title: Amendment C91moor - Moorabool Flood Provisions council: moorabool state: vic category: amendment classification: MAJOR status: unknown last_compiled: 2026-05-31 source_docs:
- moorabool-c91-panel-report.pdf
Amendment C91moor - Moorabool Flood Provisions
Amendment C91moor is a catchment-scale flood control amendment for the eastern part of Moorabool Shire, using the Land Subject to Inundation Overlay and Special Building Overlay to move flood risk assessment from informal or late-stage building review into the statutory planning permit system (Source: moorabool-c91-panel-report.pdf, p.1). Its practical effect is not to prohibit development, but to require subdivision, buildings and works in mapped flood-affected areas to be assessed against riverine and stormwater flood behaviour before approvals are granted (Source: moorabool-c91-panel-report.pdf, p.12).
The amendment matters because Moorabool previously had no flood controls in its planning scheme, despite flood risks being identified for Bacchus Marsh, Ballan and surrounding catchments (Source: moorabool-c91-panel-report.pdf, p.10). The Panel treated this as a statutory risk-management gap: the planning scheme knew about flood risk in policy and emergency planning terms, but lacked the overlay triggers needed to make that risk visible and assessable in planning decisions (Source: moorabool-c91-panel-report.pdf, pp.10-13).
Background
Amendment C91moor was prepared by Moorabool Shire Council at the request of Melbourne Water, the relevant floodplain management authority (Source: moorabool-c91-panel-report.pdf, p.1). The amendment applies to land identified as subject to inundation within the Werribee River, Lerderderg River and Little River catchments in the eastern portion of the municipality, including land in Blackwood, Ballan, Greendale, Darley, Bacchus Marsh, Maddingley and Balliang (Source: moorabool-c91-panel-report.pdf, pp.1-2).
The amendment was built on five technical inputs: the 2010 GHD Bacchus Marsh Area Floodplain Mapping report, the 2011 Halcrow Pacific Ballan Township Flood Study, the 2011 Engeny Lower Lerderderg Catchments Flood Mapping report, Melbourne Water modelling for rural areas outside those studies, and a 2017 Cardno peer review (Source: moorabool-c91-panel-report.pdf, p.1). The LSIO was proposed for riverine flooding based on a 1-in-100-year flood event probability, while the SBO was proposed for urban overland flows from drainage systems under the same design-event probability (Source: moorabool-c91-panel-report.pdf, p.1).
C91moor was the third attempt to introduce flood-related controls into the Moorabool Planning Scheme (Source: moorabool-c91-panel-report.pdf, p.2). Council first pursued flood controls through Amendment C14 in 2008, but abandoned that amendment in 2010 because the study methodology did not provide sufficient strategic justification (Source: moorabool-c91-panel-report.pdf, p.2). Council then exhibited Amendment C73 in 2016, but abandoned it after submitters raised concerns about possible inaccuracies in the flood studies and modelling (Source: moorabool-c91-panel-report.pdf, p.2). The 2017 peer review found the earlier studies and modelling were generally suitable, but recommended changes to Lower Lerderderg flood extent mapping and associated SBO shapes before the amendment process recommenced (Source: moorabool-c91-panel-report.pdf, p.2).
The amendment was authorised on 25 November 2019 and exhibited from 12 March to 18 August 2020 (Source: moorabool-c91-panel-report.pdf). The Panel hearing occurred from 15 to 18 June 2021, with a report dated 30 July 2021 (Source: moorabool-c91-panel-report.pdf). The amendment received 41 submissions, of which 35 opposed the amendment (Source: moorabool-c91-panel-report.pdf). The main submission issues were the need for flood controls, the appropriateness of LSIO and SBO controls, mapping accuracy, site-specific impacts in Bacchus Marsh, Ballan, Darley, Maddingley and Blackwood, post-exhibition changes, drainage maintenance, capital works, property values, insurance and the timing of the process during COVID-19 restrictions (Source: moorabool-c91-panel-report.pdf, pp.3-4).
Analysis
Statutory Mechanism and Planning Effect
The amendment works by adding flood overlays to mapped land rather than by changing the underlying zoning of that land (Source: moorabool-c91-panel-report.pdf, p.1). This distinction is important because the overlay does not decide that land cannot be used or developed; it creates a permit trigger so the responsible authority and floodplain management authority can assess whether a proposal would be affected by flooding or would worsen flood behaviour elsewhere (Source: moorabool-c91-panel-report.pdf, pp.12, 31).
The Panel accepted that this permit-trigger mechanism fills a real gap in the planning scheme because Moorabool had no flood controls before the amendment (Source: moorabool-c91-panel-report.pdf, p.10). In simple terms, the planning scheme was like a map that knew there were wet areas but did not place warning signs on the affected lots; C91moor adds those warning signs and requires closer checking before new works proceed (Source: moorabool-c91-panel-report.pdf, pp.10-13).
