Ngaio Gorge landslide updates - 8:45am 15.8.2017

31 July 2017

Ngaio Gorge landslide updates - 8:45am 15.8.2017

Ngaio Gorge 15 August

Ngaio Gorge landslide – Tuesday 15 August update #21 – 8.45am

There are two lanes open on Ngaio Gorge Road during peak hours with speed restrictions in place. Any further work required will be carried out under Stop / Go and or using temporary traffic lights.

All restrictions on Old Porirua Road have been lifted.

Ngaio Gorge landslide – Monday 14 August update #20 – 3.30pm

Ngaio Gorge will have one lane open during peak hour traffic from this afternoon. There will be a stop-go system operating to allow access from both directions, and speed restrictions in place. 

The section of road restricted to 30kph is wide enough for cyclists and vehicles but needs to be treated as a shared zone as there is no dedicated cycle way.

There is a dedicated footpath for pedestrians along the re-alignment section separated with delineators.

There is still a lot of work to be done on the area, so please be patient in the meantime.

Ngaio Gorge landslide – Monday 14 August update #19 – 8am

Wellington’s Ngaio Gorge Road will, all going well, be reopened to traffic in time for tomorrow’s (Monday’s) evening rush hour.

Work has been continuing this weekend to complete a temporary realignment of the uphill lane (see attached image) and also secure a line of shipping containers to protect the roadway from any further rockfalls. 

The gorge, an important link between Wellington’s CBD and the western suburbs, has been closed to traffic since a large landslide blocked the road on the weekend of 29-30 July.

The site will have a restricted speed limit of 30kmh in both directions. During off-peak periods the road just above the slip site will continue to be one-way only (controlled by temporary traffic lights) while work continues on the construction of a retaining wall (this work is not related to the landslide).

Ngaio Gorge landslide – Friday 11 August update #18 – 8am

The majority of the Ngaio Gorge landslide material has been removed, and we have started the process of installing the container wall. 

The cordon at the bottom of the work area has been moved up the road, restoring unimpeded access to all the businesses in the lower part of the area.

Four shipping containers were delivered to the site yesterday, and these will be filled with concrete blocks and placed as a rockfall protection barrier as work continues.

Most of the preparation works for a temporary road adjacent to Trelissick Park is also complete with some minor cleaning and paving works planned over the weekend.

At this stage we are aiming to have at least a temporary one way system in place with a restricted speed limit of 30kph in both directions early next week.

Ngaio Gorge landslide – Wednesday 9 August update #17 – 3.30pm

As of this afternoon, 98% of slip material has been removed, with a few truck loads being stockpiled on site to use on various areas of forward work.

Anchor drilling will start tomorrow morning, with containers and ballast blocks delivered from tomorrow afternoon.

As part of the road realignment, a vegetation crew will start clearing the garden area and overhanging trees, and any leveling required will also take place.

The road closure on the lower end of the hill will be moved closer to the site from 6am tomorrow, allowing the businesses in the area to have unobstructed access. The bottom of Old Porirua Road will still be manned to prevent uphill traffic.

Ngaio Gorge landslide – Wednesday 9 August update #16 – 9.30am

Another 1100 odd cubic meters of material was carted away yesterday with the remainder on its way today, so lunch time should see the end of the stream of heavy trucks and hopefully the reopening of the section of Ngaio Gorge Road between Old Porirua Rd and the last business.

It might be a bit tight turning around at the end so please take your time and be patient.

The next stage involves drilling some holes into the base of the slip to anchor the planned container wall. This work might take a couple of days depending on how hard the rock is. We will then install a pile of shipping containers to protect the public from further rubble that may come off the tip face.

While all that's going on we will also begin preparing a temporary road through the lay-by near Trelissick Park to allow space for us to place the container wall in the downhill lane, and leave room for traffic to flow in both directions during peak hours.

Work also continues on the removal of some loose rock from the face of the bank on the next bend down from the main slip, which should be completed in the next few days.

Following that we will also take the opportunity to remove a couple of smaller slips from further up the road to ensure things are as safe as possible when we finally get the road open to all traffic.

The work on the retaining wall that was happening before the slip is likely to continue into November, and there will be traffic signals in place to guide you around that site during off-peak hours.

Ngaio Gorge landslide – Tuesday 8 August update #15 – 9am

We have removed somewhere in the order of 4500 cubic metres of material so far with an estimated 1200 to go.

We have also started to bring some concrete blocks to site to use as a safety barrier while the lower slip area is being cleared by the abseilers. These are expected to be used for the temporary works around the main slip when scaling of the lower area is complete.

