> Environmental Assessment

The evaluation of the Environmental Impact Statement (EIS) was carried out by the Coordinator-General under the State Development and Public Works Organisation Act 1971 (Qld) (SDPWO Act).

The SDPWO Act provides a process for the Coordinator-General to evaluate changes to significant projects.

The EIS was prepared in May 2006 and provided an assessment of a range of social, environmental and economic benefits and impacts of the reference project. The EIS also recommended mitigation strategies to minimise potential impacts and maximise benefits of the construction and operation of the reference project on the local and regional area.

Changes have been proposed to the reference project assessed in the EIS to better address the project objectives and in response to the request for innovation to further mitigate impacts identified in the reference project. Some of the proposed changes are also in response to recommendations of the Coordinator-General for the need to reduce project impacts on particular localities or local communities.

They include changes to the project design, including the tunnel alignment, surface connections and changes to improve traffic movements. They also include changes to project delivery, including construction methodology and coordinating construction with the Northern Busway.

Air quality and ventilation

Maintaining good air quality is a key concern for Brisbane residents. Air quality in Brisbane is affected by many sources, such as emissions from transport, power generation, business and industry, agriculture, dust storms and bushfires.

Cars, buses and trucks are major contributors to air pollution in Brisbane, particularly due to the average age of the vehicle fleet.

Motor vehicle emissions include a range of pollutants that may impact on environmental conditions and human health.

As Brisbane’s population grows, there is the potential for air quality to decline within the region due to increases in total travel demand and increases in traffic congestion.

Recent improvements in vehicle technology and the use of cleaner fuels in our cars, buses and trucks, have reduced air pollution. Ongoing improvements in vehicle and fuel technologies and a reduction in the average age of the vehicle fleet are expected to bring about further improvements in the future.

Potential changes to air quality were assessed for the Airport Link EIS. Steps in assessing potential air quality changes included:

• determining existing air quality and climatic conditions
• determining the amount and types of emissions expected from traffic in the road network, including the tunnel system
• predicting likely changes to air quality from vehicle emissions
• comparing predicted air quality (with and without Airport Link) with ambient air quality goals.

How will air quality in the tunnel be managed?

Airport Link will incorporate a longitudinal ventilation system for each tunnel to:

• maintain air quality and visibility within the tunnel
• manage air quality in the tunnel if an incident occurs, such as fire
• ensure vented air from the outlets does not cause ambient (external) air to exceed adopted air quality goals.

The ventilation system will draw in large volumes of fresh air into each tunnel at the portals. The air will then be pushed along by fans and vehicle movement for collection and high level dispersion through ventilation outlets for each tunnel.

BrisConnections has committed to a ventilation system that complies with international criteria for in-tunnel air quality and the Airport Link’s ventilation stations have been designed to safely disperse the associated vehicle emissions into the atmosphere. The air quality goals for air outside the tunnel have been based on stringent national and state standards.

The possible health risks associated with tunnel ventilation systems were investigated for the EIS. Two health risk studies were undertaken as part of the study, the first dealing with potential impacts on respiratory systems, and the second dealing with the impacts of ‘so-called’ air toxins such as benzene.

The first investigation found that there would be no measurable change in public health attributable to changes in air quality. The second study identified that the health risk through exposure to such agents is extremely low and unlikely that there would be any adverse impacts.

How will air quality change with the Changed Project?

An assessment of air quality and health impacts was undertaken on the changed project.

The assessment found that the changed project would comply with the air quality goals specified in the Coordinator-General’s conditions and that air quality and improvements in health outcomes would be similar to those for the Reference Project.

Will the ventilation outlets be filtered?

No. Airport Link investigations have shown there is no need for filtration for air quality or public health reasons.

Studies on the effectiveness of filtration in road tunnels has shown that current filtration technologies are generally of limited effectiveness in improving external air quality. The use of properly designed ventilation systems, including ventilation outlets, is overwhelmingly favoured over the use of filtration for managing external air quality.

However the ventilation stations have been designed to allow filtration to be installed in the future, should effective technology become available.

Noise and vibration

There is likely to be some noise and vibration near to the tunnel alignment during construction of the tunnels. The levels of vibration vary according to the method of construction, depth of the tunnel and geotechnical conditions. Similarly, people’s perceptions of noise and vibration levels vary widely.

The purpose of the EIS was to identify impacts and benefits that may result from construction or operation of the tunnel. The EIS found that:

• anticipated vibration levels generated by road header construction in the north-south tunnels would be imperceptible to buildings throughout the tunnel alignment;
• anticipated vibration levels from TBM construction of the east-west tunnels will generally not be noticeable in buildings along the tunnel alignment; and
• For much of the construction with the TBM, vibration levels would be below the threshold of people’s perception.

An assessment of vibration levels for the changed project found that the potential vibration impacts along the north-south tunnels would remain within the acceptable limits, specified in the Coordinator-General’s Conditions, despite the shallower tunnel of the changed project.

Potential vibration impacts along the east-west tunnel would be reduced by constructing a deeper tunnel in this area and in better ground conditions.

Should exceedences in vibration occur, a range of mitigation measures would be implemented, in consultation with potentially affected residents and businesses.

It is anticipated that vibration levels for tunnelling under Wooloowin State School would be within the relevant Australian Standards. BrisConnections will continue to consult with the school during construction to ensure potential vibration impacts from tunnelling works are appropriately managed.

The project team will make every effort to minimise the extent of impacts and the number of properties affected by monitoring construction impacts including noise and vibration throughout construction. The community will be kept informed throughout the process.

Urban design and visual amenity

The Airport Link Changed Project proposes a number of features to improve local amenity for local communities near the project works.

Key elements include:

• reducing surface works near Kedron State High School and Wooloowin State School;
• creating a land bridge at Clayfield to provide additional open space, connect residents directly with existing parkland areas and community facilities, and more direct pedestrian and cycle access between Stuckey and Elliott Streets, Clayfield and Parkland Street and Ross Park.
• creating a landbridge at Bowen Hills to allow pedestrian and cycle connection between Mann Park and Lutwyche Road.
• landscaping improvements to Kedron Brook, including progressively re-opening of the pedestrian and cycle way along Kedron Brook.
• providing tree-lined street boulevards in some areas that enhance the liveability of the areas.
• providing a drop-off and pick-up area adjacent to Wooloowin State School at Lutwyche Road
• returning Kalinga Park to community use, including enhanced facilities, following the launch of the TBM.