Repairs to underslips on roads that sustained storm damage in Whangārei could take early into the new year as they require investigation by geotech engineers.
The Whangārei District Council has around 730 roading repair jobs from the July 17-18 storm that dumped 220mm of rain in Northland in a few hours, causing widespread flooding and slips, with water entering dozens of homes and blocking regional roads.
Damage to Northland's infrastructure, excluding private properties, is estimated to cost more than $18 million.
WDC employees and contractors have been busy carrying out repair work on infrastructure as well as on walking tracks throughout the district.
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Mike Batchelor of the Northland Transportation Alliance said clean up work was still being carried out and that permanent reinstatement of some sites have started and would continue into November.
He said the work related to repairing drainage facilities, such as unblocking culverts and rebuilding roadside drainage.
Underslips at Pataua South Rd and Abbey Caves Rd would take longer to repair, he said.
"Geotechnical engineers will be investigating these sites and design and construction of the more complex ones will follow. These could take until early in the new year to have repaired," Batchelor said.
Most tracks are now open while others are still a few weeks off from being fixed.
WDC parks technical officer Stuart Jackson said unfortunately ongoing patches of heavy rain over the past month has not helped things for workers trying to repair the damage.
"We've still got a big job ahead of us. Our contractors are working flat-out and we are trying to reopen these remaining tracks as quickly as we can."
The storm caused at least $8m in damage to WDC infrastructure.
Parihaka Scenic Reserve, the AH Reed Kauri Park and the Coronation Reserve in Western Hills were among the worst hit tracks in the storm.
For people wanting hill walking, Jackson said the Dobbie Track to the Parihaka summit track was open and the Frank Holman track (the Russell Rd end of the Quarry Garden link) were also both open.
Night-time and early morning Loop users may have noticed that some of the lights that normally brighten their way are not working and WDC is working with Northpower to fix them.
He said water got into the electrical cabinets that run the lights and caused extensive damage.
Jackson said Ross Track could reopen in two weeks while the Hatea walkway from Mair Park to Whareora Rd and at Mackesy Bush were expected to be opened in October.
Reopening of the walking track from Whangārei Falls to AH Reed Memorial Kauri Park is expected in November and the Coronation Reserve (Quarry Garden and Selwyn Ave link) in December.
Jackson said the Alexander Track at AH Reed would be the last to reopen as council contractors needed to replace a bridge that got washed away during the storm.
Consents and construction work will take more than six months to complete.
Meanwhile, in the a Far North, SH1 through the Mangamuka Gorge had been cleared to at least one lane, but there was no safe way past the biggest slip, on the northern side of the gorge, where the road was unsupported out to the centreline, according to NZTA spokesman Steve Mutton.
The highway remained closed between Victoria Valley Rd and Makene Rd, with SH10 as the detour.
Mutton said repairs to the major slip, the result of torrential rain during the July storm, would be carried out in three stages, with the first stage planned to begin this week. That would involve installing concrete piles to support the road, and would take six to eight weeks to complete, depending on the weather.