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SEYMOUR FLOOD MITIGATION PROJECT

PRELIMINARY DESIGN REPORT

Report prepared for the

SHIRE OF MITCHELL

October 2009

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TABLE OF CONTENTS

1. Executive Summary 4

2. Background 9 2.1 Previous Studies 9 2.2 Modelled Flood Impacts 10

3. Review of Structural Issues 12 3.1 Bank Profile 12 3.2 Levee Alignment 13 3.2.1 Railway Line to High Street 15 3.2.3 High Street to the Goulburn Valley Highway 15 3.2.3 Goulburn Valley Highway Crossing (Wallis Street) 17 3.2.4 Goulburn Valley Highway to Hanna Street 18 3.2.5 Hanna Street 18 3.2.6 Robert Street to Manners Street 21 3.2.7Manners and Tierney Streets 22 Goulburn Valley Highway Crossing (Tierney Street) 23 Goulburn Valley Highway to Railway Line 24 3.3 Temporary Barriers 25 3.4 Levee Use 26 3.5 Internal/Cross Drainage 27 3.6 Dwellings outside the Protected Area 28 3.7 Services 29

4. Planning & Legislative Issues 30 4.1 Mitchell Planning Scheme 30 4.2 Land Acquisition and Compensation 34 4.3 Indigenous Cultural Heritage 35 4.4 Non-indigenous & Cultural Heritage 37 4.5 Native Vegetation 39

5. Opportunities Created by the Levee Bank 40 6. Climate Change 43

7. Project Cost 45

7.1 Review of Cost 45 7.2 Cost/Benefit 46 7.3 Maintenance 47

8. Funding 48

8.1 Federal & State Funding 48 8.2 Local Funding 49

9. Implementation 54

10. References 56

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Plan A

Sheet 1 - Proposed Levee Alignment Sheet 2 – Railway to High Street Sheet 3 – High Street to Goulburn Valley Highway Sheet 4 – Goulburn Valley Highway to Robert Street Sheet 5 – Robert Street to Goulburn Valley Highway Sheet 6 – Goulburn Valley Highway to Railway Line Plan B – Drainage Catchments Plan C – Land Acquisition Schedule 1 – Alignment Photography Schedule 2 – Dwellings Impacted by the Levee Bank Construction Schedule 3 – Demountable Barriers Schedule 4 – Project Cost Estimate Attachments; Seymour Levees, Preliminary Heritage Assessment, Executive Summary,

Heritage Insight Pty Ltd. Heritage Advisor Report, Willys Keeble, Heritage Advisor, Shire of Mitchell. Geotechnical Report, Geotechnical Testing Services Pty Ltd.

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1. Executive Summary This report provides a preliminary assessment of the design and construction options and cost to construct a levee bank to protect the section of Seymour township between the railway line, Whiteheads Creek and the Goulburn River. The report is based on the flood modelling data from the WBM Oceanics Australia (WBM) 2001 report, Seymour Floodplain Mapping Study. That report drew from the State Rivers and Water Supply Commission of Victoria (SR&WSC) study in 1981 and Flood Management Options Study of 1984. These initial Studies were done on behalf of the Eildon to Seymour Flood Warning Group. In 2002, WBM identified eight structural and non structural options to mitigate the impact of flooding on the section of the township. These options were put to the Seymour community through a survey. In conjunction with the Technical Steering Committee appointed to oversee the project, WBM recommended the construction of an earthen levee bank around the area to be protected as the preferred flood mitigation option. It is not the function of this report to determine if the levee bank should be constructed, but to provide the Shire of Mitchell with a more detailed assessment of the issues, cost and benefit of construction of a levee bank to protect the identified section of township from a flood of 1 in 100 year magnitude. It also outlines the process involved in constructing the levee bank, should Council determine to pursue the project through to construction. While this report has reviewed the proposal and carried out site investigations, further investigation during detailed design will be needed to confirm the various elements of the project. This report recommends that the levee alignment remain largely as proposed in the Seymour Flood Mitigation Communication Investigation, Final Consultants Report to Council, February 2006, with the only significant variations being shifting the highway crossings away from the Tierney Street and Wallis Street intersections and using private lands instead of constructed streets to avoid the need to reconstruct the streets along the top of the levee. Much of the recommended alignment is through privately owned property. Acquisition of land of suitable width will be required along the alignment to provide for the structure and enable access along it for management purposes. The bank will cause some dislocation of land use as it passes through private property. Hence land acquisition and compensation are significant aspects of the project costs. An estimate of the cost of acquisition of the land and compensation to the landowners is $1,700,000. The construction of a levee bank in the vicinity of the Goulburn River and Whiteheads Creek will constitute a ‘high impact activity’ under the Aboriginal Heritage Act 2006. An initial cultural heritage assessment has been carried out along the proposed route of the levee. The assessment included a visual inspection of the ground surface and found that while there is no obvious evidence of cultural sites that

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would be disturbed, a number of locations along the route have the potential to contain items of cultural heritage significance. A Cultural Heritage Management Plan will need to be prepared should the project proceed at which time these locations of potential significance will be assessed in more detail. The attached report (appendix 2) provided by the Heritage Advisor to the Shire of Mitchell emphasised the heritage significance of the Emily Street environment. On the basis of the perceived disruption to the connectivity and visual amenity of the area from the historical sense, the report recommended that the construction of the permanent levee bank should not proceed through the Emily Street heritage overlay area. The principal concern of the heritage advisor is the proposed permanent earthen bank structure, given its scale would be approximately 2.2 – 2.5m high through the section of the township between Emily Street and the Goulburn River. Temporary barrier systems are available or could be designed that could be erected in time and provide protection to the height required. These systems would be approximately 5 times more costly to construct than the earthen bank of equivalent height. This is a cost that must be balanced up against the visual impact of the permanent wall and the need to provide flood protection to the town. There will be native vegetation clearance required as a result of any alignment adopted. The revised alignment is chosen to reduce the clearance required, particularly in the area of Tierney Street. The soil structure along the alignment is of a relatively uniform silt, clayey silt or silty clay. Each soil type is generally suitable as the base for a levee bank, hence there are no identified geotechnical reasons why the technical design of the levee bank would be complicated or that unexpected construction difficulties would be encountered. The levee will be a prominent physical structure on the generally flat landscape. The typical profile would be an earthen bank ranging between 2 and 3 metres high above ground level and 3 metres across the crest. With potentially a significant impact on the visual amenity of the township, some care will be required to either ensure that it does not create unwanted visual disconnection between the lands on either side or, where appropriate, is used as a feature. There is some opportunity to use the structure for additional purpose in some sections, such as relocating the walking track along the Goulburn River onto its crest. The estimate of cost provided in the WBM 2006 report was $3.91m. This cost was based largely on the direct construction costs and on making more use of road reserves for the bank route than is proposed in this report. A review of the project cost, taking into account estimated associated costs such as land acquisition and compensation, but without detailed technical design is $6.2million. The benefit/cost of the project based on the revised cost is 1.03. While this is reduced from 1.54 in the initial report, it is still within the range of benefit adequate for Council to consider proceeding with the project.

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It is assumed that if Council proceeds with the project, a funding application to the newly developed Natural Disaster Resilience Program will be made. It is intended that the federal government will provide up to 50% of the project funds, with the state government and local government providing the other 50% between them. The share between state and local government has not yet been advised. A range of local funding options have been discussed in this report. The method of providing the local contribution to the project cost is a matter for the Shire of Mitchell. Community support for the project will be an essential component of any funding application to be made. It is recommended that if Council does wish to further consider the project, a structured community consultation process be first undertaken, within the provisions of section 223 of the Local Government Act 1989. Section 223 of the Local Government Act 1989 provides the community with the ability to make formal submissions to Council on the project and requires Council to give consideration to each submission in determining whether to proceed further with the project. This provides a robustness in the consultation process that will enhance the funding application. The works to construct the levee bank are exempt from requiring planning permit within the urban floodway zone of the Mitchell Planning Scheme. A public acquisition overlay is required to provide for the future construction of the levee and the acquisition lf the portions required of private property along the route. A planning scheme amendment is required to implement the public acquisition overlay. The amendment process would provide the opportunity for consideration of other matters such as heritage and vegetation removal. The conditions or offset plans relating to these other matters should be considered at the amendment stage and provided for in the amendment. This will ensure that all planning and land use and development issues are identified and appropriate conditions can be put in place at an early stage to enable more efficient planning and design of the project and more accurate application for funding. Council should subsequently rezone the land identified in the public acquisition overlay along the proposed alignment to public use zone. Summary of recommendations It is recommended that Council:

Accept this report for the purpose of going to community consultation regarding whether to proceed to a funding application for the detailed design and construction of the levee bank.

Undertake a community consultation process inviting submissions under Section 223 of the Local Government Act 1989 regarding either aspects of the project or whether Council should proceed with the project

Consider all submissions received.

Determine whether to proceed with the construction of the levee bank as

outlined in the report, or as later refined during detailed design.

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It is recommended that the following form the preliminary design criteria for the levee bank:

The levee alignment be adopted as shown on attached Plan A.

The standard construction of the levee to be an earthen bank built to a height of 600mm above the modelled 1:100 flood level.

The standard profile of the bank is a crest width of 3m and side slopes (batter) at a maximum of 1m vertical to 2m horizontal on the protected (town) side and 1m vertical to 2.5m horizontal on the flooded side.

Where a road is to be located on top of the levee bank, to allow a safe shoulder width, the crest width be increased to 10 metres and either the batters flattened considerably or guardrails provided.

The levee bank be discontinued at the two junctions with the Goulburn Valley Highway, with temporary barriers to be installed as required to close the levee opening across the highway.

Should Council determine following public consultation to proceed with a funding application for the construction of the levee bank, it is recommended that Council:

Commence an amendment process under Part 3 of the Planning and Environment Act 1987. The amendment to apply the Public Acquisition Overlay (PAO) to privately owned land on the alignment with the intention of purchasing the land at a later date at market value or acquiring an easement over the land.

Make application to the Natural Disaster Resilience Program for the acquisition of the lands necessary, detailed design and construction of the levee bank and associated works.

Subject to the funding application being successful, Council can then;

Commence the acquisition of the portions of private titles along the alignment as recognised in the public acquisition overlay.

Complete the detailed design of the levee construction and associated works.

It is recommended that Council should give consideration to;

Give consideration to the closure to traffic of the section of Tierney Street between Goulburn Street and the Goulburn Valley Highway.

Review of the land south of Whiteheads Creek regarding its potential as a bulky goods retail precinct.

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Acknowledgements This report is based on the flood modelling and technical information contained in

the WBM Oceanics Australia 2001 report, Seymour Floodplain Mapping Study. The proposed flood mitigation works are drawn from Seymour Flood Mitigation Communication Investigation, Final Consultants Report to Council, February 2006, The author of this report would like to acknowledge the assistance of the following persons in the preparation of this Report: Climate Change research was carried out by Michael Reynolds. Planning advice was provided by David Merrett, Director, ISIS Planning. Review of the technical content of the report was provided by John McCartney, Director, MC Solutions.

Survey information and advice was provided by Duncan Salter, Eric Salter Pty Ltd

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2. Background; 2.1 Previous Studies

This report relies on the previous flood modelling and protection options assessment done by WBM Oceanics Australia (WBM). WBM carried out extensive flood modelling of the Goulburn River and other waterways, provided in the 2001 Report, Seymour Floodplain Mapping Study. That report drew from the State Rivers and Water Supply Commission of Victoria (SR&WSC) study in 1981 and Flood Management Options Study of 1984. These two initial studies were done on behalf of the Eildon to Seymour Flood Warning Group. WBM and the project Technical Steering Committee identified eight structural and non structural options to mitigate the impact of flooding on the section of Seymour generally between the Goulburn River, Whiteheads Creek and the railway line. WBM carried out a survey of residents in Seymour in 2002 to determine whether the residents would prefer either structural or non structural solutions to combat the possibility of flooding of the township in the future. Most residents identified mainly non-structural options which include “community education and awareness programs” closely followed by ‘land acquisition’ and ‘land use planning’ as the preferred options. Highly ranked though was “flood proofing or raising of individual buildings”. The residents saw this approach as adequate to provide protection from flooding and perceived it to be better than other structural approaches such as construction of levee banks and enlargement of existing waterways. The survey did not appear to indicate to the respondents the cost of the options nor the effectiveness of each in actually preventing the township from flooding. In conjunction with the Technical Steering Committee, WBM subsequently concluded that although the construction of a levee bank was one of the less preferred options by the community, protection of the township from flood inundation could only be feasibly provided by a physical flood barrier. The broad outline of the preferred option was presented to Council in the Seymour Flood Mitigation Communication Investigation – Final Consultants Report to Council, February 2006. It recommended construction of a levee bank and individual structural protection for isolated dwellings outside of the protected area. It also recommended the inclusion within the protected area of the urban area between the hospital and Catholic school by constructing the levee along Whiteheads Creek. The recommended solution is construction of a levee bank to protect the identified section of the Seymour township to the west of the railway line from the modelled 1 in 100 year flood. An alignment, which is almost entirely through properties or along road reserves within the Urban Floodway Zone, was suggested. However the report acknowledged this proposed alignment included no detailed design or technical analysis of issues and would be reviewed at the detailed design stage. That report provided a levee bank design profile but recommended further detailed technical investigation and community consultation to identify any issues impacting on the cost and ultimately the feasibility of the recommended option.

