Canberra’s Urban Boundary

5.1
Urban growth in the ACT

The 2021 Australian State of the Environment Report outlined that expansion of urban environments across Australia has had significant and increasing environmental impacts. Habitat loss and degradation is the dominant mechanism by which species are threatened in Australia, and urbanisation is one key factor driving this loss.

Land clearance is also listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

“Land clearing consists of the destruction of the above ground biomass of native vegetation and its substantial replacement by non-local species or by human artefacts….Land clearing includes clearance of native vegetation for crops, improved, pasture, plantations, gardens, houses, mines, buildings and roads.”

However, the “EPBC Act is ineffective and not fit for current or future environmental challenges, and reform is long overdue.” The failure of environment laws to protect the environment is demonstrated in the 2021 Australian State of the Environment Report. It found the number of listed threatened species had risen 8% since 2016 and more extinctions are expected in the next decades. At least 19 Australian ecosystems are now showing signs of collapse or near collapse.

Urban expansion has long been recognised as a key threat to areas of high conservation value in the ACT. The 1997 ACT State of the Environment Report identified that woodlands and grasslands and their species have suffered most from urban development and that urban development now constitutes a serious threat to their existence, regardless of how slow the urban spread might be.

Since that report, a series of reports, inquiries, submissions and investigations over more than two decades illustrates a lack of effective management action. Underpinning these reports are numerous scientific studies of the ACT that illuminate the impacts of urban expansion on the natural environment.

More recently, the Legislative Assembly Standing Committee on Environment and Transport and City Services report on the Inquiry into Nature in our City states:

“The settlement and growth of the city, however, has meant that much of region’s natural habitat has inevitably been degraded and fragmented by the urban environment.”

It is critical to acknowledge that the extent of the impacts of urban encroachment in the ACT was not inevitable. Rather, these impacts are the result of strategic planning decisions which continue to be made and continue to ensure the natural environment is threatened by land clearance activities.

During the current State of the Environment reporting period, the ACT Government has undertaken the Planning System Review and Reform Project, which commenced in 2019. The new planning system came into effect in November 2023. The reforms include the new Planning Act 2023, new district strategies and a new Territory Plan. The principal function of the Territory Plan is to guide the use and development of land in the Territory. The draft Planning Bill 2022 included ecologically sustainable development in the objects of the Bill. However, there were no provisions within the Bill that required consideration of ecological sustainable development. This exclusion is particularly important to highlight, having observed the degradation of natural ecosystems at Canberra’s urban interface over several decades.

It is within the context of this trajectory of increased degradation of the natural environment and extensive planning reform that this chapter explores the current state of Canberra’s urban boundary in detail.

Throughout this chapter, environmental and sustainability considerations around greenfield developments are explored, along with the historic and potential future expansion of Canberra’s urban footprint. The areas affected by urban expansion that are discussed fall outside of the ACT’s reserves. Regardless of the land tenure, the ACT’s two most threatened ecological communities (natural grasslands and Box-Gum woodlands) are required to be protected under both federal and ACT environment laws. Despite such protections, this chapter details how areas of deep conservation value outside reserves continue to be lost or fragmented through urban expansion despite these ostensible protections.

5.2
Environmental impacts of greenfield development

Conversion of land from any natural, semi-natural or rural state into urban development typically results in adverse environmental impacts. Effects of greenfield developments in the ACT include:

• landscape-scale removal of vegetation
• soil disturbance and displacement
• erosion and sediment mobilisation
• changes to water courses and local hydrology
• killing of invertebrates and small vertebrates during land clearing
• permanent displacement of animals from the area
• increase in impermeable surfaces
• increase in vehicle traffic
• increased human and domestic animal presence
• increase in non-native plants, including weeds
• increase in invasive animals (both native and non-native).

All of these things come with environmental consequences, from direct disruption of local ecosystems through to contributions to global carbon emissions. Even if care is taken to protect ‘high value’ ecosystems and habitat for identified threatened species, overall, the negative environmental impacts of greenfield development far outweigh any benefits that can be claimed from protecting these few small patches.

The manner in which greenfield development is undertaken can compound these effects. A typical practice for the establishment of new suburbs is to scrape the development area removing vegetation and topsoil, which may be stockpiled for future use on site. These areas may be left bare for months as the new suburbs are built. This exacerbates many negative environmental effects. Sediment run-off and wind erosion from these bare areas are impossible to mitigate completely, and this approach removes all habitat that serves as a refuge for displaced animals and plants.

5.2.1
Impacts of greenfield development on biodiversity

When natural landscapes are replaced by human settlements, the type, quality and connectedness of habitat in that area is permanently altered, leading to significant changes in the abundance and distribution of native species. Greenfield development negatively impacts biodiversity in three key ways:

1. Greenfield development involves direct land use change resulting in the destruction, degradation or conversion of existing habitat. Globally, it is predicted that 290,000km² of habitat loss will occur due to urban expansion between 2000 and 2030.
   
