The NZ Transport Agency has started work on the fifth bench at the Manawatu Gorge slip site, and has determined that it will be the final bench before work begins clearing the slip and repairing the road and bridges beneath the slip material.
Mr McGonigal says the NZTA has received encouraging advice from geologists that the benching work has been successful in stabilising the previously unstable area at the top of the slip site.
“Our plan was to finish the fifth bench, evaluate the stability of the hillside and then decide on our next steps. As it turns out, we don’t need to wait—our geologists have told us that there will be no need to keep benching once the fifth bench is done, so we’ll really be able to step up our clearing operations.
Mr McGonigal says this decision is a heartening sign that the operation is going to plan, and that the remarkable efforts of the Higgins contractors on the slope were paying off.
“Thanks to the unflagging efforts of our crews on site, we’re getting the job done, and this milestone means we’re on track towards getting the gorge re-opened mid-year.”
Once the fifth bench is complete, and assuming that clearing operations on the Woodville end are successful, the NZTA will be able to clear debris from both sides of the slip. This will speed things up considerably, and the NZTA expects that this work will take about six weeks from when the benching is complete.
“However, we don’t know how much damage has been done to the road and bridges down below. We’ll have to assess them once they are cleared. For now, our estimate is that we’ll need another six weeks to make sure they are safe for use. This will take us to the middle of the year.”
Mr McGonigal says those timings could vary depending on weather conditions and the extent of damage.
Mr McGonigal says the Higgins team have continued their efforts on the slope with the beginning of work on the fifth bench this week.
“The crews have nearly dug out to the final level at the Ashhurst end, but there’s still a lot of material to be removed before the bench can be finished.
“We’ve also started carting away material from the Woodville end. Right now, we’re not sure if carting from this end will be feasible so we are proceeding very cautiously, starting with a spotter in place and a few trucks and a digger. If the initial carting goes well and we feel we can work safely, we’ll increase the machinery and bump up operations at this end.”
“As always, safety remains paramount and we will continue to take a measured, concerted approach to ensuring all the guys working on the site remain out of harm’s way”.
Mr McGonigal says the NZTA will be keeping a close eye on the predicted bad weather this weekend, but with the benching in place it is expected the hill will hold steady.
Mr McGonigal says the top three benches are already taking on a strong shade of green from the intensive hydroseeding efforts on the bench batters (edges), where the NZTA has planted both moss and grass to help plant life on the slope regenerate.
“The planting has settled well into any cracks in the batters, and we expect to see even more strong growth over the coming weeks.“
Mr McGonigal also congratulated the organisers of the last weekend’s Gorge-ous Ball, which was such a success that they are thinking about making it an annual event. About 250 people came along, and an auction raised several thousand dollars to be shared between the Kumeroa Hopelands School and local fire brigade. Mr McGonigal says the NZTA worked with Higgins to get some rocks and a digger for the entranceway, and tangata-whenua iwi also got involved, with the Cultural Advisor to Rangitane o Tamaki nui a Rua blessing the rocks before they made their way to Woodville.
“It’s really gratifying to see that the community are getting together, having some fun, and making the best of what is a difficult time.”
All Manawatu Gorge updates and media releases, plus more photographs and diagrams, are on the NZTA's dedicated Manawatu Gorge web page(external link).