Flood problems on Taieri flood plain

The Taieri is a flood plain, with much of it barely above sea level, separated from the Pacific Ocean by a range of hills bisected by the lower Taieri Gorge.

Because it has been enriched by flood sediment for a long time it is fertile and therefore has been good for farming, when it isn’t waterlogged.

Because it is flat it has been popular for housing. Some of the biggest growth in the Dunedin area has been in Mosgiel and on other parts of the Taieri. It seems to have been easier to get consent to convert arable flat land into subdivisions than much more marginal land that is well above flood risk.

ODT: Flooded residents lash out

Taieri residents sick of their homes and properties being flooded are fed up with being ignored by local politicians.

Dunedin Mayor Dave Cull and other local government representatives at a flood recovery meeting in Coronation Hall last night acknowledged more could be done to protect residents in some areas and promised to try to address the list of issues raised.

However, solutions could come at a significant cost to the Dunedin City Council, Otago Regional Council and the city’s residents.

Earlier, residents of the flood-hit area pointed the finger at both the DCC and ORC for failing to properly invest in enough infrastructure despite repeated calls for more work to be done.

They said the DCC in particular had failed to keep pace with out-of-control growth as subdivision after subdivision in Mosgiel and Outram was approved.

The ORC was criticised for failing to properly maintain its flood protection schemes and for not coming up with an achievable solution to how flood-prone Henley could be protected.

Residents spoke of the frustration of dealing with flooding on a regular basis, with one Henley resident saying he was so fed up he and his wife planned to abandon their property.

Carlyle Rd, Mosgiel, resident Murray Hamilton said he had lived in the same house for 44 years and believed he had had sewage inundate his property 20 or 30 times.

He said the council was at fault for issuing consents for developments but failing to invest in infrastructure.

It’s not a lack of investment in infrastructure that’s the main issue, it’s why so much housing was allowed on a flood plain.

Developers have been allowed to make big bucks, and now residents are demanding all Dunedin ratepayers should now fork out for remedial work and flood protection.

Henley resident Kerrie Hooper, who was chest-deep in water when he left his property, questioned whether anything could be done to prevent serious flooding happening again in the flood-prone community.

After the meeting, he said he did not believe a solution was possible and he and his wife would likely abandon their property.

Another Henley resident accused the ORC of presenting Henley residents with a solution far too expensive for them to afford while ignoring cheaper solutions.

Henley has always been at risk of flooding.It is barely above sea level at the best of times, situated at the entrance to the lower Taieri Gorge, so when the flooding Taieri River hits the bottleneck the area floods, especially at high tide.

State Highway 1 used to go through Henley, but it was bypassed by what is known as the ‘flood-free highway’, a raised road specifically designed to keep out of the frequent floods.

It’s going to be very difficult to prevent flooding of residential areas across the lowest parts of the Taieri Plain, unless flood banks are built or bolstered.

It’s tough on residents, but they should have been aware of flood risks.

What shouldn’t be tough is the council figuring out where it’s a bad idea to allow subdivisions – a new subdivision at Outram was flooded last week.

RNZ:  Dunedin City Council to review zoning after Otago flooding

Flooding in new Otago housing developments is worrying and the council will look at all areas zoned for subdivision, Dunedin’s mayor says.

In Outram, on the Taieri Plain, the water pooled around houses in the new Anzac Court subdivision. Resident Craig Miller estimated it reached 20cm up the side of his house.

Dunedin mayor Dave Cull told Morning Report it was concerning to see some flooding in new subdivisions.

“I flew over the area on Saturday with [Minister for Civil Defence Nathan] Guy, and it did worry me that an area that is flooded now should have only partially-built homes on.”

How the fuck the possibility of this situation couldn’t have been foreseen escapes me.

Serious questions should be asked of city planners and resource consenters.

South Island flooding effects

A satellite photo of the South Island following the heavy rain and floods shows all the sediment washing out to sea:

CawthronSouthIslandFloods

Zoomed in to show the Taieri Plain flooding (just to the left of ‘Dunedin’, with the sediment outflow at Taieri Mouth washing up the coast.

CawthronTaieriFlooding

I went down the coast to Taieri Mouth on Sunday, the river looked like a swollen sludge outflow. The surf right down the coastline was very dirty.

The sediment from the Taieri River is drifting up the coast towards Dunedin.The Taieri River comes from the Maniototo where there was also heavy rain.

The sediment outflow in the bottom right of the photo is from the Clutha River. There was also flooding upriver there.

From:

CawthronSouthIsland.jpg

From the CawthronEye Satellite.