Rainwater tanks for on-site detention in urban developments in Western Sydney : an overview

Increases in population, pollution and environmental controls require government authorities to review policies towards sustainable water management. A holistic approach is increasingly becoming popular to integrate water demand, supply and stormwater management in urban developments. This is likely to affect current on-site detention and rainwater tank practices. On-site detention, a common feature of modern urban drainage systems, is to cope with under capacity street drainage and for flood and erosion control purposes. Rainwater tanks though primarily used for water supply can be used for on-site detention. Some councils and government authorities have combined on-site detention systems and rainwater tanks to achieve an overall cost saving. This paper presents a brief overview of the on-site detention and retention practices adopted in greater Western Sydney. It has been found that policies differ significantly for different councils. Recent studies have focused on the use of on-site retention instead of on-site detention, which has raised the question on the scale of modelling. A research project has been set up to compare the flow characteristics and water quality of conventional on-site detention system with a rainwater tank fitted with appropriate WSUD device on redeveloped properties in Western Sydney to enhance the applicability of total water cycle management.