Since 2011 flood, a number of mitigation measures have been implemented for reducing the risk of flooding in Toowoomba and surrounding region. However, an assessment of the vulnerabilities of existing infrastructures under extreme flood events and the future expansion load is necessary to determine the effectiveness of the measures for flood proofing. Toowoomba Regional Council (TRC) has developed and maintained a suite of hydrological and hydraulic models for catchment planning and management. A confidence needs to be built in the existing modelling tools accounting the recent upgrades in the drainage system and changes in hydrologic characteristic. The change in land use pattern considerably affects the runoff characteristics. The loss of open space and floodplain storages has been the issue for major flooding. The drainage system has been upgraded recently with detention basins for reducing the floods risks. However, the undersized structures such as culverts, bridges and sluices gates create drainage congestion in various parts of the catchment from low to moderate level flooding. A proper water balance of catchment storages and accounting of hydrologic losses are necessary components for improved modelling, which will be investigated in this study. The project aims to be undertaken through 1) hydrological monitoring of runoff and infiltration losses in various part of the catchment; 2) development of the methodology to improve the loss function used in the hydrologic model; 3) updating the existing models and evaluation of models performance; 4) Assessment of land use and climate change impact on runoff characteristics; and 5) evaluation of the drainage performance in upgrading and accommodating the future changes. The research will be highly innovative through adopting latest technology and advanced methods in computational modelling. The study will develop a tool for proper accounting of hydrologic losses, which will provide a greater accuracy in Council’s existing models for predicting catchment runoff and stream flow.

Dr Md Jahangir Alam

• Dr Md Jahangir Alam

• School of Engineering and Built Environment

• Civil Engineering
• Environmental Engineering
• Other Earth Sciences

• Doctor of Philosophy (DPHD)