Hydraulic Impact Assessment for Enoggera Road

Lloyd Street Service Station

Location: Alderley, Brisbane, QLD


A Hydraulic Impact Assessment was carried out to support the development application for a proposed service station located on the corner of Enoggera Road and Lloyd Street, Alderley. The site hydrology was subjected to a highly urbanised catchment, consisting of 14 sub-catchments, with the proposed development significantly altering the local storage of the site. Subsequently requiring a new stormwater drainage system underneath the site. The scope of the project was to develop, calibrate, and test hydrologic and hydraulic models for the catchment to inform and devise appropriate mitigation strategies for the proposed development.


  • Extrapolation and mapping of flood levels and afflux, discharge and velocity where required to prove post-development flow mitigation.
  • Hydraulic modelling for the 1, 2, 5, 10, 20, 50 and 100 year Average Recurrence Interval (ARI) design storm events for pre- and post-development scenarios.
  • Two dimensional, unsteady hydraulic model incorporating sub-grid scale piped drainage networks using one-dimensional modelling to estimate flood levels within the area.
  • Hydrologic modelling for the 1, 2, 5, 10, 20, 50 and 100 year ARI design storm events.