:
Components of the Infill Performance Evaluation Framework (Renouf et al., 2020. Water Sensitive Outcomes for Infill Development: Infill Performance Evaluation Framework. Melbourne, Australia: CRC for Water Sensitive Cities., p. 15.)
Cause and effect framework linking urban design parameters to water sensitive performance criteria (Renouf et al., 2020. Water Sensitive Outcomes for Infill Development: Infill Performance Evaluation Framework. Melbourne, Australia: CRC for Water Sensitive Cities, p. 26.)
Example of multi-indicator performance reporting (Renouf et al., 2020. Water Sensitive Outcomes for Infill Development: Infill Performance Evaluation Framework. Melbourne, Australia: CRC for Water Sensitive Cities, p. 53.)
Site selection for the maximised water sensitive scenario (London et al., 2020. Water Sensitive Outcomes for Infill Development: Knutsford Case Study Final Report. Melbourne, Australia: CRC for Water Sensitive Cities, p. 63.)
Overview of performance analysis of the Existing (EX), Business as Usual (BAU), Water Sensitive Conservative (WS-Con) and Maximised (WS-Max) scenarios (Renouf et al., 2020. Salisbury case study final report: water sensitive outcomes for infill development. Melbourne, Australia: CRC for Water Sensitive Cities, p. 14.)