   In the ACT, an important feature of the landscapes being developed is mature eucalypts. These ‘keystone structures’ provide critical resources that many native species, particularly birds, depend on for survival. In order to make way for new suburbs, most mature trees are cleared during development and the services they provide cannot be adequately recovered by replacing them with younger trees.
2. Greenfield development fragments habitat. Connectivity is essential for ecological processes such as migration, gene flow and repopulation where species have become locally threatened or extinct. When landscapes are divided into isolated or poorly linked patches, species are also less able to adapt to climate pressures by moving in response to environmental change. Acute physical barriers like roads prevent and alter species movement as well as causing high levels of native fauna mortality. Furthermore, as overall patch size becomes reduced and corresponding edge length increases, habitats are at higher risk of external disturbance, exacerbating edge effects as described below.
3. Greenfield developments continue to negatively impact biodiversity through a range of ‘edge effects’. For example, exotic plants and animals that commonly occur in urban settings can encroach upon adjacent habitat, predating, displacing or dominating local native species. These range from aggressive birds to backyard weeds and unrestrained pets like cats and dogs. While the ACT has now introduced cat containment laws, effective enforcement will be necessary to ensure compliance and prevent negative biodiversity impacts. Another edge effect comes from light and noise pollution, which can produce changes in animal behaviour, increase risk of predation, and reduce reproductive success. Meanwhile, the heat island effect can also impact biodiversity on the urban fringe, for example, by increasing numbers of heat-tolerant invasive species.
   
   Finally, the establishment of Asset Protection Zones around suburbs adjacent to bushland, while vital for mitigating bushfire risk to the community, can have negative impacts on wildlife. Appropriate planning — for example, designing Asset Protection Zones so that they fall within the suburb’s urban footprint — can help to minimise these impacts. However, avoidance of the need for such measures altogether can be achieved by pursuing more sustainable development pathways such as urban infill.

For more, see The Little Victims of Urban Expansion.

5.2.2
Impacts of greenfield development on waterways

Greenfield development also has important implications for waterway health. 

1. Urban areas are predominantly comprised of hard impermeable surfaces. During rain events, water running over these surfaces — such as roads, roofs and footpaths — picks up pollutants and carries them downstream as stormwater runoff. In urban contexts, runoff frequently flows into a drain or pond with minimal filtration by plant roots or soil. In contrast, when rain falls on rural, natural or semi-natural landscapes, the majority is absorbed into the soil and receives some degree of filtration before seeping into rivers or groundwater with low levels of pollutants and sediment. This means that simply changing an area of land from rural or natural use to urban use will have an unavoidable negative impact on water quality.
2. Urban stormwater runoff contains an array of pollutants that impact waterways. Excess nutrients from lawn clippings, fertilisers and pet excrement can decrease dissolved oxygen concentrations and cause excessive plant growth including toxic algal blooms. Physical sediments like soil, clay and sand also have major environmental impacts on waterways, increasing turbidity, altering flow, and smothering flora and fauna. This is an acute problem during the construction phase of greenfield developments, in which large-scale civil works displace significant amounts of earth as land is cleared and levelled. Runoff from urban environments can also contain heavy metals like lead, copper and zinc which can have toxic effects on aquatic life, while substances like oil and grease can suffocate aquatic species by forming a film across the surface of water.
3. The rate of runoff in urban contexts is significant. Concrete stormwater channels and other impermeable surfaces rapidly transport stormwater downstream. These high runoff rates can increase the risk of flooding and result in erosion, flow disturbance and accelerated distribution of the pollutants described above — all of which have negative impacts on aquatic ecosystems.

For more, see Sedimentation in Deep Creek.

5.2.3
Impacts of greenfield development on greenhouse gas emissions

Low-density urban fringe development is associated with increased greenhouse gas emissions — as much as 2.5 times that of high-density urban core development on a per capita basis, according to some assessments. This stems primarily from the materials used in construction and emissions associated with transportation.

1. Emissions from construction. Greenfield developments require the establishment of new public facilities and utilities such as roads, sewage and stormwater networks, while infill developments can rely on existing infrastructure. A 2018 cost analysis of developments in the ACT found that greenfield developments have significantly higher capital costs than infill sites per dwelling for this reason (the clearest example being $68,600 per dwelling in Whitlam versus $6,530 per dwelling for a high-rise infill development in Woden). The large-scale construction required by greenfield development has an associated environmental impact: increased use of materials like concrete and asphalt for roads and utilities has a substantial embedded carbon cost. More on embedded carbon and scope 3 emissions can be found in Chapter 6: Circular Canberra.
2. Emissions from transportation. Greenfield developments also typically result in a higher reliance on private vehicles for transportation, with increased associated emissions. Numerous studies have found significantly higher rates of per capita vehicle kilometres travelled in greenfield areas compared with infill zones — some finding that brownfield residents drive as much as 60% less. Several factors influence this including proximity to workplaces and cultural centres, availability of public transport options and neighbourhood design that enables active travel like walking and cycling. While the ACT’s switch to renewable energy and prospective transition to electric vehicles will eventually curb these emissions, the historic and ongoing global impact of sprawl-driven energy and transport emissions remains significant.

