Flooding in Wairoa after the river burst its banks due to heavy rain from Cyclone Gabrielle. Photo: Wairoa District Council's Emergency Controller
Analysis - Wairoa is years behind on some high-priority water supply projects, but the jobs it did put first paid off when Cyclone Gabrielle hit.
The Hawke's Bay town's 8000 residents had to rely on water from reservoirs for five days after February's flooding submerged and silted up the intake on Waiau River and a major pump.
But while the district council has not got its main supply pipe replaced on time, it had been fixing up a lot of leaks and renewing water connections pre-cyclone - with the result that the water in the reservoir lasted longer than it otherwise would have.
"Our focus has been on based on the greatest area of need, which was to improve water resilience and safety," the council told RNZ.
Like many other small, cash-strapped councils, Wairoa District has been having to make tough 'Three Waters' choices for years that then went under the blowtorch of Gabrielle.
No one emerged unscathed from that, but Wairoa has at least been able to report:
"Even though we were not able to make water in the early stages of Cyclone Gabrielle, we were still able to supply water to residents in a limited capacity."
Like many others, the town's legacy has not helped: Reports show a third of its reticulation pipes are in poor or very poor condition, as are 37 percent of its wastewater pipes, and half its stormwater pipes.
Its main supply pipe was meant to be replaced in 2019 but would not be until 2024-25, the council said.
"The main line replacement is behind schedule."
A 54-page water safety report, prepared late last year as part of new government-ordered requirements following the Havelock North water poisonings, shows a "high risk" rating of the main pipe deteriorating and causing a reticulation failure.
The water management plan for this decade added to that with: "Limited amount of reticulation renewals has been completed in the last 10 years.
"This means there is a 'backlog' of pipes needing replacement."
A bridge in Wairoa where the river burst its banks, inundating houses in the cut-off northern Hawke's Bay town. Photo: Hawke's Bay Civil Defence Emergency Management Group
A couple of stretches of main pipeline at Achilles Street, and Mitchell Road, have been replaced.
Another high priority - securing an alternative water supply, so not all eggs are in the Waiau River basket - is not in the council's work programme until 2028-29. But, at least it has made the choice of adopting a "mobile" supply.
However, the council is insisting its system was resilient when Gabrielle came hammering.
Its "greatly improved" monitoring via smart meters at all Wairoa, Frasertown and Tuai properties had provided "more resilience".
"We have a really good understanding of our water supply network and have been managing it accordingly."
That butts heads a bit with a 2022 analysis which found about 45 gaps where key information was partial, not up to date, or not available at all.
That included inadequate info on catchment hazards and how to respond to an emergency; "It is recommended to include more events in detail (plant failure due to power outage or flood)".
Another gap was the need for an updated risk assessment table.
Such a table would have big consequences for the costs and timeframes for drinking water improvement plans, the gaps analysis showed.
After the February weather events, navigating all that has become horribly harder.
The council told RNZ: "A challenge in the aftermath of Cyclone Gabrielle will be around the limitations of contractors to do this work, particularly as our neighbouring regions will also have increased demands because of the cyclone."