The 2 cyclones in early 2023 caused significant damage to the Tairāwhiti local road network. Almost all of our rural network was closed and we completely lost 8 bridges and 54 have significant damage.
Following these events, our focus is always to reopen roads to residents who are cut-off and to get access for heavy freight to support our rural communities. Priority is given to school bus routes, safe access to connect communities and forestry and farm access routes for animal welfare.
We have funding of $29.3 million for the initial clean-up, this is 100% funded by the government. This money needs to be spent by 30 June.
Our estimate of the initial clean-up costs are around $45 million. We're still investigating the total cost of repairs to the network - it could range from $465 - $725 million.
How the initial $29 million funding will be spent
The $29.3M will be spent opening or providing temporary access for disconnected communities. This could include alternative access like temporary bridge repairs, ford crossings, using private land for road access and state highway detours.
It also includes clearing slips, removing slash from under bridges, silt clearing, roadside drainage works and tree removal.
We have 5 project work streams
S1: Repair or replacement of 61 bridges
Costs: $140-160M to repair back to normal. Or $255-$320M if we add resilience (revised cost)
All this bridge work could take up to 3-4 years.
We assessed all 424 bridges in our region and found 61 were either destroyed or had major issues.
8 bridges destroyed beyond use
This includes 6 in the Waipaoa area:
The Hollywood Bridge on Bushy Knoll Road, St Ledgers Bridge on Ruakaka Road, Hangaroa Bridge on Hangaroa Road, Burgess Bridge on Burgess Road, Grays Bridge on Bruce Road Kanakanaia, Mangatai Bridge on Te Kowhai Road.
And 2 in the Uawa area - Mata Bridge on Upper Mata Road and Pauariki Bridge on Hikuwai Road.
We're assessing options to either replace in the same location, or find an alternative route, or build back better with resilience. But in the interim we're providing temporary solutions.
Engineers, designers and bridge builders will work together to develop a plan for all the fixes.
To construct a new bridge could take up to 3-4 years.
Bushy Knoll Road will have a temporary bridge installed to allow for urgent stock movement. A Bailey Bridge is being installed by the end of June, and the long term replacement will be scoped.
10 bridges with major structural issues
These require immediate repairs otherwise we could lose them completely if we get another flood event.
The bridges are:
3 in Waipaoa area - Littleworths Bridge on Pehiri Rd, Waikereu Bridge on Riverside Rd, Waitangi Bridge on Waitangi Rd
3 in Uawa - Arakihi Bridge on Arakihi Rd, Mata Bridge on Mata Rd, Mangaheia #4 Bridge on Tauwhareparae Rd.
4 in Hikurangi area - Awatere Bridge on East Cape Rd, Makarika #2 Bridge on Makarika Rd, Mangareia Bridge on Walker Rd, Carlsons Bridge on Waikaura Rd
43 bridges have major scouring
With major scouring around the abutments, work is needed before they become bigger structural issues. There are 20 bridges in the Waipaoa area, 17 in Uawa and 6 in Hikurangi.
S2: Tiniroto Road at the Hangaroa Bluffs
Cost: $35 - $50M to repair back to normal. Or $65-$130M if we add resilience (revised cost)
We're looking at all options to fix this but a long term fix could be up to 3 years away,
The road suffered significant damage at the bluffs - 1400m of road was undermined with river protection works partly or fully destroyed. The 2 lane road has been scoured away and reduced to less than one lane in parts. It needs repairs to the retaining wall structures and rock protection works.
For access Hangaora and Tiniroto residents are having to use the Parikanapa Road bypass. This is only for 4WD vehicles and trucks. Light or 2WD vehicles have to drive to Wairoa and then on to the state highway back to Gisborne.
Road open to single lane
Tiniroto Road reopened to all vehicles between 6am - 6pm, at set times every half hour each way. The road will be closed overnight.
Contractors are still working on the road, so please plan for delays. The road has been lowered and you will feel closer to the river.
Note - the road will close when any heavy rain is forecast, as this section is prone to rock falls and the rising river level may overtop the road.
Gates will be installed at either end to stop traffic using the section when it's closed.
S3: Drop outs and retaining wall repairs
Cost: $80M-$105M. Or if we add resilience $120 - $255M
Work could take up to 2-3 years to fully complete.
We estimate there are over 200 major drop outs or sections of roads impacted by river erosion across the entire network.
These sites will have signs and road cones to make them safe until we can get engineers and geotechnical assessments completed. Initial site assessments could be completed by June 2023 .
The more complex issues may not be completed until the end of September 2023.
S4: Silt removal
Cost : $15-20M
It's estimated that there's over 650,000 cubic metres of silt to be removed from drains, slips and roads. This needs to be carted to a disposal sites once the sites are ready to take the material. In places the silt still needs to dry out before it can be removed.
S5: Slash removal
77 bridges require slash removal in the Hangaroa, Waimata, Uawa and Hikuwai catchments.
Staff are scoping the cost to remove all the slash in the catchments where bridges have been destroyed or majorly impacted. The risk is if this debris is not removed it may compromise any future bridge repair work.
Once the assessments are completed. A plan on how to remove and dispose it needs to be developed. Costs are unknown at this stage.