The LSIO and SBO were selected because the mapped hazards were not treated as the highest-order flood risk categories (Source: moorabool-c91-panel-report.pdf, pp.14-17). The Panel recorded that the Urban Floodway Zone is used where further intensification is unsuitable, the Floodway Overlay is used for active flood flow or flood storage areas with lesser risk than the UFZ, the LSIO is used for mainstream flooding with lesser risk than the FO, and the SBO is used for urban stormwater flooding (Source: moorabool-c91-panel-report.pdf, p.15). Council applied the LSIO to mainstream flooding from rivers and waterways, and the SBO to poor stormwater drainage and overland flow areas (Source: moorabool-c91-panel-report.pdf, p.14).
The schedules were drafted to reduce unnecessary permits for minor or routine works (Source: moorabool-c91-panel-report.pdf, pp.15-17). The SBO schedule had broader exemptions than the LSIO schedule because stormwater flooding was treated as having a different and generally lower risk profile than the riverine flooding captured by the LSIO (Source: moorabool-c91-panel-report.pdf, pp.15-16). Examples of SBO exemptions included certain landscaping, driveways, small extensions, alterations, outbuildings, replacement buildings, permeable fencing, pools and small domestic animal enclosures where specified flood-level or flow-path conditions were met (Source: moorabool-c91-panel-report.pdf, pp.15-16).
Strategic Justification and Policy Fit
The Panel found strong statutory and policy support for the amendment under the Planning and Environment Act 1987, the Planning Policy Framework, the Local Planning Policy Framework, Ministerial Directions, planning practice notes and the Victorian Floodplain Management Strategy (Source: moorabool-c91-panel-report.pdf, pp.5-13). Clause 13.03-1S was especially relevant because it seeks to protect life, property, community infrastructure, flood storage, flood carrying capacity and floodplain environmental values from flood hazard (Source: moorabool-c91-panel-report.pdf, p.6).
The amendment aligns with the Victorian Floodplain Management Strategy because that strategy keeps the 1 percent Annual Exceedance Probability flood as the design flood event for Victoria’s land use planning and building systems (Source: moorabool-c91-panel-report.pdf, p.7). The Panel rejected objections based on the low probability of a 1-in-100-year flood because that design event is the statewide planning benchmark for identifying and mapping flood risk (Source: moorabool-c91-panel-report.pdf, p.13).
The amendment also aligns with the Central Highlands Regional Growth Plan, which identifies Ballan and Bacchus Marsh as settlements susceptible to flood risk and supports implementation of floodplain modelling, flood strategies and consistent designation of flood-prone areas across the region (Source: moorabool-c91-panel-report.pdf, p.8). This means C91moor is not just a local mapping exercise; it implements a regional policy direction that settlement planning should account for known natural hazards before growth or redevelopment intensifies exposure (Source: moorabool-c91-panel-report.pdf, pp.7-8).
The Panel recommended deleting proposed local policy clauses 21.02-12 and 21.02-13 because they duplicated State floodplain management policy and the purposes of the LSIO and SBO (Source: moorabool-c91-panel-report.pdf, pp.17-19). That recommendation narrows the amendment’s statutory work: instead of adding extra local policy words, C91moor relies on the overlay maps, schedules and existing State policy framework to manage flood risk (Source: moorabool-c91-panel-report.pdf, pp.17-19).
Technical Basis and Mapping Risk
The core technical dispute was whether flood studies from 2010 and 2011 remained suitable for planning scheme mapping in 2021 (Source: moorabool-c91-panel-report.pdf, pp.20-23). Thirteen submissions challenged the modelling or flood extent mapping on grounds including outdated inputs, incorrect assumptions, lack of observed flooding and site-specific changes since the studies were prepared (Source: moorabool-c91-panel-report.pdf, p.20).
The Panel accepted the technical basis because the studies used standard hydrological and hydraulic modelling methods, including RORB, HEC-RAS, XPStorm and TUFLOW, and because the 2017 peer review and Melbourne Water’s expert evidence supported the modelling as fit for purpose (Source: moorabool-c91-panel-report.pdf, pp.21-23). The Panel also accepted that the overlay maps do not need absolute parcel-level precision at amendment stage because their function is to identify flood risk and trigger more detailed assessment when a permit application is made (Source: moorabool-c91-panel-report.pdf, pp.21-22).
The age of the studies remains a practical limitation even though the Panel accepted them as suitable (Source: moorabool-c91-panel-report.pdf, pp.22-23). Melbourne Water advised that the flood studies were likely to be revised in the next 5 to 10 years and that climate change modelling was expected to be addressed during that future model renewal (Source: moorabool-c91-panel-report.pdf, p.22). The Panel accepted evidence that the current models remained fit for purpose, but observed that future flood studies should show how climate change has been considered (Source: moorabool-c91-panel-report.pdf, p.23).