Another day and a half and we can start some remedial works which will at this stage include a bit of road realignment and building a container wall.

We are also removing a small amount of debris from the hillside about 30m down the hill so we don't need to go back again. This will be done by abseilers at the same time as the current work is completed and is unlikely to cause any additional delay.

There is a possibility that the road might be open early next week. Watch this space for updates as things progress.

Ngaio Gorge landslide – Monday 7 August update #14 – 10am

Carting of material continued over the weekend with 3500 cubic meters taken away over the couple of days.

It looks like we are somewhere about a third of the way through the pile at the moment and this phase of the operation will continue into mid–late this week, with some safety related works to follow including realignment of the road away from the slip and installation of an appropriate barrier system to catch any further rocks or material that may be dislodged by the forces of nature.

As our primary responsibility is safety we have installed some monitoring points in and around the slip face so we have some idea of what is happening in the general vicinity. We will be monitoring these on a daily basis and implementing any needed solutions if things change.

Old Porirua Road remains one way down for safety reasons. Residents, pedestrians and cyclists continue to have access with general traffic still excluded for now. We appreciate that it can be a bit of a trip around for residents but believe that the measures in place should ensure that there are no serious incidents on this narrow windy road in the short term.

Ngaio Gorge landslide – Friday update #13 – 4.30pm

We started carting material out early this afternoon with the operation going full blast into next week. From tomorrow morning we expect to have 10–12 truck and trailer units operating from dawn to dusk with a similar number of 10 yard trucks.

Material will be carted to various sites around the region and all going well we are expecting that part of the operation to be completed towards the middle part of next week.

Work will then commence on a temporary re-alignment of the road and installation of appropriate safety measures to minimise the risk of falling debris to passing traffic when the road is finally reopened.

Ngaio Gorge landslide – Friday update #12 – 9am

The landslide removal is progressing as planned today, with removal of material likely to start this afternoon.

Old Porirua Road is open from the downhill route to residents in cars, cyclists. Pedestrians are permitted to walk either way, but to do so with caution..

Trelissick Park is open to public for walkway thoroughfare from upper Ngaio Gorge Road to Kaiwharawhara Road.

Businesses inside the cordon are open for business as usual. Just have a chat with the traffic control management team.

Ngaio Gorge landslide – Thursday update #11 – 4.30pm

There was a significant slip (rough estimate of 100 tonnes) at Ngaio Gorge this afternoon, but the safety plans we’ve got in place worked as expected, and there was no risk involved. 

The digger that was working in the area had forewarning from the monitors in place, and was out of range 12 minutes before any materials fell.

We’re working closely with the Geotech crew, monitoring systems are in place, and we are now reassessing the plan so we can move material from a new angle.

Plans to start removing materials are still in place for tomorrow.

Ngaio Gorge landslide – Thursday update #10 – 1pm

Good progress is being made with the long reach excavator and depending on progress between now and the end of the day we may be able to start carting material out by mid-morning Friday.  

At this stage we are planning to cart all weekend and hope to have that part of the operation completed sometime on Wednesday.  

There will be a need to install some protection for traffic which should be installed over the following couple of days after spoil removal.

Trelissick Park is open to public for walkway thoroughfare from upper Ngaio Gorge Road to Kaiwharawhara Road.

Businesses inside the cordon are open for business as usual. Just have a chat with the traffic control management team.

Ngaio Gorge landslide – Wednesday update #9 – 10am

A lot of material was removed from top right hand of slip overnight.

This work was carried out while sluicing took place as separation of work site was deemed safe.

An access ramp to a large work platform from the uphill-left side of the slip is in action with some very solid bedrock uncovered.

All going well, possible that material can be removed starting Friday.

Please note: Old Porirua Road is accessible from the downhill route to residents (checking in with Traffic Management Team) and cyclists only. Businesses are open as per usual within the cordon. 

Ngaio Gorge landslide – Tuesday update #8 – 5pm

Work continued today to clear the slip in Ngaio Gorge Rd with sluicing of the loose material from the upper parts of the slip zone. A helicopter was utilised to drop water onto the slip.

A large excavator was used to put in a track from where further areas of unstable mainly rocky material was being dislodged and this work will continue tomorrow.

This afternoon the geotechnical experts and abseil specialists were checking the area above the current slip to determine if further work will be necessary in this area.

Monitoring of the slope using special survey equipment was also implemented.

The experts will convene tomorrow morning and if it is deemed safe the excavator will continue to bring down the unstable slip face tomorrow. When this work is completed the contractor will commence removal of the slip debris, which we think will be later in the week.