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The option proposed was presented to an open community meeting. There was also ongoing communication with a community based ‘focus group’ which provided some additional feedback to the community about the preferred option. Council subsequently gained additional funding Natural Disaster Mitigation Program to undertake an additional step in the usual funding phases for a flood mitigation project. It is this report that provides a more detailed assessment of the issues and cost of the preferred option. The assessment is provided to assist the Council to decide whether to undertake further community consultation on the project and to determine if there is sufficient community support to proceed with a funding application to the federal and state government for the detailed design and construction of the levee bank. The Seymour Flood Mitigation Communication Investigation – Final Consultants Report to Council, February 2006 needs also to be presented to the community as an adjunct to this report, as it contains information and conclusions that this report relies upon. This report does not review the recommendation of the WBM in a levee bank being the preferred flood mitigation option, but seeks to provide additional information to assist Council and the community to determine whether to proceed on that recommended basis.

2.2 Modelled Flood Impacts Flood modelling has been done by WBM over the Goulburn River, Whiteheads Creek and Sunday Creek catchments in determining the design flood levels and duration affecting the western area of the township. The 1 in 100 year flood level was determined as varying from 139.4m Australian Height Datum (AHD) at the upstream section of the levee to 137.0m AHD in the area of the junction of the Goulburn River and Whiteheads Creek. This is influenced by flood flows in both the Goulburn River and Whiteheads Creek. The flood level profile is provided in figure 6-3 ‘100 Year ARI (annual recurrence interval) Levee Long-Section’ within the 2006 WBM report. The profile indicates a level of inundation by a 1:100 year flood of generally between 1.5m and 2.5m depth of water along the levee alignment. Flooding of Seymour is often influenced by combined high flows in the Goulburn River and Sunday Creek. The report used 100 year ARI flows in both catchments at the same time (section 5.5.4) to calculate peak flood height. This is a conservative approach, but it has been estimated that the water level through the town under this scenario would be increased by only 50mm compared to a 1:100 year flood in the Goulburn River coinciding with a 1:20 year flow in Sunday Creek. Hence the more conservative approach has been used to determine the modelled 1:100year flood levels in the township. Although the impact of Whiteheads Creek has been taken into account in the hydraulic modelling, it is not included in calculation of the flood peak or mapping as

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it has a very short time of concentration and generally peaks well before the main flows in the Goulburn River and Sunday Creek. It is assumed there is little chance of the two flood peaks coinciding. There is a view locally that it is Whiteheads Creek which causes the nuisance floods, which is possibly so, but the report found that the main impact through flood level and duration comes from convergence of the other two streams, and mainly from the Goulburn River. While the flood modelling indicates that not all of the section of township within the proposed protected area will be inundated during a 100 year flood, Figure 6.2 in the 2006 WBM Report indicates only the north-east section between the hospital, railway line and a line 100m east of Wallis Street will remain above water. Four hundred buildings within the section of township to the west of the railway line were identified as impacted by flooding at 1:100 year ARI. The 1974 flood inundated 200 buildings and is now regarded as a 1:30 year event. Only localised flooding occurred in 1993. WBM calculated the existing Average Annual Damage (AAD) to the township due to flooding at $715,000. It was assumed that the residents of Seymour are sufficiently experienced with floods that they are regarded as ‘prepared residents’ and are subsequently able to carry out some flood minimisation works to reduce the impact. The existing AAD was therefore reduced to $490,000. The 2006 report assessed the capital cost of the levee bank and associated works at $3.91M with a construction life of 30 years before substantial rebuilding would be required of the bank. In the event of the levee being built as recommended in that report, the protection afforded to the township by the levee would reduce the AAD to an estimated $20,000. At that reduced AAD the benefit cost ratio (BCR) of constructing the levee was calculated as 1.54.

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3. Review of Structural Issues

The 2006 WBM report acknowledged the need for review of the construction cost and a closer examination of the issues which were not considered in the assessment. To identify the issues and to review the assumptions regarding the alignment and profile of the levee structure in the previous reports, a series of further investigations were done. These included a land level survey, a preliminary archaeological assessment, and a geotechnical investigation of the existing soil structure along the route and local earthfill sources.

3.1 Bank Profile The recommended levee structure is a compacted earthen bank. The general standard profile of a flood protection bank is a crest width of 3m and side slopes (batter) at a maximum of 1m vertical to 2m horizontal on the protected (town) side and 1m vertical to 2.5m horizontal on the flooded side. The side batter on the flood side is flatter to reduce the erosive impact of the flood waters. The bank profile proposed in the 2006 WBM report was flatter side slopes of 1vertical to 3 horizontal on both sides. While this would provide additional structural strength to the bank, its wider base by on average 3m would also infringe more on the properties through which it passed, and the earthworks cost of the bank construction would be approximately 15 - 20% more than the standard proposed in this report. For these reasons this report has adopted for discussion and costing the side batters of the levee bank of 1:2 on the protected side and 1:2.5 on the flooded side be adopted. The height of bank (freeboard) above the modelled 100 year flood level is 600mm as proposed in the 2006 WBM report. Freeboard provides a margin of safety in the modelled flood levels and minimises the risk of erosion by wave action and failure of the top of the bank.

Portion of the levee alignment was proposed to run along road reserves to minimise the impact on the private lands. The road reserves are either 20 or 30

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metres in width and some contain constructed and sealed streets with kerb and channel. The footprint width of the standard (non trafficked) bank profile at 2m height is 13m across. This makes it generally not possible to locate a separate levee bank and constructed road within the 20m road reserve, particularly where there is the need to provide vehicle access to properties on both sides of the bank. Where it is proposed that the levee bank be constructed along a road reserve, to allow for reconstruction of the roadway along the top of the levee, then a widened bank profile is proposed. The bank crest would be sealed to prevent excessive wear of the surface level and protect the freeboard height required above flood level. To provide an adequate and safe road shoulder the crest width is increased to 10 metres and either the batters flattened considerably or guardrails are required. The bank base width then increases to 19m at a bank height of 2m above the existing road surface. Access for vehicles from the road on top of the levee to adjoining properties can be provided by a ramp down into the property. Generally this is only an option within rural areas as a ramp would become a significant imposition on a residential property so that levee bank construction along the road reserve within the residential areas is generally not appropriate.

Generally, the bank profile and location will be determined by the environment and land use along its length. Much of the length is through paddocks, which have the potential to contain stock. It is proposed the bank that be fenced out of the paddock to confine the points where stock and vehicles can cross to protect the bank from excessive wear. Where stock and vehicle crossing is provided, the crest and sides of the bank will be gravel paved, and sealed if necessary.

3.2 Levee alignment

The alignment proposed in the 2006 WBM report generally skirts the developed area of the section of town to be protected. However the report acknowledged a more detailed ’ground truthing’ of the proposed alignment and cost of construction of a bank was required. This review of the route issues was done with the aim of not constricting the extent of the floodplain significantly beyond that proposed by the WBM report and without

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excessively increasing the length of the bank. Any significant additional restriction of the floodplain could have an upstream impact of raised flood levels. The focus of the project is to protect the urban or potential urban areas, with protection of rural lands to occur generally as a consequential benefit from adopting the most efficient and logical route and connection between sections of the bank. There are a number of unused road reserves around the perimeter of the township. To minimise the impact on private properties it is preferred where possible to run the bank along unused road reserves where available, or sections of private land which is either not intensively developed or is not likely to be developed. Constructing the bank along constructed roads or streets is possible and is considered along some sections. This however is generally not appropriate, particularly in a developed urban setting, due to the increased width required of the bank making it difficult to provide access to the adjoining residential properties and the high cost to reconstruct streets including the kerb and channel and drainage infrastructure into the bank. Hence the levee would of necessity pass through a number of private titles along the route. The impact on the private lands varies depending on their use or level of development. The Goulburn Valley Highway passes through the area to be flood protected. The levee alignment was proposed to cross the highway at the Wallis Street and Tierney Street intersections. Wallis Street is a major link from the highway to the town centre and is fully constructed with kerb and channel. Tierney Street is constructed and sealed to a rural standard on the south side of the highway, but is a formed earthen track on the north side. The location of the highway crossings is discussed in some detail in this report. Some variation is proposed to the levee alignment so that the crossing points are not at the road intersections. There is generally a discernable broader ‘secondary’ stream channel outside of the main stream channel of the Goulburn River and Whiteheads Creek. This would largely contain the higher stream flows that spill out of the main channel, at a level prior to the water breaking out overland. There is no building development within this secondary channel. It is wholly contained within the Urban Floodway Zone, so no development is allowed that would restrict any flood flow. There is then a ‘plateau’ above this which is the more general natural ground surface level on either side of the streams. This is the point at which the water would break out overland. To reduce the bank height and cost and to not reduce the floodway of the two streams too significantly it is proposed that the alignment of the bank is generally on the higher land just outside the secondary channel. On review of the levee alignment, variation is proposed to any significant extent only over two sections. For the purpose of describing the proposed alignment and

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the issues the overall levee length has been broken down into six segments as below, and as outlined in Plan A: Levee Alignment. Schedule 1, ‘Alignment Photography’, provides a photographic representation of the existing conditions along the proposed levee alignment.

3.2.1 Railway line to High Street, through the catholic school grounds; This segment of approximately 280m length links the raised railway embankment and High Street through the catholic school grounds. The design bank height is generally between 2.0m above the ground level at the railway embankment, diminishing to 1.8m toward High Street. The land rises rapidly up to the High Street road formation so that the bank diminishes to virtually nothing at the road shoulder. The connection to the High Street road formation is approximately 20m from the bridge abutment. At this point the centreline of the sealed road surface is only 0.1m below the design height of the levee. The road formation will need to be lifted by 0.2m so the whole of the road and shoulders is at or above the levee bank height. The road shoulders should also be sealed to reduce the traffic wear on the road structure. The alignment passes through a number of undeveloped titles, all in the ownership of the school. There are though no major physical impediments to the construction of the levee bank. The bank would generally skirt the school buildings and carpark areas and the playing oval. The land on the creek side of the route is open grassland and treed. The alignment is proposed to provide a reasonable floodway width for the creek, but to protect the physical assets on the site.

3.2.2 High Street to the Goulburn Valley Highway; The initial route through this segment proposed following Callen, Gloster and Wallis Streets from the hospital to the highway crossing at Wallis Street. The sections of Callen Street and Wallis Street proposed to be used are both sealed with kerb and channel. Gloster Street is unconstructed but provides access to one residential property. Callen Street provides access to two residences and to the hospital and ambulance base. The levee bank height that would be required in the areas of Callen and Gloster Streets is approximately 1.2m above ground. If the levee ran along the road reserves and the streets were reconstructed along the top of the bank, it would be at least 15m wide at the base, effectively the width of the Callen and Gloster Street reserves.

Wallis Street is a major link road from the highway into the township centre. It is a wider sealed road with kerb and channel both sides. It is suggested that to build the sealed and kerbed Callen St and Wallis St road structures up to the top of bank height would cause a considerable additional cost. Access to the residential properties fronting Callen and Gloster Streets would be very difficult, with a ramp required to intrude some distance into the properties.

