This email is intended to update you on our progress with the investigation around the slips on Pukerua Bay Beach Road.
Our thanks to the residents who have worked with the Council and geotechnical specialists ENGEO to share their knowledge, and allow us access to their properties.
We received ENGEO’s latest report yesterday. We will make it available once we’ve had time to review it and are able to confirm our preferred options. We are looking at several stability options with ENGEO and will need to align them with available funding.
We appreciate you are keen to see some action and we ask you to be patient so we can fully understand the cause of the slips and plan accordingly.
Our maintenance contractor Downer continues to monitor the road during heavy rain, and clear rock falls, as it did last weekend.
ENGEO has good local knowledge of the area and underlying issues having been involved with investigations into the following slips:
• 6 Ocean Parade (November 2016).
• 7A Haunui Way (2017 – 2018).
• 41 Haunui Road (October 2018).
• 57 Haunui Road (November 2020).
• 47 Haunui Road (December 2020).
• 19 Ocean Parade (March to August 2021).
• 1 Ocean Parade (8 December 2021).
The two (2) crib walls on Pukerua Beach Road are a separate matter to the slips but will also be investigated (to come).
Wellington Water recently undertook a leak detection survey of the water pipes in the area above Pukerua Beach Road:
• Two (2) minor leaks were discovered.
• To the best of their knowledge there are no stormwater pipes in the area.
• Residents’ stormwater is discharged to the ground via soakage pits.
• The likelihood that a leaky potable and/or stormwater pipe is contributing to the groundwater concerns in the area is very unlikely.
• An assessment of potential leaks from sewerage pipes is ongoing.
The common theme in all these slips is that they appear to be the result of erosion from water flow of both surface water and groundwater. It is understood that many, if not all, of the stormwater drains from the properties along Haunui Way and Haunui Road discharge directly to the ground, and this combined with natural infiltration of surface water through highly permeable surface soils, is the likely main reason for high groundwater flows in the area.
Rest assured remedial actions are in the planning phase and will be programmed accordingly (especially external funding).
We will continue to keep in touch as our investigations continue, and welcome your feedback.