Mayor wants help for flood-prone 'right now'

GREAT FOR DUCKS: Flooding in Thornton St, Mairehau, last year.
GREAT FOR DUCKS: Flooding in Thornton St, Mairehau, last year.

For residents living in flood-prone areas of Christchurch the sound of rain falling on the roof is cause for alarm.

They have come to dread rain and the potential it brings for flooding. Too often they have watched helplessly as nearby river levels have risen and their homes have become awash with muddy water.

They want their homes and their equity protected and are putting their faith in the mayoral taskforce on flooding to deliver solutions.

Broad-brush solutions have been outlined but details on what area-specific protection could be put in place have been sketchy until now.

That changed on Monday when the council issued further technical reports outlining the solutions the taskforce is looking at in each specific catchment area.

"We want residents to have access to further technical details of the flood mitigation work in their community," Mayor Lianne Dalziel said as she announced the publication of the reports.

The council has divided the technical reports into easy-to-read sections (Appendix A and B) in which residents can read through detailed area reports and the flood defence tools proposed to help with flood mitigation in their particular area.

"The taskforce team has been asked to focus all its energy on flood mitigation work that will benefit residents right now," Dalziel said.

Today The Press looks at what flood-protection works are planned for some of the worst-hit communities.

The Avondale area

Significant slumping of the banks of the lower Avon River, caused by liquefaction and lateral spread, has increased the area's vulnerability to flooding.

Temporary stopbanks have been constructed along the river's edge but bank slumping and fill consolidation are still happening, which means the stopbanks are lower than the river flood level. They cannot be removed until an alternative alignment for permanent stopbanks has been determined.

Temporary fixes the taskforce is looking at include checking, repairing and replacing as required, all the flap gates along Avonside and Hulverstone drives and installing pumps during major events to keep ponded run-off from reaching low-lying property.

Longer term the taskforce believes holding basins could be formed in the residential red zone, away from the residential green zone properties. Run-off could be directed to these basins.

The Lower Heathcote catchment (riverside properties)

River flooding has been seen along the lower reaches of the Heathcote River and the streets next to it.

Water depths of up to one metre have been reported. Ground levels in the area have changed since the quakes and the capacity of the river has reduced due to bed heave and sediment deposition. Stormwater pipes next to the river have also been damaged.

The taskforce says for the 13 most vulnerable homes, individual protection solutions (such as house raising or house wrapping) will be the only option that will protect them from major flooding.

It says temporary bunding (using large and small sandbags) and relocatable pumps could reduce the flood risk for up to 168 properties in the area while longer-term solutions are investigated.

Due to the nature of the flooding in the catchment, the taskforce is also recommending that the existing tidebank heights are increased beyond to current design level to incorporate flood level protection, sea-level rise and climate-change considerations.

The Dudley Creek catchment

This area has a long history of flooding but has experienced five big floods since the earthquakes. Significant settlement has occurred in the catchment, and lateral spreading and bed heave have affected Dudley Creek and its tributaries, which have reduced their capacity.

Long-term options for easing the flooding risk are expected to be implemented within three years. In the meantime the taskforce is looking at temporary protection measures. These include lower catchment capacity enhancement works, street bunding, local drain improvements, house raising, house tanking, and temporary buy-outs.


Slips, rather than flooding, have been the problem in Lyttelton. To reduce the risk of further slips, the taskforce says street sumps should be regularly cleaned and where possible protected from blockage from gravel and floating debris.

It is also recommending the stormwater drainage network on hillsides susceptible to slipping should be increased in capacity and that work should be done to locate and repair water supply leaks.

Little River

Little River has a long history of flooding and no evidence has been found showing a difference between flooding that happened before or after the earthquakes. Field investigations have identified the predominant cause of the recent flooding as inadequate channel capacity of the Okana River corridor and the constraining impact of the Wairewa Pa Rd bridge.

The task force is looking at clearing the river and stream channels throughout the area and creating secondary flow channels to contain spill from the main channel.

It also wants to increase the capacity of the Wairewa Pa Rd bridge and investigate options for re-routing drainage from the Christchurch Akaroa Highway.


Living in flood-prone Flockton Basin means moving your car when it rains and hoping your house is far enough off the ground. GEORGINA STYLIANOU talks to some Thornton St residents about how the flooding affects their lives.

