Topic 3: How do we protect critical assets in a changing climate?

Let's talk more about Beach Road, coastal erosion and the cost of protecting our infrastructure

Coastal erosion is a significant issue along the northern Otago coast, particularly around Beach Road. NIWA (2019) has identified this area as an erosional hot spot due to the dramatic shoreline retreat. Approximately 60% of the coast in the Waitaki district is retreating at a rate of 15cm per year.

Even though Council doesn't own all the coastal land, we brought in a consultant in 2024 to check out the key spots in Waitaki that are at risk from coastal erosion. This gives us better information on the risks so we can figure out the best options for future coastal resilience work

While not all of the key locations in the report are Council assets, two areas were flagged as having more immediate risk with a bigger impact on Council assets. These are Beach Road and the Orwell Street Sewer Pumpstation.

We talk about the Orwell Street Sewer Pumpstation in our consultation document. This is critical infrastructure that is challenged in a heavy rain event – and is vulnerable to coastal erosion due to its proximity to the sea.

Council is exploring options on how to address the Orwell Street Sewer Pumpstation as part of a larger study of the Oamaru wastewater network.

We also talk about Beach Road in the consultation document and presented the options we have.

As a country we are lucky to be surrounded by a stunning rugged coast, enjoyed and accessed widely via local roads and state highways. However, while we are blessed with the beauty of our coastlines, we are challenged by coastal erosion which is occurring up and down the country.

We've already seen the serious impact of coastal erosion along Beach Road. A section was closed to vehicles in 2008 and then to walkers and cyclists in 2012 because the unstable land posed a risk to everyone in the area.

In 2024, Council started working on Project Reclaim which was focused on removing old landfills on two sites – one in Hampden and one on Beach Road (at two locations on Beach Road).

If we didn’t remove the landfills along Beach Road, the ongoing erosion would have continued to undermine the cliff faces, which could cause the landfill sites to collapse and expose hazardous waste resulting in contamination of the soil, ocean, marine life and ecosystems.

So, removing the landfills was crucial to mitigate these environmental risks and restore the natural coastal processes in the area.

That's why we started the significant environmental remediation project along the coastal cliffs off Beach Road near Oamaru. This section of Beach Road has been closed since August 2024 to allow for Project Reclaim to be completed.

The meticulously planned and reviewed remediation project involved excavating and removing waste material to the Palmerston Landfill. However, the excavation uncovered a much larger deposit of historic fly-tipped waste than the estimated 12,000 tonnes concealed under the road. The removal of this waste, totalling 19,000 tonnes—58% more than estimated—required larger earthworks at both sites.

With Project Reclaim undertaken on Beach Road at a much larger scale than initially foreseen, and the waste now successfully and safely removed eliminating the risk of an environmental disaster, the funds that were allocated to reinstate the road have been absorbed in the additional excavation and transfer of waste from the site.

This leaves our community with an important decision: do we want to restore the cherished road connecting Oamaru to Kakanui or transform the road into a recreational space?

We need to choose the best course of action from three options, each with its own benefits and challenges.

We invite you all to consider the options below and share your feedback on what you see is the best option for Waitaki now, and for the future.

Option A: Reinstate the Road

The first option is to rebuild the road in a new alignment around the holes left by Project Reclaim. This approach has several benefits.

The reinstatement will be cheaper than filling the holes left by Project Reclaim, costing $720,000.

This option preserves the existing levels of service that our community has come to rely on.

However, there is concern about the long-term viability of the road due to coastal erosion. Just shifting the road around the holes isn't going to make it last any longer. Right now, we're doing minor reactive coastal erosion protection, which is keeping the road intact, but it's a losing game. We really need to do some additional major work to keep the road open for good, otherwise the investment in realigning the road will shortly be wasted as Beach Road North slips into the ocean.

Protecting the road in the long term comes with a hefty price tag as it requires the installation of 42,000m³ of rock armouring to protect the 2.8km stretch of coastline to remain open in the long term. We are currently undertaking small amounts of rock protection work to keep the road open, at an average cost of $50,000 per year, but this won't work long term as the coastline is creeping closer and closer to the road. This means we need to increase the amount of rock armouring, which is estimated to cost a whopping $11,930,000 over 30 years.

Expected costs for maintaining the road in its current location range a great deal as it is highly dependent on the rate of coastal erosion. Using rates for works undertaken recently at Katiki Straight by NZTA indicate it would cost $11,900,000 to properly armour the road over a 50-year period. The road would also need to be closed for a significant period during the installation of rock armouring.

The estimated total cost for this option is $12,650,000 (debt Funded).

Option B: Leave the Road Closed

The community could see this as a chance to transform the area into a recreational space, allowing people to enjoy the beautiful coastline.

There is potential to enhance the area with native plants, seating, and tracks for walking and cycling. We would be preserving Oamaru's natural beauty and ensuring the safety and well-being of its residents and wildlife.

This option is the simplest and most cost-effective - we would leave the road closed and maintain the current detour indefinitely.

This option would cost only $50k in 2025/26 for the establishment of a walking/cycling track giving direct access to the beach.

Option C: Close Beach Road North to Awamoa Road and realign the intersection.

Close a section of Beach Road North, reinstating the connection between Kakanui Beach Reserve and Awamoa Road intersection at a cost of $353,000.

Protect the 900m section of road from erosion in the same manner as Option A with rock armouring estimated at $3,847,000.

The estimated total cost of this option is $4,200,000 (Debt funded).

When complete, this option is projected to cost $30k less in annual maintenance and depreciation than it has been costing to maintain Beach Road, which will have a minor positive long-term rate impact.

We are committed to making an informed choice that balances cost, safety, and public satisfaction.

The story of Beach Road is far from over, but with careful consideration and community involvement, a solution will be found.