title: Underbank Urban Release Area council: moorabool state: vic category: strategy classification: MAJOR status: approved last_compiled: 2026-05-31 source_docs:
- smc-agenda-170914.pdf
- approved-underbank-development-plan-1-27.pdf
- approved-underbank-development-plan-28-66.pdf
Underbank Urban Release Area
Underbank is a major greenfield residential release area west of central Bacchus Marsh, structured through Amendment C62, Development Plan Overlay Schedule 6, a Section 173 infrastructure agreement, and the March 2017 approved development plan for 174 Mortons Road. (Source: smc-agenda-170914.pdf, pp.7-15; Source: approved-underbank-development-plan-1-27.pdf, p.4) Its planning importance is that only 82.7 hectares of the 151.72 hectare development plan site is identified as net developable area, so waterways, escarpments, open space, roads, heritage, drainage, slope and servicing constraints are not secondary details; they define the actual urban capacity and staging pathway. (Source: approved-underbank-development-plan-28-66.pdf, p.55)
Background
The land originated in the planning process as the former Underbank Stud Farm, generally described in the 2014 council report as 174 Mortons Road, Pentland Hills and part of 5 Randwick Avenue, Bacchus Marsh. (Source: smc-agenda-170914.pdf, p.7) The 2017 development plan describes the broader Underbank community as about 167 hectares, split between approximately 15 hectares at 5 Randwick Avenue and approximately 152 hectares at 174 Mortons Road. (Source: approved-underbank-development-plan-1-27.pdf, p.4) The approved development plan applies specifically to 174 Mortons Road, while the 5 Randwick Avenue balance land was already subject to an existing permit and was being developed as the first stages of Underbank. (Source: approved-underbank-development-plan-1-27.pdf, p.4)
Amendment C62 rezoned the Underbank land from Farming Zone to General Residential Zone, introduced Development Plan Overlay Schedule 6, and retained a planning framework requiring a whole-of-site development plan before subdivision proceeds in detail. (Source: smc-agenda-170914.pdf, pp.7, 14, 61-69) Council resolved to seek authorisation for Amendment C62 on 13 July 2013, the amendment was exhibited from 28 November 2013 to 26 January 2014, 18 submissions were received, and a Panel heard submissions on 2 June and 4-6 June 2014. (Source: smc-agenda-170914.pdf, p.7) On 17 September 2014, the council agenda recommended adoption with changes and submission of Amendment C62 to the Minister for Planning under the Planning and Environment Act 1987. (Source: smc-agenda-170914.pdf, p.34)
The strategic setting is explicit: Bacchus Marsh is identified in the local policy context as Moorabool Shire’s largest township and major urban growth centre, and the development plan states that the land is identified for potential residential development in the Bacchus Marsh Framework Plan. (Source: approved-underbank-development-plan-1-27.pdf, p.12) The development plan also links the release area to Plan Melbourne and the Central Highlands Regional Growth Plan, both of which support housing growth in Bacchus Marsh as a regional centre. (Source: approved-underbank-development-plan-1-27.pdf, p.13)
Analysis
Statutory Mechanism and Practical Effect
The core statutory mechanism is DPO6, which works like a gateway control: it does not itself subdivide the land, but it requires the responsible authority to approve an integrated development plan before ordinary subdivision permits can translate the urban release area into lots, roads, reserves and infrastructure works. (Source: smc-agenda-170914.pdf, pp.61-69) DPO6 requires the development plan to address site analysis, design response, density, movement, utilities, drainage, community facilities, open space, environmental management and escarpment management. (Source: smc-agenda-170914.pdf, pp.62-69) The effect is that subdivision is tied to a coordinated structure rather than being assessed as disconnected permit stages. (Source: smc-agenda-170914.pdf, pp.61-69)
The 2014 council report is clear that rezoning was only the first step in the delivery chain, followed by development plan approval, subdivision permit, certification, engineering approval, civil works, statement of compliance and title creation. (Source: smc-agenda-170914.pdf, pp.12-13) Council estimated in 2014 that, even if rezoning proceeded quickly, 100 lots might take 3 to 5 years from that point to be delivered on the ground. (Source: smc-agenda-170914.pdf, p.13) That timing statement matters because the planning control was designed to sequence land release with infrastructure delivery rather than simply establish a residential zoning. (Source: smc-agenda-170914.pdf, pp.10-13)
