Case study

Redbank Motorway Estate

ProjectRedbank Motorway Estate Flood & Stormwater Assessment
ClientGoodman Property Services Pty Ltd
LocationRedbank, Australia
Completion2013
Disciplines/ServiceHydraulic Model Analysis
Hydraulic Model Development and Verification
Flood Hazard Mapping
WRM ContactGreg Roads

The Challenge

WRM Water and Environment were engaged by Goodman Property Services Pty Ltd to prepare a flood and stormwater management plan for the proposed 86 hectare Redbank Motorway Estate industrial development located adjacent to the Brisbane River in Redbank. The key challenges for this project included the development of stormwater quality and drainage infrastructure and maximising the developable area above the Brisbane River Flood Planning Level, which changed following the January 2011 flood.

Approach and Key Activities

The proposed development incorporated major earthworks within the flood fringe areas of the Brisbane River.  No works were proposed within the waterway corridor.  Mike 11 models of the Brisbane River were developed to assess the impact of the earthworks on peak flood levels due to the loss of flood storage for a range of events including the historical January 1974 and January 2011 events, which were much higher than the previous defined flood level for the site. Further detailed modelling was undertaken using the TUFLOW hydraulic modelling package to assess flood hazards for the 1974 flood event and January 2011 flood events and prepare a flood risk assessment for the site.

Detailed hydraulic modelling  of the stormwater drainage system across the site using the TUFLOW model was also undertaken.  The results of the modelling were used to design the size of the proposed drainage infrastructure and stormwater easements.  Site based plans have also been developed to determine water quality infrastructure for each site.

Outcomes

The stormwater management plan, including a bulk earthworks plan for the entire development and a detailed stormwater management plan for Stage 1 was approved by Ipswich City Council.