Christies Beach Wastewater Treatment Plant Creekbank Repairs

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The Christies Beach Wastewater Treatment Plant began operating in 1970 and services homes and businesses in Adelaide’s south. It also provides recycled water for toilet flushing and irrigation of agricultural areas in McLaren Vale and Willunga.

Running inside the plant's southern boundary and out to the sea lies Christie Creek, whose catchment covers 34sq/km, spanning the Onkaparinga Hills face from Bains Road to Piggot Range Road.

Where the creek runs through our site, we identified 3 key erosion zones in 2024 which we have been monitoring over the last year to determine their rate of decline and how to fix them. Using collected water flow data to inform our design process, we will be repairing these sites starting in 2026.


Erosion repair sites along the Christie Creek alignment:

Site 1: This eastern-most site has been impacted by a change in the creek's floodplain due to invasive reeds growing in the creek bed. Firstly, we will install a temporary alignment fence at the base of the erosion zone which will catch coarse material and build a buffer between the fast water and exposed bank, then we will reinforce the toe of the bank using a combination of large rocks and concrete blocks. These will run the height of the embankment but leave room for new vegetation, which will be planted around the repair site to control further erosion.

Site 2: This is adjacent the main vehicle access point to the plant for heavy traffic and has been impacted by storm water ingress off Hunter Road. This run-off has caused the creek bank to erode and crack the support wall on the bridge's western side. To repair this, we will be renewing the concrete at the bridge's edge and constructing a support wall where the creek bank meets the waterline. This will provide the necessary support to the upper sides of the bridge to prevent further cracking and stabilize the embankment.

Site 3: Due to stormwater outflows from the treatment plant at the creek mouth and erosion caused by significant rain events, this site will be repaired adjacent the coastal path and down at the waterline. These works will require the use of heavy machinery and impact path users at times. Any restrictions to pathway access during works will be advised in advance using signage on site and will be limited to weekdays only. Access from the northern end to the beach path near the creek will still be open.

Site 4: Revegetation and pathway changes:

The area within the blue lines shown above has another erosion site within it on the creek’s southern side. For public safety, we have temporarily fenced this erosion site off as a short-term measure. Stock-style fencing will be erected extending from the bridge's eastern-side railings to continue through the adjacent scrub, follow the creek and then connect back with the old path. This fence will funnel path users along a pathway to discover newly constructed seating options and interpretive signage explaining the Kaurna people's connection to the area.

We will be planting trees and shrubs along the existing old path to revegetate the area, attracting birds and butterflies. By fencing-off and revegetating this erosion site, we will keep the existing trees whilst adding more.

Creating a safe corridor for pedestrians using the treatment plant access bridge over Christie Creek:

in 2026 we will separate pedestrian and vehicle traffic using the bridge on the plant’s Hunter Road-side. We aim to create a safe separation between vehicles and people with a protective barrier, to install fit-for-purpose railing and have clearly marked entry and exit points for all bridge users.


This project is complex in its nature due to working next to and over the waterway. Our construction delivery partners will be working to strict environmental guidelines to ensure minimal impact upon the creek, so our completion timeframe is currently projected to be by the end of 2026.

Sign up to the project using the Follow Project widget. Here you will be able to receive updates as things progress on site, be able to view timelines, and ask questions.

We will be seeking the community’s input into landscaping design options for site 4 in early 2026; just add your details to the Follow Project widget at the page's top right to stay informed.

The Christies Beach Wastewater Treatment Plant began operating in 1970 and services homes and businesses in Adelaide’s south. It also provides recycled water for toilet flushing and irrigation of agricultural areas in McLaren Vale and Willunga.

Running inside the plant's southern boundary and out to the sea lies Christie Creek, whose catchment covers 34sq/km, spanning the Onkaparinga Hills face from Bains Road to Piggot Range Road.

Where the creek runs through our site, we identified 3 key erosion zones in 2024 which we have been monitoring over the last year to determine their rate of decline and how to fix them. Using collected water flow data to inform our design process, we will be repairing these sites starting in 2026.


Erosion repair sites along the Christie Creek alignment:

Site 1: This eastern-most site has been impacted by a change in the creek's floodplain due to invasive reeds growing in the creek bed. Firstly, we will install a temporary alignment fence at the base of the erosion zone which will catch coarse material and build a buffer between the fast water and exposed bank, then we will reinforce the toe of the bank using a combination of large rocks and concrete blocks. These will run the height of the embankment but leave room for new vegetation, which will be planted around the repair site to control further erosion.

Site 2: This is adjacent the main vehicle access point to the plant for heavy traffic and has been impacted by storm water ingress off Hunter Road. This run-off has caused the creek bank to erode and crack the support wall on the bridge's western side. To repair this, we will be renewing the concrete at the bridge's edge and constructing a support wall where the creek bank meets the waterline. This will provide the necessary support to the upper sides of the bridge to prevent further cracking and stabilize the embankment.

Site 3: Due to stormwater outflows from the treatment plant at the creek mouth and erosion caused by significant rain events, this site will be repaired adjacent the coastal path and down at the waterline. These works will require the use of heavy machinery and impact path users at times. Any restrictions to pathway access during works will be advised in advance using signage on site and will be limited to weekdays only. Access from the northern end to the beach path near the creek will still be open.

Site 4: Revegetation and pathway changes:

The area within the blue lines shown above has another erosion site within it on the creek’s southern side. For public safety, we have temporarily fenced this erosion site off as a short-term measure. Stock-style fencing will be erected extending from the bridge's eastern-side railings to continue through the adjacent scrub, follow the creek and then connect back with the old path. This fence will funnel path users along a pathway to discover newly constructed seating options and interpretive signage explaining the Kaurna people's connection to the area.

We will be planting trees and shrubs along the existing old path to revegetate the area, attracting birds and butterflies. By fencing-off and revegetating this erosion site, we will keep the existing trees whilst adding more.

Creating a safe corridor for pedestrians using the treatment plant access bridge over Christie Creek:

in 2026 we will separate pedestrian and vehicle traffic using the bridge on the plant’s Hunter Road-side. We aim to create a safe separation between vehicles and people with a protective barrier, to install fit-for-purpose railing and have clearly marked entry and exit points for all bridge users.


This project is complex in its nature due to working next to and over the waterway. Our construction delivery partners will be working to strict environmental guidelines to ensure minimal impact upon the creek, so our completion timeframe is currently projected to be by the end of 2026.

Sign up to the project using the Follow Project widget. Here you will be able to receive updates as things progress on site, be able to view timelines, and ask questions.

We will be seeking the community’s input into landscaping design options for site 4 in early 2026; just add your details to the Follow Project widget at the page's top right to stay informed.

Page last updated: 16 Dec 2025, 09:40 AM