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The bank would also provide a considerable visual impact on the residences, which would generally be no more than 10metres from the toe of the structure. Two dwellings on the north side of Gloster Street route would be left outside the protected area if the route followed Callen and Gloster Streets. It is not apparent these dwellings have been accounted for in the WMB 2006 report regarding impact on dwellings due to the increased height of floodwater outside the levee bank. Consequently it is not regarded as appropriate that the route follow developed residential streets and an alternative route through this part of the township is proposed. The levee crossing of the highway is proposed to be between the Wallis Street intersection and Whiteheads Creek. The preferred location of the highway crossing is reviewed in section 3.2.3. There is an unused road reserve (Federation Street) running across the open paddock area between the hospital and the (former Wallis Street) road reserve where the large open drain is located. The paddock area was initially proposed to be outside the levee bank; excluded from flood protection. The paddocks on either side of this unused road reserve are subdivided into a number of undeveloped residential size lots. All of the lots are in the same ownership, except for one owned by the Shire of Mitchell. The modelled flood level through this section reduces rapidly from the High Street bridge to about the helipad, from where the flood plain opens out more considerably. The levee bank height need only be about 1.1m as it passes around the hospital and raised helipad area. It increases to 2.0m across the paddock area and along the open drain. The bank height increases to approximately 2.7m inside the property at the High Street end. Constructing the levee bank along the road reserve between the paddocks will cause a dislocation to existing use of the property (although it is in a number of titles) but it will include the southern portion of the paddock inside the levee. This alignment will include an additional (potential) seventeen residential lots within the protected area. It will also include the two residences fronting onto Callen Street. The unused Federation Street reserve intersects the unused Wallis Street reserve at about 90m from Whiteheads Creek. The overall length of the open drain is approximately 220m from the pump station to Whiteheads Creek. It discharges into Whiteheads Creek immediately upstream of the highway bridge. The open drain is up to 10metres across and 2m deep, occupying about half of the road reserve area. It is therefore not possible to build the levee bank within the reserve without relocating or piping the open drain. If the levee bank is built, the drain from the pump will need to be piped to the outside of the levee bank to enable the pump station to discharge stormwater from inside the protected area during periods of flooding and to prevent entry of floodwater back up the drain. Piping the drain would enable the levee to be constructed along the reserve to the highway.

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Whiteheads Creek passes within 20m of the property between the highway and unused road reserves. There is insufficient room to construct the levee bank entirely on the or the drain reserves while maintaining an adequate distance from the creek to avoid either intruding on the flow of water approaching the highway bridge crossing or to enable the bank to be constructed without collapsing the creek bank. The levee bank is proposed to cross the northern portion of the private property to the highway reserve to ensure an adequate setback from the creek. It is proposed that the northern most 20m of the lot, approximately 200m2, would be acquired for the bank. The trade off for the lot is that the balance would be flood protected whereas it was initially proposed to be on the flood side of the bank and therefore excluded from protection. The unused road reserve contains a number of trees and shrubs. The majority are red gum trees ranging in height from saplings to 15m. It is mainly the saplings growing within the open drain. The largest of the trees are along each side of the reserve. To minimise the number of mature trees affected, it is proposed that the levee bank be located generally centrally within the reserve. On review it is proposed that the levee run as proposed from High Street to the hospital, where it skirts the helipad to ensure it is flood protected. From this point the levee is proposed to run westward within the unused road reserve to meet the former Wallis Street reserve and open drain. It will then follow this reserve to the highway. While additional land will be included by this route, it is not considered that the loss of flood storage outside the levee bank will have an adverse impact on the flood levels in the immediate area. The proposed length of the levee bank is reduced by approximately 170m and the need to raise both Wallis and Callen Streets and the highway is removed. Two additional dwellings would be included within the protected area. Piping the open drain is an additional cost to the project to the initial proposed route.

3.2.3 Highway Crossing (Wallis Street) The modelled flood level at the eastern highway crossing, in the area of Wallis Street and Whiteheads Creek is 137.1metres Australian height datum (AHD). The Whiteheads Creek bridge deck height is approximately 137.1m AHD; about the modelled flood level for the location. The highway level falls by about 0.6m from the bridge to the Wallis St intersection. The design height of the levee bank above the highway is 0.6m at the bridge and 1.2m at Wallis Street. So a location toward Wallis Street is to be chosen. It is preferred to maintain a reasonable width of waterway for Whiteheads Creek, particularly at the bridge approach, to reduce the backing up of water levels caused by the highway and bridge flow constriction. VicRoads officers raised concerns regarding the raising of the highway affecting sight distance for vehicles at the Whiteheads Bridge and the need to also lift and reconstruct Wallis Street to grade back from the intersection with the highway.

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The estimate to construct the highway over the levee bank and raising Wallis Street to match is $400,000. To provide a reasonable sight distance from Wallis Street and to provide adequate waterway for the creek, a crossing point at approximately 50m from the bridge is proposed. The level of the centre of the highway carriageway at this location is 136.8m AHD. The design bank height on either side of the highway is 0.9m above the carriageway. The level of the highway is generally lower than Whiteheads Creek bridge for approximately 1km to the east. In this section there are two significant dips in the highway, at 0.8m and 1.0m below the level of the bridge deck and the design flood level. Each dip is approximately 200m in length. This means the highway outside the protected area will be under up to 1m of water before the Whiteheads Bridge deck is inundated. Hence there is no purpose in building up the highway over the levee as the highway outside the levee will not be trafficable in any case during a 1:100 flood event. The preferred option is to leave the existing highway at its existing level, and to leave a gap in the levee across the road width. The gap is to be closed with a temporary barrier as required. The temporary barrier will not need to be installed until the water outside the protected area makes the highway non trafficable in any case.

3.2.4 Goulburn Valley Highway to Hanna Street The proposed alignment through this section is generally in accord with that in the WBM 2006 report. The height of the bank (including 0.6m freeboard above flood level) would range from 1.5m in the private property at the highway to 2.5m at Hanna Street. The height of the bank at the Hanna Street section is largely a result of the steep flood level gradient along the Goulburn River, which would be exaggerated due to the floodplain confinement caused by the levee bank. The alignment would skirt the sewerage pump station to include it within the protected area. From that point it crosses the paddock behind to link to Hanna Street. The Hanna Street reserve extends past Bolton Street, with another unused road reserve linking back down toward the highway. These would provide options for the levee alignment, but the bank would then intrude further into the flood plain and would include additional rural land within the protected area. Neither is the intention of this investigation, so it is proposed that the levee alignment follow and skirt the developed sections of the properties along Bolton Street to Hanna Street. At the bank height approaching 2.5m toward Hanna Street, it is not considered appropriate to locate the bank immediately adjacent to the dwellings. It is proposed that the bank be located 40m from the dwellings.

3.2.5 Hanna Street Hanna Street runs parallel with the Goulburn River. There are three properties between the street and the river. The most northern property at the Bolton Street intersection contains a dwelling; the middle contains a shed and the third (closest to Robert Street) contains some fruit trees, but no buildings.

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The northern property is of significance as it is the site of the original brewery recognised in the Mitchell Planning Scheme. The dwelling is not the original brewery building. The three lots between the river and Hanna Street are within the Urban Floodway Zone, within which they will remain unless they receive flood protection. Within the Urban Floodway Zone there can be no further buildings constructed which would retard flood flow. Consequently a dwelling cannot be constructed on the central or southern lots. The height of the bank along the Hanna Street section would need to be approximately 2.3m to 2.5metres (including freeboard) above the existing road surface. The three properties will be inundated by up to 1.9m of water during a 1:100 flood. The dwelling is already on raised stumps, but to get the floor level to 300mm above the flood level it will need to be lifted a further 1.6m. The alignment initially proposed was along the road reserve, with the road to be located on top of the levee bank. The Hanna Street reserve width is 20metres. To include the road structure the width of the bank crest would need to be 10metres. Without the road structure, the crest width can be reduced to 3metres. At the batter gradients proposed of 1:2 on the protected side and 1:2.5 on the flood side, the width of the base of the bank would be;

20.8m to include the road structure along the crest, or

13.8m without the road structure on the crest. Hanna Street provides rear access to the majority of the properties on the protected side, most of which front onto Emily Street. There are two properties on the Emily Street side with either legal or developed frontage to Hanna Street. The main function of Hanna Street appears to be to provide access to the lots fronting onto it. The options considered included reducing Hanna Street to an ‘access road’ providing access only to the abutting lots. The Bolton Street reserve continues past Hanna Street toward the river, to an informal rest area. There is a property to the east of Bolton Street which relies on this extension of the road reserve for access. Hence access over the levee at Bolton Street is required to be maintained in any case. The depth of the properties is only up to 50m, reducing to 35m at the Robert Street end. So there is little area between the buildings or the road and the river bank. The river bank is only approximately 30m from the sheds associated with the residence. An option considered is to construct the bank between the properties and the river. However the river has eroded the bank adjacent to the properties to the extent that the waterway is now partially outside the river reserve and has consumed about 50% of the vacant southern lot and intrudes into the middle lot containing the shed.

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Due to the heavy vibration required to achieve the soil compaction requirements for the levee bank, it is not appropriate to construct the levee bank within 10m of the river bank. The footprint of the levee at 2.5m height would be about 14m width. Due to the proximity of the buildings there is insufficient room to construct the levee along the river side of the properties due to the intrusion of the river channel toward and into the properties. At the Robert Street end the river has eroded into the Hanna Street reserve by approximately half of its width. To retain a sufficient distance between the bank and the river bank, the levee bank route will need to pass through the tennis court section at the rear of the rear of the hotel property. Acquisition will be required from the rear of the hotel site to provide for the bank construction. The width of the land acquisition will depend on whether it is determined to maintain access to Hanna St from Robert St. The options considered and their issues and impacts is summarised below. Option 1. Construct the bank within the road reserve, with the road constructed along the crest.

the minimum base footprint is approximately 21m width. The road reserve is 20m wide. A low retaining wall structure can be used to confine the bank to the road reserve.

the toe of the bank would still be within 10metres of the dwelling on the northern lot.

a ramp is required from the top of the bank if it is needed to maintain access into the property. Council’s design standard is a maximum gradient of 10% so the ramp would extend 20metres into the properties.

access to the dwelling property could be altered to the Bolton St frontage.

the southern and central properties on the river side of the street rely entirely on Hanna St for access.

it is not considered feasible to provide a ramp for vehicle access into the properties.

most of the properties on the protected side have main access from Emily Street, using Hanna Street as a secondary access.

Option 2. Construct the bank along the road reserve, but with the minimum 3m

crest width.

requires a bank footprint of 14m width.

vehicle access along the toe of the bank is required to maintain access to the lots on either side.

width of at least 3.6metres is required on either side, sufficient to provide laneway access.

Hanna Street could cease to be a public road, providing access only to the adjacent properties.

Option 3. Construct the bank through the properties to the river side of the road.

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requires acquisition of the lots and removal of the dwelling.

enables a bank of 3m crest width to be built.

Provides sufficient land width to locate bank so as to avoid removal of mature red gum trees.

Option 4. Construct the bank through the properties on the protected side of the

road.

requires acquisition of 20m width from the frontage of all lots.

requires acquisition of one entire lot.

There are large red gum trees along the road/property boundary. Option 5. Construct the bank within the properties between the dwelling and shed

and the river.

Requires a minimum of 10m setback from river bank, to prevent adverse impact from compaction of bank.

Need to acquire a minimum of 16m from the rear of the properties.

There is insufficient space between the dwelling and river for the levee bank, with the toe adjacent to the dwelling

Requires removal of all sheds from the properties. Conclusion The lots to the river side of Hanna Street cannot be further developed unless they are flood protected. Effectively though they cannot be protected to enable their development. There is not sufficient room between the dwelling and river to construct the bank without acquiring at least 26m from the rear of the properties and having a significant impact on the dwelling. The dwelling is set back approximately 10metres from the road title boundary. The proposed levee structure would have a significant impact on the lands adjacent to Hanna Street and particularly those between the proposed structure and the river, from the aspect of vehicular access and from the visual and amenity disruption of an earthen bank of 2.5m high within 10m of the dwelling. Access to the dwelling outside the levee could be gained via the Bolton Street reserve at the side of the property. However access could not be physically provided to the other two lots due to the presence of the levee bank. On balance it is concluded that the levee bank would have such a significant access and amenity impact on the three lots along the river side of the road that Council should consider acquiring them to enable the levee bank to be constructed through these properties.

