Environmental Impact Statement Chapter 20.0 Cumulative impacts

20.0 Cumulative impacts

This chapter provides an assessment of the potential cumulative and facilitated impacts of the Project with other nearby developments.

20.1 Cumulative impacts defined

Cumulative impacts have the potential to occur when benefits or impacts from a project overlap or interact with those of other projects, potentially resulting in a larger overall impact (positive or negative) on the environment or local communities. Cumulative impacts may occur when projects are constructed or operated concurrently or consecutively.

The extent to which another development or activity could interact with the construction and/or operation of the Project would depend on the scale, location and/or timing of the development or activity. Generally, cumulative impacts would be expected to occur where other long-duration or large magnitude construction activities are undertaken close to, and over a similar timescale to, construction activities for the Project; or where consecutive construction occurs in the same area. Additionally, operation of the Project could cause cumulative benefits when the Project interacts with or possibly enhances the benefits of other Projects.

20.2 Assessment approach

The cumulative impact assessment methodology for the Project included:

• Identifying relevant developments that could be included in the cumulative impact assessment
• Applying screening criteria to determine which developments should be included in the cumulative impact assessment
• Assessing the potential cumulative impacts of the projects screened into the cumulative impact assessment, including identification of relevant issues likely to have material cumulative impacts during construction and/or operation of the Project (e.g. traffic, noise and vibration, landscape character and visual amenity, etc.)
• Identifying suitable mitigation measures to manage potential cumulative impacts.

The Cumulative Impact Assessment Guidelines for State Significant Projects (DPIE, 2022) has been adopted in the absence of Territory specific qualitative criteria.

A summary of the cumulative impact assessment methodology is shown on Figure 20-1.

20.2.1 Criteria for inclusion of potential projects

Potential projects identified for consideration in the cumulative impact assessment included those that met the following criteria for inclusion:

• Spatially relevant (i.e., where a development is considered to overlap with or occurs in close proximity to the Project)
• Timing (i.e., the expected timing of its construction and/or operation overlaps or occurs consecutively to construction and/or operation of the project)
• Scale (i.e., large-scale major development or infrastructure projects that have the potential to result in cumulative impacts with the Project, as listed on the Infrastructure Canberra (iCBR) and other ACT Government websites. Minor developments such as alterations to residential properties for example, were not included due to the nature and limited extent of those developments to interact cumulatively with the Project)
• Status (i.e., projects in development with sufficient publicly available information to inform this environmental impact statement and with an adequate level of detail to assess the potential cumulative impacts).

20.2.2 Projects included in, or excluded from the cumulative impact assessment

Projects identified and considered in the cumulative impact assessment are listed in Table 20-1. This table identifies construction and operational timeframes for each project (where known) considered in the cumulative impact assessment and how these overlap with the Project. Subject to planning approval and procurement, construction of the Project is anticipated to commence in 2029 and would take about four to five years to complete. The first passenger services are proposed to start in 2034.

The developments in Table 20-1 were identified as meeting the screening criteria at the time of the assessment. As noted in Section 20.2.1, projects have been screened out if insufficient project and environmental assessment information is publicly available.

Several large-scale infrastructure projects and developments within 1km of the Project area have been screened out from the cumulative impact assessment for the Project, primarily due to their planned timeframes for construction and operation. Developments anticipated to be in operation before the start of this Project's construction phase were excluded from further analysis because they would not overlap with the Project's construction timeline and thus would not generate cumulative construction impacts. Without concurrent construction periods, the potential for interaction between these projects and this Project would be minimised, removing the likelihood of compounded effects. As a result, these operational projects were not considered further in the cumulative impact assessment. Key projects screened out for these reasons include:

• National Security Office Precinct (Block 5 Section 1 Barton)
• Commonwealth Avenue Bridge Renewal Project
• CIT Woden Youth Foyer
• CIT Woden Education Campus
• Woden Interchange
• Southern Cross Club Build-to-Rent project.

These developments were assumed to be operational in relevant environmental assessments in Chapter 12 (Commonwealth Avenue precinct) to Chapter 19 (Mitchell Depot site), with traffic generated from their operations accommodated in the strategic traffic model.