The Panel accepted the General Residential Zone as the appropriate zone where moderate growth and housing diversity were expected. (Source: smc-agenda-170914.pdf, pp.16-17) Council had sought tighter neighbourhood-residential-style outcomes, but the Panel replaced some prescriptive controls, including an 11 dwellings per gross developable hectare measure, with performance-based criteria for lot diversity, landscape character, slope response and open-space interface. (Source: smc-agenda-170914.pdf, pp.26-28) The result is a planning framework that controls form mainly through DPO6 performance requirements, detailed design guidelines and later permit conditions rather than through a fixed yield cap. (Source: smc-agenda-170914.pdf, pp.26-28, 63-69)
Land Budget, Yield Logic and Constraint Geometry
The approved development plan identifies a total site area of 151.72 hectares for 174 Mortons Road. (Source: approved-underbank-development-plan-28-66.pdf, p.55) Of that land, 44.5 hectares, or 29.33 percent, is assigned to creek environs; 18.1 hectares, or 11.93 percent, is escarpment unusable as open space; 6.42 hectares, or 4.23 percent, is open space, local parks or active open space; and 82.7 hectares, or 54.51 percent, is net developable area. (Source: approved-underbank-development-plan-28-66.pdf, p.55) In simple terms, almost half of the development plan site is not treated as net developable land before lot design is even considered. (Source: approved-underbank-development-plan-28-66.pdf, p.55)
This land budget is not a cosmetic open-space gesture; it is the spatial consequence of the site’s waterways, flood extents, steep land, escarpments and environmental corridors. (Source: approved-underbank-development-plan-1-27.pdf, pp.18-22; Source: approved-underbank-development-plan-28-66.pdf, p.55) The development plan identifies four waterways within or adjacent to the development area: the Werribee River, Korkuperrimul Creek and northern and southern tributaries of Korkuperrimul Creek. (Source: approved-underbank-development-plan-1-27.pdf, p.21) Minimum waterway setbacks are stated as 50 metres from top of bank or the 100 year ARI flood extent for the Werribee River, 30 metres from top of bank for Korkuperrimul Creek, and 20 metres from top of bank for the tributaries. (Source: approved-underbank-development-plan-1-27.pdf, p.21)
The slope rule is also central to the urban form. (Source: smc-agenda-170914.pdf, p.9) The 2014 council report stated that about 55.5 percent of the gross land area was above the 125 metre contour, where the minimum lot size was generally to be 700 square metres except where gradients were less than about 1:10, while about 45.5 percent was below the 125 metre contour, where the minimum lot size was generally to be 400 square metres except near the neighbourhood activity or community infrastructure centre. (Source: smc-agenda-170914.pdf, pp.8-9) DPO6 later embedded this contour-based lot-size logic into the development plan requirements. (Source: smc-agenda-170914.pdf, pp.63-64)
The planning implication is that density is intended to vary with landform and access rather than spread evenly across the whole site. (Source: smc-agenda-170914.pdf, pp.8-9, 63-64) Smaller lots are directed to high-amenity and accessible locations around open space, activity areas and services, while larger lots are expected on steeper land and rural interfaces. (Source: smc-agenda-170914.pdf, pp.63-64; Source: approved-underbank-development-plan-28-66.pdf, p.53) Because the documents do not provide a final lot yield for the 82.7 hectare net developable area, the actual dwelling yield cannot be verified from the available sources. (Source: approved-underbank-development-plan-28-66.pdf, p.55)
Movement, Halletts Way and Staging Triggers
Transport is the main off-site dependency in the C62 record. (Source: smc-agenda-170914.pdf, pp.10-12) The 2014 council report identified construction of Halletts Way as a key outcome for the wider Darley, Bacchus Marsh and Maddingley road network, and stated that other local street upgrades were important but less fundamental to overall network performance. (Source: smc-agenda-170914.pdf, p.10) Until the Halletts Way link was provided, the main access for the development was expected to operate through the existing Underbank Estate, with local network improvements to be provided as part of development. (Source: smc-agenda-170914.pdf, p.10)
The Panel required further traffic work on the Rosehill Drive and Ascot Avenue intersection and the number of lots that could be approved without the Halletts Way connection. (Source: smc-agenda-170914.pdf, pp.16-18) The traffic consultant measured 112 metres of sight distance to the north and 75 metres to the south at Rosehill Drive and Ascot Avenue, found that the southward sight distance was below the 95 metre requirement if a 50 kilometre per hour speed was assumed, but concluded that the local geometry made speeds above 41.3 kilometres per hour unlikely on that approach. (Source: smc-agenda-170914.pdf, pp.39-40) The consultant therefore concluded that no road safety audit was required, while recommending formalisation of the T-intersection with give-way line marking and a splitter island before occupancy of 100 lots. (Source: smc-agenda-170914.pdf, pp.40-41)