3.2.6 Robert Street to Manners Street There is a row of mature Monterey Cypress trees along the south side of Robert Street. There are two very large red gum trees at approximately 18m apart at the trunk and located at about either side of the preferred alignment. Between the red

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gum trees are three of the pines which will require to be removed for the levee bank construction. There are four properties throughout this segment, each of which front onto Emily Street and run through to the river reserve. Any buildings on the lots are located toward the Emily Street frontage. The rear portion of each is not developed and is within the Urban Floodway Zone. As such they are currently not able to be developed in any way that causes an impediment to flood flows. The natural surface at the Emily Street frontage is approximately 136.7m AHD. The surface level falls to approximately 136.2m at about 10 - 20m inside the rear boundary of the lots. The rear portions of the four properties then fall relatively steeply away toward the river. As recommended by the WBM 2006 report, to reduce the height of the bank it is proposed to locate the bank within the rear portion of these properties, on approximately the line where they start to drop awat toward the river. The bank height would be approximately 2.2m to 2.3m through this section. A 20m width strip of the rear of each of the properties is proposed to be acquired for the levee construction.

3.2.7 Manners and Tierney Street Manners Street is a sealed roadway providing access from the highway to the New Crossing Place Lions Park boat ramp and picnic area at the Goulburn River. Tierney Street is a formed earthen road providing an alternative connection from Manners Street back to the highway. The section of Manners Street along the levee route is crown reserve (river frontage). The sealed road is located in a cleared section along the edge of the reserve of about 22m width adjacent to the private title. The private land is higher than the road area by up to 0.8m. The road structure, including gravel shoulders, is approximately 15m from the private property boundary. So adequate space is available to locate the levee bank between the road and private property. The height of the levee bank at the point where it would intersect Manners Street is about 1.7m to 1.8m. The road level falls by approximately 1.6m toward the intersection with Tierney Street. The design bank height would increase to 3.1m at the river end if it were combined with the roadway. The bank height at the fenceline would need to be less at 2.7m. Manners Street does not provide direct access to any private property over this section. Given that the boat ramp and picnic area on the river bank are not accessible during floods there is no incentive to ensure the roadway remains open to traffic during such times. If the road and the bank were separate structures the bank base width would be 10.2m at the highway end, increasing to approximately 17m at Tierney Street. It is proposed that the levee bank be built immediately adjacent to the private title boundary to reduce the height of the bank required and to retain the road between the bank and the tree area.

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The road would need to be shifted approximately 5m toward the tree area. Some additional tree removal may be required to shift the road, particularly at the river end. The unconstructed section of Tierney Street is significantly lower, by up to 1.3m, than the adjacent private land that it skirts to the east. Deep Creek crosses the road at the rear of the properties fronting the Highway. The road reserve and particularly the creek area is heavily timbered, mainly with river red gum. If Tierney Street were raised to form part of the levee, the structure would generally exceed 3m height throughout, effectively requiring the clearing of the entire road reserve between Manners Street and the highway. The road structure would cross the highway at a height of 2.2m to 2.3m above the highway surface. The highway will need to be lifted by a similar amount over the levee bank to retain vehicle connection to Tierney Street. At an estimated cost of $500,000, it is regarded as too costly to raise the highway over the levee bank. Temporary barriers is not an option at this location as vehicle access cannot be provided from the top of the bank along Tierney Street to the highway. The issue of the highway crossing is discussed in detail later. It is proposed that the levee alignment be shifted to the west, through the paddock area, so it can cross the highway away from Tierney Street. The first point at which the bank can cross the highway is approximately 100m to the west of the Tierney Street intersection. The bank height through the paddock ranges from 2.5m to 3.2m. The alignment crosses over a large gully in the paddock. The height of the bank at the invert of the gully would be approximately 6.8m. A pump station has been allowed in the costing at the gully. But this alignment allows the Highway to be crossed at a point away from the intersection with Tierney Street and at a higher elevation. It also skirts around and includes an additional dwelling inside the protected area, to that which was initially proposed. Council should give consideration to closing the section of Tierney Street from Manners Street to the highway. It does not provide access for any properties and Manners Street has been developed as the preferred access to the river. The Tierney Street road level drops over a length of about 50m where Deep Creek crosses. There is only a 300mm pipe under the road so it acts more as a causeway when the creek is flowing. If Tierney Street remains open, the height of the bank where it crosses Deep Creek will be approximately 4m above the existing road level.

3.2.8 Goulburn Valley Highway Crossing (Tierney Street) The design height of the levee bank in the area of the Tierney Street intersection is 2.2m above the roadway. The depth of water over the highway is estimated to be 1.6m in the 1:100 year flood event. Lifting the highway would require raising the adjoining Tierney Street, at least on the southern side. Given the high cost of reconstruction of the highway and Tierney

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Street and given also the highway is not trafficable during flood on the outside of the bank, there is no rationale to lift the highway over the bank. Tierney Street is not considered to be an appropriate alignment for the bank in any case. The constructed and sealed section of Tierney Street to the south of the highway is 30m wide, but only for approximately 100m from the highway. It then narrows to about 20m with a large drainage depression immediately adjacent on the west side. The section nearest the highway runs beside a caravan park, which has alternative access options. However there are three dwellings fronting onto the street along the subsequent narrower road section. The land along the west side of Tierney Street is developed to rural use. For the same reasons as discussed earlier in that the bank height along the street would need to be 2.2 to 2.3m in height and a base width of approximately 20m, access and the amenity of the adjacent residents would be compromised. Shifting the crossing point from the Tierney Street area would eliminate the need to raise and reconstruct either of the intersecting roadways and it allows also the option to use temporary barriers across the highway. The highway rises by up to 0.5m toward the west from the Tierney St intersection, so a shift in this direction means the levee bank will have a lower profile. It is proposed to relocate the levee bank crossing of the highway to approximately 100m south-west of the Tierney St intersection. At that point the design height of the levee bank above the northern road shoulder is 1.6m and 2.1m above the southern shoulder. This alignment will include another dwelling inside the protected area from that initially proposed.

3.2.9 Goulburn Valley Highway to Railway The alignment from the highway to the railway embankment follows generally the initially proposed alignment through the paddocks. The variation proposed is the changed location of the highway crossing at approximately 100m to the east of the Tierney Street intersection. The alignment from the highway crossing point passes through rural lands, generally following title boundaries which run directly to the railway embankment. Deep Creek passes through this segment and there are some drainage lagoons within the properties. The bank will be located generally along the property title boundaries and fencelines to reduce impact on the properties, but will need to skirt around the lagoon areas as required. The railway embankment is a significant height above the adjacent rural land. The height of the levee bank at the embankment connection is 3m, while the bank height through the paddocks will vary from 2m to 3m.

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3.3 Temporary Barriers across Goulburn Valley Highway VicRoad’s preference is to keep the highway open at all times, if that is possible, as it is the main traffic arterial into the township from the Hume Freeway and the Puckapunyal Road. The flood modelling indicates that the depth of water over the highway in a 1:100 flood event will be up to 1.6m at the levee crossing in the vicinity of Tierney Street. The highway outside the levee near Whiteheads Creek is under up to 1m of floodwater. In that circumstance, the highway is not trafficable in the case of a flood of 1:100 year magnitude. It is proposed that the highway profile remain as is and that temporary barrier systems be used to close off the highway as the water approaches the highway carriageway level. It is also considerably more cost effective to retain the current highway carriageway level and use temporary barriers to close the opening in the levee as required. To provide a safe trafficable width it is proposed that the opening in the bank be set back 3.0m from the edge of the seal on either side. Temporary barrier systems are available in a range of forms, either as a proprietary product or purpose designed on a project basis. Some provide just a temporary freeboard height on top of a permanent bank. This project requires a system that will provide temporary protection from the highway sealed surface to the top of the adjacent levee bank. The western crossing adjacent to Tierney Street requires a water-tight structure which can provide protection to a height of 2.2m above the road surface. Most of the proprietary products have been developed in Europe, where they are widely used to protect cities from flood waters which rise at a more rapid rate than is generally the case in Australia. They are in use at various locations across Australia. While the detail design has not yet been done, for the comparison of estimating the cost to acquire and fix a temporary barrier system, the style selected to close off the Murray Valley Highway at Nathalia from the Broken Creek flood waters is used as an example. This provides a conservative costing and some flexibility to select a preferred design at a later date. A foundation is required to be cast into the highway surface to attach the temporary structure. Discussions with Vic Roads have identified that provided the integrity of the road surface is not compromised in vehicle travel comfort, then the foundations can be incorporated into the road structure. The cost of that system including purchase of the components and installation of the foundations in the highway surface at $7,500 / lineal metre. The eastern crossing requires a considerably smaller barrier at 900mm above road level. It would be holding back only 300mm of water at 1:100 flood level, providing mostly freeboard protection.

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A smaller freestanding product is able to be used at this water depth. $1,300/m is used as the cost estimate. This will again give some flexibility in final design of the barrier.

3.4 Levee Use There has been some discussion within the community regarding the perception that travellers along the highway into Seymour may gain by passing through a gap in a large levee bank at the township entry. The perception may be that they are passing through a dam wall. There is concern this could reinforce the threat to the township of flooding in the mind of the visitor or investor and may be detrimental for future investment into the town. This impression is likely to be less if the highway passes over the levee than if it passes through it, as the bank profile is not as visible or intrusive. However the preferred option in this report is to leave the highway as is and to use temporary barriers to close the opening in the bank as required. As a result there will be a bank of up to 2.2m above the southern carriageway at the western entrance to town and 0.9m above the carriageway adjacent to Whiteheads Creek. Levee banks are generally constructed with top soil over and seeding as necessary to promote grass cover. This serves to assist the retention of moisture within the structure, making it less susceptible to cracking. It also assists the bank to blend into its environment. Larger trees should not be planted within the bank structure as the roots provide lines of weakness in the structure through which flood water can pass. If the bank becomes saturated through a long period of wetting by flood waters, then the trees become more susceptible to uprooting in high wind, tearing out a section of the bank. The levee bank profile can either be screened with planting in the vicinity of the highway or could be used as a ‘gateway’ to the town and used as a feature, particularly at the western (Melbourne) entrance. Such actions would serve to disguise any adverse perceptions but the approach to this issue would be a matter for the community to determine. The walking track along the Goulburn River generally follows the proposed bank alignment between Robert Street and Manners Street. It will need at least to cross the bank at Robert Street. Consideration could be given to relocating the walking track onto the levee bank through this section so that it remains accessible at all times. The cost estimate allows for the reconstruction of this section of walking track onto the bank. The other sections where a walking track could be incorporated into the bank are Hanna and Goulburn Streets. Due to the raised height of the bank, with the possibility of pedestrians seeing into private property, issues of privacy for residents along the walking track need to be considered. This may mitigate against using the bank as part of the walking track network.

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3.5 Internal/Cross Drainage The 2006 WBM report identified (in Figure 6.5) the three principal drainage sub-catchments within the protected area. The review of the levee route has not altered the essential characteristics or points of discharge of those sub-catchments. Where drains from each of these sub-catchments cross the levee route, culverts and backflow control structures are needed. The backflow control is usually provided by flap gates or pumps. Pump stations have been allowed in each of the main drainage points of the sub-catchments. A pump will be also required at each to ensure the protected area can discharge stormwater through the levee bank during a flood event. The central of these sub-catchments discharges through the Wallis Street pump to Whiteheads Creek or the open drain and pipe in Robert Street, outfalling directly into the Goulburn River. The levee will not affect the pump station in Wallis Street, other than it is proposed to pipe the open drain from the pump station to Whiteheads Creek to allow for the construction of the bank across and to prevent back up of floodwater into the township. The cost of the pipeline is included in this report. A pump station is proposed at the Robert Street open drain and pipe outfall. The cost of the pump station has been allowed in this report. The eastern sub-catchment is confined by High Street, the railway embankment and the higher ground to the west. It discharges toward the east into Whiteheads Creek, upstream of High Street. The levee through the catholic school area will cut off the natural drainage path for this section of the township. A new pump station is allowed adjacent to the railway embankment, to drain this sub-catchment. The western sub-catchment drains overland into various depressions or gullies which eventually link to the river or creeks. The topography of the area includes a number of natural overland flow paths running through the protected area. Most of these connect eventually to the Goulburn River, principally through Deep Creek. Deep Creek is fed from a series of depressions which pass through the protected area. It is understood that water can pass in either direction along Deep Creek, but it principally discharges into the Goulburn River at the eastern section of the catchment. The WBM report proposed that the open rural nature of this sub-catchment may mean it can contain its stormwater inside the levee without needing to pump to outside the levee. This is a reasonable assumption, but for the purpose of this report, and until detailed design is done, a pump station has been allowed to be installed on Deep Creek and the large gully in the paddock at the eastern end of the catchment. Retention storage will be required to balance the pumps’ lower discharge rates to the higher rates of runoff generated by storm events when the levee is operating. These will require investigation at the detailed design phase. There is a possibility

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there may be sufficient storage within the drainage system and associated natural depressions without the need for substantial additional basins. Backflow control structures will be required where each of these natural flow paths cross the levee alignment. Generally, these structures will be pipe culverts through the levee with closable gates to stop the flow of water. The cross drainage locations requiring flow control structures are illustrated in Plan B. Schedule 2 provides a photographic illustration of the existing drainage crossings. A number of the properties along the levee route have drainage pipelines discharging directly to the river or creek. These have not been identified in totality but the detailed design stage will establish where they are located. Each will be upgraded as required to enable them to be closed off to ensure they do not back-feed flood water into the protected area. As the protected area is encircled by the levee and railway embankment, a system of escape channels may be needed should the levee bank fail. These have yet to be investigated in detail but there will be an interconnection between the main drainage outfalls and pump stations.

