23 Nov 2017

Christchurch City Council will soon begin contacting home owners near the Heathcote River who may be eligible for a voluntary property purchase offer under the Flood Intervention Policy.

The Council today approved using the Flood Intervention Policy to help those owners whose properties have repeatedly experienced above-floor flooding since the earthquakes and who will not benefit sufficiently from the floodplain management projects in the pipeline for the Heathcote catchment.

A flooded street next to the Heathcote River.

Heavy rain in July saw streets near the Heathcote River flooded.

“We believe between 25 and 35 properties may be eligible for assistance under the Council’s Flood Intervention Policy,’’ says Council Land Drainage Manager Keith Davison.

“Council staff will make contact with those property owners over the coming days so we can begin discussing their situation with them. It is possible the Council may make a voluntary offer to purchase their property as a result of those discussions.’’

The Flood Intervention Policy was introduced by the Council in December 2015, initially to provide a way of helping property owners in the Flockton area whose homes had been repeatedly hit by above floor-flooding since the earthquakes.  As a result of the policy, the Council purchased seven of the worst affected properties.

It was always envisaged the policy would be applied to other high-risk flood areas of the city once the Council had investigated potential area-wide solutions.

Mr Davison says the properties in the Heathcote catchment identified as potentially eligible for a purchase offer are unlikely to benefit sufficiently from the catchment engineering works approved by the Council today.

“The floodplain management projects we have planned will mitigate the risk of frequent flooding for many homes but they will not reduce the risk for all properties,’’ he says.

The floodplain management projects approved today for the Heathcote catchment include:

  • Completing the design and construction of four new storage basins in the Upper Heathcote area. The storage basins will store flood waters during the peak of a storm and slowly release them after water levels downstream have dropped. Construction of all four will be under way or completed in 2018.
  • Dredging the Heathcote River to remove silt that has built up in the river over the years and deepening the channel so it can handle bigger flows of water. It is estimated about 60,000 cubic metres of material needs to be removed from the river channel.
  • Investigating the technical feasibility of building low stopbanks upstream of Hansen Park to reduce the risk of frequent underfloor flooding and street flooding in the most vulnerable areas.

Preliminary estimates put the costs of the projects at about $72 million. That figure includes the cost of implementing the Flood Intervention Policy but does not include the cost of the low stopbanks.

Of the $72 million, about $28 million is already budgeted for in the Council’s Annual Plan. The remainder will require funding through the Council's Long Term Plan and its Land Drainage Recovery Programme.