Smythesdale Flood Study

The first stage in managing flooding risk for a particular catchment involves a flood study, which is a comprehensive technical investigation of flood behaviour for that catchment. A flood study will show the distribution, extent, levels and velocity of floodwaters across sections of the floodplain for a range of different flood events.

The study assists in updating flood related overlays within the Golden Plains Planning Scheme utilising advanced flood mapping techniques. The study will also improve future land use planning and development decisions to minimise the risks to the Smythesdale community from flooding. 

The study will also assist Council in understanding existing drainage problems and inform new infrastructure to be planned to mitigate potential flooding.

The study assists Corangamite Catchment Management Authority (CCMA), Golden Plains Shire and Victorian State Emergency Service (VICSES) prepare for and respond to a flood emergency in Smythesdale. 

The Victorian Government and the Australian Government’s Disaster Ready Fund (DRF) are funding the flood study.

Council are project managing the flood study with technical support from Corangamite Catchment Management Authority (CCMA), Victorian State Emergency Service (Vic SES), and Wadawurrung (Wadawurrung Aboriginal Traditional Owners Corporation.

The study is being prepared by expert consultants Water Technology, who will work closely with Council, key stakeholders and the community.

In addition to this a Project Working Group has been established that brings a broad range of stakeholders, knowledge and experts into the project. Representatives from Corangamite Catchment Management Authority (CCMA), Victorian State Emergency Service (Vic SES), Wadawurrung (Wadawurrung Aboriginal Traditional Owners Corporation) and Council officers from Strategic Planning, Development Engineering, Roads and Drainage Engineering, and Emergency Management teams have been included.

The Smythesdale Flood Study is a medium-term project, which includes the following stages:

• Preliminary assessment of frequency and severity of flood events and the impacts of climate change.
• Investigation of options to manage flooding.
• Development of the draft Smythesdale Flood Study.
• Development of flood protection and preparedness activities based on the results of the draft Smythesdale Flood Study.

There is existing flood mapping applying to properties in the vicinity of the Woady Yaloak River. It is understood that this mapping is outdated and underestimates the extent of the flood hazard based on indicative evidence/advice from the Corangamite Catchment Management Authority (CCMA). Existing flood mapping also does not account for impacts from climate change, which are anticipated to be substantial.

The Smythesdale Flood Study results will also inform the development of any necessary flood-related planning tools, which will include a planning scheme amendment. If specific properties are identified as likely to be affected by flooding in the future, those properties may be impacted by new flood-related planning controls.

Any proposed flood-related planning controls will guide current and future property owners and developers to consider flood risk while developing properties, which may include the need for planning permits.

What is a Flood Overlay (FO)?
The FO is a planning tool applied to land that's identified as carrying active flood flows associated with waterways and open drainage systems and high hazard areas. This overlay requires a planning permit for buildings and works.

What is a Land Subject to Inundation Overlay (LSIO)? 
The LSIO is a planning tool applied to land designated as being subject to inundation in the event of a 1% AEP flood. It triggers development proposals which require planning approval to be designed in a manner compatible with the flood risk to the site.

What is a Special Building Overlay (SBO)? 
During severe storms in urban areas land can be affected by overland flows if the rainfall run-off exceeds the design capacity of the existing drainage system. This is called stormwater flooding and can occur in areas where there is a high density of existing development, and a high potential for flood damage. The Special Building Overlay (SBO) identifies areas affected by stormwater flooding in planning schemes to ensure new development is designed accordingly. 

Property values are determined by many different factors including economic conditions, public economic policies, location, streetscape and amenity. It is difficult to assign what effect the identification of land as flood prone may have on the value of a property. The property market determines the value of any residential property.  Individual owners should seek their own valuation advice if they are concerned that flood classification may influence their property value.

The insurance industry has developed its own database of flood risk Australia wide for individual properties, which has regard for both depth of flooding and frequency of flooding. If you are concerned that a premium is excessive, you may ask for a review by your insurance company or you may consider alternative quotes from other insurance providers.

There are several opportunities for the community to get involved:

• Data Review: this will introduce the project, share historical data and take input from the community. Hardcopy and online data maps will be available to help discussion and knowledge reporting. 
• Consideration of potential protection options; the sharing of study results, mapping and possible response options (subject to feasibility).
• Exhibition of a Planning Scheme Amendment; this will present the final results and inclusion of any overlays. 

We are keen to hear your knowledge and recollections, and we encourage you to share any photos, recordings or materials that will help us understand the locations, dates, times and depths of previous flood events in 2011, 2016 and 2022.

If you are sharing photos, please let us know when and where photos were taken, and use landmarks, items or building measurements to describe depths.

For example:

• "The water was up to the bonnet of my car in the driveway at 2 Pope Street on Monday 10am in October 2000."
• "The water was at the top of the culvert on Flooded Road on Thursday at 4pm in January 2011."

We will also ask for your contact details in case we need to investigate further.

If you would like to discuss this further, please contact Council’s Strategic Planning Division at Golden Plains Shire on 5220 7111.