The Challenge

Toowoomba Regional Council was planning to widen the bridge crossing of Condamine River at Lemontree-Bostock Road. The bridge crosses a branch of the Condamine River. The Condamine River is fed by a large catchment that extends significantly beyond Council’s LGA and has a wide, complex floodplain. Flood levels and velocities were required to support the bridge design process.

Approach and Outcomes

WMS developed cut-down, fine resolution TUFLOW CPU and GPU models of the study area fed by inflows from a complex MIKE FLOOD Flexible Mesh model also previously developed by us. Simulations were undertaken for the 10 yr, 20 yr, 100 yr, 500 yr, 500 yr and 2,000 yr ARIs with 2,000 yr flows estimated from a multiplier of 500 yr flows. Modelled velocities were then validated using HECRAS.