South Auckland community - road repair updates South Auckland community - road repair updates

East Street, Pukekohe

3 May 2023

Replacing the damaged retaining wall

The main works to replace the damaged retaining wall at East Street will start from Wednesday 3^rd May.

The works site is located between Prospect Terrace and Kowhai Place.

Works are expected to take 4 weeks to complete (weather permitting) and will involve:

• Excavation of the existing embankment
• Installation of rock anchors to stabilise the face of the escarpment
• Erection of a block retaining wall with associated drainage and sundry earthworks to protect the properties and private access way above East Street
• Traffic control and detours will remain in place until work is completed

Utilities

Utility companies such as Chorus, Watercare and Downer Utilities have been onsite to repair or maintain their infrastructure.

31 March 2023

A failure of a 15m section of an existing concrete retaining wall (approx. 55m in length) occurred following a period of extreme rainfall on 27 Jan 2023.

• The wall retains the bank on the southern side of the road, in front of properties 25 and 27 East Street and supports a shared driveway which provides access to these and 2 other properties.
• The remaining section of wall show signs of deterioration and may fail in the future.

Traffic flows and detours

• The eastbound lane remains open, but a detour is in place via Valley Road to Reynolds Road for west bound traffic.
• For safety reasons the road cannot be opened to two-way traffic due to the narrow lane widths, the horizontal alignment, risk to failed wall and the close proximity of the footpath would create an unacceptable level of risk for pedestrians and motorists.

We have completed a geotechnical investigation and design for the new wall is complete.  The design is being reviewed.

• The whole length of the existing wall (approx. 55m long) will be removed and replaced with a mass block wall to provide support to the driveways above and to enable East Street to be fully opened to two-way traffic.
• There are multiple water pipes and a power pole in the vicinity of the wall. A street lighting pole that was present above the wall was impacted by the failure and has subsequently been removed from the slope and will need to be reinstated as part of the permanent works.
• Various utilities will need to be relocated before construction of the new structure can commence.

Opening the road

• It is expected to take about a month for the utilities companies to complete their relocation works and then construction of the new structure will start.
• The new structure is expected to be completed by the end of June 2023, weather permitting.

Manukau Heads Road, Awhitu Peninsula

17 May 2023

On Manukau Heads Road, Awhitu Peninsula, a major slip occurred just a few hundred meters from the Manukau Lighthouse. The slip severed the road connection, and public access is unavailable to the lighthouse and other nearby properties. The aerial photo below shows the extent of the slip, which extends approximately 80m downwards from the road.

It has been estimated that around 90,000m3 of soil moved during the slip.   

Initial assessment

The initial assessment indicates that stabilising the slip and restoring the road connection will not be a short process. A robust evaluation of potential repair options is needed, along with site investigations, to ensure that the correct information is available to make an informed decision before committing funds to design and constructing a permanent solution. 

With the prospect of the restoration of the road connection being 12 – 18 months away, a discussion is needed on whether there is a need to restore temporary public access in the interim. This would also not be a short process because it would require land that AT does not own.

The most recent traffic data indicates that before the slip, approximately 240 vehicles per day travelled to the lighthouse during the summer of 2020.

Manukau Lighthouse

Road access to the Lighthouse remains closed to the public.

Next steps

• Speaking with property owners and interested parties to discuss constructing temporary road access
• Geotechnical investigation
• Overland flow study
• Engineering option