5.3
How sustainable are Canberra’s newest suburbs?

Canberra’s urban footprint is continuing to expand in the north and west with several greenfield developments in the Molonglo Valley (Whitlam and Denman Prospect), Gungahlin (Taylor, Throsby, Jacka and Moncrieff) and West Belconnen (Ginninderry).

Sustainability principles are increasingly being embedded into the design of new developments to improve the liveability for future residents and to reduce environmental impacts during construction and post-construction phases. Common sustainability features of greenfield developments include incorporating green open spaces, retaining habitat trees, enhancing active travel routes, establishing mandatory energy efficiency requirements for new buildings, and implementing water sensitive urban design principles to manage stormwater runoff.

While such sustainability considerations represent an improvement, these measures alone do not adequately counterbalance all the negative environmental effects of greenfield developments outlined in the section above.

The following section examines the environmental impacts of two current greenfield developments in the ACT — Ginninderry in West Belconnen and Whitlam in the Molonglo Valley.

5.3.1
Ginninderry

The Ginninderry development is a 1600 hectare cross-border development across NSW and the ACT, bounded on two sides by the Murrumbidgee River and Ginninderra Creek. The development, which is due to be completed in 2055, will eventually see 11,500 homes built across four new suburbs and accommodate up to 30,000 residents. Ginninderry’s first neighbourhood, Strathnairn, is close to completion while construction of the second neighbourhood, Macnamara, is due to commence in December 2023.

The design of Ginninderry has set out to demonstrate best practice in nature conservation, long-term liveability for residents and sustainable design, construction, and urban management techniques. Key sustainability features of the development include:

• Awarded 6-star rating under the Green Star system by the Green Building Council of Australia. Ginninderry is the first development in the ACT to be certified as a Green Star community.
• Incorporation of water sensitive urban design principles through establishing a network of bioretention swales, wetlands and basins to capture, cleanse, recycle and infiltrate stormwater runoff before entering the Murrumbidgee River.
• All homes in Strathnairn are required to install solar panels, a solar or heat-pump hot water systems and an efficient reverse-cycle air conditioner.
• A diversity of housing typologies will be made available across the development including apartments, townhouses, and sections of semi-detached and attached houses.
• Pollinator corridors have been established along the suburb’s streets for native birds and insects.
• Several roads in Strathnairn have been made from Reconophalt, an asphalt manufactured from recycled soft plastics, glass, and toner cartridges.

In addition to these sustainability features, 596 hectares of the 1600 hectare development will be set aside as a conservation corridor to manage the extensive urban edge between the residential development and the Murrumbidgee River and Ginninderra Creek. The corridor serves as a boundary to protect a raft of threatened species and ecological communities existing within the area, including Box-Gum woodland and Pink-tailed Worm-lizard (Aprasia parapulchella) habitat, both of which are listed as Matters of National Environmental Significance (MNES) under the EPBC Act. The Ginninderry Conservation Trust has been established to manage the corridor for biodiversity and cultural heritage conservation and restoration, and to facilitate sustainable recreational use within the corridor.

The development proposal was subject to both Commonwealth and ACT statutory approval processes, in the form of a strategic assessment and EIS exemption respectively. Despite these approvals and the establishment of the conservation corridor, the development has unavoidable impacts on a number of species and ecological communities existing within the area, some of which are identified as MNES under the EPBC Act. The Application for EIS Exemption for the Ginninderry Stage 2 development identified that the development is likely to directly impact 12 listed threatened species and two ecological communities due to clearance of habitat, disturbance of vegetation, increase in sedimentation and erosion and increased edge effects such as weed invasions and pollution. Significant environmental impacts stemming from the development include:

• the clearance of 3.8 hectares of Box-Gum woodland as part of the future Drake Brockman Drive upgrade (listed as a critically endangered ecological community under the EPBC Act)
• the clearance of 3.1 hectares of natural temperate grasslands (listed as a critically endangered ecological community under the EPBC Act)
• the clearance of 0.28 hectares of forest and woodland habitat (excluding Box-Gum woodland), including the removal of 28 habitat trees (nine high and three moderate quality trees, and the remainder of poor or unknown quality) for birds such as the Swift Parrot (Lathamus discolor), Superb Parrot (Polytelis swainsonii), and Regent Honeyeater (Anthochaera Phrygia) (the Swift Parrot and Regent Honeyeater are listed as critically endangered under the EPBC Act; the Superb Parrot is listed as vulnerable under the EPBC Act)
• the clearance of 9 hectares of Golden Sun Moth (Synemon plana) habitat to accommodate the proposed Ginninderra Drive extension, with a further 0.96 hectares potentially impacted due to overshadowing by the proposed bridge over Ginninderra Creek (listed as vulnerable under the EPBC Act)
• the clearance of 16.4 hectares of Pink-tailed Worm-lizard habitat (listed as vulnerable under the EPBC Act), and
• impacts to the Macquarie Perch (Macquaria australasica) and Trout Cod (Maccullochella macquariensis) considered likely due to changes in water quality associated with increased runoff and sedimentation (both species are listed as endangered under the EPBC Act).

In addition, the development has the potential to result in indirect and cumulative impacts on the threatened species and ecological communities inhabiting the corridor due to increased public access, recreational use and introduction of associated services and visitor infrastructure. This may result in increased invasive species and other pollution.

These potential indirect impacts are particularly concerning given the proposal to develop Ginninderry’s Riverside Parkland and Pavilion — an 11 hectare bush park and visitor centre by the Murrumbidgee River in the corridor. At the time of writing this report, the Riverside Pavilion Park is still under assessment and has not been approved under the Planning and Development Act 2007.

Once completed, the parkland is expected to host up to 90,000 visitors per year and up to 300 vehicles each day. This high rate of visitation in the corridor is likely to lead to general disturbance, incidental damage or removal of native vegetation and habitat. Additionally, the Ecological Impact Assessment of the Riverside Park identifies the following direct environmental impacts stemming from the proposed development:

• clearance of 0.18 hectares of Box-Gum woodland
• clearance of 1.03 hectares of Natural Temperate Grasslands
• clearance of 0.55 hectares of Pink-tailed Worm-lizard habitat, and
• clearance of 3.93 hectares of Nature Conservation Act 2014 identified native vegetation which constitute habitat for a number of Nature Conservation Act 2014 listed species and includes 0.48 hectares of listed Box-Gum woodland.

The Ginninderry Conservation Corridor is designated as an International Union for Conservation of Nature (IUCN) Category IV reserve. The IUCN’s Guidelines for Applying Protected Area Management Categories identifies the primary objective for reserves with this designation as “to maintain, conserve and restore species and habitats”. The secondary objectives for these reserves include “to develop public education and appreciation of the species and/or habitats concerned” and “to provide a means by which the urban residents may obtain regular contact with nature”. While the proposed development is ostensibly designed to deliver these secondary objectives, it is evident that the environmental impacts of the Riverside Parkland and Pavilion will be substantial and therefore incompatible with the primary management objective.

5.3.2
Whitlam

The Whitlam development is located in the Molonglo Valley, adjacent to the Molonglo River and Kama Nature Reserve. The project, which will be completed in 2025, will eventually house 5,000 residents across 2,100 dwellings.

The development has set out to incorporate sustainability principles and manage adverse environmental impacts. This has encompassed retaining mature trees where possible, planting nearly 6,000 new trees, enhancing active travel with planned cycling and pedestrian routes and offering exclusive rebates of up to $10,000 to buyers who design their homes to be all-electric, install solar PV and choose a light-coloured roof.

In addition, the Innovation Precinct, located at the Suburban Land Agency display village in Whitlam, is comprised of various demonstration homes showcasing best practice sustainable building techniques to be emulated by homeowners and developers. Techniques include the use of living infrastructure solutions such as passive irrigation, permeable driveways, and climate-sensitive street trees; using recycled and/or repurposed materials where possible, or using materials that have low environmental impact; and passive design.

Despite stated efforts to retain mature trees within the development, Whitlam was listed as one of the areas experiencing the largest percentage of mature tree loss per suburb in the ACT between 2015–2020, alongside Coombs, Throsby, Taylor and Wright. This was identified through a LiDAR analysis conducted for the Draft Action Plan to Prevent the Loss of Mature Native Trees, which found that the ACT has lost 6.2% of its mature urban native trees between 2015 and 2020, primarily due to land clearing for new urban development.

