title: Amendment C73 - Flood Controls council: moorabool state: vic category: amendment classification: MAJOR status: abandoned last_compiled: 2026-05-31 source_docs:
- 170215-agenda-place-making-advisory-committee.pdf
- 2015-06-03-030615-omc-agenda-no-attachments.pdf
- 2015-06-03-030615-omc-minutes.pdf
Amendment C73 - Flood Controls
Amendment C73 was a proposed hazard-control amendment for the eastern half of Moorabool Shire, designed to translate Melbourne Water flood modelling into statutory planning controls across the Werribee River, Lerderderg River and Little River catchments. The amendment mattered because it would have changed flood information from background mapping into permit triggers, referral pathways and planning-certificate disclosure for approximately 3,000 parcels. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.68)
The amendment did not reach gazettal: after exhibition and 44 submissions, including 36 objections or requests for change, Council resolved on 22 June 2016 to abandon it rather than refer the submissions to a Planning Panel. A February 2017 committee report framed the next step as an independent peer review of the modelling, funded by Melbourne Water but commissioned by Council, before any new amendment was prepared. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-17)
Background
The immediate statutory problem was that Moorabool had flood studies and mapping, but the relevant land was not consistently controlled by flood overlays in the planning scheme. Council officers described the design flood event for Victorian land-use planning and building purposes as the 100-year average recurrence interval flood, which is the basis for declared flood levels and flood areas under the Water Act 1989 and minimum floor levels under the Building Act 1993. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.65)
The local history began before C73. In 2005, Council commissioned WBM Oceanics Australia Pty Ltd to prepare the Bacchus Marsh Flood Risk Study, which mapped areas subject to inundation in a 100-year ARI flood event and recommended flood-risk mitigation. Council then prepared Amendment C14 to apply the Land Subject to Inundation Overlay and Floodway Overlay, exhibited it in 2008, and received submissions questioning the data and methodology. Council and Melbourne Water later determined that the study methodology did not provide sufficient strategic justification to support the exhibited LSIO and FO, so Amendment C14 lapsed. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.65)
C73 was the replacement pathway. Melbourne Water prepared three named flood study reports in 2010 and 2011: Report for Bacchus Marsh Area Floodplain Mapping by GHD, Lower Lerderderg Catchments Flood Mapping Report by Energy Water Management, and Ballan Township Flood Study Final Report by Halcrow Pacific Pty Ltd. Melbourne Water also prepared rural flood extent mapping for the Werribee River, Lerderderg River and Little River catchments from modelling undertaken over a number of years. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.65-66)
On 1 November 2013, Melbourne Water requested Amendment C73 to introduce flood controls into the Moorabool Planning Scheme. The requested controls included the LSIO, the Special Building Overlay, Municipal Strategic Statement updates, a new local floodplain-management policy, and three flood mapping reports as reference documents. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.14)
Analysis
Statutory Mechanism
C73 was not a drainage works program; it was a planning-scheme control mechanism. Its central legal effect was to identify land affected by the 1% flood event and require planning assessment before subdivision, most buildings and works, and some fences proceeded on affected land. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.67-68)
The proposed LSIO dealt with riverine flooding in urban and rural areas, particularly flood storage and flood fringe land affected by the 1-in-100-year flood. Its planning function was to maintain floodwater passage and temporary storage, minimise flood damage, match development to local flood hazard and drainage conditions, and prevent significant rises in flood level or flow velocity. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.69-70)
The proposed SBO dealt with urban overland flows from the piped stormwater drainage system, rather than riverine flooding. Its practical role was to set conditions and floor levels so redevelopment and new development in overland flow paths did not obstruct or divert floodwater. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.70)
The amendment therefore separated two flood mechanisms that can look similar on a property map but operate differently in planning decisions. LSIO land was linked to river and catchment flooding, while SBO land was linked to urban drainage surcharge and overland flow. That distinction matters because the evidence base, referral advice and mitigation response can differ between a riverine floodplain and a stormwater flow path. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.67-70)
C73 also proposed to amend Clause 21.02 Natural Environment, add floodplain-management objectives and strategies, insert a new Clause 22.07 Floodplain Management local policy, update Clause 21.11 reference documents, update the Clause 61.03 map list, and insert 32 new planning scheme overlay maps. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.67)
The effect would have extended beyond permit assessment. Once mapped into the planning scheme, flood risk would have appeared on Planning Certificates and then in vendor statements under section 32 of the Sale of Land Act 1962, meaning the flood constraint would become visible during land transactions as well as planning applications. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.68)
Spatial Reach and Land Affected
The amendment applied to land subject to inundation in a 100-year ARI flood event within the Werribee River, Lerderderg River and Little River catchments in the eastern portion of Moorabool Shire. Council officers estimated that approximately 3,000 parcels would be affected. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.68)
The mapped geography included the major population centres of Bacchus Marsh and Ballan as well as rural areas in the same catchment system. The February 2017 report described C73 as applying to the Werribee River, Lerderderg River and Little River catchments, including rural areas and the major population centres of Bacchus Marsh and Ballan. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.14)