As part of the revised, final Environmental Impact Statement (EIS), the cumulative impacts of the Project would be reassessed and would consider any new publicly available information that has been made available since the preparation of this assessment. Prior to the commencement of construction, proponents of other projects in the area would be identified and engaged with to understand potential cumulative impacts and coordinate mitigation and management (refer to mitigation measure CU1 in Section 20.7).

20.3 Previous Light Rail network stages

The Project would extend the existing and planned Light Rail network in Canberra. Light Rail Stage 1 (LRS1) is currently operational. Based on current program information LRS2A is anticipated to begin operation prior to the start of main construction works of the Project.

Given that previous stages of the Light Rail network would be operational by the time the Project commences construction, and due to the linear nature of the Project, and previous stages, cumulative impacts are not predicted to occur. LRS1 and LRS2A have been considered throughout Part B (Environmental impact assessment) as part of the baseline environment for the Project (e.g. the existing environment in which this Project would be constructed).

Construction compounds A1 and A2 are currently used as construction compounds for the LRS2A project. Off-street parking losses associated with the use of these construction compounds for LRS2A would continue for the Project. However, there would be a gap between completion of construction of LRS2A and construction of the Project commencing where the construction compound is not in use.

Benefits of the extended Light Rail network (including this Project and the previous Light Rail network stages) are considered in Chapter 2 (Need for the Project).

20.4 Cumulative impacts - construction

Potential cumulative impacts during construction are related to:

• Traffic and transport
• Biodiversity
• Non-Aboriginal heritage
• Landscape character and visual amenity
• Air quality
• Socioeconomic
• Hydrology, flooding, and water quality
• Noise and vibration.

These impacts are summarised in the following sections. Further details on the potential cumulative impacts during construction are presented in the respective technical reports.

The timeline for construction of several of the identified surrounding developments is currently unknown. For the purposes of this construction cumulative assessment, it was conservatively assumed that all of these surrounding developments would be under construction at the same time as the Project.

20.4.1 Traffic and transport

The Project would involve temporary construction traffic arrangements and construction activity at the construction compounds and ancillary facilities along the alignment. The construction impact assessment presented in Technical Report 1 - Traffic and transport considers the cumulative impacts of various temporary traffic arrangements being implemented concurrently along the Project alignment and the additional construction traffic generated by the Project.

The following developments were identified as potentially resulting in cumulative traffic impacts with the Project during construction:

• Acton Waterfront - future city neighbourhood - construction traffic would likely use Commonwealth Avenue, a proposed construction haulage route for the Project
• Canberra Brickworks redevelopment - construction traffic would likely use Yarra Glen, which is a proposed construction haulage route for the Project
• North Curtin Residential Area and Diplomatic Estate - construction traffic would likely use Yarra Glen, Carruthers Rd and/or Cotter Rd, which is a proposed construction haulage route for the Project
• Hellenic Club redevelopment - construction traffic would likely use Launceston Street, Yamba Drive, and/or Melrose Drive, which are proposed construction haulage routes for the Project
• Matilda Street car park redevelopment - construction traffic would likely use Launceston Street, Yamba Drive, and/or Melrose Drive, which are proposed construction haulage routes for the Project. Construction of this site would result in a further reduction in available off-street public car parking within the Woden precinct.

Construction traffic volumes associated with these surrounding development projects are currently unknown. However, these projects would be spread across the extent of the study area for the traffic and transport assessment, and therefore, the construction traffic associated with each of these projects would be distributed across various haulage routes.

The proposed construction methodology for the Project would retain road network accessibility by maintaining traffic flow along key transport corridors during the construction works. Intersection and track crossing works would occur during weekend closures when traffic volumes on the surrounding road network are lower. Diversions would be available when block closures are implemented during the construction of the National Triangle-Barton alignment option.

While the proposed construction haulage routes for the Project have been identified to be the most direct to the construction compounds from the arterial road network, construction vehicles associated with the surrounding projects would likely use some of the same routes, resulting in a cumulative construction traffic impact on road network operations.

Most construction vehicle activity (travelling to and from site) during the Project's construction would occur outside of AM and PM peak road network periods. Considering the distance between the surrounding developments and the likely distribution of construction vehicle volumes on the surrounding road network, the cumulative construction traffic impact of these developments with the Project would represent only a small proportional increase in the total traffic volumes on the broader road network. This may result in a minor increase in vehicle delay and travel time on the surrounding road network.

