The Granite Creeks Regional Flood Mapping Study is one of several Victorian regional flood studies currently in progress. The objective of these studies is to develop valuable flood intelligence for rural Victorian floodplains, where currently very little information is available.
This article provides a short description of the project and asks for anyone with knowledge of flooding in the study area to provide feedback via the online map.
The Granite Creeks study area includes the floodplain from Avenel to Baddaginnie along the Hume Fwy and north through to the Goulburn and Broken Rivers. It includes many waterways with complex flow patterns.
A Complex Study
The estimation of historic and design hydrology was difficult given the number of ungauged waterways within the study area and the complex anabranching and cross catchment flows. A floodplain of this size also held challenges in the hydraulic modelling. This was solved by using a flexible mesh model which enabled model resolution to vary across the floodplain, with models running on the computer’s Graphical Processing Units (GPUs) to speed up model run time. Without this technology, detailed studies of floodplains of this size would not be feasible.
Given the various challenges modelling an area of this size, it was important to ensure the models accurately reproduced observed flooding. Multiple community information sessions were held at four different locations across the study area, and at each, we received good feedback on the accuracy of the modelling. We have begun capturing a number of the most recent comments on our online map.
Have Your Say
We invite anyone with knowledge of flooding in the Granite Creeks study area to review the Draft 1% Annual Exceedance Probability (AEP) flood mapping via the online map, and leave a comment on the map. A 1% AEP flood has a 1% chance of occurring in any given year, this is much larger than any flood event in recent history in the study area. Users can leave a comment by accessing the online map and following the instructions set out below.
The detailed mapping has shown that in many locations, the flooded area is less than that shown in the older coarse mapping that was largely done by hand, and results have been well received by community members across the study area. This is a good example of where technology and local information are combined to create more accurate flood mapping extents which can be used for land use planning, emergency response and insurance purposes. In this instance, many landholders will be better off as a result of this flood study.
This study was completed by Water Technology on behalf of the Department of Environment, Land, Water and Planning, in conjunction with Goulburn Broken CMA, Strathbogie, Shepparton and Benalla Councils, and VIC SES.
For more information please contact Ben Tate or Lachlan Inglis on (03) 8526 0800.