Our infrastructure

Tūāhaka

Our draft Infrastructure Strategy sets out how we intend to manage Ōtepoti Dunedin’s significant three waters and transport infrastructure issues over the next 30 years.

The strategy clearly defines the planned three waters (water supply, stormwater, and wastewater) and transport activities, with each area having distinct management and budget provisions in the 9 year plan.

Transport and three waters are both part of the Infrastructure Strategy for a few reasons. It is a requirement under the Local Government Act 2002, so it’s something we must do. The two areas face similar challenges. Their assets share many of the same physical spaces, and coordinated planning between the two areas prevents inefficiencies, e.g., avoids renewing a road’s surface and soon afterward digging it up to work on three waters pipes.

Past investment by the DCC has prioritised responding to the highest need and highest risk areas, as they were understood at the time. Further funding is now needed to keep up with a range of regulatory changes introduced over recent years, including allowing for future growth projections.

Infrastructure upgrades are required across the city to improve performance or address assets near the end of their useful life.

The strategy describes how we will meet the changing regulatory requirements regarding public safety and health, addressing climate change and improving the resilience of our key infrastructure.

We aim to maintain affordability for ratepayers as far as possible, while balancing the need to meet the demands of projected urban growth, public safety, resilience needs and catching up on maintenance/ renewals put off in the past.

Three Waters infrastructure

Our 9 year plan capital budget for Three Waters infrstructure is $1.015 billion.

Ōtepoti Dunedin is one of the oldest cities in Aotearoa New Zealand and has water supply, stormwater and wastewater plant and pipe networks of widely ranging age and condition.

This reflects periods of growth and expansion in the city and the timing, priority and level of funding put into asset renewal work. Significant funding is needed each year to maintain assets and manage risks to service levels, public health and the environment if infrastructure assets fail.

Like many other councils, Three Waters has a backlog of renewals work, and this is currently estimated at $1,003 million. We have opted to develop a renewals budget across the 30 year infrastructure strategy to progressively complete these renewals, so that there will be no backlog by 2055. We have planned to address the backlog over this time frame because we need a programme of works that is affordable to ratepayers.

The strategy adopted by Council to address the renewals backlog seeks to balance asset risk in a pragmatic and affordable way. The planned 30 years phased approach means that there will be a modest reduction in the total backlog (approximately 4%), over the life of this 9 year plan. However, our focus in the first nine years will be to prioritise renewals at highest risk such as at our treatment plants. Beyond this period, a reprioritisation in capital expenditure will be required to address the remaining backlog by the end of the 30-year horizon of the Infrastructure Strategy.

Whilst the risk that critical assets may fail during this period may be high, we believe that this risk is mitigated as we have significantly increased our provision for repairs and maintenance over the term of this LTP. We will also increase focus on the monitoring of critical assets and respond proactively to changes in condition and performance to ensure continued service delivery. This allows

our focus to remain on planning for the renewal of critical assets before a deterioration in their condition materially impacts on service levels and the environment. Forward planning will also ensure that the capital needed to fund the work (both debt and rates), and the contractors required to do the work, are in place.

Around 22% of our assets have passed or are rapidly approaching their end of life based on age. To manage our risks, we are continually improving our knowledge about the condition of our assets. Some assets are in better condition than expected, given their age, and they still work well, but others need replacing sooner.

Renewals are prioritised, based on their condition and performance, and not just their age – fixing those assets that need it most. The 30-year infrastructure strategy sets out the funding to meet fixing those assets that need it most, and to address historically deferred renewals (the backlog), to ensure that levels of service are maintained in the future.

Prioritising our renewals in this way means that we will reduce the risk of having reactive responses to asset failures that would impact our levels of service.

Key drivers and challenges ensuring the community receives fit for purpose services that meet its needs include:

• looking after our people and places, through projects supporting public health and environmental outcomes
• looking after what we have, by replacing and renewing our ageing infrastructure
• meeting our changing needs, through projects that address changes in population, regulation and standards, and customer expectations
• providing for infrastructure resilience, to ensure our assets can withstand and respond to extreme events and adapt to changes in the environment
• delivering on our city and DCC emissions reductions targets by reducing our own emissions and supporting urban intensification to reduce city emissions
• living within our means, making financially prudent choices that are affordable for our community.

The first five years of work focuses on areas of highest risk and the activities most in need of investment. New capital investment across the nine years of the plan and beyond aims to improve water supply resilience, water use efficiency, and to upgrade wastewater and stormwater networks.