The Molonglo Valley Strategic Assessment, which was approved by the Commonwealth in 2011, identified the Whitlam area as being suitable for urban development. Despite this, the location of the development – which is on steep slopes adjacent to Deep Creek and the Molonglo River — has the potential to result in increased sedimentation and erosion during large rainfall events during and post-construction. High turbidity measurements have already been recorded in Deep Creek, which is expected to have adverse impacts on habitat and environmental values in the Lower Molonglo River. Concerns of increased sedimentation coming from the Whitlam development on local platypus populations in the Molonglo River have already been raised. In response, the Suburban Land Agency is currently constructing the Lower Deep Creek Pond to manage and treat urban stormwater runoff from Whitlam prior to entering the Molonglo River. The Suburban Land Agency also established the Whitlam Water Quality Control project in 2020 and implemented increased sediment and erosion measures beyond those required by the EPA, which are being audited by an independent auditor. The outcomes of these measures will be assessed in the next State of the Environment Report.

For more, see Sedimentation in Deep Creek.

Additionally, the closeness of Whitlam Stage 4 — the final stage of the residential development — to the ACT Heritage-listed Kama Nature Reserve has raised concerns of the potential urban edge effects and indirect impacts on the high-quality Box-Gum woodland and Natural Temperate Grasslands, native grasslands and aquatic habitat within the reserve. As stipulated in the Molonglo Valley Plan for the Protection of Matters of National Environmental Significance, a buffer must be established between the reserve and the adjacent development to protect the reserve from edge effects such as noise, weeds and introduced animals. The buffer must be consistent with the recommendations of the Kama Interface Management Strategy Report, requiring a variable width buffer of 200 m in the northern section, tapering to 70 m in the southern section. In comments provided to the Office of the Commissioner for Sustainability and the Environment (OCSE) by Government throughout this reporting period, the status of the Kama Interface Buffer remains unclear.

Despite expert advice on this requirement, concerns have been consistently raised by other experts and community members that the recommended size of the buffer is insufficient to protect the significant biodiversity values of Kama Nature Reserve against urban edge effects. The Kama Interface Management Strategy Report identified that even with the implementation of the buffer, the threat level to MNES and other environmental values within the reserve from weed invasion, exotic pest incursion, reduced abundance of urban-avoiding woodland birds and an increase in ‘urban-adapted’ birds such as the Noisy Miner remain high.

The buffer is also required to establish a minimum 60m Inner Asset Protection Zone along its full length to mitigate bushfire hazards for the adjoining development. As it will be managed in accordance with the ACT Strategic Bushfire Management Plan, no midstorey or shrubstorey will be established, coarse woody debris will be removed, and short grass/pasture will be maintained throughout the IAPZ. These requirements, which pertain to a significant portion of the buffer, will decrease vegetative and structural diversity and therefore attenuate the effectiveness of the buffer.

Both developments have taken important steps to embed sustainable principles into the design of each suburb, spanning individual houses to the broader precinct. However, the outlined adverse environmental impacts — clearance of habitat, disturbance of ecological communities, increased urban edge effects, and increased sedimentation and erosion — are pressures that would not have occurred otherwise, highlighting the immense environmental costs of expanding Canberra’s footprint. This is the case even when greenfield developments are planned with sustainability in mind and statutory processes have been adhered to.

5.4
Future expansion of Canberra’s urban footprint

5.4.1
Lawson grasslands

Lawson is in the Belconnen region and is divided into two areas. The first area is an established suburb in the south and the second is an undeveloped area in the north. The undeveloped area, Lawson North or Lawson grasslands, is administered by the National Capital Authority on behalf of the Commonwealth and is managed by Defence Housing Australia. Defence Housing Australia has proposed a residential development on the Belconnen Naval Transmitting Station site for approximately 416 dwellings. The area is shown in Figure 1 and details of proposal impacts are outlined in Table 1.

  Table 1. Details of the Lawson North Residential Development Proposal application (01246)

The proposed action has the following trigger under the EPBC Act: MNES: ecological (s18 – listed threatened species or endangered communities; s20 – listed migratory species) and National Heritage places (s15B)

The site contains remnant native vegetation, disturbed areas, and planted vegetation consisting of both native and exotic species. Areas of remnant native vegetation within the site align with threatened ecological communities listed as Critically Endangered under the EPBC Act and the Nature Conservation Act 2014. These communities are: Natural Temperate Grassland of the South Eastern Highlands White Box-Yellow Box-Blakely’s Red Gum Grassy Woodland and Derived Native Grassland (Box-Gum woodland).

The Referral area contains known or potential habitat for a number of threatened flora and fauna species listed under either or both the EPBC Act and the Nature Conservation Act 2014, including: Golden Sun Moth Striped Legless Lizard (Delma impar) Grey-headed Flying-fox (Pteropus poliocephalus) Superb Parrot

The Referral area also provides potential habitat for the following threatened species listed on the Nature Conservation Act 2014: Scarlet Robin (Petroica boodang) Perunga Grasshopper (Perunga ochracea) Little Eagle (Hieraaetus morphnoides) White-winged Triller (Lalage tricolor)

The broader retained area of the site also contains habitat for the following MNES: Ginninderra peppercress (Lepidium ginninderrense) Latham’s Snipe (Gallinago hardwickii) Murray Cod In addition, habitat for the rare Canberra Raspy Cricket (Cooraboorama canberrae) also occurs within areas of native grassland.