3.6 Dwellings Outside the Protected Area An adverse impact of the construction of a physical flood protection system is the increase in the height of flood levels that it causes outside the protected area. Seven dwellings outside the protected area were identified as potentially being impacted by a change in the flood level if the levee were built as proposed in the WBM 2006 report. Each would experience higher flooding levels; some up to 800mm in a 1:100 year event. As a result their current floor levels would be below the modelled 1:100 flood level. This review does not seek deliberately to vary the alignment to include the dwellings identified outside of the protected area as being impacted by the levee construction. Nevertheless the revised levee alignment proposed in this report has included two of these dwellings within the protected area. Individual solutions are required for each of the remaining five dwellings to mitigate the impact of the levee construction. The individual solutions for each of the dwellings will be negotiated with the owners during the detail design stage. The five dwellings are identified on Plan A (sheets 2 – 6) in this report. The possible solutions include;

- lifting the building so the floor is 300mm above the flood level, or - constructing a physical wall or bank around the building.

Most of the dwellings are timber framed, weatherboard-clad structures on stumps. Others are timber framed but with rendered external walls. These can be lifted and external walls reinstated, but with more difficulty and cost. Each of the dwellings has a bricked chimney. The solution would be negotiated, depending on the depth of flooding and impact on the amenity of the dwelling as a result of the mitigation works.

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A cost of $60,000 to protect each of the dwellings has been included in this report. The winery/restaurant building adjacent to the highway at the western approach to the township is a block work and rendered structure on concrete foundation. It is unlikely that it can be readily raised to an adequate height to protect it from floor inundation. The modelled 1:100 year flood level is 1.2m depth of water across the site. The height of a flood protection system would need to be 1.5m above the natural surface to provide at least 300mm freeboard above the 100 year flood level. The range of solutions to be considered include;

a structure to freeboard height (at least 1.5m) around the immediate building site, and

structural modifications to the building. The area to be protected by a physical structure would be determined in

conjunction with the landowner. This option could create some aesthetic and amenity concerns.

The most cost effective option is generally an earthen bank around the building. With some additional work to provide vehicle access over the bank, the cost of this option is estimated at $60,000. A wall structure around the site is estimated from similar construction projects to be a more costly option. The estimated cost to construct a wall is $80,000. Structural modifications to the building could include closing up of the windows below 1.5m above ground and demountable door barriers. These barriers are available as propriety products, used to close over driveway and door openings. The estimated cost of this option is $60,000. The preferred solution is to be negotiated with the landowner. A cost of $80,000 has been provided in the report.

3.7 Services The services of various authorities will pass under the levee potentially providing access for flood water. Some structures including sewer access pits and power lines are close to the proposed levee alignment. A cost of $50,000 has been allowed in this report for services will also require adjustment or sealing of affected pits to prevent ingress of flood waters or relocation away from the levee alignment.

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4. Planning & Legislative Issues There are several legislative issues that need to be addressed prior to the commencement of construction of the levee bank, principally driven by the following legislation:

Planning and Environment Act 1987;

Mitchell Planning Scheme

Aboriginal Heritage Act 2006.

Local Government Act 1989

Land Acquisition and Compensation Act 1986

4.1 Mitchell Planning Scheme

The Planning and Environment Act (Section 12) requires each local government to develop a planning scheme to administer land use and development within its municipality. The new format Mitchell Planning Scheme was approved in 1999. All of the private land along the levee route is within the Urban Floodway Zone of the scheme. The Heritage Overlay and Environment Significance Overlay impact on sections of the route. As a consequence there are requirements for permits under the provisions relating to heritage, environmental significance and native vegetation removal. Urban Floodway Zone The majority of the route is within the Urban Floodway Zone (UFZ). The principal purposes of the UFZ (clause 37.03) of most relevance to this project are;

To identify waterways, major floodpaths, drainage depressions and high hazard areas within urban areas which have the greatest risk and frequency of being affected by flooding.

To ensure that any development maintains the free passage and temporary storage of floodwater, minimises flood damage and is compatible with flood hazard, local drainage conditions and the minimisation of soil erosion, sedimentation and silting.

A permit is needed for the construction of a building or to carry out works. The scheme provisions effectively prevent the construction of any structure within the UFZ that will impede the flow of floodwaters. The provisions of clause 37.03-2 of the UFZ in Mitchell Planning Scheme exempt ‘flood mitigation works carried out by the responsible authority or floodplain management authority.’ from the need to get a permit. This exemption applies to the buildings and works component of the project. This exemption allows the structure to be built within the UFZ, but with consideration of the flowing matters. Heritage Overlay A heritage overlay applies over the properties between Manners Street and Robert Street. It extends also over portion of Manners Street between Ballendella

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Place and Tierney Street and over the southern portion of Hanna Street and the southern half of the property closest to Robert Street.

There is a proposed amendment of the scheme to extend the heritage overlay over the balance of the properties between the Goulburn River and Hanna Street. The purpose of the heritage overlay is;

To conserve and enhance heritage places of natural or cultural significance.

To conserve and enhance those elements which contribute to the significance of heritage places.

To ensure that development does not adversely affect the significance of heritage places.

To conserve specifically identified heritage places by allowing a use that would otherwise be prohibited if this will demonstrably assist with the conservation of the significance of the heritage place.

A permit is required for the demolition or removal of a building or the construction of a building or carrying out of works.

Environmental Significance Overlay The Environmental Significance Overlay (ESO) applies principally to the Goulburn River and adjacent crown lands. Relevant to this project, it applies also over the private land along and to the north side of Hanna Street between Robert Street and Bolton Street. The overlay does not include land to the south side of Whiteheads Creek. The ESO aims in part to; Identify areas where the development of land may be affected by environmental constraints, and Ensure that development is compatible with identified environmental values. A permit would be required for any works for works on the land north of Hanna Street.

Native vegetation The principal objectives of clause 52.17 is to;

Avoid the removal of native vegetation,

If the removal of native vegetation cannot be avoided, to minimise the removal of native vegetation through appropriate planning and design, and

Appropriately offset the loss of native vegetation.

For that purpose a permit is required for removal of any native vegetation for this project.

Preferred Approach A single step approval process would be preferred for a significant infrastructure

project such as this to cover all aspects relating to the planning approvals requirements.

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A common aspect of the many large scale developments that spread across many land titles and are typically linear in nature is to carry out a single approval process to exempt any need for subsequent permit approvals for that particular project. The comparisons that come to mind is the Calder Freeway alignment and the Sugarloaf pipeline project. The levee bank proposal would be one such project where this approach could be adopted. Two options are possible to provide the single approval process. Option 1 Any approval required for the work can be removed by creating an easement in favour of the proposed use on the affected private land titles along the route. This would result in the ability to construct the levee within the easement without further approvals from Council. This option can be administered by the planning permit process for the creation of an easement across the private land and would not require an amendment to the planning scheme. The acquisition of the easement would be governed by the provisions of the Land Acquisition and Compensation Act. The timing of the process would be greatly assisted by landowner consent to create the easement. The limitation of this is the land remains in private ownership, yet its use and management is in favour of Council. It is understood the state government does not favor this option as there is still an expectation of the land owner to maintain or change the use of the land. Option 2 To provide greater surety to the floodplain manager and an ongoing ability to maintain the levee, an alternative approach is to compulsorily purchase the land along the route of the levee through the use of a Public Acquisition Overlay (PAO). This is a mechanism in the Victoria Planning Provisions (VPP) to facilitate the purchase of land for a public need. The purpose of the Public Acquisition Overlay is to:

identify land which is proposed to be acquired by an authority.

reserve land for a public purpose, and

ensure that changes to the use or development of the land do not prejudice the purpose for which the land is to be acquired.

The Public Acquisition Overlay is implemented by amendment to the planning scheme. As such it is subject to appeal by landowners and consideration by a Planning Panel. A PAO should not be used as an ongoing measure to validate the use of the land for a levee. Rezoning of the land, suggested to Public Use Zone 6 (local government), should occur at some future point once the land purchase has occurred.

Heritage issues would be considered as part of the amendment and conditions applied within the scheme provisions. The deletion of the Heritage Overlay restrictions should be based upon a heritage assessment by a suitable

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professional. It is assumed any post contact buildings of significance such as the old brewery site that is within the levee alignment would be demolished and therefore any built form considerations will be lost which provides additional support to the deletion of the heritage overlay restrictions. The Heritage Insight report (reference section 4.4) found that ‘Although no historical archaeological sites places or structures listed on the Register of National Estate or National trust were identified within the study area, there is the possibility that subsurface historical archaeological sites may be present within the study area. Further investigation will be required to determine whether any such sites are present within the study area, and if so, to determine their status.’

An ecological assessment is required along the route and an offset ‘net gain’ plan developed for the vegetation proposed to be removed should be completed to support the amendment at any Planning Panel. Any trigger for a further approval for the removal of native vegetation should be avoided as a full net gain assessment would be completed during the scoping of the project.

Indigenous culture is a matter under the Aboriginal Heritage Act 2006 and remains a consideration outside of any planning scheme amendment. A cultural heritage management plan involving a more detailed investigation of the alignment will be developed as part of the detailed design phase. The Mitchell Planning Scheme (clause 43.01-2) provides that a permit is not required if works are done in accord with an incorporated document within the scheme. The heritage assessment and vegetation offset management plan can become incorporated documents for this purpose.

In summary the planning scheme amendment would: Apply the Public Acquisition Overlay, Insert into the planning scheme the conditions relating to heritage and native

vegetation removal and other relevant matters. The use of the Public Acquisition Overlay is recommended on the basis that it flags the intention of a public authority to purchase the land for a public purpose and ensures that in the intervening period between the application of the overlay and the eventual purchase of the land it is not used or developed in a fashion that would not enable the land to be developed for its intended purpose (ie a levee bank).

Timing

There are a range of options open to Council in regard to the timing of the planning process; largely linked to the likely timing of the funding availability to allow the construction of the levees. A commitment to a funding application is not required to commence the amendment process nor is any indication of government support. However in this instance it would be helpful to have the Goulburn Broken CMA demonstrate its clear support for the proposal. Any amendment to a planning scheme takes a considerable amount of time and resources. It is not unreasonable to assume the amendment process would take

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12-24 months from the start to the ministerial approval of the amended scheme. The key steps are:

Complete all amendment documentation;

Ministers’ authorisation to prepare an amendment;

Formal exhibition of amendment;

Consideration of submissions;

Request formation of Planning Panel to consider submissions;

Directions hearing;

Full panel hearing;

Report writing;

Council to consider Planning Panel Report;

Council to forward amendment to Minister for approval; and

Minister approval to the amendment. The process to commence the acquisition of land could commence at any time however as a demonstration of good faith and respect for the public process this should not formally start until the amendment has been approved or at the very least considered by the Planning Panel.

4.2 Land Acquisition and Compensation An easement or reserve (recommended) is required to provide for the bank structure and allow access to maintain the levee as required and to enable patrolling and monitoring during a flood event. The ability for public authorities to acquire land is considered under Section 187 of the Local Government Act 1989 which states: (1) A Council may purchase or compulsorily acquire any land

which is or may be required by the Council for or in

connection with, or as incidental to, the performance of

its functions or the exercise of its powers.

