Thursday 23 October 2014

Council identifies preferred option for flood protection

The Council has identified its preferred option to protect against regular flooding in the Flockton area.

Flood risks across the city have changed since the Canterbury Earthquakes and 70 per cent of the homes with repeated flooding above the floor since the quakes are in the Flockton area, part of the Dudley Creek catchment.

Councillors chose an enhanced version of Option 2 as their preferred option, which expands the benefits of the Tay Street Drain pump station (PS202), a gravity-piped diversion and some upgrading of surrounding waterways at a cost of up to $48 million. The public will have a chance to give their feedback.

Councillors considered the staff report in a public excluded section of the meeting today because they wanted to avoid causing unnecessary concern which may have arisen in relation to the full retreat option. The report that has been released publicly has been edited to preserve the privacy of individuals who may be directly impacted by the preferred option and also to avoid prejudicing ongoing negotiations with funding partners. Affected owners will be contacted individually in coming weeks.

"Option 2 offers improved protection to the problem of regular flooding for many vulnerable homes and will reduce the risk from major floods for about 144 homes," says General Manager Infrastructure Rebuild John Mackie.

"This will be a huge relief for these residents as we know the profound impact repeated flooding has had on their health and wellbeing."

Overall, the work will protect about 585 homes from flooding of 100 millimetres or more on their properties.

"We also considered the economic impact of flooding on local businesses and residential property values, and the effect of flooding on the landscape and the environment," said John Mackie.

Meanwhile, the planned Tay Street Drain pump station is under construction and will be operating by February 2015. This pumping station will not protect against extreme flooding, but will significantly reduce the risk of regular above-floor flooding for many Flockton area residents.

The Council has been working since 2012 on ways to reduce flooding in low-lying parts of the city. Sixty-five projects were identified as part of the Council's Land Drainage Recovery Programme, prioritised according to greatest need.

"We've focused on Dudley Creek first because of significant flood risks, but work is also underway to address the issues faced by flood-affected residents in other parts of Christchurch," says John Mackie.

Engineering works mean the Council may need to purchase at least two properties, and discuss a possible full or partial purchase with a number of other owners.

The Council is expected to make a decision to progress consenting and detailed design, informed by feedback from the community and technical advice, on 11 December 2014. Consultation is running alongside design on the preferred option and consenting. This means early construction work can get underway in April 2015 on part of the scheme, with the rest completed within two years.

A significant amount of work has already been completed in the Flockton area this year.

"These measures are working effectively and we know this has already significantly reduced the risk of flooding in some of the most affected areas."

While this work and the preferred option offer greater protection for most Flockton area residents, unfortunately there are 14 properties that may experience regular flooding until Option 2 is in place. Three of these properties may still flood regularly even once Option 2 is in place. Council staff will contact and visit these residents in the next week or two before consultation starts.

"The Council has a responsibility to be prudent with ratepayers' money, so Council is investigating other long-term options for these vulnerable properties, still exposed to regular flooding. The Council is continuing to work with funding partners to understand the contributions each may make to funding other longer-term options, and on what basis. It is vital these discussions are finalised before long term financial commitments are made," says John Mackie.

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