Core Three Waters infrastructure projects in our draft 30 year strategy

Looking after what we have

Network renewals | $573 million for the period 2025/26-2034/35

Renewals spending significantly increases from previous 10 year plans. Renewals work is being targeted in high risk areas and where possible, working with other DCC projects to enable efficiencies.

Wastewater projects

Rural wastewater schemes | northern wastewater treatment plants (Waikouaiti, Seacliff, Warrington) | $102 million for the period 2025/26-2038/39

Construction of a new centralised wastewater treatment plant (WWTP) to manage flows from the Waikouaiti, Seacliff, and Warrington communities is planned. Consolidating the three rural WWTPs into one centralised facility will support capital efficiency by reducing maintenance costs, enhance plant efficiency, and streamline operational processes

Wastewater | Musselburgh to Tahuna link | $49 million for the period 2026/27-2031/32

The Musselburgh wastewater pump station and rising mains transports wastewater from approximately 65% of Dunedin city’s wastewater network directly to the Tahuna WWTP. Construction of a tunnelled gravity pipeline and a final lift station at the Tahuna WWTP is proposed. This replaces ageing and vulnerable infrastructure and improves network resilience in severe weather events, earthquakes and power outages.

Wastewater network resilience and efficiency | decommission Mosgiel WWTP and pump to upgraded Green Island WWTP |

$43 million for the period 2027/28-2031/32

Mosgiel WWTP is an ageing plant needing significant upgrades to continue working well and address health and safety concerns. Wastewater from the WWTP is currently pumped to Green Island WWTP for final treatment and disposal. Pumping wastewater directly to Green Island WWTP from Mosgiel would reduce ongoing maintenance and operating costs and increase operational and capital efficiency. The Green Island WWTP will require upgrades to take the increased treatment volume.

Carbon reduction | Bioresources facility | $62 million for the period 2025/26-2041/42

We’ll start the initial phase of establishing a bioresources facility. This will repurpose biosolids, a byproduct of wastewater treatment, into beneficial resource, reducing waste to landfill, carbon

emissions and minimising environmental impacts. Transforming waste into usable products, such as compost or energy, aligns with sustainability goals, enhances resource recovery, and supports circular economy principles. It also addresses regulatory requirements and public expectations for responsible waste management, while reducing long-term operational costs and ensuring compliance with environmental standards.

Water supply projects

Water supply resilience | Waikouaiti, Outram and Dunedin city |$39 million for the period 2029/30-2042/43

We plan to investigate and develop new or alternative groundwater supplies to the Waikouaiti, Outram and Dunedin city areas. Long term modelling shows future shortfalls in water supply capacity are possible in the river intakes which provide the bulk of the water supply to Dunedin city and Mosgiel. Changes to legislation or resource consent requirements are expected to result in changes to water take limits during low flow conditions in rivers and streams. Expanding sources of water supply by using new groundwater supply will provide better resilience to any future changes in consent conditions, drought and other climate related water supply issues.

Mosgiel water supply improvements | $15 million for the period 2025/26-2033/34

Mosgiel is growing, and demand for water is high. The pumped water connection from Mt Grand water treatment plant (WTP) has recently been upgraded to handle the demand in the short to medium term. An alternative gravity-supply route from the southern WTP is proposed to feed Mosgiel. This will reduce our reliance on pumping treated water to Mosgiel, improving efficiency, reducing our carbon footprint and improving resilience.

Port Chalmers water supply upgrade | $14 million for the period 2025/26-2027/28

A project to upgrade the water main connecting Dunedin city and Port Chalmers is already underway. The upgraded connection will allow the DCC to decommission the Port Chalmers WTP and associated raw water storage dams, an expensive supply which operates seasonally only to support periods of high demand.

Stormwater projects

Stormwater | South Dunedin flood alleviation | $44 million for the period 2025/26-2033/34

South Dunedin is highly vulnerable to climate change impacts such as rising sea levels, increased rainfall, and rising groundwater. Three short term projects costing $29.2 million are proposed to mitigate flood risk while a variety of adaptation strategies are being explored in the South Dunedin Future (SDF) programme for the medium to long term, including upgrades to three waters infrastructure and potential modifications to stormwater systems. The final shape of the medium to long term projects will be informed by the SDF adaptation plan, due in 2026.

Mosgiel stormwater upgrades | $9 million for the period 2025/26- 2030/31

Comprehensive modelling has been completed to identify the most effective ways to reduce flood risk, optimised for cost and performance. Funding of $2.5 million is provided in the first two years for increasing pipeline capacity and further projects are proposed in later years.

Transport infrastructure

Our 9 year plan capital budget is for transport infrastructure $433.1 million.

