Flooding can affect your development plans. One of the CMA's main functions is providing advice and recommending building controls on proposed development for councils in the Corangamite region. The CMA assesses flood risk associated with depth and velocities of the modelled 1 % AEP flood and applies the best-practice flood management methods to apply controls that will reduce flood damages and risk to life.
Where flood extents are known, Council’s are accountable for ensuring that their Planning Schemes correctly identify the areas of risk of a 1% AEP flood. Not all flood mapping has been identified in Council’s Planning Schemes, so it is important to check with the CMA and Council for any available mapping.
You can generate a planning property report free of charge for any property in Victoria which will tell you if your property has a flooding overlay.
Information about zones and overlays is also available through the relevant Planning Scheme via Planning Schemes Online or by contacting your local council.
Corangamite CMA is responsible for a range of statutory functions under the following state government acts, relating to floodplain management:
Under Part 10 (sections 201 to 212) of the Water Act 1989, Corangamite CMA has floodplain management responsibilities for its declared CMA region.
Key functions include:
- To find out how far floodwaters are likely to extend and how high they are likely to rise
- To declare flood levels and flood fringe areas
- To declare building lines
- To control developments that have occurred or that may be proposed for land adjoining waterways
- To develop and implement plans and to take any action necessary to minimise flooding and flood damage
- To provide advice about flooding and controls on development to local councils, the Secretary for Planning and Environment and the Community.
Statutory Referral Process & Planning Permits
Their key purpose is to:
- minimise the effects of overland flows and flooding on new buildings
- ensure new developments don’t adversely affect existing properties
Overlays are based on the extent of flooding resulting from a 1 in 100 year storm. This relates to a storm event of such intensity, based on historical rainfall data, which has a one per cent chance of occurring in any given year.
Having this information means drainage issues can be addressed at the start of the development process and proposals are properly designed.
Types of overlays
There are four types of overlays within Councils Planning Schemes that relate to flooding. They are:
Special Building Overlays (SBO)
These are planning scheme controls that identify areas prone to overland flooding. The purpose of these overlays is to set appropriate conditions and floor levels to address any flood risk to developments. These overlays require a planning permit for buildings and works.
Land Subject to Inundation Overlays (LSIO)
These are planning scheme controls that apply to land affected by flooding associated with waterways and open drainage systems. Such areas are commonly known as floodplains. These overlays require a planning permit for buildings and works.
Floodway Overlays (FO)
These apply to land that's identified as carrying active flood flows associated with waterways and open drainage systems. This overlay is categorised by depths in excess of one metre.
Urban Floodway Zone (UFZ)
Unlike the overlays, the UFZ controls land use as well as development, with land use being restricted to low intensity uses such as recreation and agriculture. Development is generally not encouraged in the UFZ.