Groundwater Risk Assessment & Management Strategy, Perth Stadium, Burswood Peninsula
The recently completed Perth Stadium and Sports Precinct is located on the Burswood Peninsula, which has a number of man-made and natural geotechnical and environmental constraints including:
- the site was used as an industrial waste landfill between 1950 and 1980;
- former mud flats comprising deposits of Swan River Alluvium (SRA) which is a compressible riverine unit with acid sulphate soil properties;
- a large lake which is fed by the Swan River and is a key element to the Stadium landscape design.
The site required ‘geotechnical improvement’ to ensure the structural integrity of the stadium super structure and associated infrastructure. Settlement of the SRA would result in groundwater being expelled into the overlying man made and underlying natural geology. Groundwater within the SRA contains relatively higher concentrations of nutrients compared to the other geological units, and given that the shallow aquifer is connected to the River-fed Lake and Swan River, there was a risk that increased nutrient concentrations could impact surface water quality. Tasks undertaken included:
- A water balance of the River-fed Lake was constructed to assess the relative magnitude of inputs and outputs to this key receptor.
- Groundwater modelling (MODFLOW 2000; MT3DMS 5.3 Solute Transport Model) to assess the likelihood that measurable changes in groundwater quality would occur and impact the River-fed Lake and Swan River.
Based on the River-fed Lake water balance, the predicted and measured changes in nutrient concentrations in groundwater flowing into the Lake were considered unlikely to measurably impact water quality. The low potential risks from nutrients therefore did not justify a pre-emptive management approach during construction works, i.e. groundwater abstraction did not need to be implemented.
Monitoring was undertaken in key ground improvement areas and the results supported model predictions. The model and risk assessment were reviewed and endorsed by the Contaminated Sites Auditor, State Government Environmental representative and environmental regulators including Department of Water and Environmental Regulation. By adopting a risk based approach cost savings of approximately $1M were achieved.
Aurora provided strategic environmental advice in relation to groundwater management during planning stage for ground improvement works by strongly encouraging a risk based approach which went against precedence established by other projects in the vicinity and the prior civil works phase at the Site. This required Aurora to instil a high level of confidence in the regulators that the approach was appropriate.
For further information on this project please contact:
Name: Pamela Lee
Phone: (08) 9227 2600
- Groundwater monitoring
- Stakeholder engagement and negotiations