A newly installed $330,000 seawall underpass in Ahuriri has failed after the cycle path flooded amid the recent large swells. Photo / Warren Buckland
Hawke's Bay Regional Council is considering installing additional walls beside a new $330,000 seawall cycle underpass in Ahuriri because it floods in mysterious ways.
Opened in April, the 47-metre long seawall was built after cyclists and pedestrians were crossing the Hawke's Bay Expressway during high tides due to dangerous conditionson the underpass.
Hawke's Bay Regional Council is considering building additional walls on the inside of the path after "seeping" was spotted in the area at high tide.
Council group manager asset management Chris Dolley said until a permanent fix is found for the issue, contractors will pump out any water during high tides.
Offshore swells in the region reached 4-5m metres last week and cyclists reported on social media significant ponding on the cycle lane.
"The engineers have come up with a range of solutions that are currently being assessed," Dolley said. "The issue is more complex than simply filling a hole, as the water doesn't appear to be coming through the wall."
One option is building additional walls on the inside of the path and additional water proofing, he said.
"We're aware that this is an inconvenience for users of the underpass, and are working as fast as we can to fix it," Dolley added.
The total cost of the project was $330,000 – made up of $125,000 of NZ Community Trust funding, $125,000 from HBRC and $80,000 from Waka Kotahi NZ Transport Agency.
Dolley apologised for any inconvenience caused to users of the underpass.
Other cycle paths under the Hawke's Bay Expressway - on the opposite side of the estuary - were also flooded by the swells.
A council spokeswoman said warning signs were in place near the entrances to the underpass to warn users of potential flooding when tides are high.
Council said flooding of the Ahuriri Lagoon cycle trail used to occur at the four underpasses due to the low lying nature of the trail as it passes under the expressway and the old Embankment Bridge.
Before the installation of the seawall, the trail at these locations was inundated for 30 per cent of all high tides as a result.
As the water receded, the trail was often left covered in debris and silt while the surface became slippery in places, making it unrideable and unsafe for most users.
As a result, some cyclists and walkers chose to cross the Hawke's Bay Expressway, while others opted for longer detours that used formal road crossings.
Crossing of the expressway was not considered a safe long-term option and work to address the issue began in 2017, with improvements made at three of the four underpasses.
To address the southern expressway underpass, the 47-metre-long seawall was built next to the cycle path and was officially opened by Tourism Minister and Napier MP Stuart Nash in April.
A formal blessing of the new works was done by Te Taiwhenua o Te Whanganui ā Orotu chairman Hori Reti.
The Ahuriri Lagoon cycle trail forms part of the Hawke's Bay Trails Water Ride - one of the 22 Great Rides of Ngā Haerenga, The New Zealand Cycle Trail.
Construction of the seawall was carried out by McNatty Construction Ltd and overseen by NZTA.