The mechanism for dealing with changed ground conditions is therefore incremental rather than wholesale (Source: moorabool-c91-panel-report.pdf, pp.22-23). Where a site has been filled, drained or otherwise altered, the amendment can be adjusted through post-exhibition mapping changes or later planning scheme changes, but the Panel did not support withholding overlays simply because future works might reduce flood exposure (Source: moorabool-c91-panel-report.pdf, pp.22-23, 27, 31, 35-36).
Site-Specific Contested Issues
The Rijk Zwaan land at 406-420 Bacchus Marsh Road was a key test of how the amendment interacts with intensive horticulture in the Bacchus Marsh Irrigation District (Source: moorabool-c91-panel-report.pdf, pp.24-25). Rijk Zwaan was preparing a permit application for a major expansion of its seed production facility involving glass greenhouses, and it proposed a policy strategy encouraging innovative flood-risk management for intensive horticulture (Source: moorabool-c91-panel-report.pdf, pp.24-25). The Panel acknowledged the importance of the enterprise and the proposed greenhouse design response, but found that site-specific flood design should be assessed at permit stage rather than by changing the amendment (Source: moorabool-c91-panel-report.pdf, p.25).
The Ballan South land raised the relationship between flood controls and future residential rezoning (Source: moorabool-c91-panel-report.pdf, pp.26-27). Ballan South owned Farming Zone land south of Ballan within the Ballan Township Boundary, had lodged a May 2021 rezoning request to General Residential Zone Schedule 4 with a Development Plan Overlay, and argued that flood risk could be managed through that later development plan and permit process (Source: moorabool-c91-panel-report.pdf, p.26). The Panel rejected removal of the LSIO because the rezoning, drainage works and construction timing were uncertain, and because removing the overlay in advance would leave the planning scheme failing to reflect existing mapped flood risk (Source: moorabool-c91-panel-report.pdf, p.27).
The land at 94-98 Main Street, Bacchus Marsh turned on whether site filling had removed the mapped flood condition (Source: moorabool-c91-panel-report.pdf, pp.28-31). Urban Land Development argued the LSIO should be removed because the land had been filled, but the certified survey plan showed a low point of 99.34 metres Australian Height Datum and part of the site below Melbourne Water’s 99.86 metre AHD design flood level (Source: moorabool-c91-panel-report.pdf, pp.29-30). The Panel recommended applying the LSIO only to land below 99.86 metres AHD, which shows a precise statutory response to verified ground levels rather than either accepting or rejecting the overlay across the whole parcel (Source: moorabool-c91-panel-report.pdf, p.31).
Submissions, Post-Exhibition Changes and Non-Planning Issues
The amendment generated a high level of objection, with 35 opposed submissions out of 41 total submissions (Source: moorabool-c91-panel-report.pdf). The pattern of objections was mainly site-specific rather than a successful challenge to the strategic basis for flood controls (Source: moorabool-c91-panel-report.pdf, pp.3-4, 10). The Panel’s response was to retain the strategic framework while accepting targeted mapping reductions and removals where site evidence justified them (Source: moorabool-c91-panel-report.pdf, pp.35-36).
Post-exhibition changes reduced LSIO extent at 5 Walsh Street Ballan, 15 Walsh Street Ballan, 2A Lay Street Ballan, 5 Griffith Street Maddingley, Parwan Creek south of the Ballarat-Melbourne Railway Line, 48 Connor Court Ballan and the Ballan Wastewater Treatment Plant at Ingliston Road Ballan (Source: moorabool-c91-panel-report.pdf, p.35). The changes also removed LSIO extent from 8 Hall Street Ballan and 4 Albert Street Blackwood, and removed SBO extent from 10 Cairns Drive Darley (Source: moorabool-c91-panel-report.pdf, p.35). Because these changes only reduced or removed overlay coverage, the Panel found they did not materially affect other parties (Source: moorabool-c91-panel-report.pdf, p.36).
The Panel treated property value and insurance concerns as outside the merits of the amendment (Source: moorabool-c91-panel-report.pdf, p.32). Eleven submissions raised devaluation or insurance concerns, but the Panel accepted Council’s position that such matters are not relevant considerations when introducing flood provisions and that compensation under the Planning and Environment Act is essentially limited to circumstances such as public purpose reservations or road access denial (Source: moorabool-c91-panel-report.pdf, p.32).
