Levee banks project frequently asked questions

The Castlemaine and Campbells Creek Levee Banks project includes construction of levees and minor waterway improvements in areas identified within the Castlemaine, Campbells Creek and Chewton Flood Management Plan, which Council adopted in 2015.

The project aims to reduce the impact of flooding from Campbells Creek, Barkers Creek and Forest Creek on homes, businesses, community buildings, roads and footpaths.

Where is the project up to?
We are in the Development phase of this project. Within this phase we will finalise designs and secure all required permits and approvals so the levee banks can be built.

Please note this phase DOES NOT include construction of the levees. Construction will only begin once all the permits and approvals are obtained, funding has been sourced and the budget is approved by Council.
We expect to complete the Development phase of the project in 2021.

What rainfall events are the levees designed for?
During the Development phase we will:
• Finalise design drawings so they are ready to send for tender
• Provide the community with project information
• Formalise a Cultural Heritage Management Plan and Land User Activity Agreement
• Resolve land encroachment issues, establish easements and acquire land if and where required
• Obtain planning permit approvals for levee construction
• Update cost assumptions
• Prepare required documentation for Council to consider entering the Delivery phase (construction).

What levee banks and works are planned?
The project includes:
• 100m earthen and concrete levee at Central Cabins and Van Park in Castlemaine
• 430m earthen and concrete levee at Elizabeth Street in Castlemaine
• 580m earthen and concrete levee at Campbells Creek township
• 50m earthen levee at National School Lane in Campbells Creek
• Waterway improvements downstream of Alexandra Street bridge in Campbells Creek.

Why were those sites selected for the levee banks?
Consultants GHD determined the best locations for levee banks and waterway works based on flood modelling through the development of the Flood Management Plan. As part of this work they investigated historic flood information and conducted hydrological, hydraulic, flood damage and flood mitigation option assessments.

Why does the project not include levees at Gingell Street?
The Flood Management Plan recommended levee banks be constructed to the north and south of Gingell Street in Castlemaine. However, there was not consensus from local residents on the preferred designs for these levees. Levee designers Cardno Victoria Pty Ltd recommended that Council investigate other flood mitigation options with land owners and local residents. As a result the Gingell Street levee banks are not included in this project. They will be handled as a separate project. There is currently no timeline to undertake further design but Council will inform the community as progress is made.

What are the waterway improvements planned for Campbells Creek?
Introduced trees such as willows will be removed downstream of the Alexander Street bridge. Some native saplings in the middle of the creek will be removed to improve water flow and the health of the creek. Native plantings will be added along the edge of the creek. Council has liaised with local Landcare group Friends of Campbells Creek to undertake these works, which are included in a landscape design plan.

Who will benefit from the levees?
The main beneficiaries of these levees are nearby residents and businesses who will have will greater protection from floods. The works will also protect public infrastructure such as roads, footpaths and public buildings.

How will nearby properties be impacted?
Properties will have improved protection from flood events. Other impacts are outlined below.

Easements
A small number of properties in Campbells Creek (fewer than ten) have been identified as possibly requiring a drainage line to be installed inside the rear of their property boundary. This would require a narrow two-metre easement to be created to the rear of the property.

The easement does not impact access to the land, but requires the space to be clear of sheds or structures.
The purpose of the underground drainage line is to collect stormwater run-off and direct it through the levee wall into the creek. This would be through one drainage point rather than several. This protects the structural integrity of the levee wall and ensures nearby properties are better protected in the event of a flood.
Council will discuss easements directly with identified property owners.

Encroachment on to Crown Land
Council will carry out a detailed boundary re-establishment survey to map the exact location of the levee banks in relation to property boundaries. Some properties may have encroached beyond their boundary onto Crown Land. In these cases Council in partnership with the Department of Environment, Land, Water and Planning (Crown Land owners) will contact property owners directly to resolve the encroachment.

What order will the levees be built?
The levees can be built in any order but are dependent on approvals and funding. No decision has been made regarding the order of construction.

When will the levees be built?
Construction will depend on how long it takes to obtain approvals and secure funding. The earliest that construction could occur would be 2022.

