Post-blaze rockfall risk ‘not a big issue’

New rockfall risk caused by Christchurch’s Port Hills fires is ‘‘not a major issue’’, assessments have found.

Selwyn District Council environmental services manager Tim Harris said a geotechnical engineer had assessed the area and the risk was mainly along Early Valley Rd, where the first of the two fires started. There was a small risk to three properties, he said.

Remediation would likely be starting next week, Harris said.

‘‘There’s also a bit of risk of rock falling onto Early Valley Rd itself. So we have decided to do some works up there, which is basically just digging holes to move the rocks into or creating little platforms with raised sides.’’

Rocks were unlikely to fall in the meantime, Harris said.

‘‘There would need to be a substantial seismic event or a very big rain storm to create any sort of real risk.’’

Terry Howes, a task group leader in the Christchurch City Council’s recovery team, said rockfall was ‘‘not a major issue’’.

It was a problem for the Christchurch Adventure Park, but the council’s geotechnical engineers had found other areas were less affected.

Howes said work done assessing rockfall risk after the 2010 and 2011 Canterbury earthquakes made the job easier this time.

‘‘We weren’t starting from scratch,’’ he said.

‘‘There were a lot of areas mapped, so we were able to target our effort to those. And our initial impressions were that by and large there was no properties that are likely to be impacted by any additional risk of rockfall.’’

The council has approved funding for continued assessments of rocks, sediment and land stability over the next two or three weeks.

It was still determining the cost but expected it to be ‘‘reasonable’’, Howes said.

Speed and stopping restrictions on Dyers Pass Rd were to protect the public, but there was a low risk, he said.

‘‘We’re just being on the precautionary side at the moment and that’s to mitigate any small rocks or anything like that that might come off.’’