Korong Vale Flood Study

The Korong Vale Flood Study involved the development of hydrologic and hydraulic models to assess flood risks in the township and surrounding areas. These models were validated using three historic flood events from September 2010, January 2011, and October 2022. Various design flood events, ranging from the 20% to 0.01% Annual Exceedance Probability (AEP) and the Probable Maximum Flood (PMF), were modelled along with storm durations from 3 to 12 hours.

The study also evaluated sensitivity scenarios such as roughness variations, blockages, and downstream boundary conditions. Climate change scenarios were modeled for both RCP4.5 and RCP8.5 emissions pathways for the 10% and 1% AEP events projected for 2090. Four structural and non-structural flood mitigation options were assessed, including modeling the full range of design events, cost estimation, damage assessment, and benefit-cost analysis. However, none of the options achieved a high benefit-cost ratio (BCR), with the highest BCR at 0.84.

The study recommends that the Council consider voluntary house raising as the most feasible mitigation measure and advance it for further discussion. Additionally, a range of flood intelligence outputs has been developed to support flood response efforts and is recommended for adoption by the Council and VICSES for improved emergency management during flood events.