Fix is coming for flood prone road
Whakatā ne District Council approved frunding
Drainage work costing up to $200,000 will be carried out on Manawahe Rd in the Bay of Plenty to help protect the area against flooding.
The Whakatāne District Council’s infrastructure and planning committee approved funding for the resilience work at a recent meeting.
Extremely high rainfall in 2022 and 2023 caused sustained flooding of surrounding properties and the closure of the road from May 12 until June 12 last year.
Two homes on the road became uninhabitable, and the owners received total loss insurance settlements. More than 6ha of land between 1757 and 1849 Manawahe Rd was affected for several months as the flooded area is a ponding basin with no natural drainage outlet.
The committee adopted the cheapest of several options provided by consultants to relieve future flooding of the road. This option involves installing a culvert across the road connected to a manhole into which suction hoses can be fed, combined with legal agreements with affected landowners to discharge pumped water on to their land when required.
Other options had costs of between $1 million and $2m.
A report to the committee described the rainfall levels as having an annual exceedance probability of 2.2 per cent – or a recurrence likelihood of once every 46 years.
In another report, the committee heard repairs to damaged roads caused by storms across the Whakatāne district in 2022 and 2023 had cost more than $1.4m.
New Zealand Transport Agency Waka Kotahi would cover a large part of that cost, leaving just over $450,000 needing to be retrospectively approved from the council’s roading storm reserves.
Work on the culvert replacement and under slip on Braemar Rd and one of two under slips on Stanley Rd continues, while work has finished on other under slips across the district, including the second section of Stanley Rd, another on Galatea Rd and two on Herepuru Rd.
Transport manager Annelise Reynolds said while the repair work would leave a small deficit in the roading storm reserves as it was close to the end of the financial year, it was due to be replenished. It showed the amount allocated to the reserve fund was “about the right amount”.
Rangitaiki ward councillor Gavin Dennis asked whether anything could have been done to prevent the culvert damage on Braemar Rd in May last year if the council had responded more quickly to residents’ reports that it was blocked.
“I was approached by a number of people concerned that they had warned us a month beforehand that the culvert was blocking up and that they notified council a couple of times. In their words, they were ‘ignored and as a result of that there was a massive blow-out’.”
Reynolds said that in May last year, the council had to attend to several events due to the high rainfall, including under slips on Herepuru Rd, and staff responded to calls as quickly as possible.
“When resources are stretched that’s not always as quickly as some people may like. At the time that the underslip occurred, we had been on site for about three days trying to unblock that culvert. It appears that culvert had some damage inside it, so water tried to get around it and that is what caused the slip.”
I was approached by a number of
people concerned that
they had warned us a
month beforehand that the culvert was blocking up and
that they notified council a couple of
times.
Gavin Dennis