The City of Ballarat Council Plan 2021-2025 and Ballarat Strategy 2040 identifies a need to better understand the effects of flooding and introduce planning controls to enable authorities, residents and businesses to understand and manage possible flood risk.

Identifying flood risks will minimise the impacts of flooding on the community through improved planning and development decisions and assist in prioritising where infrastructure improvements and flood mitigation should occur.

Ballarat City Council will consider the flood mapping and the proposed planning scheme amendment at a Planning Delegated Committee Meeting and decide whether to adopt the flood models and request to start a planning scheme amendment to implement the flood modelling into the Ballarat Planning Scheme.

The community will have an opportunity to participate in another community engagement and are invited to make a formal submissions during the notice period.

Any evidence-based inputs from the community that require the flood modelling to be updated will be considered.

There are 11 waterways that are part of this project, with some tributaries (streams flowing from waterways) counted as one.

The waterways included are:

• Yarrowee River
• Gnarr Creek
• Canadian Creek and tributaries
• Bonshaw Creek
• Redan Creek
• Kensington Creek
• Chase Waterway
• Little Bendigo Creek
• Hit or Miss Gully
• Warrenheip Creek
• Ryans Drain.

There are several waterways, including defined waters, drains and gullies not included in the project.

The Winter Creek was not included due to its location on the municipality's outskirts. It also does not directly impact any densely populated areas or areas identified for future development.

The Union Jack Creek was not included but has been identified for modelling soon due to potential flood impacts within the township of Buninyong.

Burrumbeet catchment, including Miners Rest township, is not included, as it currently has flood overlays. These overlays are due to be updated soon.

The information generated by the flood study will be used by the City of Ballarat to inform the application of the Land Subject to Inundation Overlay and Floodway Overlay. The information will also be used by VICSES and the City of Ballarat to plan flood response activities (cleaning drains, sand bagging, road closures etc) and mitigation planning and implementation.

Flood events are described as an annual percentage likelihood (Annual Exceedance Probability – AEP). For example, a 1 per cent AEP event would have a one per cent likelihood of occurring in any given year, this would be the same as once in a 100-year period.

Climate change has been incorporated in the flood modelling undertaken. The models depict the 1%AEP (1 in 100 year) flood levels in 2100 based on RCP 8.5.

This study has been confined to flooding from waterways so there are two overlays that are likely to be introduced to the flood prone land, the Floodway Overlay and the Land Subject to Inundation Overlay.

Some development on properties affected by one of these overlays require a planning permit. Most planning permit applications would be considered by the Corangamite Catchment Management Authority and the City of Ballarat. The application process would seek to ensure, amongst other matters, that any development maintains the free passage and temporary storage of flood waters and the minimisation of risks from flood hazard.

Flood overlays do not stop development. They provide a trigger for the Catchment Managment Authority and the Planning Authority to ensure development is designed to minimise the risk to life and property.

Where a proposed development does not expose people to an unacceptable hazard or does not make flooding worse elsewhere, it may be permitted subject to conditions. Some buildings and works can be exempted from requiring a planning permit and these are detailed in the Schedules to the Floodway Overlay (FO) and Land Subject to Inundation Overlay (LSIO). These schedules are to be included in the planning scheme amendment.

The property market determines the value of any residential property. Property 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 for individual properties, the National Flood Information Database (NFID), which has regard for both depth and frequency of flooding. This national flood database is based on the most up-to-date flood studies, rather than flood overlays.

Flooding is a natural hazard in Victoria’s river systems and natural and constructed drainage systems. 

Understanding flood behavior enables us to assess the likely impacts and costs of flooding. It also enables us to assess the benefits of different options for managing the community’s exposure to flood risk. There are no quick fixes in reducing the damage caused by flooding. Two centuries of development on flood plains and low-lying areas mean that legacy issues will remain for a very long time.

To help us understand the flood risk in Ballarat, we have undertaken extensive flood modelling of the waterways using the latest land and rainfall data and computer technology. We are using this data to introduce overlays into our planning scheme to reduce the risk in flood-prone areas and to investigate a range of mitigation options in the smaller catchments (drainage systems). These mitigation options include detention systems, pipe augmentation projects and constructing open spaces that introduce Water Sensitive Urban Design and Integrated Water Management that include mitigation strategies. Each option will be prioritised and funding will be sought in future budgets.

For areas that are affected by inundation caused by stormwater drainage networks reaching capacity, we have an on-going pro-active and planned maintenance program of drainage pit cleaning to reduce nuisance flooding in high risk areas.

The City of Ballarat works closely with our relevant Catchment Management Authorities, the State Emergency Services, VicRoads (Regional Roads Victoria), Department of Transport and Planning and other government agencies on flood prevention, response, recovery and mitigation activities.

Larger flood projects currently underway include the Miners Rest Flood Mitigation Plan. This plan includes actions that will reduce the impacts of flood during large rainfall events. The city is also progressing with two dam wall projects: Buninyong Gong Dam wall upgrade and Charlesworth Street dam wall construction, Ballarat East. These two projects, earmarked for construction in 2025, will protect downstream properties from large scale flood events.