As outlined in Chapter 21 (Environmental management and mitigation measures) and Appendix L (Environmental Management Plan outline), a Construction Traffic Management Plan (CTMP) would be prepared for the Project to provide details on proposed measures to minimise the cumulative traffic impact of construction works on surrounding road users. Chapter 21 (Environmental management and mitigation measures) also includes mitigation measures that would be applied to manage impacts to the transport network.

Measures which would contribute to management of cumulative traffic impacts could include:

• Scheduling of most deliveries outside of peak road network periods (including outside of standard construction hours where required to minimise impacts on the road network)
• Encouraging workers to use alternative transport arrangements, such as active and public transport or to car-pool, thereby minimising the number of single-person private vehicles generated by the works
• Use of shuttle buses to transport workers to/from the Project area and between construction compounds and work areas.

Construction environmental management is discussed further in Chapter 21 (Environmental management and mitigation measures).

20.4.2 Biodiversity

The Project area is positioned within a highly modified urban environment. While it does not support ecological communities listed under the Environment Protection and Biodiversity Conservation Act 1999 or Nature Conservation Act 2014, it does support habitat for a number of threatened species and contributes to connecting core habitat within the urban context.

A review of available information associated with the developments identified in Section 20.2.2 was carried out to determine the potential cumulative impacts on biodiversity-related Matters of National Environmental Significance (MNES) under the EPBC Act and protected species under the Territory's NC Act.

The North Curtin Residential Area and Diplomatic Estate had sufficient ecological information available to inform this assessment. The ecological assessment report for this project (Umwelt, 2022a) confirmed that this site supports patches of native vegetation, including native grasslands and amenity plantings, which provide habitat for woodland birds and Golden Sun Moth (Synemon plana) habitat. It is not known whether options to avoid or mitigate impacts on MNES and protected species from this project have been determined.

The Project area also supports Golden Sun Moth (Synemon plana) habitat that is contiguous with an adjacent site for the proposed National Security Office Precinct development (within the Barton precinct). These project examples demonstrate that current planned developments within the local landscape may contribute to a cumulative impact on the Golden Sun Moth and other species, which when combined with the impacts from this Project, may be significant.

20.4.3 Non-Aboriginal heritage

Cumulative heritage impacts have the potential to occur where developments near to the Project are constructed concurrently or consecutively. These are discussed in Table 20-2 and further detail can be found in Technical Report 3 - Heritage.

Further consideration of other permanent changes to the setting of heritage items as a result of other projects, including those which would be complete prior to the construction of this Project, can be found in Technical Report 3 - Heritage.

20.4.4 Landscape character and visual amenity

Cumulative landscape and visual impacts have the potential to occur where developments near to the Project are constructed concurrently or consecutively. Potential cumulative landscape and visual impacts during construction are discussed in Table 20-3.

20.4.5 Air quality

The adoption of mitigation measures set out in Chapter 21 (Environmental management and mitigation measures) and the construction management approach set out in Appendix L (Environmental Management Plan outline) are expected to result in the adequate management of dust and other emissions for the Project. The air quality risks associated with construction of infrastructure are well known and generally well managed using standard mitigation measures. Potential cumulative air quality impacts would be temporary and managed through consultation with the relevant stakeholders and coordinating construction activities with other nearby developments.

20.4.6 Socioeconomic

The construction of the Project has the potential to result in socioeconomic benefits associated with increased employment and training opportunities, particularly for construction workers. Should other identified projects be constructed concurrently, this benefit may be enhanced.

Potential cumulative socioeconomic impacts during construction may arise where these projects are constructed concurrently with the Project, and could include economic, health and wellbeing and traffic and access benefits and challenges.

Economic

The cumulative economic effects associated with the construction of Project, alongside other concurrent projects, could result in both benefits and challenges. If other projects are constructed concurrently with the Project, the cumulative impact could amplify the socioeconomic benefits associated with employment and training opportunities. The combined demand for construction workers, traffic professionals, planners, and related professions could create a broader pool of jobs across multiple sectors. This increased demand would particularly benefit local workers, as well as vulnerable communities, including Indigenous and disadvantaged groups, who may have targeted employment opportunities.This could lead to workers gaining experience from multiple large-scale projects resulting in a more skilled local workforce, and increase future employability in infrastructure development.

