Major flooding hit Waihī Beach on May 29, forcing residents to evacuate and the town’s dam to overflow. In the second of a two-part series, Local Democracy Reporter Alisha Evans looks at whether the flash flood could have been avoided.
“The most violent of weather” pummelled the coastal community of Waihī Beach on May 29, causing flash flooding and the town’s dam to overflow.
Water rushed through the northern end of the Western Bay of Plenty town, filling up creeks and flowing over roads.
Heather Cumming was one of 27 people forced to evacuate her home that day alongside 11 elderly residents from the nearby pensioner housing and two families from the holiday park.
”It was that most violent of weather. You’ve got your rain, your lightning and your thunder. And I thought, wow, this is it,” Cumming said, her voice shaking as she recalled the event.
Sue Hope said the May 29 flood was “history repeating itself” after a similar event in 2012.
The Western Bay of Plenty District Council recorded 67mm of rain between 1pm and 2.30pm and a total of 91.4mm on May 29.
The town’s dam overflowed into the emergency spillway for 40 minutes from 1.26pm.
The council admitted the stormwater network did not have the capacity to deal with the amount of rain that fell that day. A 2017 Tonkin & Taylor report, titled Waihī Beach Stormwater Model and commissioned by the council, showed several pipes in the network were “under capacity” for a two-, five- and 10-year average recurrence interval (ARI).
ARI is the average period between floods of a certain size.
It also said some pipes were full from being surcharged by backwater from the sea or stormwater ponding.
Flooding caused by backwater surcharged pipes could not be mitigated without making significant changes to the rest of the connected stormwater network, the report said.
Cumming’s home on Marine Ave was one of those in the low-lying area more prone to flooding. She was “stunned” when told by Fire and Emergency that she needed to evacuate.
She got some neighbours to take her elderly dog, Sparky, and tried to “pick up a few things up off the floor”.
The 61-year-old waded through chest-high water, contaminated with sewage, that reached 1.2m. It flooded the raised sleepout, turned into an Airbnb, at the back of her property and came into the main house.
”I walked out and I was soaking wet, absolutely freezing, so I got the dog and drove to Mum’s in Pyes Pā.”
The days that followed were a blur of friends and family pitching in and helping to replace floorboards, remove sodden underfloor insulation, cut out wet gib board and clean the silt and debris that permeated every crevice of Cumming’s home.
”For the first couple of days, I couldn’t actually speak. It’s very confronting when everything you own is on the front lawn because it’s not worth anything.”
Cumming was uninsured for flooding because her home was affected by the 2012 floods when about 1cm of water came into the rear of the main house. She said her husband was looking forward to cutting back at work but now they couldn’t do that because of the repair bill. They may now look at raising their home, as recommended by the council for properties in low-lying areas.
The council will waive the consent processing fees for at-risk properties.
Cumming echoed a lot of the community’s sentiment in saying: “Thank goodness it happened in the daytime and not night, because the old people’s [flats], someone might’ve died over there.”
Waihī Beach Community Board chair Ross Goudie agreed: “They’d have been asleep and the water would’ve been up around their beds … up to the window tops and in the dark no one knows what’s going on.”
Cumming said: “It’s really sad because I don’t think it [the flooding] really needed to happen.”
Hope, a Waihī Beach resident for 36 years, formed the Storm Water Action Team (SWAT) in 2013 because of the 2012 flood. In her view, “a lot of this could have been avoided”.
She and others worked with the council for two years on stormwater projects that were included in the council’s 2015-25 Long-Term Plan (LTP).
These included upgrades to the dam, One Mile Creek that runs through the holiday park, as well as the Darley Drain outlet.
”Unfortunately a lot of those things didn’t get done and they got deferred.”
The Waihī Beach community has also paid $15.8 million in a targeted stormwater rate since it was established in 2000 but Goudie said, in his opinion, this had not been invested back into the town.
The 3186 rateable properties in the Waihī Beach area pay the yearly rate.
Goudie said: “I have no problem demanding that stormwater projects happen in Waihī Beach because, in the last 10 years, we’ve paid approximately $11m or $12m into the stormwater [fund].”
Goudie said, in his view, about $1m of that had been spent in Waihī Beach.
Asked how much had been spent in the town, council Waihī Beach stormwater project leader James Abraham said the money went into a district-wide stormwater fund.
”The money isn’t split as such, so it’s challenging to account for how much of that money has been spent on Waihī Beach stormwater.”
Asked if some of the low-lying areas were indefensible against flooding, Abraham replied: “It’s definitely a conversation that needs to be had.
”Looking at climate change, large events like this are only going to become more intense and more, more frequent.”
He said the main outlet of the stormwater catchment for Marine Ave, Walnut Ave and Jenkinson St was Darley Drain.
Improving this catchment was a “high priority” because of the low-lying area and number of homes affected.
”The biggest improvement that can be made to the Darley Drain catchment is diverting water away from it.”
The water could be diverted to Two Mile Creek, which required the embankment to be protected from erosion.
This project was put into the 2015-25 LTP but had been delayed because of the “lengthy process” of getting landowners’ permission and resource consent from the Bay of Plenty Regional Council, Abraham said.
It began in June 2023 but a stop-work notice was issued in early July.
Abraham said the regional council asked the district council for further information after a property owner felt the work may have an adverse effect on them. The project would not resume until November because the council had to wait until a fish migration period was over.
Presented with the view that the floods could have been avoided, Abraham said there were several locations that were below sea level.
”There are definitely areas where the tidal influence is a lot higher than the rainfall influence.
”Regardless of the amount of infrastructure that we would build in there to combat stormwater, it’s not going to solve the issue of some of those properties being flooded.”
He confirmed that the council did not compensate for the damage that had occurred from flooding.
In response to the floods, a community liaison group has been formed with Waihī Beach community board members, the mayor and three councillors, hapū representatives and members of SWAT.
They held their first meeting in July to discuss the $19m in stormwater upgrades planned over the next few years.
The draft project list will go to the council’s projects and monitoring committee for approval on Tuesday.
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