22 Aug 2017

Short-term options to reduce the risk of flooding in Southshore will be considered by the Council on Thursday.

Flooding on Rockinghorse Rd, Southshore.

Southshore's Rockinghorse Rd was among the streets hit by flooding during last month's storm surge.

Southshore residents have raised a number of concerns about erosion and the flooding risk in their area since the earthquakes.

During last month’s heavy rain a record high tide saw water overtop the estuary edge at Southshore and flow through gaps in a grassed embankment created by Land Information New Zealand (LINZ) on red zoned land.

Some streets, garages and gardens in the area subsequently flooded, along with two homes.

Christchurch City Council took emergency steps to prevent a repeat of the flooding during the next high tide by raising the level of the embankment in places and building a bund to protect vulnerable areas.

On Thursday Councillors will consider a report which examines short-term options for reducing the flood risk in Southshore, including an option put forward by OCEL Consultants Ltd, on behalf of the Southshore Residents Association, for a levee to be built along the estuary edge.

In the report Council staff say they believe more work needs to be done on the feasibility of the levee but it could be worth looking at as part of investigations into longer term options for adapting to the effects of climate change and sea level rise.

As a short-term, temporary intervention they are recommending the Council stabilise the emergency work done last month and to extend the bund north through South Brighton Park to Bridge Street.

The report says it will cost about $2 million to do the work but it should lessen the risk of tidal flooding in extreme events to about 36 homes in Southshore and South New Brighton.

The report notes that Council staff need to have further discussions with Land Information New Zealand and Environment Canterbury to clarify roles and responsibilities in the coastal environment and funding options.

It also notes the Council is working with Regenerate Christchurch on a long term regeneration strategy for Southshore and South New Brighton.

Read the full report.(external link)

Thursday 25 August update: Please note the Council decided at its meeting today to defer consideration of this report until 9am on Thursday 31 August to give elected members more time to consider the issues raised.