This made C73 a major amendment despite its subject matter being hazard management rather than rezoning. A control that affects about 3,000 parcels changes the planning pathway for a broad class of future subdivision, building and works proposals, including proposals that otherwise may not have triggered flood-specific assessment. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.68, 72)
Permit and Referral Consequences
The key downstream consequence was a new permit trigger. Council officers stated that the introduction of the LSIO and SBO would require planning permits for subdivisions, buildings and works on land affected by the overlays, whereas buildings and works often did not then require a planning permit. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.72)
That change would have increased the number of planning permit applications. The increase was not described as an incidental administrative effect; it was the mechanism by which Council would gain the opportunity to assess flood risk before development occurred. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.72)
The amendment would also have made Melbourne Water a statutory referral authority for planning applications on flood-affected land. In practical terms, Council would remain the responsible authority for permits, but Melbourne Water would have a formal role in providing advice and recommendations on applications affected by flooding. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.68, 73)
The referral pathway was financially and operationally significant because Melbourne Water agreed to provide planners to answer technical flood enquiries during exhibition and respond to formal submissions. Melbourne Water also agreed to pay the amendment application fee, Planning Panel hearing costs if required, and Council mail-out costs. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.71)
Risk Transfer and Council Liability
The officer report treated flood controls as a risk-management obligation for Council, not simply a policy preference. It stated that Council had a duty of care as planning authority to translate available flood extent mapping into meaningful planning controls and apply it transparently. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.72)
The risk mechanism was straightforward: where no overlay existed and no other permit trigger applied, Council could miss the chance to consider known flood risk before development occurred. Officers identified this as creating potential negligence or liability exposure for Council in its roles as planning authority and responsible authority under the Planning and Environment Act 1987. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.72)
Council’s own risk table classified the financial risk of flood risk not being considered in development approvals as High, with potential litigation as the risk detail and implementation of appropriate planning controls as the control measure. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.72)
The February 2017 report sharpened this point after abandonment. It stated that although Council had abandoned C73, Clause 21.02 of the planning scheme still expressed adopted local policy to apply effective planning controls to address flood risk, but those controls did not exist. The report described Council’s risk exposure as high, particularly where building applications were being processed with regard to Melbourne Water flood risk mapping outside a completed overlay framework. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.15)
Exhibition, Submissions and Breakdown Point
Council resolved on 3 June 2015 to authorise the Chief Executive Officer to finalise C73 in consultation with Melbourne Water, request ministerial authorisation to prepare and exhibit it, exhibit it after authorisation, notify affected property owners, and schedule exhibition and any Planning Panel according to Melbourne Water availability. The resolution was carried, with Councillors Comrie, Spain, Sullivan and Dudzik voting for it and Councillors Toohey and Tatchell voting against it. (Source: 2015-06-03-030615-omc-minutes.pdf, p.85)
The Minister for Planning granted authorisation on 21 August 2015. C73 was then exhibited and attracted 44 submissions, of which 36 either objected or sought changes. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.14)
At a Special Meeting on 22 June 2016, Council considered the submissions and an officer recommendation to request a Planning Panel, refer C73 and submissions to that Panel, and adopt a position on submissions for the Panel process. Some submitters raised concerns about possible inaccuracies in the flood modelling and mapping. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-15)
Council resolved to abandon C73 rather than refer the matter to a Planning Panel. The February 2017 officer report described this as unusual, stating that as far as could be determined no other Victorian council had abandoned a flood mapping amendment based on Melbourne Water modelling, with other amendments being referred to a Planning Panel and ultimately gazetted. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.15)
The abandonment meant the dispute was never tested in the usual independent forum. The 2017 report noted that a Planning Panel would have allowed Melbourne Water, Council and submitters, including experts, to present their respective cases, but that opportunity was not taken. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.15)
Evidence Standard and Peer Review Pathway
After abandonment, the central issue became confidence in the mapping rather than whether flood controls were needed. The February 2017 report stated that the issue did not appear to be whether flood extent mapping was required in the Moorabool Planning Scheme, but whether Council had sufficient confidence in the accuracy of the flood modelling. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.15)
The proposed response was an independent peer review. Two delivery models were identified: Melbourne Water could commission, select consultants and pay for all assessments, or Council could commission the peer review independently of Melbourne Water while Melbourne Water reimbursed the full cost. The officer preference was the second model, because it allowed Council to choose the consultant while retaining Melbourne Water funding. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14, 16)
