Role of North East CMA Floodplain management is a core function of the North East CMA. Floodplain management functions within Victoria have been delegated to CMAs, and are described under Section 202 of the Water Act 1989. The North East CMA plays an important role in the development of flood studies and floodplain management plans, provides relevant referral advice and ensures development does not compromise the storage functions of floodplains.
North East CMA’s regional floodplain management vision:
"With the involvement of the community, maintaining and enhancing the importance of floodplains by implementing flood management measures which reduce flood risk to lives, health and property, and flood damage costs, whilst allowing for natural floodplain storage and enhancing the environmental values of floodplains".
Key floodplain management activities undertaken by the North East CMA include:
- Improved flood mapping and land use planning controls
- Advise councils on individual planning applications associated with floodplains and river health
- Collecting of recent as well as historic flood information
- Develop and implement floodplain management plans
- Assist in flood warning processes to lead emergency agencies
- Declare flood levels for building and planning purposes
Environmental Benefits of Floodplains
A floodplain is described as the area of land that is inundated with water when the flow in a waterway (river, stream or creek) exceeds the discharge capacity of the main channel. Flood flows are distributed over a broad, relatively flat area of land often inclusive of wetlands and flood channels.
Floodplains are an essential part of a catchment’s ecosystem processes. The ecological values they encompass and the significance of the habitats they provide is extremely important for our native species. Since the late 1980s and early 1990s it has been increasingly recognised that the health of a river and its floodplain is interdependent and that periodic flooding that maintains the connection between the two. Waterways and their connecting wetlands and floodplains provide substantial areas of habitat for native flora and fauna; they move food sources through the system and allow for the migration and emigration of aquatic animals– often a critical factor in the survival of many native species.
While there are many benefits to natural flood events, they are also known to impact the economic and social wellbeing of local communities.
Development of Floodplains
Floodplains in Australia are regarded as a national asset, given that from the time of early settlement to the present they have been supporting our nation. Most of our major cities and towns are located on floodplains, for reasons relating to: water supply, transportation and waste disposal (more important in the past), productive soils and recreation purposes. Consequently, many towns and cities are exposed to flood risk.
Many communities that have settled within floodplains are today exposed to hazards in times of major flooding. Significant consequences are a reality, in terms of both flood damage and human suffering, as a result of historic development within floodplains. This is known as the existing (or legacy) flood problem.
The broad floodplain management objective in land use planning is described in the State Planning Policy Framework Clause 13.02-1 (Victoria Planning Provisions) in all planning schemes.
The floodplain management objective is to assist the protection of:
- Life, property and community infrastructure from flood hazard
- The natural flood carrying capacity of rivers, streams and floodways
- The flood storage function of floodplains and waterways
- Floodplain areas of environmental significance
Statutory land use and development planning seeks to manage the growth in future flood risk. The 1% Annual Exceedance Probability (AEP) flood event (or 100 year Average Recurrence Interval (ARI) flood) is identified as the design flood event for regulation of new development and construction standards in Victoria. Catchment Management Authorities are responsible for identifying land along rivers and streams in Victoria lying within the extent the 1% AEP event. These areas are generally incorporated as overlays in Council Planning Schemes and are shown as either a Land Subject to Inundation Overlay or a Floodway Overlay. The overlays provide a trigger for a planning permit to review of proposed developments to ensure it is compatible with flood risk. In so doing, the aim is to avoid or minimise the increase in future flood risks.
All land use and development applications must be consistent with the above objectives. Accordingly land use planning and development controls, seeks to:
- Steer inappropriate land uses and developments away from floodplain areas;
- Minimise the exposure of new developments to flood hazard, and avoid intensification of development on flood prone land;
- Minimise adverse impacts on existing settled areas from new development and intensification;
- Preserve flow conveyance and temporary flood storage so they are not unduly compromised;
- Minimise the demands on emergency and community services;
Protect environmental values and water quality within floodplain and waterway areas.
ASSESSING FLOOD RISK
What information is available from the North East CMA?
The North East CMA provides flood level information for individual properties upon request.
Information is provided based on the available evidence of the 1% AEP event (Water Act 1989, sections 203 and 204) and will generally include a description of the depth and extent of flooding on a property. Additional information, such as floor levels of existing dwellings is generally not available. Requests for individual flood information of the 1% flood level must be made in writing.
Flood information forms are available from the link below. The North East CMA attempts to respond to such requests for information within 14 days from receipt of the request.
Flood Plain Advice Request Form
NE CMA Floodplain Advice - MS DOCX
Individual property owners concerned about their flood risk insurance premiums are advised to check first the Planning Report for their property (available from the Victorian Land Channel website) and, if applicable, request their insurance company or insurance agent to review the premium if the property is outside the 1% AEP and as such the flood risk is extremely rare.
It should be understood that any flood information provided represents the best estimates based on currently available information at the time the Planning Scheme was approved. This information is subject to change as new information becomes available and as further studies are carried out. North East CMA may be able to provide more recent information at the property scale. It should also be recognised that larger flood events (i.e. larger than a 1% AEP flood event) may occur, and the Insurance Industry has to assess this risk in the establishment of insurance premiums. Insurance providers may differ in their assessment of flood risk and therefore insurance premiums may vary.
ENVIRONMENTAL BENEFITS OF FLOODPLAINS
A floodplain is described as the area of land that is inundated with water when the flow in a waterway (river, stream or creek) exceeds the discharge capacity of the main channel. Flood flows are distributed over a broad, relatively flat area of land often inclusive of wetlands and flood channels.
Floodplains are an essential part of a catchment’s ecosystem processes. The ecological values they encompass and the significance of the habitats they provide is extremely important for our native species. Since the late 1980s and early 1990s it has been increasingly recognised that the health of a river and its floodplain is interdependent and that periodic flooding that maintains the connection between the two. Waterways and their connecting wetlands and floodplains provide substantial areas of habitat for native flora and fauna; they move food sources through the system and allow for the migration and emigration of aquatic animals– often a critical factor in the survival of many native species.
While there are many benefits to natural flood events, they are also known to impact the economic and social wellbeing of local communities.
FLOODPLAIN FENCING
Fences are exposed to damage from flood waters as the build-up of flood debris against the fence provides a large surface area for the flowing water to push against. These guidelines are intended to help managers of riparian areas optimise the siting, design and construction of fences in flood‐prone areas. This will help ensure that the maximum benefit is gained from the significant government and private resources applied to riparian fencing.
Riparian fencing in flood‐prone areas factsheet
Guidelines for riparian fencing in flood-prone areas