Ōtaki Gorge Road slip
Cracks in the Ōtaki Gorge Road at Blue Bluff (12km inland from SH1) have required the road to be closed at this site since September 2020. There's a large under slip, and it is unsafe for vehicles and people to cross.
Vehicle access to Ōtaki Forks remains closed.
Walkers are not to cross at Blue Bluff, for their own safety.
The Department of Conservation has established an alternative public walking access to the Tararua Forest Park.
The wild weather during the weekend of 26/27 June 2021 worsened the slow slip at Blue Bluff – as you can see from the new pictures is in very poor condition. It's very important to stay off this section of road, as it's unstable and unsafe for both vehicles and walkers.
This section of the Ōtaki Gorge Road is an active slip area and slips are a regular occurrence.
The road is on a steep embankment above the Ōtaki River, which is naturally degrading the river bed and embankments. The Ōtaki Forks area receives intensive rainfall further adding to the challenges of this road.
The road has been closed to walkers and vehicles since September 2020, when heavy rain caused new damage to the bank. The road had been closed for seven months in 2016 due to slip activity at the same location.
Starting in April 2021, we began looking at how we might be able to open road access to Ōtaki Forks, moving from monitoring the slip to active investigation on the site. This involves specialised geotechnical work, including test pits, core holes, and installing equipment to monitor groundwater levels.
A geotechnical investigation shows that the slip zone runs deep into two types of material and that wet periods and heavy rain are key factors that accelerate movement. By the end of May, our investigation had found several metres of river gravels deposited when the river was much higher many thousands of years ago, with fractured greywacke bedrock underneath that.
Using this information we’ll start developing options and a design for how the road can be reopened.
This is a large piece of work, and there is no timeframe at this stage for when the road might be reopened.
Access to the Ōtaki Forks and the Tararua Forest Park via the road is closed to motorists and walkers. Walkers are strongly urged to not cross at Blue Bluff, for their own safety.
The Department of Conservation has established an alternative public walking access to the huts and walks in the Tararua Forest Park but it is currently closed until further notice due to a major slip.
Visit the Department of Conservation website for more information on this.
17 March 2021
- Investigative work to restore access to Ōtaki Forks kicks off (20 April 2021)
- Ōtaki Gorge Road to remain closed at Blue Bluff for summer peak (3 Nov 2020)
- New damage at Blue Bluff, Ōtaki Gorge Road causing concern (25 Sept 2020)
- Minor slip cleared at Ōtaki Gorge Road (24 August 2016)
- Ōtaki Gorge Road reopens after seven-month closure (15 July 2016)
- Council urges people to stay clear of Blue Bluff slip (22 Feb 2016)
- Fresh slip at Blue Bluff, Ōtaki Gorge Road (20 Feb 2016)