The DCC Transport Plan sets out our programme of work to maintain, operate and renew the roading network in Ōtepoti Dunedin. The work includes roading, footpath, cycle path and bridge maintenance. We aim to ensure

the city has a safe, resilient and sustainable transport system.

We know from your feedback over the years that residents want transport options that connect people easily, safely and affordably, getting them where they want to go, whether it’s by foot, bike, car or public transport.

We work closely with NZ Transport Agency Waka Kotahi (NZTA), which co-funds many DCC transport projects. NZTA is also responsible for the state highways running through our city. Many local roads, footpaths, cycle ways and other transport infrastructure adjoin those highways, so a close working relationship around their future design and funding is essential.

The DCC Transport Plan has close alignment to zero carbon targets, supporting low emissions forms of transport such as walking and cycling networks, enabling public transport, and shifting to low emission forms of motorised transport.

Core transport infrastructure projects in our draft 30 year strategy

Renewing transport assets | $380 million for the period 2025/26-2034/35

The DCC intends to increase renewals investment over the first two years of the 9 year plan, retaining that momentum for the remainder of the plan and beyond. Without this $382 million investment, the condition of the network would continue to deteriorate, and future work would need more expensive interventions. The renewals work will take place across the transport network, city-wide.

The renewals investment is based on asset lifespan and condition rating. Prioritising projects within our renewals programme to repair or replace transport assets is done based on asset condition and age.

Examples of renewals include:

• footpaths
• kerbs and channelling
• road resurfacing and rehabilitation
• seawalls and railings
• traffic signals, signs and street lights

Future Development Strategy | $20 million for the period 2025/26-2032/33

We’ll address network gaps between the current network and areas of development, including roundabouts, safe crossing points, footpath extensions and managing speed by making kerb build outs. These areas have been identified as needing additional infrastructure because of growth which has been identified through the Future Development Strategy process.

Low cost, low risk improvements | $9 million for the period 2025/26-2033/34

We plan to design and construct safer areas around Dunedin's schools, improving dangerous intersections and enhancing road safety for all users.

Princes Street bus priority and corridor safety plan | $7 million for the period 2025/26-2028/29

Princes Street work aims to improve road safety, especially for pedestrians and at intersections, improve bus reliability and efficiency. It will also improve safety and access for people who walk, cycle or have disabilities.

Mosgiel park and ride | $5 million for the period 2025/26

This project will provide a convenient space for Mosgiel and Taieri residents to park their car/ scooter/bike or walk to catch a bus service between Mosgiel and Ōtepoti Dunedin.

Harbour arterial efficiency improvements | $4 million for the period 2025/26-2026/27

These improvements aim to provide a safe and efficient route connecting State Highway 1 with State Highway 88. They also provide an alternative route for SH1 traffic, especially heavy vehicles, allowing them to avoid passing through the central city, by the existing Dunedin Hospital and either side of the chosen site for the new Dunedin Hospital. Stage 1 is complete, modifying Wharf Street and surrounding intersections. Stage 2 work on Thomas Burns (from Fryatt Street to the pedestrian crossing signals north of Bombay Street) and Stage 3 work on Strathallan Street and the Strathallan Street/Portsmouth Drive intersection, are next.

Te Awa Ōtākou – Peninsula Connection

Te Awa Ōtākou (the Peninsula Connection) is part of Te Aka Ōtākou (The Otago Vine), a set of road safety improvements that incorporate a shared path winding along both sides of the harbour.

While we are only responsible for the Peninsula side, it connects with Te Ara Moana (The Ocean Path), which runs alongside State Highway 88. These projects make key harbour roads safer, more resilient and more accessible while encouraging cycling and walking.

Completing the 3 sections would improve safety and align with the values of Te Taki Haruru, and honours the commitment made to mana whenua.

We have looked into costs and options for completing them and estimate the cost is $18.5 million, with co-funding from NZTA unlikely. This option shifts the route to the inland side near Portobello School.

• $8 million Ellison Rd to Ōtākou Fisheries Wharf section – in 2026/27
• $6.9 million Tidewater Dr to Ellison Rd section – in 2027/28
• $3.6 million Portobello to Weir Rd (inland route) – in 2028/29

Costs for maintenance, interest and depreciation will be added to the annual operating budget as each section is completed.

You can find more information about this project at dunedin.govt.nz/peninsula.

Roadside verges

As with many aspects of our work, costs for mowing roadside verges have increased significantly. We had decided to reduce the frequency of mowing to keep costs down but propose that the funding for this service be reinstated in this 9 year plan to allow us to bring the frequency of mowing back to previous levels, starting in the new financial year. Our budget for roading vegetation control for 2025/26 is $2.8 million.