‘Get out of the gorge’ says Massey academic
An alternative route to the damaged highway through the Manawatu¯ Gorge should avoid the troublesome gully completely – and the railway should be moved too, a senior geographer says.
The NZ Transport Agency has released 13 alternative-route options for the main highway between Hawke’s Bay and Manawatu¯ , as the old State Highway 3 through the gorge is closed indefinitely after unstable rock was discovered.
The transport agency predicts up to 630,000 cubic metres of further material could fall, which is 170 times more rockfall than the two slips that closed the road in April.
Three of the 13 options run through the gorge, which Massey University physical geography senior lecturer Sam McColl said should be avoided. The railway track through the gorge, on the Ruahine Range side, should also be moved, as it was prone to landslides, McColl said.
Although that would significantly increase costs in the short term, it would have long-term benefits, he said. ‘‘If there was any cost efficiency to be gained from realigning road and rail at the same time this might be an option worth considering.’’
KiwiRail spokesman Todd Moyle said there had been 19 reported slips or debris on the rail line through the gorge in the past five years, but most of those were minor. Only one slip led to the closure of the rail corridor, for about three hours, Moyle said. ‘‘We have no plans to shift or close the line.’’
A major slip in 2010 closed the railway line for about a week. Before that, the last train through the gorge to hit a slip was in 1998. In August 1946, engine driver Basil Craighead and fireman R Hoskins were killed when their 140-tonne steam engine hit a slip and crashed into the flooded Manawatu¯ River.
Horizons Regional Council chairman Bruce Gordon said the gorge was still an good option as a viaduct similar to the one at Arthur’s Pass in the South Island could work.
Gordon didn’t say which option he preferred, but he said a flat route would be best.
Gordon was surprised at the number of options and said it should have been narrowed down before it went to public consultation. Transport agency regional transport systems manager Ross I’Anson has said the public asked the transport agency to share the information as it was developed.
Manawatu¯ District mayor Helen Worboys said people were quick to criticise the transport agency. ‘‘In this instance, I know they’ve dropped everything and fasttracked it.’’
Open days to discuss the options will be held at the Palmerston North Conference and Function Centre and the Woodville Sports Stadium on October 11 and 12.