Drainage maintenance and flood mitigation works were also treated as outside the amendment’s scope (Source: moorabool-c91-panel-report.pdf, pp.32-33). The Panel acknowledged that drain capacity works and waterway maintenance may alter flood behaviour, but found the amendment was about identifying flood-affected land and assessing future development, not delivering capital works or solving the causes of flooding (Source: moorabool-c91-panel-report.pdf, p.33).
Western Water raised concern about whether new residential development should proceed in flood-affected areas because of water and wastewater servicing challenges (Source: moorabool-c91-panel-report.pdf, p.34). The Panel found that servicing implications for future residential subdivision were outside the amendment and should be assessed at permit stage, while also noting that the LSIO would help identify flooding issues relevant to servicing decisions (Source: moorabool-c91-panel-report.pdf, p.34).
The Country Fire Authority raised a bushfire interface issue because much of the proposed LSIO land was also within a Bushfire Management Overlay (Source: moorabool-c91-panel-report.pdf, p.36). Council resolved that concern through a proposed explanatory report change clarifying that the amendment manages flood risk and does not involve or facilitate revegetation or other on-ground works that could increase bushfire risk (Source: moorabool-c91-panel-report.pdf, pp.36-37).
Current Status
The available source is the Panel report dated 30 July 2021, so this page can confirm the Panel’s recommendations but cannot confirm whether Council adopted the amendment, whether the Minister approved it, or whether it was gazetted (Source: moorabool-c91-panel-report.pdf). The Panel recommended adoption as exhibited subject to deletion of Clauses 21.02-12 and 21.02-13, amendment of the LSIO at 94-98 Main Street Bacchus Marsh to land below 99.86 metres AHD, adoption of the post-exhibition mapping reductions and removals in Appendix D, and amendment of the bushfire-risk wording in the explanatory report (Source: moorabool-c91-panel-report.pdf, pp.ii, 31, 36-37).
Dependencies
- Blocks: The amendment does not itself block development, but it creates permit-stage flood assessment requirements for subdivision, buildings and works on mapped LSIO and SBO land (Source: moorabool-c91-panel-report.pdf, pp.12, 31).
- Blocked by: Final statutory certainty is blocked in this analysis by the absence of adoption, approval and gazettal documents in the source set (Source: moorabool-c91-panel-report.pdf).
- Informed by: The amendment is informed by the GHD Bacchus Marsh flood mapping report, Halcrow Pacific Ballan flood study, Engeny Lower Lerderderg flood mapping report, Melbourne Water rural modelling and the Cardno peer review (Source: moorabool-c91-panel-report.pdf, p.1).
- Implements: The amendment implements State floodplain management policy, the Victorian Floodplain Management Strategy, relevant Ministerial Directions, Planning Practice Notes 11 and 12, and regional policy directions in the Central Highlands Regional Growth Plan (Source: moorabool-c91-panel-report.pdf, pp.5-9).
- Conflicts with: The amendment creates practical tension with urban consolidation and township growth policy where land identified for growth or redevelopment is also mapped for flood risk, including land in Bacchus Marsh and Ballan South (Source: moorabool-c91-panel-report.pdf, pp.17-18, 26-27).
Cross-Jurisdictional Links
Melbourne Water is central to the amendment because it requested the amendment, provided or commissioned key technical inputs, supported post-exhibition mapping changes, and is the floodplain management authority whose advice informs permit-stage flood assessment (Source: moorabool-c91-panel-report.pdf, pp.1, 21, 35-36). Western Water, now part of the regional water servicing context, raised wastewater and water servicing implications for future residential development in mapped flood-affected areas, which creates a direct link between flood mapping and infrastructure servicing decisions (Source: moorabool-c91-panel-report.pdf, p.34). The Central Highlands Regional Growth Plan provides the regional planning link by identifying flood susceptibility in Ballan and Bacchus Marsh and supporting consistent flood-prone area designation across the region (Source: moorabool-c91-panel-report.pdf, p.8).
Gaps in This Analysis
This analysis is constrained by having only the Panel report and not the full amendment package, technical flood studies, expert evidence, submissions, Council adoption report, Ministerial approval decision or gazettal notice (Source: moorabool-c91-panel-report.pdf, pp.40-41). The missing primary studies limit parcel-level assessment of flood depths, velocities, flood storage, model assumptions, climate-change allowances and exact mapped overlay boundaries (Source: moorabool-c91-panel-report.pdf, pp.20-23). The missing final statutory documents mean the current legal status of C91moor cannot be confirmed from the provided corpus, so the status is recorded as unknown rather than approved or abandoned (Source: moorabool-c91-panel-report.pdf).
Current-Status Guardrail
This is a material planning-signal page, but production legal-status advice requires the final approval, gazette, EES/assessment or adopted implementation record to be cited on the page. Until that evidence is present, use this page for mechanism and dependency intelligence rather than final operative-law status.