On a stunning autumn day in Christchurch it is difficult to imagine Thornton St submerged in dirty, brown floodwater.

The sun encourages people outside to tend to their gardens and play with their children. The rush of moving cars to drier ground and the misery of spending an evening watching the water level rise around their homes seems far away.

Even so, the fact remains that this little street in the Flockton Basin has flooded about seven times since the February 2011 earthquake.

Unlike its neighbour Carrick St - where most people have been forced to abandon their damp, mouldy homes - Thornton St residents are still able to live in their properties for the most part.

Speaking to residents, it becomes clear that a one-size-fits-all solution will not work for this frustrated community. Some people don't want to leave their homes so talk of red-zoning and buyout offers is another thing to worry about. Others are fed up and just want out.

Several homes on the street are empty as repair work is done but whether the work relates to earthquake or flooding damage is unclear.

"Our neighbour's house was two weeks away from all the work being done - new carpets and everything - when it flooded," Violet Lawson says. "I don't know whether repairs will still go ahead and you have to wonder what the point is because it will just flood again."

Lawson, a student and part-time worker, rents the Thornton St property from her parents and says it is lucky the house is higher off the ground than many others.

"The worst thing for us is not being able to get out of the house sometimes."

Lawson's partner was unable to get to university to sit an exam during the March 5 floods.

"It's pretty awful watching families and people who have worked to own their homes to live like this."

Jocelyn Buttriss is a new mum who starts the conversation off by asking for forgiveness if she cries.

Her twin baby girls were born on March 16 and spent seven weeks in hospital before coming home.

"When I was heavily pregnant I had to pee in a bucket.

"It was horrible as a pregnant woman wading through knee-deep water and watching the levels rise on the street and up the driveway."

What worries Buttriss most is not being able to leave the house if she needed to and not having working toilets.

"The toilets just don't work anymore when it rains.

"But you do what you have do to, everyone around here does."

The family, and every other resident on the street, have learned to move their cars on to Aylesford St so they won't be flooded out.

"We know now that as soon as there's a certain type of rain that goes for a certain amount of time that it will flood again."

Buttriss says she asked for a chemical toilet but was told because it was not an earthquake- related issue, she was not entitled to one.

When the nation was preparing for the tail-end of Cyclone Lusi in March, Buttriss was in hospital waiting to be flown to Wellington to give birth to her babies.

"And I was just worrying about what state our house would be in when we got home. It's just not a nice feeling at all."

Buttriss and her partner bought their home about two and a half years ago.

"We had no idea how bad the flooding was. We had never heard of the Flockton Basin.

"Whether that was just our naivety as first-home buyers or what, I don't know."

On top of flooding worries, it has been more than a year since an engineer has inspected their home and the couple still do not know how and when their claim will be resolved.

Buttriss fights off tears when she talks about the future and what she would like to see happen in the area.

"This is where we wanted to raise a family. It's a great area and we don't want to leave."

As for any potential red- zoning decisions, she worries the family would be forced to take a financial loss.

"I just want to feel like we're not forgotten, you know?

"Maybe they could deliver little care parcels or give away family passes to things or give elderly or vulnerable people a chemical toilet. Just little things that reassure us and make us feel like we're still a community."

It's too late for Carrick St, she says.

"Most people are already gone."

Buttriss admits to feeling emotional and overwhelmed as a new mum and concerned home owner.

"But we can't fix the big picture right now and everyone has to accept that."

A few doors down a fence outside a vacant property displays a For Rent sign.

"They couldn't sell it. I'm not sure who would rent it either," Elaine Lucie says.

Lucie, her husband and their two children moved into their rental property in September and the house has never flooded.

"But we lost our car in the March floods and that had a big financial impact for us."

The family has moved three times since moving to Christchurch from Ireland about 16 months ago and Lucie doesn't want to move again.

"It's exhausting . . . and we like it here.

"Plus, finding an affordable rental in Christchurch is not easy."

Lucie remembers coming home one evening and having to carry her two-year-old daughter while wading through shin-deep water.

"I was drenched and it's really not pleasant and it just seems to flood so quickly."

Their house became "an island in a lake" in March and Lucie now develops a mental plan when she hears about a heavy rain warning for the city.

The Press