Why these works are needed

During the playground upgrade in 2021, material was found close to the surface that required further investigation. Investigations confirmed the site had historically been used as landfill and that additional protective layers, known as capping, were needed to help make the site safe and stable.

Investigations also identified groundwater contamination, which means the existing groundwater reticulation system needs to be decommissioned.

The restoration program has been designed around these site conditions. This includes adding protective layers where required and using native vegetation to help stabilise the landscape and reduce erosion.

While the site conditions place some limits on the types of landscaping and infrastructure that can be installed, the City is committed to making Trinity Green as safe and enjoyable as possible for the community.

What we have achieved so far

Significant restoration and revegetation works were completed during the 2025/26 financial year.

This included:

• Installing a mulch cap using approximately 640 cubic metres of bushland mulch
• Planting more than 1,000 native trees, shrubs and groundcovers
• Direct seeding across 6,379 square metres
• Using 20 native species local to the South West.

The planting supports the mulch cap while helping to stabilise the landscape, provide habitat and improve the park's natural appearance as the vegetation establishes.

What’s happening in 2026

Throughout October and November 2026, the focus is on helping the recently planted and direct-seeded areas establish.

Ongoing maintenance includes watering new plants, controlling weeds such as oxalis and castor oil, and monitoring plant growth. The City will also undertake additional planting where needed.

The landscape will take time to establish, so this ongoing care is an important part of ensuring the restoration works are successful over the longer term.

What’s planned for 2027

Further improvements are planned throughout 2027 to provide more shade and amenities, support vegetation establishment and continue the rehabilitation of Trinity Green.

Planned works include:

• Installing two new seats and one picnic table near the playground
• Planting 11 advanced trees to provide more shade as they grow
• Adding tube stock to recently planted areas where required
• Targeted weed control before and after planting
• Planting and stabilisation works along the northern bank.

Works will be delivered progressively to give new vegetation the best opportunity to establish.

What to expect during the works

Trinity Green will remain a community space while the restoration progresses, although residents may notice temporary changes to access in some areas, weed control activities, mulch stockpiles and active planting and restoration works.

These impacts will be temporary and carefully managed. Signage will be provided around active work areas where required, and newly planted areas will take some time to establish.

What will Trinity Green Park look like in the future?

The long-term vision is for Trinity Green Park to provide a greener, more resilient space with different areas for the community to enjoy.

This includes:

• Open grassed areas near the playground for informal play, picnics and community use
• More shade and canopy trees to create cooler, more comfortable spaces
• A three-metre-wide limestone walking and maintenance path
• Expanded native vegetation to provide habitat for wildlife, increase shade and help stabilise the landscape
• Improved seating and picnic facilities.

The transformation will happen gradually as the new vegetation establishes and matures. Each stage will build on the last, creating a greener and more inviting Trinity Green for the community to enjoy for many years to come.

You can view the Trinity Green design, future visualisation and plant selections in the Project Document Library.

July 2026 - Groundwater and Underground Gas Monitoring at Trinity Green

The City of Bunbury will be undertaking environmental monitoring works at Trinity Green between Monday 13 July and Friday 17 July 2026 as part of its ongoing management of the site under the Contaminated Sites Act 2003.

These works involve the installation of three groundwater monitoring wells and six underground gas monitoring wells. The information collected will help the City better understand groundwater and underground gas conditions within and around Trinity Green and will support future restoration and improvement works.

What works will be undertaken?

The City will use hand augers (manual drilling tools) and a small drilling rig to install the monitoring wells. Drilling will generally extend to approximately two metres or deeper, depending on groundwater levels. Monitoring locations have been carefully selected to meet environmental monitoring requirements while minimising impacts on residents, trees and surrounding vegetation. Following installation, groundwater and gas sampling will commence and continue every two months over the next 12 months.

Works are expected to occur between 7.00am and 5.00pm during the monitoring period.

Safety and environmental management

All ground disturbance and ongoing sampling activities will be undertaken in accordance with the City's approved Asbestos Management Plan and Health and Safety Site Plan. The gas monitoring wells will be sealed and fitted with protective covers to ensure they remain airtight. This will prevent odours from being released and minimise impacts on nearby residents. A map showing the proposed monitoring locations is available in the document library.