The lot trigger became the contested mechanism. (Source: smc-agenda-170914.pdf, pp.18-19) The traffic consultant supported an 800 lot trigger for the Halletts Way connection based on intersection capacity, traffic generation of 9.5 external daily trips per dwelling and 0.9 peak-hour external trips per dwelling, and environmental capacity on Ascot Avenue. (Source: smc-agenda-170914.pdf, pp.41-43) Council officers considered 300 lots more appropriate because the consultant’s work focused mainly on the Bacchus Marsh Road and Ascot Avenue intersection rather than the broader Grant Street and Gisborne Road network. (Source: smc-agenda-170914.pdf, pp.18-19) The recommended Section 173 changes therefore capped titles at 300 lots before full construction of Halletts Way from Bacchus Marsh Road to Werribee Vale Road, and capped titles at 600 lots before a road connection from the development area to Halletts Way, unless revised traffic assessment justified alternative thresholds. (Source: smc-agenda-170914.pdf, p.34)
The approved development plan then uses the south-eastern Halletts Way interface as the logical first development front, because it aligns with the proposed Halletts Way extension and gives access to sewer for initial stages. (Source: approved-underbank-development-plan-28-66.pdf, p.54) The internal movement plan identifies connector roads, access streets, access places, laneways, pedestrian links, creek crossings and a proposed bus route. (Source: approved-underbank-development-plan-28-66.pdf, pp.36-39) The proposed bus route would connect Bacchus Marsh Railway Station, the town centre, Ascot Avenue, Rosehill Drive, Randwick Avenue, Underbank’s internal connector road network, Halletts Way and the Stonehill neighbourhood activity centre, subject to Public Transport Victoria sign-off. (Source: approved-underbank-development-plan-28-66.pdf, p.39)
Servicing, Drainage and Water Management
The servicing strategy is partly resolved and partly conditional. (Source: approved-underbank-development-plan-28-66.pdf, pp.30, 54) Sewer outfalls are proposed via 225 millimetre diameter sewers to the south-east corner of the site, but the servicing investigation states that an ultimate Underbank sewer assessment would not be undertaken until the Bacchus Marsh sewerage model was verified or calibrated and the master plan updated. (Source: approved-underbank-development-plan-28-66.pdf, p.30) That means the early-stage sewer pathway is identified, but the full catchment-level sewer capacity is not proven in the available extracted documents. (Source: approved-underbank-development-plan-28-66.pdf, p.30)
The water strategy is more specific in geometry but still subject to authority strategy. (Source: approved-underbank-development-plan-28-66.pdf, pp.30, 54) The development plan identifies an upgrade to the Underbank water pump station, connection to the proposed 375 millimetre Underbank main, two looped 300 millimetre water mains totalling 2,400 metres west of that main, and a lower-level 225 millimetre loop of 1,800 metres serving about 300 lots east of Korkuperrimul Creek. (Source: approved-underbank-development-plan-28-66.pdf, pp.30, 54) Western Water is identified as responsible for potable, recycled water and sewer reticulation, while the developer is required to construct reticulated water and sewer infrastructure within the development. (Source: approved-underbank-development-plan-28-66.pdf, p.54)
Drainage is shaped by the scale mismatch between the development and the receiving waterways. (Source: approved-underbank-development-plan-28-66.pdf, p.56) Melbourne Water correspondence is reported as indicating no specific requirement for flood retarding, because Korkuperrimul Creek and its tributaries have a combined catchment of about 4,000 hectares and the Werribee River catchment is larger again, while the broader Underbank Farm development is about 167 hectares. (Source: approved-underbank-development-plan-28-66.pdf, p.56) The development plan’s drainage task is therefore mainly water quality, floodplain avoidance, waterway setbacks and stormwater harvesting, rather than regional flood peak attenuation. (Source: approved-underbank-development-plan-28-66.pdf, pp.56-57)
The stormwater system is proposed as a combination of a consolidated wetland and smaller bioretention areas, with potential treated stormwater harvesting from Wetland 1 and Bioretention 3 to a pond, lake or tank storage system for irrigation of active and passive open space. (Source: approved-underbank-development-plan-28-66.pdf, pp.56-57) DPO6 requires MUSIC modelling, Melbourne Water requirements, a costed construction and maintenance implementation plan, and stormwater harvesting or wastewater reuse strategies for open space and streetscapes. (Source: smc-agenda-170914.pdf, pp.65-66)