(2) The Land Acquisition and Compensation Act 1986 applies

to this Act and for that purpose-

(a) the Local Government Act 1989 is the special Act; and

(b) the Council is the Authority

The Land Acquisition and Compensation Act 1986 sets out the process for the compulsory acquisition of land. Without detailing the process it is sufficient to say it involves a transparent and public process with the ability to lodge and consider public submissions and a separate appeal process to the Victorian Civil and Administrative Tribunal (VCAT). On the assumption that there will be some delay in gaining the construction funding, placing a public acquisition overlay over the privately owned lands to be later acquired lends some protection to the use and development of that land pending its acquisition. It does however open Council up to the need to purchase the land upon request by the landowner. Given that the entire route through private land is within an Urban Floodway Zone, which significantly limits the development of the land, the imposition of the overlay

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should not be regarded as an unfair impost on the land, particularly if the ultimate construction of the levee bank protects section of the land now within the Urban Floodway Zone, allowing it to be developed. However it can be argued that unless the overlay is placed or rezoning is not implemented and there is a significant delay in achieving the funding, then the level of uncertainty and inconvenience caused to the landowner is increased. Both the acquisition of the strip of land or easement through the private property and the physical presence of the levee across the land can cause dislocation and reduce the value of the land. An assessment of the costs associated with the alignment across the private land involves consideration of two factors: a) An assessment of the cost of acquisition of the land; and b) The compensation owed to the landowners due to the levee structure causing dislocation to the use of the property. A global estimate provided by Council’s Valuation Contractor of the cost of acquisition of the land and the assessed compensation due to the landowners for the impact of the levee easement and structure within their land is $1,600,000. Additional legal and survey costs of $100,000 can also be expected and have been allowed for in this report.

4.3 Indigenous Cultural Heritage

The proximity of the proposed levee structure being adjacent to both the Goulburn River and Whiteheads Creek over much of its length, and the natural drainage paths through the site require a detailed assessment of the potential for sites of indigenous cultural significance. Heritage Insight was engaged to undertake an initial assessment of the potential for sites of heritage significance along the alignment.

The assessment included a visual survey of the proposed alignment. The preliminary advice of the archaeologists is that there are no apparent sites but there are some sites of potential importance along the route that will require additional investigation during detailed design. Following consideration of this report, if Council decides to proceed further with the project, a Cultural Heritage Management Plan will be required. If items of significance are uncovered, either during the detailed investigation or construction, variation of the route may be required. Monitoring of the works during construction will be required and may be adequate if no sites are discovered.

The following extract from the Preliminary Heritage Assessment by Heritage Insight outlines the statutory approvals required for the project as it relates to indigenous heritage. The full report is contained in Appendix 1

‘Indigenous cultural heritage in Victoria is protected by the Aboriginal

Heritage Act 2006. The Act defines Aboriginal cultural heritage as

‘Aboriginal places, Aboriginal objects and Aboriginal human remains’

(Section 4). An Aboriginal place is defined as ‘an area in Victoria or in the

coastal waters of Victoria that is of cultural heritage significance to the

Aboriginal people of Victoria’ (Section 5). The term ‘area’ under the Act

includes ‘an archaeological site, feature or deposit’.

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It is an offence, under Section 27 of the Act, to knowingly carry out an act

which causes harm to, or is likely to harm Aboriginal cultural heritage. Any

proposed activity that is likely to harm Aboriginal cultural heritage must

comply with the guidelines set out under the Act for the protection of this

heritage. Some activities, as defined in the Regulations of the Act, will

require the preparation of a Cultural Heritage Management Plan (CHMP)

prior to the works taking place. A CHMP is defined as involving ‘an

assessment of the area to determine the nature of any Aboriginal cultural

heritage present’ and the production of a report that describes the results

of said assessment, and includes ‘recommendations for measures to be

taken before, during and after an activity to manage and protect the

Aboriginal cultural heritage identified in the assessment’ (Section 42).

Aside from those CHMPs required under the Regulations of the Act, the

Minister for Aboriginal Affairs has the authority to direct that a CHMP be

undertaken, and a CHMP is required for the production of an Environmental

Effects Statement. CHMPs can also be undertaken voluntarily. (Sections 46-

49). When a person or ‘Sponsor’ under the Act is required or elects to

prepare a CHMP, they must invite the relevant Registered Aboriginal Party

(RAP) to comment. The relevant RAPs are appointed under the Act by the

Aboriginal Heritage Council, and may elect to evaluate a CHMP. A permit

cannot be granted to a sponsor unless the assessment has been approved

by the RAP who has elected to evaluate the management plan (Section

63). In areas where no RAP has been appointed, the Secretary for DPCD will

evaluate the plan.

Regulation 6 of the Aboriginal Heritage Act 2006 requires that a CHMP be

undertaken if:

a) all or part of the activity area for the activity is an area of cultural

heritage sensitivity and

b) all or part of the activity is a high impact activity.

Parts of the study area (Sections A-C) fall within the nominated ‘areas of

cultural heritage sensitivity’ as defined by regulation 23 of the Aboriginal

Heritage Regulations 2007. See figure 11 for a plot of these areas. Areas of

cultural heritage sensitivity are defined in regulation 23 as ‘a waterway or

land within 200 metres of a waterway’ that has not been subject to

significant ground disturbance. Significant ground disturbance is defined by

regulation 4 of the act as disturbance of:

a) the topsoil or surface rock layer of the ground or

b) a waterway –

by machinery in the course of grading, excavating, digging, dredging or

deep ripping, but does not include ploughing other than deep ripping.

The results of the field inspection (section 4), in association with what is

known about historical land use within the study area (section 3.2) indicate

that parts of the study area that fall within the areas of cultural heritage

sensitivity as defined in figure 11, have not been subject to significant

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ground disturbance. Part of the activity area for this project is thus defined

by the Act as ‘an area of cultural heritage sensitivity’.

Figure 1 - Showing areas of cultural heritage sensitivity as defined by AAV.

Note: these zones are a guide only and do not necessarily represent all

such areas within the region indicated on the map. Source: DPI Geovic,

accessed 16/07/08.

The proposed works constitute a high impact activity under Regulations

43(1) and 54(1) of the Act. These Regulations define the proposed works as

high impact in that the works will result in significant ground disturbance, are

associated with the use of the land for a listed activity, namely a utility

installation, and require a statutory authorisation to use the land for that

purpose.

As part of the activity area for this project falls within an area of cultural

heritage sensitivity, and is a high impact activity as defined by the Act, the

preparation of a Cultural Heritage Management Plan will be required

should the proposed works proceed.’

4.4 Non Indigenous and Cultural Heritage The following extract from the Preliminary Heritage Assessment by Heritage Insight relates to the non-indigenous or cultural heritage considerations and approval process.

‘Non-Indigenous historical archaeological sites are protected under the

Victorian Heritage Act 1995.

A Consent from the Executive Director of Heritage Victoria is required to

disturb or destroy historical archaeological sites, places, buildings or

structures listed on the Victorian Heritage Inventory.

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A Permit from the Executive Director of Heritage Victoria is required to

modify, disturb or destroy historical archaeological sites, places, buildings or

structures listed on the Victorian Heritage Register. Permit applications must

be approved by the Heritage Council.

Fees apply for the issue of Consents and Permits and a conservation bond is

required for artefacts from a historical archaeological site. The issue of a

Permit or Consent is not automatic and will be subject to furnishing of

adequate supporting documentation.

Heritage Victoria has introduced a ‘D’ classification for places of low

historical or scientific significance. Sites assigned a ‘D’ classification are

listed on the Heritage Inventory but there is no requirement to obtain a

Consent from Heritage Victoria to allow the removal of these sites.

Provisions for the protection of historical places or precincts identified within

a Heritage Overlay are defined within clause 43.01 of all Victorian Planning

Schemes. Heritage areas or precincts are designed to ‘ensure the

conservation of those elements that contribute to the area’s significance’

(http://www.heritage.vic.gov.au/page.asp?ID=132#6 - accessed 15/07/08.

To ensure this protection, a planning permit from the local council is

required to construct or carry out works within an area identified by a

Heritage Overlay. Tree controls may also apply in these areas.

Parts of the study area for this project fall within areas protected by Shire of

Mitchell Heritage Overlays. As such a planning permit from the local council

will be required if this project is to proceed along the proposed alignment.

Although no historical archaeological sites places or structures listed on the

Victorian Heritage Register or Inventory, or the Register of the National

Estate or National Trust were identified within the study area, there is the

possibility that subsurface historical archaeological sites may be present

within the study area. Further investigation will be required to determine

whether any such sites are present within the study area, and if so, to

determine their status.’ A report by the Shire of Mitchell Heritage Advisor emphasised the historical significance of the Emily Street section of the township, as one of the main locations of an early river crossing and stopping place on the route between Melbourne and Sydney. The Heritage Advisor’s report noted sufficient concerns about the visual impact on the heritage area of Emily Street to recommend that a levee bank is not appropriate within this area. The heritage report is attached as Appendix 2 This report however intends to review the technical feasibility and the cost of constructing a levee bank system to provide the flood protection required. Whether the levee bank is built is a matter for subsequent consideration by Council and the community. The options that can be considered to reduce or remove the visual impact of the earthen levee bank through the heritage overlay section include a levee bank of

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reduced height to flood level, with freeboard provided by demountable barrier, or a demountable barrier throughout. The length of the levee through the overlay section is approximately 400m. The height of the bank ranges from 2.5m at the Hanna Street end to 2m along the rear of the properties between Robert Street and Manners Street. The average bank height is assumed at 2.2m. The construction cost for an earthen bank through the overlay section is $175,000. This cost does not include the pump station at Robert Street as that is required to be constructed with any option. The estimated cost of a proprietary demountable barrier system to 2m height is $6,000/m; a total cost of $2.4m. The cost of a purpose designed demountable barrier wall tends to be about 5 times the cost of an earthen bank from the considerable experience of the New South Wales Department of Commerce, which has responsibility for design and construction of the flood mitigation systems throughout that state. The cost of such a system for the overlay section is estimated at $875,000. The estimated cost of an earthen bank to 1.7m height (average water depth) is $120,000. At the general standard of five times the cost for the freeboard barrier compared to an earthen bank of the same size, the demountable barrier is estimated at $110,000. The total cost of this option is $230,000. An earthen bank to the height to include freeboard is significantly cheaper than any other physical option. It is only 20% of any demountable option. On that basis, the only viable physical protection over the 400m length is an earthen bank.

4.5 Native Vegetation The levee alignment follows close to the Goulburn River and Whiteheads Creek for much of its length. There is a considerable amount of native vegetation within the proposed construction area. Much of this is River Red Gum, some of significant maturity and size, with the potential to provide habitat for fauna, mainly birds and bats in nesting and roosting hollows. Inevitably with such projects there will necessarily be the removal of an amount of native vegetation. While the recommended planning scheme amendment removes the requirement for planning approval for removal of native vegetation relating to the construction of the levee bank, the final design should include a strenuous examination of the opportunities to avoid as much as is possible any removal of mature native vegetation. The principal of avoid vegetation removal where possible and minimise where removal is necessary should apply. An ecological assessment should be done along the levee route, which would identify the significant or threatened flora within the construction area and provide a framework for final decisions on the alignment and on offset planting rates. Where possible the bank should be aligned to the protected (township) side of any mature trees. That would then provide an opportunity to maintain both the maximum flow path as possible and to enable the periodic flooding needed for the health of the trees on a regular basis.

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5. Opportunities Created by the Levee Bank The Mitchell Planning Scheme was approved in 1999 and it does not as appear to have had a thorough review since then, so most statements contained in the Municipal Strategic Statement (MSS) need to be viewed in the current day circumstances also. The Scheme confirms most residential development in the Shire has traditionally focussed on Seymour, Kilmore and Broadford. However the smaller settlements closer to Melbourne have also experienced considerable recent growth. Most towns have sufficient residential zoned land to accommodate future growth. The planning scheme states: The key features of Seymour are:

An integrated settlement with a broad range of facilities and services.

A balanced social and economic profile with a high proportion of lower income residents.

A broad range of recreational and tourist uses located within and near to the township.

A concentrated commercial centre with some dispersed nodes along the major approach routes.

Commercial facilities which benefit from the highway associated locations, have created an extended ribbon-form of development along key arterials.

A broad range of residential environments have been established including those which offer a strong relationship with open space - recreation facilities.

Dispersed residential precincts with good pedestrian accessibility to the town centre and other community facilities.

A strong relationship between the transport interchange location and the commercial centre facilities.

A broad based economy including some local manufacturing, defence force related employment and agricultural services.

Access to airport facilities at Mangalore.

A variable range of housing stock including areas potentially suitable for redevelopment, especially in the public housing rental accommodation sector.

A need for continued investment in civic facilities following recent projects to construct an aquatic centre, walking tracks and transport interchange facilities.

