Two government agencies and a local council disagree about how to fix the flooding in Featherston.
For several years, the corner of Daniell St and SH2 Fitzherbert St has flooded, sometimes even flooding the highway as high as the SuperValue supermarket steps.
SuperValue deli manager Georgene Valentic said the corner had flooded for the six years she had been there.
“You can hardly get through in your car, and it’s come up as high as my knees,” she said.
When the rains arrive in Featherston, the natural contours of the land sent stormwater southeast down Fox St, under the railway line, then southwest down Daniell St, then draining into two sumps on the supermarket corner and by the railway line.
The sumps carry water to two culverts belonging to Waka Kotahi NZTA, which carry water under the highway to the other side of Daniell St.
But something stops that flow and in heavy rain, water quickly pools on the corner, making it near impassable for vehicles.
Wellington Water is the water services operator for the South Wairarapa District Council [SWDC], and its district programme delivery leader Adam Mattsen said the poor condition of the two culverts might be contributing to the flooding.
“Both culverts have been inspected by CCTV. They are partially collapsed, causing water to pool in the corner,” Mattsen said.
An SWDC spokesperson said Waka Kotahi would be responsible for deciding when to replace or upgrade the culverts.
But Waka Kotahi disagreed that their culverts were causing the flooding. Wellington regional manager Mark Owen said that despite the cracks, the culverts had adequate stormwater capacity.
“We believe there is a wider catchment issue, potentially exacerbated by recent drainage work carried out on adjoining land,” he said.
Kiwirail owns the adjoining land in question, but they also deny responsibility.
A Kiwirail spokesperson said the agency had not made any earthworks or drainage improvements near that corner.
“We have noticed some flooding at this location during past weather events.
“The question of what is causing the flooding is best addressed by the local council,” they said.
Mattsen acknowledged that Waka Kotahi did not yet have enough information to fix the culverts.
“Even if they enlarge the culverts, they might just be moving the flooding down the road into somebody else’s backyard,” he said.
The council and the two government agencies did not agree on the cause of the floods and could not agree on who should fix it.
But Wellington Water’s head of modelling, Nadia Nitsche, is working towards a solution.
Nitsche’s team is developing an urban stormwater model for Featherston to map overland flows and flooding locations within the town’s catchment.
Wellington Water plans to hold drop-in centres in Featherston in April and May, where residents will come in with their flood photos, which will either validate the model or reveal new problems.
Once the model is peer-reviewed and completed, Wellington Water can provide strategic advice to Waka Kotahi, Kiwirail, and SWDC about what is causing the flooding and how to fix it.
Nitsche said the model would be useful to all agencies involved.
“Once our model is complete, Wellington Water will hub advice about what we see as the best course of action.”
I lived in Featherston 1998-2012, and this area flooded regularly then.
I would have thought that checking the flow of stormwater in this area would confirm where the blockage or restriction is located. This would mean opening up the road either side of SH2 but not impossibe. It could also be done in a way that would not restrict movement of our Fire Service.