Increased employment for construction workers would likely lead to greater local expenditure, benefiting businesses and services in the surrounding areas. The influx of workers and the economic activity generated by large-scale projects could also stimulate further investments in the region, potentially leading to long-term economic growth.

Conversely, the increased demand for construction workers, engineers, planners, and other skilled professionals could reduce the availability of labour for other local community projects or services. This reduction in available labour could increase wages and competition for workers, which may lead to delays in project timelines or cost overruns. This could also limit resources available for other sectors. For example, essential services, housing developments, or smaller-scale municipal projects might struggle to attract labour, particularly in trades like residential construction, leading to delays or higher costs impacting housing affordability.

Health and wellbeing

Cumulative impacts related to the construction of the Project, particularly when combined with other nearby projects, may substantially affect the wellbeing of some residents and communities. Continuous construction activities can impact daily life through increased traffic, noise, reduced pedestrian accessibility, and a decline in local amenity. These disruptions can lead to frustration, stress, and even construction fatigue, which may have a detrimental effect on both mental and physical health. The Commonwealth Avenue and Woden precincts are especially vulnerable due to the extended timeline and scope of overlapping large-scale developments.

For individuals with mobility constraints, these impacts may be even more pronounced. Reduced pedestrian accessibility and construction-related obstacles could affect their ability to navigate through impacted areas, exacerbating feelings of isolation and stress. Addressing these concerns through coordinated construction activity and engagement with nearby projects would mitigate some of the potential negative effects experienced by vulnerable groups.

Traffic and access

As identified in Section 20.4.1, there is potential for cumulative construction traffic impacts, which may further impact access to social infrastructure, events, and attractors in the area, causing inconvenience for residents and visitors.

Concurrent construction projects, such as the Acton Waterfront development the Canberra Brickworks redevelopment and development projects in Woden, would likely share proposed construction haulage routes or generally lead to an increase in construction vehicles. This could exacerbate congestion, especially during peak hours, leading to delays that affect access to local amenities and social infrastructure. It is also important to recognise that these cumulative impacts may disproportionately affect individuals with mobility constraints. Increased delays and reduced accessibility to public spaces can significantly hinder their ability to navigate the community effectively.

20.4.7 Hydrology, flooding and water quality

Potential cumulative hydrology, flooding, and water quality impacts during construction are discussed in Table 20-4.

Predicted cumulative impacts of these developments and the Project would be similar in nature to those discussed in Section 11.5.1 such as changes to surface water quality (e.g. through run off from construction sites) or changes to flood characteristics. Hydrology, flooding, and water quality mitigation measures would be implemented (as outlined in Chapter 21 (Environmental management and mitigation measures)) which would appropriately manage these risks. Potential cumulative impacts would also be managed through consultation with the relevant stakeholders and coordinating construction activities with other nearby developments.

20.4.8 Noise and vibration

The following developments have been identified as potentially having cumulative construction noise and vibration impacts with the Project:

• Acton Waterfront - future city neighbourhood
• Canberra Brickworks redevelopment
• North Curtin Residential Area and Diplomatic Estate
• Hellenic Club redevelopment
• Matilda Street car park redevelopment
• Woden Zone Substation to Canberra Hospital Underground High Voltage and Optical Fibre Connection.

These developments are located at varying distances from the Project and may have an impact on the construction noise levels experienced at noise sensitive receivers depending on the construction activities occurring simultaneously and the distance from the Project. If another construction activity outside of the Project was occurring at a similar noise level to the Project construction activities, the resulting construction noise level may be 3 dB higher than the construction noise levels presented in the construction assessment for the Project (refer to Section 5 of Technical Report 9 - Noise and vibration). Similarly if two construction activities outside of the Project were occurring at a similar noise level to the Project construction activities, the resulting construction noise level may be 5 dB higher than the construction noise levels presented in the construction assessment for the Project (refer to Section 5 of Technical Report 9 - Noise and vibration).