The existing landfill site has only enough remaining air space for 1 to 2 years and a new site should be identified

Significant enclaves of public housing stock providing rental accommodation for low income and in many cases disadvantaged residents.

The Seymour Structure Plan contains in clause 21.05 what could be described as a growth boundary (though not specifically defined) and notes that future expansion to the north west, west and south west is constrained by flooding, future residential expansion to the north is constrained by industrial land and the freeway and future growth is only possible through infill and to the south east. Should the levee bank proceed this will provide a 1% AHD flood protection to areas of land that could not previously be developed. These areas are located principally in the south west and smaller areas in the north adjacent to Whiteheads Creek.

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(Source Mitchell Planning Scheme – clause 21.05)

It seems from a review of the planning scheme and discussion with Council staff that development is constrained by a number of environmental and socio-economic issues and the population growth rate in recent years has stagnated. On the basis

Presumed growth boundary

Alignment of levee bank

Area outside growth boundary

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of the amount of undeveloped residential zoned land in the south east and north it is still considered there is sufficient land zoned for development, however it needs to be considered whether this land is in the most appropriate location to encourage private land investment. Infill development to the north of Whiteheads Creek would be constrained by the industrial precinct, the railway line and the wastewater treatment plant further to the east. Infill development to the south is affected by the perceived stigma associated with the adjoining public housing estates and the reluctance of private landowners to initiate development in this area. The provision of housing should be predicated on providing diversity in the type and location of opportunities for all socio-economic levels. There is modest infill opportunity to the north, however from a greenfield perspective it is the south-west section that provides the greatest opportunities. This area remains undeveloped and in principle could provide another corridor for residential growth. An inspection of the site does however indicate a number of constraints that require further investigation. These would include:

A review of the policy framework for Seymour contained in the Mitchell Planning Scheme;

Native vegetation retention including trees and native grasses;

Watercourses or drainage lines that could form a linear open space opportunity;

Access to infrastructure;

A thorough assessment of residential land supply and demand; and

The need for a development plan to guide the future development and release of land.

A review of the land to the north of the Seymour CBD indicates it is flat, has good vehicle access and is within walking distance of the CBD and other urban areas. The Seymour CBD provides generally for all forms of retail but there is no precinct that could be said to serve bulky goods retail and the more traditional retail activities envisaged by the Business 1 Zone. This is not uncommon for regional towns however as these towns grow there will inevitably be pressure for the larger format retailers to locate in Seymour. There has been a tendency for these uses to locate on the Goulburn Valley Highway, however there are lot size and heritage constraints in this area. The land south of Whiteheads Creek does provide for these opportunities. It is therefore recommended this land be reviewed as part of the planning opportunities review with the intention of its potential as a bulky goods retail precinct.

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6. Climate Change Discussions with residents identified there is some opposition in principal to flood mitigation works being considered for Seymour. The publicity surrounding climate change with its predicted significant reduction in annual rainfall and with greater prevalence for droughts to occur has caused some people to question whether any form of flood protection will be needed into the future. It is apparent that some people in the community perceive that flooding will not be a problem for Seymour in the future as the water storages in the regions dry out and climate change is predicted to cause less rainfall generally within the catchment. Therefore, it is felt that there will still be adequate capacity in Eildon to prevent the impact of any downstream flow peaks. However, the modelling carried out in the 2001 WBM report has shown although dam storages can reduce flow volume, they have little impact on peak flow levels. Peak flows affecting Seymour generally arise from the catchment below Lake Eildon. The state government sponsored Sugarloaf pipeline is designed to take up to 75GL per year from the Goulburn River. This project is causing further belief that the Goulburn River will continue to dry out, and provide a considerable buffer against flood flows. There is a view that the pipeline will draw down the Eildon Weir, so providing an additional buffer to flooding downstream. According to the Murray-Darling Basin Sustainable Yields Project (CSIRO, 2008), the best prediction of climate change on water availability in 2030 is that average surface water would be reduced by 14% and volume of water diverted for use in the Goulburn-Broken catchment area would be reduced by 6%. This is confirmed by data sourced by the Victorian State Government (2008) which suggests that the projected percentage change in annual average runoff for the Goulburn River is a 35% reduction in the driest scenario for 2030. Much of this would be brought on by rainfall change which the Bureau of Meteorology (BOM) forecasts will be somewhat lower in the State of Victoria from between 2 to 5% in 2030. To be specific to the Goulburn Broken region, the Victorian State Government (2008) has assessed data from both the CSIRO and the Australian Bureau of Meteorology and indicated that for medium greenhouse gas emissions, the average temperature would increase by 0.9 degrees centigrade and rainfall would decrease by 3%. This is also confirmed in earlier data by CSIRO (2005) which, in addition to predicting temperature increases from 0.3 to 1.0% by 2020 in the Melbourne water catchment areas, it was also suggested that even with diminishing rainfall patterns, more hot and dry days may be accompanied with increased rainfall intensity during storms. This latter effect of greater rainfall intensity is also confirmed by a later CSIRO document (CSIRO, 2007) which suggested that more extreme rainfall events would damage infrastructure including roads, railways and bridges Schreider et al. (1996) looked at the effect of climate change based on dry and wet scenarios. They indicated that drought frequency would increase by 35% for the dry scenario classifications for the State of Victoria and even 80% for 2080. A further study by Schreider et al. (2004), although only looking at some river systems in NSW north of Sydney, estimated that climate change reflected by double carbon dioxide conditions would significantly change the 1 in 100 year flood event to the 1 in 35 year flood event for the Upper Parramatta River. This seems to

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give some credence to the possibility of increased rainfall intensity as indicated by CSIRO (2005) above. Schreider et al. (1996) also qualified their results of the possibility of extreme events based on soil wetness indicators. This is discussed by Chiew et al. (1994) where they found that soil moisture has a significant effect on water runoff. In fact, the accepted figures for runoff suggest that for every 1% reduction in rainfall, there is an approximately 3 to 4% reduction in runoff (Walker & Robert, 2008,). It would appear that the effect of climate change on flooding patterns in rivers is multi-factorial and any conclusions have to be made from inferences that greenhouse gas emissions lead to rainfall reductions, temperature increases and intensity of weather patterns. Bronstert (1996), however, was one of few researchers to look specifically at climate change effects on flooding. Although his work is based on research on German river environments, climate change has the greatest effects on the meteorological conditions and lesser effects on the river catchment surface. It would therefore be difficult to provide definitive effects of climate change on flooding levels due to the many factors involved. Furthermore, with this mixed picture in mind, it would appear that particularly for rural areas in Australia the status quo should be maintained for any future planning of water or flood management issues.

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7. Project Cost

7.1 Review of Cost The WBM 2006 report estimated a capital construction cost in the order of $3.91M. A range of issues were flagged but not brought to account in the estimate of cost, requiring further investigation. This report has identified and included a range of additional costs into the project. The principal cost elements of the project are:

1. Detailed design and survey and preliminaries

2. Site investigation and approvals process 3. Construction of earthen levee bank; 4. Cross drainage structures; 5. Drainage pump stations and associated works; 6. Land acquisition and compensation; 7. Protection of dwellings outside protected area; 8. Demountable barriers across highway 9. Relocation, raising or capping of services;

A contingency of 40% is usually allowed as a standard on projects which are at the concept design stage, where the detailed design is yet to be done. However with the relative thoroughness of the development of this project with both the flood modelling and 2006 WMB report followed by this review, the cost contingency of 40% could be regarded as unnecessarily conservative. Consequently it is proposed to adopt 30% contingency on the cost elements yet to be finally determined. Based on the review of the alignment, the addition of the land acquisition and compensation costs, with a 30% contingency pending detailed design and construction, the total project cost is estimated at $6.2m. The break down of the principal costs is contained in Schedule 4, Project Cost Estimate. The size and length of the levee bank structure is critical to assessment of the cost of construction and ultimately the benefit/cost ratio. A survey of the revised alignment natural surface levels was carried out to improve the estimate of earthfill volume required. A major factor in the cost of the project is the volume and availability of earth fill suitable for the construction of the bank.

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Based on the bank profiles recommended in this report of 1 vertical:2 horizontal on the protected side and 1 vertical:2.5 horizontal on the flood side, the estimated volume of material required to construct the levee bank is 120,000m3 loose. Access to this volume of earth fill of suitable characteristics within a reasonable haulage distance is critical to containing the project cost. Some preliminary testing has been done on material available from a nearby quarry. The material is a silty clay with a permeability well within the parameters required for earthen fill, and it is not classed as dispersive. These two characteristics indicate the material is suited for the project. The quarry operator indicates there is adequate supply of the material within the site, which is only approximately 5km from the construction site. Another source of some material is available if required at the Council owned waste disposal site; again within 5 km of the project site. Land acquisition and compensation to affected landowners is the other cost item which has been included and added considerably to the overall project cost.

7.2 Cost/Benefit The cost and benefit parameters identified in the WBM 2006 report were;

Current situation;

Average Annual Damage (AAD) - $715,000

AAD reduced to $490,000 as community regarded as prepared.

If the levee is constructed;

AAD - $20,000.

construction life of 30 years At the cost estimate in the report of $3.91M, the benefit cost ratio (BCR) of constructing the levee was calculated to be 1.54. The revised construction cost estimate of $6.2 reduces the cost/benefit ratio to 0.97. It can be argued that with the passing of time since the last flood event in 1993, the level of awareness and preparedness of the community will diminish. Discussions with members of the community indicate also a view that the ongoing drier than normal conditions has created a significant buffer against flood impact through the low level of the Lake Eildon being able to absorb much of the flood waters. There is also scepticism that with the changing climate conditions, there will ever be flood events as previously experienced as discussed in section 6, Climate Change, in this report. While these comments provide only anecdotal evidence of a view that may be more widely held, they are indicative of a view indeed held by some community members. It can be expected to be a view more widely held if/as dry conditions continue. Consequently it is reasonable to review the AAD assumptions made only three years ago in 2006.

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The benefit/cost ratio is a function of the present value of the annual savings due to the flood protection, over the assumed life of the levee bank. A reduction in the AAD discount assumption through diminishing community preparedness would have the effect of increasing the benefit gained by building the levee bank. Similarly an increase in the assumed life of the levee bank structure would have the effect of increasing the benefit/cost ratio. While the assumption was used in the WBM 2006 report that the construction life of the bank is 30 years it can be argued that an earthen structure, properly constructed and maintained would have a significantly greater life. It would not be necessary at the end the assumed life period to rebuild the bank, but rather to strengthen and perhaps raise it to match new modelling levels. If the construction life of the levee bank were extended to 40 years then the present value of the reduced damage benefit gained by its construction increases to $6.35m. The benefit/cost ratio would then be 1.03. It is proposed that 40 years, or indeed 50 years provides a more accurate construction life of the bank, given that it would not need complete rebuilding at the end of that period. On that basis it is proposed that a benefit cost ratio of 1.03 is gained from the construction of the bank.

7.3 Maintenance The Shire of Mitchell will assume the ongoing role of maintenance and operation of the levee bank and pump stations and associated structures. The construction life assumed for the bank structure is 30 years before significant repair or reconstruction can be expected to be required. The principal source of maintenance is the pumps and the flow control structures. The levee bank will require ongoing inspection and removal of tree seedlings and weed spraying. An annual cost of $5,000 is allowed for inspection, weed spraying, removal of tree seedlings and pump maintenance. The walking track maintenance is assumed to be the responsibility of another cost centre within Council.

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8. Funding

8.1 Federal and State funding It is anticipated that if Council decides to proceed with the flood protection project, due to the significant cost involved a funding application would be made to the relevant state and federal government program. The project is likely to proceed only if the application is successful. The decision to proceed is in that respect ultimately out of Council’s control. The previous program was the Natural Disaster Mitigation Program (NDMP). The federal government has reviewed that program, in the process providing a one year program extension, which has now ceased with the last year of funding being 2008-09. The Commonwealth has developed a revised State natural disaster and emergency volunteer support funding program titled the Natural Disaster Resilience Program (NDRP). Victoria’s share of the Fund is expected to be $3.3 million for 2009-2010.

The Commonwealth will provide up to 50% of the costs of the projects. The remaining 50% is to be provided by the States and other sources such as local government and the private sector. Fully costed “in-kind” contributions are acceptable.