The peer review scope was deliberately mechanism-based. It asked whether the data and processes used to derive the proposed LSIO and SBO were fit for purpose, whether the data were sufficient in quantity and quality, whether the models were appropriate, whether model parameters were within the normal range, whether hydrology results were correctly incorporated into the hydraulic model, whether model runs and results were appropriate, and whether the final mapping was produced using appropriate measures. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.16)
The proposed timing was early 2017 for quotations from suitably qualified and experienced consultants, with the review intended to be completed within the current financial year. The recommendation was that the peer review findings be tabled at the Place Making Committee and then at an Ordinary Meeting of Council. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.16-17)
The intended outcome was not to revive C73 exactly as exhibited. The recommendation stated that after the peer review was tabled and any identified modelling data or process concerns were addressed under an agreed methodology, Council should seek authorisation for an appropriate new planning scheme amendment to map and address flood risk in the eastern half of the Shire. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.17)
Current Status
Based on the supplied source set, Amendment C73 itself was abandoned by Council on 22 June 2016. The latest supplied document, dated February 2017, proposed an independent peer review as the precondition for a future amendment, but does not provide the completed peer review, the later Council decision, or any gazettal outcome. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-17)
The current source-supported status is therefore: C73 abandoned, flood-control policy issue unresolved in the supplied record, and a new amendment pathway dependent on peer review findings. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.17)
Dependencies
- Blocks: Without flood overlays, Council may lack a flood-specific permit trigger for some subdivisions, buildings and works on mapped flood-prone land, which can prevent systematic consideration of flood risk in development assessment. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.72)
- Blocked by: A new amendment pathway was blocked by Council confidence in Melbourne Water modelling, with the February 2017 report proposing an independent peer review before seeking authorisation for another amendment. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.15-17)
- Informed by: C73 was informed by the Bacchus Marsh Area Floodplain Mapping report, the Lower Lerderderg Catchments Flood Mapping Report, the Ballan Township Flood Study Final Report, and additional rural mapping for the Werribee River, Lerderderg River and Little River catchments. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.65-67)
- Implements: The amendment implemented Clause 13.02 Floodplains, Clause 11.05-4 regional planning principles, Clause 21.02 flood-management policy and Clause 21.02-9 landowner awareness and responsibility objectives. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.70-71)
- Conflicts with: The supplied documents do not identify a policy conflict, but they do identify an evidentiary conflict between Council’s need for statutory flood controls and submitter concerns about mapping accuracy. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-16)
Cross-Jurisdictional Links
Melbourne Water was the relevant floodplain management authority and the initiating agency for C73, so the amendment depended on a state water authority evidence base and referral role rather than Council-only technical work. Melbourne Water requested the amendment, prepared or held the flood mapping basis, agreed to fund amendment and Panel-related costs, and was proposed to reimburse Council for an independent peer review. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14, 16; Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.71)
The amendment also intersected with Victorian planning and building frameworks because the 100-year ARI design event was used for land-use planning, building floor-level purposes, flood declarations under the Water Act 1989 and minimum floor levels under the Building Act 1993. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, p.65)
Gaps in This Analysis
The source set is thin for a major flood-controls amendment. It contains the June 2015 agenda report, the June 2015 minutes confirming Council’s initial resolution, and a February 2017 committee agenda report proposing peer review, but it does not include the exhibited amendment documents, overlay maps, schedules, explanatory report, submissions, 22 June 2016 Special Meeting minutes, Attachment 3 submission table, the three flood studies, the Melbourne Water rural mapping, the peer review report, or any later amendment documents. (Source: 2015-06-03-030615-omc-agenda-no-attachments.pdf, pp.65-74; Source: 2015-06-03-030615-omc-minutes.pdf, p.85; Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-17)
Because the maps and studies are missing, this page cannot quantify flood depths, affected land area, overlay hectares, individual township impacts, floor-level implications, parcel-by-parcel constraints, or the technical validity of the hydraulic modelling. The available documents support the statutory mechanism and decision history, but not a technical flood-modelling assessment. (Source: 170215-agenda-place-making-advisory-committee.pdf, p.16)
Because the submissions and 22 June 2016 decision record are missing, this page cannot categorise the 44 submissions by issue, identify who objected, separate property-specific mapping objections from methodology objections, or test whether the abandonment decision responded to technical evidence, political concern, landowner impact, or procedural risk. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-15)
The most important corpus gaps are the exhibited C73 amendment package, the 22 June 2016 Special Meeting agenda and minutes, Attachment 3 submission table, the three named flood studies, and the post-2017 peer review report. These gaps should be recorded in _gaps because they are necessary to assess whether a later flood-controls amendment corrected the C73 evidentiary problem or simply restarted the same statutory pathway with an additional review step. (Source: 170215-agenda-place-making-advisory-committee.pdf, pp.14-17)