Essential Infrastructure Repairs

In March 2022, a request was submitted to central government to fund emergency repairs to the infrastructure damaged in both the July and February flood events in Buller. This is separate from the Kawatiri Business Case which is seeking co-investment in long-term flood resilience measures for Westport.
Government agreed to fund $17.1 million for emergency infrastructure repairs (100% central government funding). This includes $10.6 million granted to Buller District Council (BDC) for infrastructure repairs that were outside policy for Government funding.
In addition to this, BDC was also granted additional funding for the emergency repairs to the Westport and Carters Beach water supply damaged in the February event which has a total budget of $1.6m.

The essential infrastructure projects are:
• Wharf damage
• Shipping channel dredging
• Tiphead – complete
• Reefton stop bank
• Reefton landfill
• Three waters
• Betterment.

Wharf Damage

 

 

 

 

 

 

 

 

Wharf update 

Repairs to the Holcim and Kawatiri wharves in Westport is one of the largest projects under this programme. Design work is complete and is currently being peer-reviewed.

The project has a $5.9 million budget and once design is finalised, it will go out for procurement. The repair work is expected to take about a year.

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Meanwhile, the demolition of the old KiwiRail buildings adjacent to the port is complete.

KiwiRail started work removing the two buildings from its land north of the port at Westport in February/March.

The buildings were deemed to be unsafe. 

Up until late last year the building was leased from KiwiRail by the Railway Preservation Society and the Buller Cricket Association. New homes have been found for the machinery and artefacts previously housed there. The building was originally a storage facility for freight coming onto and leaving the rail network.

This work permits Buller District Council better access to the Kawatiri Wharf for essential repairs. 

 

 

 

 

 

 

 

 

 

Background

Buller District Council is responsible for more than 1.5km of wharf assets. This project focuses on an area of around 300 metres of flood-damaged wharf (at the upstream area of the river wharves). This portion of the overall wharf area is considered critical to current and future Port operations.

Repairs to the Holcim and Kawatiri wharves will enable fishing and bulk shipping vessels to continue to use the port. Among other issues, holes have opened up in the decking of the Ex-Holcim Wharf due to underlying flood induced failure and significant deflection has occurred in wharf piles.  Holes and slumping are visible.

A project manager has been appointed to oversee repairs to the Holcim and Kawatiri wharves.

A crucial part of the wharf repair project is understanding ground conditions so that the repair design is appropriate. In September 2022, a specialised drilling rig drilled three 20-metre-deep holes along the length of the damaged wharf and tested ground conditions at regular (1m) intervals.

Shipping Channel Dredging

Project approx 30% complete

Dredging of the shipping channel is an ongoing project. The goal is to remove 240,000 cubic metres of debris, silt and gravel in total for this programme.

As at July 2023, the project is about one third complete with around $1.7 million of its $4.6 million budget used. More than 73,000 cubic metres of debris and silt have so far been removed by the dredge for the purposes of keeping the shipping channel clear.

 

 

Background

The floods caused a build-up of debris and gravel/silt in the navigable part of the river and port. Approximately 240,000 m3 of debris, gravel and silt that needs to be removed to return the river to a state that it can be serviceable to the bulk carriers expected to be using the port in the future.

Expert advice we’ve received indicates that dredging as part of flood resilience isn’t seen as cost effective. This is because the river in flood moves enormous amounts of silt and gravel to create space for itself. The objective of the current work is to keep the Buller River’s shipping channel clear.

Note, the dredge is working regularly in the river from its berth out to the dump site past the tipheads at the entrance to the river.  The dredge is restricted in its ability to manoeuvre when dredging.  Boaties are asked to call on VHF radio channel 14 to seek permission and instruction for safe passing.  All recreational and commercial boat users to keep well clear of the dredge to ensure that all river users are kept safe.

Tiphead

 

Project 100% complete

Flood repairs to Eastern Tiphead wall are complete.

From mid January to late March this year, more than 6,000 cubic metres of rock was placed. The budget for this project was $1 million. Trees and shrubs that were removed to allow access to the site were replanted in May, along with over 2,000 new native plants.

Background

The tiphead at the mouth of the Buller River sustained damage during both the July 2021 and February 2022 weather events.

The tiphead is a Buller District Council port asset at the mouth of the Buller River.

Rosco Ltd carried out the work since to reinforce the tiphead wall and the road on it, with more than 6,000 cubic metres of rock put in place. The project, which started in January was completed in March. It came in on time and within budget.

 

 

 

 

 

 

 

 

 

 

 

 

Fun fact about the tiphead

You may notice a large wooden beam in place on the side of the cycle path near the recent works. This is an historic artefact believed to be one of the timber piles used in building the original tipheads in the late 1800s. The piles supported a temporary railway used to drop granite from the Cape Foulwind quarry into the sea to build the tipheads. They were left behind afterwards.