While the exact details of the new funding arrangements are yet to be finalised the key features of the program are:

allows funding to be allocated to projects which extend beyond 12 months,

permits States to allocate funds in the form of grants or targeted to address specific priorities,

funded activities must accord with specified priorities specified by the Commonwealth – improving volunteer attraction and retention; developing climate change adaptation strategies for the emergency management sector; building a strategy for enhancing national partnerships with the private sector and NGOs; developing national strategies for community engagement, education and enhancing self-reliance and recovery, and

payments from the Commonwealth will be in accord with the Agreement, and could be quarterly or monthly

Formal announcement of this program will take place at the end of 2009. Given it is anticipated that Council will be putting forward a total funding request of up to approximately $3.1m to the federal government, clearly it is not an option to request the funding be provided within a short time period of one or two years. The share arrangement with the state government is not confirmed at present. Given that the previous NDMP operated with an equal share between state and local government it is reasonable to assume that relationship will continue. Council could then be required to fund 25% of the overall project cost. The state government is not likely to fund only one project in any year, hence it is advisable to apply for the funding to spread across at least 4 years. This timeframe is generally suitable for a project such as this, particularly involving a number of

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land acquisitions. The land acquisition process alone is anticipated to take in the order of 12 – 18 months. The works program has been broken down into logical stages over four years to reflect the possible funding application timing.

Year Project Works Project Cost Federal Funding Application

1 Investigations Detailed Design Preliminary works

$820,000 $410,000

2 Land acquisition Levee construction Drainage structures

$1,760,000 $880,000

3 Land acquisition Levee construction Drainage structures

$1,750,000 $875,000

4 Land acquisition Levee construction Drainage structures Demountable barriers

$1,870,000 $940,000

8.2 Local Funding Based on the updated cost estimate, and assuming that the NDRP provides up to 50% funding from federal government and 25% from state government, the local government portion of the funding is likely to be in the order of $1.55m over the period of the project. Given it is likely that any NDMP funding for the project would be provided over a period of years, the local funding can be provided over up to 4 years. The flow of funding required from Council, based on a four year project is could be;

Year 1 $205,000 Year 2 $440,000 Year 3 $437,500 Year 4 $470,000

There is no restriction on local government as to how it chooses to raise those funds, including the following.

1. General revenue: Council may fully fund the project over the four years as part of the annual capital works program. This option is the simplest provided Council is able to allocate $1.55m to one project over a period of four years. 2. Special charge on benefitting properties: Council may choose to require those properties which gain a particular benefit from the works, in this case the levee construction and associated works, to contribute to the cost. This approach is available to local government under section 163 of the Local Government Act 1998. It enables Council to bring forward works that would be beyond the capacity to fund wholly within the capital works budget.

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This approach focuses on properties which can be identified as gaining a ‘special benefit’ from the works and hence will contribute to them in the proportion of the relative benefit gained. The benefits gained by the properties within the township are both direct and indirect, depending on the location of each. Council can contribute to the cost on any basis, but must contribute at least in proportion to the identified general community benefit from the works on the behalf of the broader community. Ministerial guidelines were developed in 2004 to assist in determining the community benefit.

3. Special rate on a defined area of properties: A special rate can be determined for a defined period over properties within an area which gains a range of benefits from the project. 4. Differential rate over the properties across the township. A differential rate does not require any special benefit to be determined for each property. It can apply to a defined area as benefiting generally from the works. 5. Any combination of the above. The Council contribution may come from general revenue or loan or other sources in all cases and shall be a decision made by Council as required. Direct Benefit The principal direct benefit is gained by the protection from periodic flood inundation of property and buildings and the associated property damage experienced by properties within the township. Consequent direct benefits are the removal of the Urban Floodway Zone and the Flood Overlay within the Planning Scheme from those properties within the protected area. Urban Floodway Zone – properties within the zone are not able to construct any new structures which cause a restriction to the flow of flood waters. This in effect limits any new buildings to open structures such as hay sheds. The levee is proposed to be built largely within this floodway. Flood overlay – this overlay over the majority of the properties in the flood protected area causes any development to be referred to the Catchment Management Authority for approval. If approval is given, the floor level of the building is required to be constructed to a height of no less than 300mm above the 1% flood level. In general:

Properties will be relieved from the inconvenience and damage caused by flooding.

Properties will be able to be developed to uses and to an extent currently not allowed.

Properties will have more flexibility in development currently allowed; principally in floor level.

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Indirect Benefit Indirect benefits will accrue more generally to a broader area, which is less easy to define, including;

Flow-on benefit to the business properties from the increased confidence in investment in the town, and

Flow-on benefit to balance of properties in town from the growth in services and employment opportunities from business investment, new business and general growth of the town.

Special Charge Scheme Structure Options Some possible special charge scheme scenarios are provided as examples, having regard to the varying impact of flooding on properties and the lifting of existing restrictions on development or use of the properties within the protected area. As a guide to the quantum of the costs to properties, the following assumptions are a reasonably accurate reflection of Seymour. There are approximately 540 separate lots within the protected area, 400 of which would be inundated to varying degrees by a 100 year flood. There are approximately 1,500 lots within the overall township. The special charge scheme scenarios include: 1. 50% Council contribution;

50% contribution by the properties within the township. Under this scenario both Council and all 1,500 properties within the township would collectively contribute $0.775 million. It is the case though that the special benefit would vary significantly across the lots, with the 400 lots no longer to flooding benefiting both directly and indirectly, more than those gaining only an indirect benefit. This is a complicated exercise which would require closer assessment of the numbers of lots within each of the land use zones and the extent of flood relief or degree of development opened up to each. Some predictions would be made regarding likely future zoning changes. It is likely the range of contributions would vary between $200 for properties receiving an indirect benefit to $2,000 per property receiving a direct benefit. Council would contribute $775,000. 2. 25% Council contribution;

25% contribution by all 1,500 properties within the township for indirect benefit; 50% contribution from directly benefits properties within the protected area.

Under this scenario all 1,500 properties within the township would collectively contribute $387,500 (25% of the local contribution). Therefore, each property would contribute approximately $300 to the cost of works for indirect benefit. Those 400 properties which are also gaining a direct special benefit would collectively contribute an additional 50% or $775,000.

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The 400 directly benefiting properties are those which would gain relief from inundation, and/or are currently encumbered by the Flood Overlay or Urban Floodway. There would be variation to the degree of benefit to properties depending on the use or development options opened up for each property as outlined in scenario 1. It is expected that generally the maximum benefit accrues to those properties in the Urban Floodway, all of which would also be inundated by a 100 year flood. A lesser benefit would be gained by the properties within the Flood Overlay and which would be inundated by a 100 year flood. The least benefit would be gained by the properties which gain only relief from flooding during a 100 year event. The directly benefiting properties would contribute on average an additional $2,000 to the works. A detailed analysis would be required to determine the relative benefits, but for the purpose of comparison it is estimated that the range of contribution required from the directly benefiting properties would be $1,000 to $5,000 per property. The total contribution: 400 properties with direct and indirect benefit would each contribute $1,000 - $5,000 1,100 properties with indirect benefit would each contribute $200 - $300. Council would contribute $387,500. 3. 50% Council contribution;

25% contribution by all 1,500 properties within the township; 25% contribution by 400 directly benefiting properties within the protected area.

The assessment of the relative degree of direct benefit is the same as scenario 2. In this case though 400 properties are sharing an additional $387,500 cost burden for direct benefit. The contribution could be expected to be in the range of $500 to $2,000 per property. The 1,500 properties within the township share equally the indirect benefit at $200 - $300 per property. Total contribution; 400 properties with direct benefit - $700 - $2,300. 1,100 properties with indirect benefit only would each contribute $200 - $300. Council would contribute $775,000. 4. 100% contribution by directly benefiting properties within the protected area. (400 properties) The assessment of the relative degree of direct benefit is the same as scenario 2. In this case 400 properties are sharing the $1.55 million cost burden. The variation in contribution would likely to be $1,000 to $8,000 per property. The upper level costs to each property reflected in scenario 4 are within the general range of contribution required by beneficiaries of the special charge

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scheme works of urban road construction and sealing. The other scenarios reflect more the level of contribution which might be expected from a footpath or drainage works scheme All are within the range of consideration by Council as a funding scenario to provide the local government contribution to the construction cost of the project. Summary

Scenario Cost/property or to Council

1. 50% Council contribution 50% contribution by the properties within the township

- with direct benefit - with indirect benefit

$775,000

$2000 $200

2. 25% Council contribution 25% contribution by all 1,500 properties within the township for indirect benefit 50% additional contribution by 400 directly benefits properties within the protected area

$387,500

$200 - $300

$1,000 - $5,000

3. 50% Council contribution; 25% contribution by all 1,500 properties within the township 25% additional contribution by 400 directly benefiting properties within the protected area.

$775,000

$200 - $300 $700 - $2,300

4. 100% contribution by 400 directly benefiting properties within the protected area.

$1,000 - $8,000

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9. Implementation In Council making a funding application the minimum expectation of the Catchment Management Authority is that at least the community consultation will have occurred prior to the application. The application will have a greater chance of being successful if it can demonstrate general community support. It is not expected that the planning amendment to impose the public acquisition overlay and land acquisition processes will have been commenced, but adequate time must be allowed in the project timeframe for their completion.

Any amendment to a planning scheme takes a considerable amount of time and resources. A commitment to a funding application or any indication of government support is not required to commence the amendment process. However in this instance it would be helpful to have the Goulburn Broken Catchment Management Authority clearly indicated its support for the proposal. An amendment process to implement the public acquisition overlay can take 12-24 months from the start of the formal process. The key steps are:

Complete all amendment documentation;

Ministers’ authorisation to prepare an amendment;

Formal exhibition of proposed amendment;

Receipt of submissions;

Request formation of Planning Panel to consider submissions;

Directions hearing;

Full panel hearing;

Report writing;

Council to consider Panel Report;

Council to forward amendment to Minister for approval; and

Minister approval to the amendment. The process of the acquisition of land could commence at any time, however as a demonstration of good faith and respect for the public process this should not formally start until the amendment has been approved or at the very least has been considered by the Planning Panel. It is likely to be the case that Council would not be instantly successful with a funding application for the construction phase. As outlined, the federal flood mitigation program includes significant limitations in the amount of annual funds available.

The process from this report to the possible ultimate construction of the levee bank is outlined below. Consultation and application phase;

Council consideration of this report and determine if to proceed to community consultation.

Community consultation, providing for submissions under sec 223 of the Local Government Act 1989.

Council to consider any submissions made and determine whether to apply for federal and state funding through the Natural Disaster Resilience Program (NDRP).

Council to determine how to provide the local contribution and to make provision as a future budget item.

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Funding application made by Council to the Natural Disaster Resilience Program (NDRP).

Implement a public acquisition overlay over the private land along the proposed route.

If funding is provided by the state and federal governments;

Funding allocated to the project.

Detailed design, including Cultural Heritage Management Plan and ecological assessment of vegetation impact of route option.

Commence purchase of the lands within the public acquisition overlay.

On completion of the above;

Construction of flood protection system.

Commence planning scheme amendment of the land within the alignment to Public Use Zone.

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References WBM Oceanics Australia, (2001) Seymour Floodplain Mapping Study. WBM Oceanics Australia, (February 2006) Seymour Flood Mitigation Communication Investigation, Final Consultants Report to Council. Bronstert, A., (1995). River flooding in Germany: Influenced by climate change. Physics and Chemistry of the Earth, 20, 445-450. Chiew, F. H. S., Whetton, P. H., McMahon, T. A., & Pittock, A. B. (1995). Simulation of the impacts of climate change on runoff and soil moisture in Austrlalian catchments. Journal of Hydrology, 167, 121-147. CSIRO, (2005). Melbourne water climate change study. Available from http://www.csiro.au. CSIRO (2007). Climate change – how it is likely to affect your region. Available from www.csiro.au. CSIRO, (2008) Murray-Darling Basin Sustainable Yields Project available from http://www.csiro.au/partnerships/MDBSY.html. Schreider, S.Yu., Jakeman, A.J., Pittock, A.B. & Whetton, P.H., (1996). Estimation of possible climate change impacts on water availability, extreme flow events and soil moisture in the goulburn and ovens basins. Victoria. Climatic Change, 34, 513-546. Victorian State Government, (2008). Climate change in the Goulburn Broken region. Online paper as part of the Victorian Climate Change Adaptation Program(VCCAP) available from http://www.climatechange.vic.gov.au/Greenhouse/wcmn302.nsf/childdocs/-9440F41741A0AF31CA2571A80011CBB6-74D21942F1E6DE7CCA2571A80011F124?open. Walker, J., & Robert, G., (2008). Lack of resolution on water increases threat to river Murray-Darling. The Australian, July 4, page 4.