The proposed action would see 23.52 hectares of native vegetation cleared, including 15.8 hectares of listed Natural Temperate Grasslands and 1.31 hectares of Box-Gum woodland. Both ecological communities are listed as critically endangered under the EPBC Act and are thus MNES.

Clearing 15.8 hectares of listed Natural Temperate Grasslands would constitute a significant detrimental impact on this critically endangered ecological community. The ACT Government’s Natural Temperate Grassland Endangered Ecological Community Action Plan estimates there are only around 880 hectares of Natural Temperate Grassland remaining in the ACT, meaning that this development would reduce its extent by 2%. This will further fragment the community and increase the likelihood of its extinction.

OCSE estimates that less than 0.2% of the pre-settlement range of Natural Temperate Grasslands is formally protected in reserves. While precise figures are hard to determine, less than 10% of Natural Temperate Grasslands survives today compared with pre-settlement times. The proposal in its current iteration is unacceptable per Division 1A of the EPBC Act as it will have unacceptable impacts on MNES, specifically Natural Temperate Grassland.

The destruction of Box-Gum grassy woodland — while not sufficiently extensive to be deemed a significant impact under the EPBC Act — will still be reducing the extent of this critically endangered community in Australia. It is important to consider the cumulative impact of destroying small habitat patches of these communities. Any and all remnants of such critically endangered communities have irreplaceable ecological value and must be protected. In this regard the EPBC Act is currently inadequate to ensure proper protection of endangered ecosystems.

The environmental impacts are noted in the project description.

Substantial effort has been made in the design phase to avoid impacts to the site’s environmental values, however, the nature of construction activities (e.g. land clearing, excavation, and construction) would result in potential direct and indirect impacts on the environment. These potential impacts and the appropriate mitigation and management measures to address them are described in section 4 of this referral.

The proposed offsetting approach for the development involves the conservation and ongoing management of retained vegetation within the site to the east and west of the proposed development. While options for avoiding and mitigating impacts to MNES on the site have been outlined, the proposal does not put forward any alternative sites with less impact on MNES.

The referral states that “no other locations offer the historical connection for Defence families or are able to be developed into a viable project, and Defence Housing Australia do not consider the option of an alternative location as feasible”. This reasoning is manifestly insufficient given the significant impact it will have on MNES. The monitoring undertaken for the biodiversity assessment to support the referral is inadequate to accurately determine which species are present on the site. The surveys were not conducted over multiple years and were therefore not able to capture the effect of climatic and seasonal variability on the relevant populations. It is not possible to determine whether the proposed offsets site is adequate to achieve no net loss of MNES.

The status of the project in 2023 is that an assessment approach has been determined. Although this project does not involve development on the peri-urban fringe of Canberra, it is a valuable example for discussing greenfield development. The ecological value contained within the site, including the presence of 15.8 hectares of listed Natural Temperature Grasslands, is hugely significant given that all occurrences of this ecological community are considered critical to its survival.

5.4.2
Western Edge Investigation Area

The 2018 ACT Planning Strategy identifiedThe Western Edge was first identified in the 2012 ACT Planning Strategy and refined in the 2018 version. the Western Edge Investigation Area (WEIA) as an area for investigation for the purpose of potential future urban growth (Figure 2).

Within the 2018 ACT Planning Strategy, Action 1.2.1 requires that the Government:

• undertake environmental, infrastructure and planning studies for the western edge of the city to identify suitable areas for:
  • potential urban areas (excluding Central Molonglo)
  • nature reserves
  • environmental offset and potential environmental offset areas
  • the consideration of cultural and heritage values, and
  • other uses, for example rural, broadacre, major infrastructure, transport and services.

The WEIA is approximately 9800 hectares in extent and comprises 161 blocks across four districts (Belconnen, Stromlo, Tuggeranong, and Weston Creek). It lies within the Molonglo Valley and is bordered by the Murrumbidgee River to the west, north–west, and south, and existing suburbs and future suburbs (Ginninderry, Whitlam and Denman Prospect) to the north and east.

Completed preliminary reports outline the ecological and water values of the area. The results of these preliminary reports are detailed in Table 2.