Environmental, Geotechnical and Heritage Constraints
The geotechnical evidence divides the site into eastern escarpment, southern escarpment, waterways and upland areas, with high potential risk identified for the eastern escarpment, southern escarpment and waterway areas, and moderate potential risk identified in upland areas affected by exposed soils and scour. (Source: approved-underbank-development-plan-1-27.pdf, p.22) The development response is to avoid development on escarpments and slopes exceeding 20 percent, control stormwater runoff, use weed control and revegetation, construct barriers at escarpment toes where required, and restrict public access to unsafe escarpment areas. (Source: approved-underbank-development-plan-28-66.pdf, p.49)
The biodiversity and arboricultural assessments show a modified landscape with local ecological value concentrated in scattered old trees, small intact understorey patches, creek corridors and saltbush areas. (Source: approved-underbank-development-plan-1-27.pdf, p.23) The arboricultural assessment counted approximately 765 live trees, including 220 Peppercorns, 200 Monterey Cypress, 205 indigenous self-sown eucalypts and 140 other trees. (Source: approved-underbank-development-plan-1-27.pdf, p.23) The development plan requires later permit-stage review of final tree retention because the vegetation impact assessment was approximate while the subdivision layout remained unresolved. (Source: approved-underbank-development-plan-28-66.pdf, p.47)
The heritage layer is both Aboriginal and historical. (Source: approved-underbank-development-plan-1-27.pdf, p.24) Five Aboriginal isolated artefact sites were registered as Underbank Stud Farm IA1 to IA5, and a possible scarred tree was registered as Underbank Farm Scarred Tree 1 but classified as a non-site to prevent re-recording. (Source: approved-underbank-development-plan-1-27.pdf, p.24) The 2017 plan states that future subdivision and major earthworks will trigger a mandatory Cultural Heritage Management Plan under Aboriginal heritage legislation. (Source: approved-underbank-development-plan-28-66.pdf, p.58) The historic Underbank Stud Farm Equine and Water Management Project, listed on the Victorian Heritage Inventory, covers a significant part of the study area and requires Heritage Victoria consent for investigation, damage or destruction. (Source: approved-underbank-development-plan-1-27.pdf, p.24; Source: approved-underbank-development-plan-28-66.pdf, p.58)
Noise from the Western Freeway is a specific northern-edge constraint. (Source: approved-underbank-development-plan-28-66.pdf, p.59) Acoustic modelling predicted 2022 traffic noise above LA10 18 hour 63 dB(A) at exposed residential locations without a barrier, and the recommended barrier system is approximately 430 metres long and 5 to 5.5 metres high. (Source: approved-underbank-development-plan-28-66.pdf, p.59) DPO6 also prevents new allotments being created where there is insufficient space below the 63 dB(A) threshold at one metre from the most exposed facade of a dwelling. (Source: smc-agenda-170914.pdf, p.64)
Community Infrastructure and Contributions
Underbank is subject to a Section 173 infrastructure agreement rather than a conventional Development Contributions Plan in the available documents. (Source: smc-agenda-170914.pdf, pp.14-15) The 2014 council report states that the agreement funds major infrastructure projects to the value of 13 million dollars, including Halletts Way, Bacchus Marsh Road and Halletts Way roundabout upgrades, Grant Street and Main Street and Gisborne Road intersection upgrades, Werribee Vale Road upgrades and shared path works, Bacchus Marsh Road and Underbank Boulevard intersection upgrades, Ascot Avenue and Rosehill Street works, active recreation facilities, regional open space upgrades, integrated path and passive open space works, and family and children’s services upgrades. (Source: smc-agenda-170914.pdf, pp.14-15)
The approved development plan carries this into a spatial list of contribution items: active open space, irrigation water connection, Peppertree Park upgrade, a family services hub at West Maddingley, pedestrian and shared trails, strategic planning, road upgrades and pedestrian links to the north. (Source: approved-underbank-development-plan-28-66.pdf, pp.62-63) The active open space concept includes an AFL oval, netball courts, tennis courts, cricket nets, car parking and a combined pavilion, with temporary facilities contemplated before the pavilion is delivered. (Source: approved-underbank-development-plan-28-66.pdf, pp.43-44)
