Project Number # 3023
Background and Relevance
Stormwater is recognised as a major untapped resource to augment Australia’s water supply in a context of increased water demand and climate change uncertainty. Public, political and technical acceptance of stormwater harvesting requires robust hazard assessment and risk management. Pilot schemes in Australia have been developed over the last 5-10 years and are now at a stage where they can be used as the basis for developing meaningful tools to assist with the creation of further schemes.
WaterRA Project 3023 performed 3 case studies of Australian stormwater harvesting schemes in order to better understand the role of the catchment as a treatment barrier. The three schemes included: Parafield City of Salisbury, Barker Inlet Adelaide and Fitzgibbon Qld. The case studies identified land uses and sources of hazards, modelling of flow pathways, fate modelling of contaminants under the expected flow regimes, and hence identification of contaminants with greatest risk.
Using these case studies and other water quality data provided by the project participants, the project team developed a decision support tool, Chemical Hazard Assessment of Stormwater Micropollutants (CHASM). The purpose of CHASM is to provide water professionals with a rapid, simple and yet robust and defensible method to 1) identify the chemical hazards associated with land use and activities in potential stormwater catchments, and 2) provide guidance on a monitoring program that would most efficiently and effectively identify chemicals of concern to ensure safe use.
CHASM has been designed to complement the Australian Guidelines for Water Recycling - Stormwater Harvesting and Reuse (NRMMC-EPHC-NHMRC, 2009b), which provides more detailed guidelines on harvesting stormwater for use in Australia (including dealing with pathogen hazards). A stormwater project screening tool is described in Section 3 of the AGWR:SHR (2009) and summarised below. This should be initially consulted to guide the user on where CHASM can be used in the process of assessing the suitability of stormwater for various potable and non-potable use options.
The latest version of CHASM is available here.
The WaterRA CHASM User Guide should be read prior to using the tool and is available here.
If you would like to be kept up to date on changes with the tool please submit your email here.