Table 2. Summary of relevant preliminary reviews and assessments of the Western Edge Investigation Area

Review/assessment	Summary
Preliminary Ecological Review and Assessment	The WEIA contains: Plant community types: an estimated 210 hectares of EPBC Act/Nature Conservation Act 2014 listed Natural Temperate Grassland an estimated 1916 hectares of Nature Conservation Act 2014 listed Box-Gum woodland 47 ‘rare and uncommon’ flora species including substantial patches of vegetation dominated by either Drooping Sheoak (Allocasuarina verticillata) Black Cypress Pine (Callitris endlicheri) or Fern species. Threatened fauna: 12 threatened bird species 513 hectares of confirmed Superb Parrot breeding habitat, as well as two of the three known Superb Parrot breeding locations in the ACT a substantial number of current and historic Little Eagle nest sites 778 Pink-tailed Worm-lizard records, 617 hectares of confirmed Pink-tailed Worm-lizard habitat, and an additional 73 hectares of potential Pink-tailed Worm-lizard habitat Additionally, almost all areas of the WEIA that support a remnant canopy are likely to contain important foraging and breeding habitat for a wide variety of threatened bird species.
Western Edge Investigation Area – Water Values and Environmental Hydrology Assessment	The WEIA straddles three water management areas (the lower Murrumbidgee, the Upper Murrumbidgee and lower Molonglo catchments). The Murrumbidgee River and lower Molonglo River are identified as conservation catchments under the ACT Water Use and Catchment General Code. The Murrumbidgee and lower Molonglo Rivers within the WEIA have been identified as unique, having significant riparian vegetation, and being among the last of the good reaches of these rivers in the ACT and downstream. A significant portion of the area should be considered carefully in the context of urban development and stormwater management activities to produce appropriate strategies for development footprints, construction activities and developed settings. The Murrumbidgee River corridor is important to local, regional and national ecology providing: freshwater aquatic ecosystems wildlife corridors and ecological connectivity for both aquatic and terrestrial flora and fauna at local and regional scales regional habitat diversity geomorphological features such as sand and rock terraces, alluvial fan deposits and evidence of channel migration. The Murrumbidgee River supports threatened aquatic fauna species such as: Macquarie Perch Trout Cod  Murray River Crayfish (Euastacus armatus). The Murrumbidgee and Molonglo Rivers within the WEIA also provide habitat for species such as: Anchor Plant (Discaria pubescens) Murray Cod  Golden Perch (Macquaria ambigua) Common Eastern Froglet (Crinia signifera) Platypus (Ornithorhynchus anatinus) Eastern Long-necked Turtle (Chelodina longicollis) Eastern Water Rat (Hydromys chrysogaster) Eastern Water Dragon (Intellagama lesueurii). Water-related constraints and opportunities associated with land use change: During construction, the major impacts on waterways are likely to be from inputs of sediment. Post construction impacts are likely to include: changes to the hydrologic regime, particularly the rapid delivery of storm runoff leading to erosive high peak flows scouring beds and banks. The WEIA has sodic soils, which are highly susceptible to erosion. This is a significant issue for peri-urban development large quantities of urban stormwater contaminants being delivered to waterways including sediments, nutrients, and urban pollutants such as gardening fertilisers, biocides, pathogens, fuel, oil, heavy metals and microplastics from roadways and carparks spread of terrestrial and aquatic weeds.

The Molonglo Valley District Strategy, as part of the Planning System Review and Reform Project, notes that the western edge of the ACT is under investigation for its capacity to accommodate future development. Potential greenfield development of this area is already considered within the evaluation of economic access and opportunities for the Molonglo Valley District.

It is, however, clear from preliminary assessments (summarised in Table 2) that the WEIA supports significant environmental values (Figure 3) and habitat corridors (e.g. the Molonglo and Murrumbidgee River corridors). Habitat connectivity throughout the WEIA is not only vital for the flora and fauna that the area supports, but also for the flora and fauna that occur in the wider locality. That is, the environmental value of the Investigation Area extends beyond the bounds of the area itself and beyond the individual species, community types or singular environmental factors that might be considered.

5.5
Environmental offsetting of urban growth

Environmental Offsetting

Environmental offsetting is a policy framework set up to compensate for biodiversity losses from development by maintaining or increasing environmental value elsewhere. Offsets should achieve biodiversity gains equal to or greater than what is lost in the development area, which is known as ‘no net loss’ or ‘net gain’. They should also incentivise developers to reduce environmental impacts due to the high cost of offsetting. 

In Australia, the Commonwealth Government regulates and enforces environmental offsets guidelines under the EPBC Act. The EPBC Act Environmental Offsets Policy emphasises that offsets should be considered only after all reasonable measures have been taken to avoid and mitigate negative impacts to MNES in the development area.

Offset sites that have been approved in association with ACT development sites include more than 2,301 hectares of land (see Figure 4). This also includes an offset site within NSW which was purchased to offset the West Belconnen development. The main MNES values currently protected within ACT as offsets include:

• White Box – Yellow Box – Blakely’s Red Gum Grassy Woodland and Derived Native Grasslands (Box-Gum Grassy woodland)
• Natural Temperate Grassland (of the South Eastern Highlands)
• Golden Sun Moth 
• Striped Legless Lizard and
• Pink-tailed Worm-lizard.