Please note: As a result of Ngaio Gorge Rd being completely closed to traffic, increased traffic volumes are most noticeable at the Onslow Road/Hutt Road and Tinakori Road/Park Street traffic signals as these are the main alternative routes from Khandallah to the City.

Ngaio Gorge landslide – Tuesday update #7 – 3pm

Trelissick Park is now open to public for walkway thoroughfare from upper Ngaio Gorge Road to Kaiwharawhara Road.  We may have to close this access area again on Thursday for health and safety reasons as the helicopter continues to sluice the hillside. Watch this space for updates.

Road closures still in place, but the businesses inside the cordon are open for business as usual. Just have a chat with the traffic control management team.

Ngaio Gorge landslide – Tuesday update #6 – 8:30am

The digger was pulled off slip face yesterday as there were concerns due to slip face stability. A decision was made to use a helicopter to sluice the slip face which loosened a significant amount of material.

Slip face to be accessed without Geo Tech consultation and approval. More sluicing may commence today if necessary.

Road closures still in place, but the businesses inside the cordon are open for business as usual. Just have a chat with the traffic control management team.

Ngaio Gorge landslide – Monday update #5 – 4:30pm

A helicopter is expected to arrive in the gorge to begin sluicing at the landslide site about 4.30pm today. The sluicing aims to bring down loose rock so a 20-tonne excavator can operate safely on the site. The stability of the landslide will be reassessed tomorrow morning.















Motorists are advised that Old Porirua Road, above the slip, is now closed to all through traffic. Residents along the road are still allowed access (downhill only) as are cyclists.















Motorists are also asked to take care and keep speeds down on alternative routes that have become busy due to the closure of Ngaio Gorge Road. This includes Onslow Road and Wadestown Road – where there have been complaints that vehicles are travelling too fast through the shopping area.















Ngaio Gorge Road is expected to be closed till at least the end of this week.

Ngaio Gorge landslide – Monday update #4 – 3pm

After talking with the on-site contractor they have agreed to allow cyclists to use Old Porirua Rd in the DOWNHILL i.e. city bound direction only.















For health and safety reasons we will NOT be permitting them to travel uphill as that would be into oncoming one-way traffic and is considered to be more dangerous than the alternatives.

Ngaio Gorge landslide – Monday update #3 – 9:30am

Following a site meeting this morning, Ngaio Gorge is expected to be closed until at least the end of the week.

No more debris came down overnight, and engineers have assessed the stability, and preparation has started for slope stability and material removal works.

Ngaio Gorge landslide – Sunday update #2 – 2pm

Plans to bring a 20-tonne digger to start work this afternoon on the Ngaio Gorge landslide have been abandoned after yet more boulders and rubble fell onto the roadway about midday.















Engineers and Wellington City Council staff agree the situation today is too dangerous. They will monitor the slip today and reconvene tomorrow morning to consider their options in terms of stabilising the site and clearing the debris.















The landslide grew significantly overnight since the first material came down off a steep bluff and closed the road early on Saturday morning. The road is now completely covered by large boulders and rubble.















Motorists are urged to use other routes like the Ngauranga Gorge, Onslow Road and Churchill Drive via Wadestown.















The nearby very narrow Old Porirua Road has been temporarily closed to through traffic due to congestion and safety problems. It will still be opened to residents.















Ngaio Gorge Road is closed to pedestrians and cyclists – but pedestrians are still able to use the Trelissick Park track, in the valley below the road, to get past the landslide site.

Ngaio Gorge landslide – Saturday update #1 – 1pm

Ngaio Gorge Road – one of the main routes between central Wellington and the western suburbs, will be closed for at least the rest of the weekend and possibly early next week following the large landslip early this morning. 

Two very closely adjoining landslips have sent large boulders onto the road from a bluff above. Contractors started removing the rubble this morning but have been pulled back because a lot of rock still coming down this afternoon.















Consultant engineers, Wellington City Council and Police are not prepared to open the road again until it’s safe. At the moment the engineers are trying to figure out how they’ll remove the large amount of material that’s still above the road – it might involve a helicopter and monsoon bucket but that decision has yet to be made.















Probably about five or six truckloads of material has come down – mainly big boulders.















The nearby very narrow Old Porirua Road has been temporarily turned one-way (downhill) following aggro between motorists this morning who’ve been trying to use it as an alternative route. Motorists are urged to use other routes like the Ngauranga Gorge, Onslow Road and Churchill Drive via Wadestown.