Central City land can be rebuilt on

All land within Christchurch’s Central City can be rebuilt on, says the geotechnical report by engineering consultants Tonkin & Taylor.

The executive summary of the Geological Interpretative Report, part of the final draft Central City Plan which will be adopted by the City Council this Thursday (15 December), says: “no areas within the CBD or adjacent commercial areas were identified as having ground conditions that would preclude rebuilding on those sites”.

However, the report does say that “more robust foundation design and/or ground improvement may be required”.

Christchurch Mayor Bob Parker says the report was timely and would give land and property owners much more certainty and confidence to begin to plan for the future, knowing their sites are suitable for rebuilding.

“As we had originally thought, detailed and comprehensive ground investigations and geotechnical assessments will still be required for individual sites before owners can begin their developments.”

He says the report notes that the worst-affected areas at risk of lateral spreading adjacent to some sections of the Avon River/Ōtakaro would be mitigated by Council’s adoption of a minimum 30m set-back required for creation of the Papawai Ōtakaro/Avon River Park.

Mr Parker says it is interesting to note in the report that Christchurch is not unique in being located on soils susceptible to liquefaction within a seismically active region.

“The report notes there are a number of cities and large urban centres around the world, including Wellington, where the level of seismic hazard is similar or greater than that in Christchurch.”

Tonkin & Taylor says in the report that there are a number of projects which have been successfully completed in recent years within the Central City which use a combination of detailed geotechnical investigations and appropriate ground improvement and/or foundation and structure design to mitigate the identified liquefaction hazard.

The full Tonkin & Taylor Christchurch Central City Geological Interpretative Report can be downloaded from the Council’s website – www.ccc.govt.nz