How much will the levee banks cost to build?
Estimates in 2017 indicate construction costs to be around $2.5 million. Council will investigate an up-to-date cost estimate as part of the Development phase. It is likely to capture some costs that were not previously assessed.
As with other infrastructure projects, Council will pursue funding through Federal and State grants. Grant funding typically requires a minimum of one-third funding contribution from Council.

Who designed the levees?
Cardno Victoria designed the levees and waterway works. This included site assessment activities, preliminary design, preliminary costings and community consultation.

What is the Flood Management Plan?
The Castlemaine, Campbells Creek and Chewton Flood Management Plan outlines recommendations to reduce the risk of localised flooding. It includes a summary of the assessments, inputs and flood modelling that was carried out to inform the recommendations.

Why was it carried out?
Castlemaine, Campbells Creek and Chewton have a well-documented history of flooding of Barkers Creek, Forest Creek and Campbells Creek. In the last ten years the towns have been impacted by four major rainfall events in 2010, 2011 and 2012. Due to the widespread impact of the floods on homes, businesses and community assets the Victorian Government provided funding to develop the Castlemaine, Campbells Creek and Chewton Flood Management Plan to identify ways to reduce the impact of flooding on the community.

Who developed the Flood Management Plan study?
Consultants GHD developed the plan. The plan North Central Catchment Management Authority (North Central CMA) is the lead agency in the area for coordinating and monitoring the region’s rivers. The authority worked with Council to engage GHD.

What were the recommendations in the Flood Management Plan?
The recommendations were to:
1. Install a levee bank near Castlemaine Central Cabin and Van Park and Bruce Street (this project).
2. Install a levee bank along Elizabeth Street in Castlemaine (this project).
3. Install a levee bank to protect the township of Campbells Creek (this project).
4. Install a levee bank at National School Lane in Campbells Creek (this project).
5. Undertake waterway improvement works downstream of the Alexandra Street bridge at Campbells Creek (this project).
6. Install a levee bank along the north of Gingell Street in Castlemaine (not included in this project. It requires further community engagement and design consideration and will be handled as a separate project).
7. Install a levee bank along the south of Gingell Street (not included in this project. It requires further community engagement and design consideration and will be handled as a separate project).
8. Carry out strategic planning for urban waterways (complete).
9. Investigate a flood warning system (complete – integrated into the Mount Alexander Shire Municipal Flood Emergency Plan).
10. Amend the Mount Alexander Planning Scheme (complete).

How did GHD come up with the recommendations?
GHD specialists reviewed the available data and historic flood information and carried out a hydrological assessment and hydraulic assessment. They also assessed the flood damage and devised and tested options to reduce the impact of flooding. They worked with the community to gain feedback and consensus on the best options.

What input did the community have in the Flood Management Plan?
Community engagement was a key element in the development of the Flood Management Plan and its recommendations. This occurred over the course of the study through community information sessions, a public questionnaire, media updates and meetings with the Technical Working Group and community-based Steering Committee.

What options were investigated?
In their assessment, GHD looked at structural and non-structural options to provide flood protection, with consideration given to community recommendations. Structural options included levees, structures (improving flow conditions under bridges), waterway management and storage (retention basins, deepening of existing storage). Non-structural options considered land use planning, flood warning and flood response measures.

Why does the project not include levees in Chewton?
As part of the benefit-cost analysis there was not found to be a levee design for Chewton that would provide substantial protection from localised flooding.

Why does the project not include levees in Newstead?
The Newstead levee bank project is being managed separately. Council will provide more information on the project as it progresses.

How are flooding events measured?
One way to measure floods is to look at how often they are likely to occur. The Annual Exceedance Probability (AEP) is the probability or likelihood of an event occurring in any given year. For example, a 1% AEP means there is a 1% chance of a flood of that magnitude occurring in a year.

What rainfall events are the levees designed for?
The Castlemaine Cabin and Van Park, Elizabeth Street and Campbells Creek Township levees are designed to provide protection against a 1% AEP (or event that has a 1% probability of occurring in a year). The levees also have an additional 300mm of freeboard which protects against variables such as waves and waterway obstructions that may increase the water level locally during a flood.

The National School Lane levee is designed as a velocity levee which aims to prevent land washing away during a flood event. A design AEP is not specified for this levee.

Return to our levee banks page.