 

[Credit westcoast.recollect.co.nz]

https://westcoast.recollect.co.nz/nodes/view/20468?keywords=westport%20tiphead&highlights=eyIwIjoidGlwLWhlYWRzIiwiMSI6Indlc3Rwb3J0IiwiMiI6InRpcGhlYWQiLCI1IjoidGlwcGVkIn0=&lsk=1d5b61b0a47f325a3106d53d8bba3278

 

Reefton Stopbank

 

Reefton stopbank – project 100% complete

River training work has been carried out to reinstate the flood stopbank that protects the Reefton campsite and reserve from flooding from the Inangahua River. 

Council has been monitoring the river and carried out additional river training in June 2023. 

The Reefton Campground is a community asset. The stop bank protects the reserve and Reefton town. A budget of $150,000 was allocated for this work.

 

Reefton Landfill

Repair work on the river rock wall protecting the historic Reefton landfill started in late May 2023 and is due to be complete.

Part of the closed Reefton Landfill was scoured away by the Inangahua River during the severe February 2022 weather event, causing waste to be swept away.

The repair has seen more than 10,000 tonnes of locally-sourced rock placed into the protection works. The work that looks to shore up the wall to withstand a 1 in a 50-year flood.

NEMA is contributing just over $1 million towards the project to reinstate the flood-damaged sections of the wall, with Council contributing an extra $250,000 to strengthen the remaining sections.

 

 

 

 

 

 

 

 

3 Waters flood recovery work programme

[Aeration diffusers that deliver oxygen to the aerobic digestion phase of the wastewater treatment process have been replaced.]

The $2.5 million Flood Recovery 3 Waters work programme is nearing completion.

The efficiency of the storm and wastewater networks was severely compromised following the July 2021 and February 2022 floods.

What’s been done?

Much of the programme of repairs funded by NEMA is complete including CCTV and pipe cleaning, grit clean out at the Westport wastewater treatment plant and the replacement of aeration diffusers, open drain clearing works, repairs to Reefton’s drinking water reservoir access track and the repair of a large tomo to the Domett street stormwater main. Repair to a flood-damaged section of the Waimangaroa water main from the February event was funded by NEMA as part of the upgrade project.

Replacement of and commissioning of the final electrical components of Westport’s Wastewater pump stations damaged by the flood events is now fully complete. This work included replacing damaged pump variable speed drives, various flowmeter devices as well as general electrical componentry.

What is ongoing?

 The repair of the historic Brick Arch section of the stormwater network running under Brougham/Palmerston Streets. Thus far this work has centred on working with stakeholders. The civil and structural design has now also been completed for this final repair.

Note, this programme of work is separate to the government’s reforms, despite being similarly named.

 

 

Betterment

 ‘Betterment’ projects largely relate to Westport stormwater and wastewater improvements. They are works that were identified as benefiting from being carried out during the overall repair programme.

Projects include:

 

  • Lifting flood damaged Wastewater Pump Station electrical cabinets above 1 in 100 year flood height. Council has recently selected a contractor to carry this out.  
  • Providing backflow prevention to 5 stormwater outfall locations. Four Wastop valves have been installed and one more are planned to be installed in September.
  • Design for the Coates Steet stormwater upgrade is underway.
  • A new sump was installed at the Westport Domain in March 23.
  • The Roebuck Street SW manhole was completed in March 23.
  • The Mill Street SW manhole was completed in June 23.

Westport Water Repairs

During the February 2022 severe weather events, significant damage was sustained to the Westport Water Supply, placing the town at high risk of running out of water.

Emergency works commenced during the response phase and continued with $1.685 million in Emergency Works funding from Central Government.

Primary Intake (Giles Creek) and Catchment works included:

• Stabilising and repairing the access road to the intake including slips, culverts and crossings.
• Initial intake repairs and maintenance including weir, gates, screens and associated infrastructure.
• Carrying out ongoing intake repairs and maintenance following heavy rainfall events.
• Ensuring ongoing raw water supply including temporary pumping and piping from usable sources.
Tunnel pipeline
Repairs were required due to a slip at the Tunnel Pipeline between the third and fourth water tunnels (T3-T4), leaving the 600mm diameter pipe unsupported over a 50-metre span.
• Temporary repairs and interim pipe support to enable water flow and serviceability.
• New, engineered pipe suspension bridge to permanently restore asset integrity and water flow.

The Primary Intake & Catchment work was undertaken by WestReef Services Ltd.

The Tunnel Pipeline T3-T4 was led by Hadlee & Brunton Ltd, with Abseil Access Ltd constructing the pipe suspension bridge.

Buller District Council Programme Sponsor Westport Water Mike Duff says the quick response from all contractors under civil defence emergency works and extremely challenging weather and site conditions was outstanding. The work was completed in August, on time and under budget, at no cost to ratepayers.

The Tunnel Pipeline following the installation of a new, engineered pipe suspension bridge to support the pipeline.