Stead Street FAQs
Why are you upgrading Stead Street Pump Station?
The pump station will provide the city of Invercargill-Waihōpai, Lake Hawkins residents and the Invercargill airport with protection from inundation for the next 50 years.
The existing building and pumps are now at the end of their life and there is increased risk of failure. This pump station is critical to the 116 properties in the immediate area and is a lifeline for the airport, supporting 320,000 passengers plus freight each year.
Why didn’t you lay the pipes when ICC were doing their works on the floodwall and road?
ICC commenced its Stead Street Floodwall Upgrade project in November 2021. At that time, the detailed design for the pump station had not been completed. Laying the outlet pipes without a complete, consented design would have meant a significant risk of rework, particularly given the significant coordination with existing services required (Chorus fibre & copper, ICC rising sewer main, Powernet HV line), archaeology (Otatara Tramway) and the levels of design with the estuary and Lake Hawkins.
ICC couldn’t delay its floodwall project as the government funding was contingent on specific project milestones.
As part of this section of work for the pump station, we had to dig up a small section of the road that the Invercargill City Council recently resealed. This also couldn’t be delayed as it would have meant significant risks to motorists.
We minimised the extent of work needed on the floodwall by omitting two lower sections in the sheet pile wall.
We also sequenced the works to ensure that complete closure of Stead Street was not required.
Who is undertaking this project?
In September 2022, Fulton Hogan were awarded the contract to build the replacement Stead Street Pump Station.
Will the road be closed?
No. Stead Street has been resurfaced, and from 7 October, it is open to two lanes of traffic.
A temporary speed limit of 50kph is in place for a 300 m section of Stead Street adjacent to the pump station to help manage vehicle traffic Monday-Friday (and Saturday when works are underway on site). The normal 80kph speed limit is in place when contractors are off-site on public holidays and weekends.
Why were two lanes for traffic not available from July to early October 2023?
Fulton Hogan reviewed its traffic management plan in July when work commenced laying the outlet pipes from the centre line towards the estuary. They determined there was insufficient space to safely accommodate two lanes of traffic, a temporary pathway for cyclists and pedestrians and access for large machinery and vehicles at the site.
A decision was made to retain a single lane for traffic managed by traffic lights until early October when the road aspects of the pump station replacement were complete.
We considered all options that could have allowed two lanes of traffic. However, this was the only option that ensured the ongoing safety of drivers, pedestrians, cyclists, and the on-site team. Several instances of poor driving behaviour in this area in July played a part in this decision.
Is the shared cycle/walkway open?
How is the project being funded?
In 2020, Environment Southland secured $2.25 million of funding from central government as a contribution to assist in replacing the ageing Stead Street pump station, one of the council’s six climate resilience projects co-funded in the region.
The contract price for the pump station is $8.3 million and brings the projected total cost of construction, including design and provision of fish-friendly Archimedes screw pumps, to a total of $11 million. This is an increase in cost of $4.5 million above the projected cost of $6.5 million in the 2021/22 Annual Plan.
Council will borrow the required funds to ensure works can begin immediately, with initial plans to repay debt over a minimum of 25 years. Council is investigating options for increased third-party funding to ensure ratepayer contribution is minimised. Until the project is completed, final costs are known and all third-party funding streams have been explored, there will be no decisions made on ratepayer contribution. The duration of the project is expected to be 18 months and there will be public consultation before June 2024 to establish how debt repayment will be managed over the life of the asset.
Will Southland ratepayers have to pay for the remedial works that were required to remedy the discrepancy between the as-built height of the concrete slab that supports the Archimedes screw pumps and what it should have been?
No. Environment Southland will recover the costs of this work from both parties responsible for the errors.
What is meant by 'remedial works'?
We identified design and construction issues in mid-June 2023 following a review of the pumps’ operation and maintenance requirements. These errors resulted in the concrete slab that supports the new Archimedes screw pumps being built 440mm higher than it should have been.
Hydro-demolition was used to break out the concrete in localised areas within the pump station and reduce the height of the supports while retaining the surrounding structure and reinforcing steel. This solution means that the new pumps will operate as originally designed.
How has the remedial works impacted on the commissioning date for the new pump station?
The remedial works took longer than anticipated, primarily due to the significant amount of hydro-demolition required to prevent damage to the existing reinforcing so that the structural integrity of the building could be maintained. Contractors had to deal with larger than anticipated volumes of water infiltrating the foundation slab cutouts, which needed to be addressed so that the remaining reinforcing steel could be installed and concrete poured without risk to the integrity of these pours. Fulton Hogan has revised the commissioning date for the new facility to mid-to-late June 2024, two months later than what was signalled in September 2023, when the remedial works began.