The key mechanism is staged payment and delivery. (Source: smc-agenda-170914.pdf, pp.12-15) Council contrasted Underbank with Stonehill by noting that Underbank contributions could be collected at each stage of subdivision, while Stonehill contributions were payable at an 800 lot threshold. (Source: smc-agenda-170914.pdf, p.13) This changes the public-infrastructure risk profile because community and road contributions are tied more closely to staged land release. (Source: smc-agenda-170914.pdf, pp.13-15)
Current Status
The available corpus supports three dated status points: C62 was at council adoption stage on 17 September 2014, the development plan document is dated March 2017, and the source filename identifies the plan as approved. (Source: smc-agenda-170914.pdf, p.34; Source: approved-underbank-development-plan-1-27.pdf, p.1) The current on-ground status of later subdivision stages, delivered lots, completed infrastructure and any post-2017 planning permit amendments is not established by the three source documents. (Source: approved-underbank-development-plan-1-27.pdf; Source: approved-underbank-development-plan-28-66.pdf)
Dependencies
- Blocks: Subdivision should not proceed in a disconnected way because DPO6 requires an integrated development plan, infrastructure sequencing, servicing evidence, drainage strategy, community infrastructure reporting and environmental management before the land is translated into detailed stages. (Source: smc-agenda-170914.pdf, pp.61-69)
- Blocked by: Larger-scale delivery is constrained by Halletts Way timing, revised traffic assessment thresholds, verified sewer catchment modelling, Western Water servicing strategy, Melbourne Water drainage approvals, Cultural Heritage Management Plans and Heritage Victoria consent for the historic equine and water management system. (Source: smc-agenda-170914.pdf, pp.18-19, 34; Source: approved-underbank-development-plan-28-66.pdf, pp.30, 54, 56-58)
- Informed by: The approved development plan relies on acoustic, arboricultural, archaeological, biodiversity, stormwater, escarpment, geomorphological, geotechnical, landscape, contamination, traffic, servicing and weed-management assessments. (Source: approved-underbank-development-plan-1-27.pdf, p.3)
- Implements: The release area implements the Bacchus Marsh Framework Plan direction for residential growth and aligns with regional planning that identifies Bacchus Marsh as a regional centre. (Source: approved-underbank-development-plan-1-27.pdf, pp.12-13)
- Conflicts with: The main policy tensions are density versus landscape character, early lot release versus network capacity, and urban development versus waterway, escarpment and heritage protection. (Source: smc-agenda-170914.pdf, pp.8-19; Source: approved-underbank-development-plan-28-66.pdf, pp.47-59)
Cross-Jurisdictional Links
The release area requires coordination with state and regional infrastructure authorities rather than only Moorabool Shire. (Source: smc-agenda-170914.pdf, pp.63-69) DPO6 requires traffic assessment to the satisfaction of the Responsible Authority, VicRoads and Public Transport Victoria, and requires waterway, drainage and shared-path matters to satisfy Melbourne Water requirements. (Source: smc-agenda-170914.pdf, pp.64-66) The development plan identifies Western Water, Powercor, NBN Co and Ausnet Services as servicing authorities for sewer, water, electricity, telecommunications and gas. (Source: approved-underbank-development-plan-28-66.pdf, p.54) Escarpment rehabilitation is also linked to bodies such as Grow West, the Port Phillip and Westernport Catchment Management Authority, Melbourne Water and Southern Rural Water. (Source: smc-agenda-170914.pdf, p.68)
Gaps in This Analysis
The source set is sufficient to explain the statutory pathway, approved land budget, infrastructure triggers and major constraints, but it is not sufficient to verify current delivery status after March 2017. (Source: smc-agenda-170914.pdf; Source: approved-underbank-development-plan-1-27.pdf; Source: approved-underbank-development-plan-28-66.pdf) Missing documents include the full Planning Panel report for Amendment C62, the executed and any amended Section 173 agreement, subdivision permits issued after development plan approval, engineering approvals, CHMP approvals, Heritage Victoria consents, Western Water servicing confirmations and any post-2017 council reports on Halletts Way or Underbank staging. (Source: smc-agenda-170914.pdf, pp.16-19, 34; Source: approved-underbank-development-plan-28-66.pdf, pp.54-58) The largest analytical gap is yield: the sources provide net developable area and lot-size principles but do not provide a final approved lot count by stage, so dwelling capacity cannot be quantified beyond the land-budget mechanism. (Source: approved-underbank-development-plan-28-66.pdf, p.55; Source: smc-agenda-170914.pdf, pp.63-64)