In accordance with measures identified to manage cumulative construction impacts (refer to Section 20.7), proponents of other developments in the area would be consulted with during construction to confirm the potential for overlapping impacts and coordinate impact mitigation and management (for example, respite periods), where relevant.

20.5 Cumulative impacts - operation

Potential cumulative impacts during operations are related to:

• Traffic and transport
• Non-Aboriginal heritage
• Landscape character and visual amenity
• Hydrology, flooding and water quality
• Noise and vibration.

These impacts are summarised in the following sections. Further details on the potential cumulative impacts during operations are presented in the respective technical reports.

The timeline for the completion and operation of several of the identified surrounding developments is currently unknown. For the purposes of this operational cumulative assessment, it was conservatively assumed that all of the identified nearby developments would be completed and operational at the same time as the Project.

20.5.1 Traffic and transport

Most of the identified surrounding developments (in Section 20.4.1) would likely generate additional traffic once operational. Operational traffic associated with these future developments were considered in the Zenith Strategic Transport Model which informed the traffic and transport assessments. Therefore, the cumulative impact of these developments with the Project has already been considered in the traffic modelling and impact assessment presented in Technical Report 1 - Traffic and transport.

The Project would provide a relatively direct, alternative route for transport from these surrounding developments to other locations along the alignment and connections to other regional public transport services. As such, the Project has the opportunity to reduce the traffic generation of these surrounding developments by providing an alternative accessible mode of transport. The active travel infrastructure being delivered as part of the Project also has the potential to create a mode shift away from private vehicle travel increasing walking and cycling travel.

20.5.2 Non-Aboriginal heritage

Potential cumulative non-Aboriginal heritage impacts during operation of the Project are discussed in Table 20-5. Further detail can be found in Technical Report 3 - Heritage.

Further consideration of other permanent changes to the setting of heritage items as a result of other projects, including those which would be complete prior to the operation of this Project, can be found in Technical Report 3 - Heritage.

20.5.3 Landscape character and visual amenity

Potential cumulative landscape and visual impacts during operation are discussed in Table 20-6.

During operation, cumulative landscape and visual impacts of the Project and other developments would be limited. The Project and developments discussed in Table 20-6 would be designed to integrate into the landscape, noting the importance of the Canberra city layout. These projects are each consistent with the continued visual nature of Canberra as a city and urbanised environment.

20.5.4 Hydrology, flooding and water quality

Potential cumulative hydrology, flooding and water quality impacts during operation are discussed in Table 20-7. Land use changes associated with planned development, where known, were included in the baseline flood models used to inform the assessment carried out for the Project. This has allowed for an assessment of impacts that considers developments which may not be existing currently but are likely to be present once the Project is operational. A complete list of these developments is included in Technical Report 4 - Hydrology, flooding and water quality.

20.5.5 Noise and vibration

No other light or heavy rail projects are currently proposed to be constructed in proximity of the Project area. Therefore, cumulative noise from operational rail activities is unlikely to impact noise sensitive receivers within the Project area.

The noise and vibration assessment of the Project in Technical Report 9 - Noise and vibration has also considered approved unbuilt developments that contain noise sensitive receivers as part of the baseline environment. This has allowed for an assessment of impacts to receivers which may not be existing currently but are likely to be present once the Project is operational. A complete list of these developments is included in Technical Report 9 - Noise and vibration.

20.6 Facilitated impacts

Facilitated impacts are consequences of actions taken by third parties, where the third-party action is facilitated to a major extent by the primary action, and the impacts of the third-party action could be reasonably foreseen. While there are developments located adjacent to the Project which would likely benefit from the extension of light rail from Commonwealth Park to Woden, these are not directly related and could occur regardless. Consideration of the cumulative impacts of these developments are detailed in Section 20.4 and Section 20.5. While these developments may give rise to environmental impacts, they would be subject to separate environmental assessment and approval activities.

20.7 Management and mitigation measures

Environmental management for this Project is detailed in Chapter 21 (Environmental management and mitigation measures). This includes construction and operational measures to manage cumulative impacts, that are applicable to the Project as a whole.

Management and mitigation measures have been proposed to reduce the potential cumulative impacts of the Project and other developments, which are identified in Table 20-8.