|Project||Bakers One Stormwater Trunk Drainage Study|
|Client||Mackay Regional Council|
|Location||Ooralea, Mackay, Australia|
|Disciplines/Service||Design Event Hydrologic and Hydraulic Modelling
Trunk Drainage Assessment
Water Sensitive Urban Design
|WRM Contact||Greg Roads|
The Ooralea development area, located to the south of Mackay, drains via small capacity constructed channels through cane fields with much of the development area inundated to shallow depths during flood events. The key challenge was to develop a system of cost-effective trunk drains that were functional, attractive open spaces that could be used for recreation when not in flood and did not impact on adjacent properties.
Approach and Key Activities
Flood discharges within the catchment were estimated using a calibrated XP-RAFTS hydrological model. These design discharges were incorporated into a TUFLOW hydraulic model to estimate design flood levels and extents and to assess the capacity of the existing drainage system. The models were validated to the February 2008 flood event, which inundated the majority of the study area.
Conceptual designs of the drainage infrastructure were developed that maximised the developable area and provided sufficient hydraulic capacity to mitigate flooding up to the defined flood event. The drainage infrastructure incorporated natural channel design principals to improve water quality and enhance the ecological value of the waterways and the downstream wetlands. Concept designs of both regional and local water quality infrastructure were developed and sized using MUSIC water quality modelling. Concept designs and infrastructure costs were developed for a range of development scenarios to maximise the development options available to council.
The study provided council with an integrated suite of water quality and drainage infrastructure for the Ooralea development area that maximised the developable area and ensured that the ecological values of the waterways and downstream wetlands could be maintained and enhanced. Each option was fully costed to allow council to make informed decisions on infrastructure charges for future developments.