Issues with offsetting

One of the main issues associated with offsets is that the “avoidance, mitigation, offset” hierarchy is not applied in practice in Australia. While this is embedded within policy, it is not embedded within the Act itself. This is according to the EPBC Act review conducted in 2020 by Professor Graeme Samuel, and also found in the 2022 NSW Auditor-General’s Report on the effectiveness of the Biodiversity Offsets Scheme.

Development proponents rarely fully explore avoidance and mitigation alternatives and instead seek offsets from the beginning of projects. The 2021 State of the Environment Report for Australia declared that more than 70% of development approvals assessed under the EPBC Act include offsets as a condition of approval.

Once an offset is established, it is challenging to assess whether no net loss or biodiversity gains have been achieved. This is because:

• offsets are rarely evaluated with respect to their outcomes after implementation
• often offsets do not replace the biodiversity features lost by the development, even though there is a policy requirement for offsets to compensate for these impacted biodiversity features (known as ‘like for like’)
• biodiversity loss data in development sites is not made publicly available, therefore it is not feasible to evaluate net loss or gain of biodiversity when approval periods for offset implementation are complete
• deficiencies in legislation and administration of offsets, such as poorly defined requirements and compliance, has also caused scepticism about their effectiveness.

A review of current public registers of offsets found that the information to determine if offsets are working as intended is not available in any offset register. Offsets registers do not provide detailed data on losses and gains relating to the specific environmental values that are being protected, which is essential to determine if offsets are achieving their goal. In some cases, including the ACT, offsets registers provide information on the biodiversity values that will be impacted (such as endangered species or ecological communities) and the area over which these will be impacted. However, these registers usually do not provide information on how offset requirements for each development are estimated, and most do not include monitoring data.

The practical complexities of measuring and monitoring ecological outcomes on offset areas remains one of the key challenges to any successful implementation. This is relevant to all offset sites across the ACT.

Understanding the use and effectiveness of offsets in the ACT is critically important. In terms of the specific evaluation of biodiversity retention through offsetting – such as whether no net loss has actually occurred – this has not been undertaken on any site in Australia and is not currently required under the EPBC Act.

This is essential as environmental offsets are now embedded in our environmental processes. If biodiversity condition requirements have not been met at the end of the approval stage for the offset site, there are no possible procedures for remedying this as the biodiversity present on the development site has already been destroyed.

5.6
Building within our boundary

The ACT’s population is projected to grow over the period of 2022–2060 to approximately 784,000 people. As of June 2021, the population was 453,5581 people. This growth will drive further demand for housing. It is estimated that the ACT will need more than 100,000 new dwellings, along with the construction of associated infrastructure, to accommodate the projected population growth (see Land). Canberra’s expansion must include a concerted focus on infill development, which involves increasing the intensification of housing in existing developed areas.

The 2018 Planning Strategy reports that between 2016–17, the ACT achieved 70% of new housing as infill. It states that “up to 70% of Canberra’s future development will come from infill and only 30% from greenfield development in the future”. Further, it reports that between 2012 and 2018, an average of 63% of all new housing occurred through infill development. The 2018 target is reinforced in the Parliamentary and Governing Agreement for the 10^th Legislative Assembly, which outlines the following action to “Require at least 70% of new housing development to be within Canberra’s existing urban footprint, with an ambition to increase this share, in the context of an overall increase to the number of dwelling sites released over the coming decade”.

It is unclear precisely what this strategy will achieve. First, it is unclear what constitutes “up to” in the provision for “up to 70%” of development coming from infill. Second, the 70% target is stipulated in the 2018 Planning Strategy, which is not a statutory document and hence there are no clear ramifications for not meeting this target. Third, infill targets are based on the number of homes, including apartments, and not the amount of land altered to accommodate development. In addition, replacement of existing housing stock (i.e. ‘knock down rebuilds’) are included in infill totals.

The urban footprint of Canberra continues to grow. Between 1991 and 2016, the ACT’s urban land area grew by 57%. Spatial analysis of aerial imagery undertaken by OCSE for this report has determined the actual growth in Canberra’s urban area and corresponding loss of greenspace over the period from 2006 to 2022 (Figure 5).

Analysis reveals that between 2006 and 2022 there was a 9% expansion of the urban footprint of the ACT (Table 4). In the four years between 2018 and 2022, there was a 2% increase in the urban footprint. During this period the population growth rate was approximately 1.1%, which is lower than the projected growth rate to 2060 of 1.4%.

Table 4. Summary of changes in the urban footprint of the ACT.

Year	Urban area (ha)	Difference from previous assessment  (ha)
2006	22,226	–
2018	24,487	+ 2260
2022	24,986	+ 500