GHW and sea level rise

GHW incorporates wave protection on Marine Drive to Eastbourne

How will the Great Harbour Way/ Te Aranui o Pōneke manage with the sea level rise? Average sea levels are predicted to rise by between 0.2m and 2m by 2100. Much of the GHW is around 0.5m above mean sea level, so this is a natural concern.

However the GHW is pretty resilient against sea level rise, and indeed offers resilience to other critical infrastructure.

  • For a significant period, the issue will not be the overall rise in sea level, but the increase in storm events, higher high tides etc. We’re already seeing this, for example with the June 2013 storm that undercut part of the Ngauranga – Petone Rail line.

Storm damage to Petone -Ngauranga rail line, June 2013. The planned P2N section of the GHW would have protected the rail line against this.

  • While the GHW is an important active transport route, it’s less critical than road or rail routes. In the storm events that would close sections of the GHW, it’s likely that walkers and bikers will use alternatives or work from home.
  • A cycling/walking route acts as a resilient buffer between waves and road, as already happens on the GHW on Marine Drive between Seaview and Eastbourne. Adding resilience to the strategic Hutt Railway line is an significant benefit of the planned Petone to Ngauranga seaward cycling and walking path.

As mean sea level rises (for example if significant Antarctica or Greenland ice sheets melt), it’s likely that the GHW along with other infrastructure will need to be moved or modified – perhaps using floating boardwalks as is used on parts of the Waikato River Trails. But this will be easier than raising roads or rail lines.

The GHW, by providing good active transport alternatives, will reduce our fossil fuel emissions to levels that will hold off the worst effects of climate change and sea level rise. WCC has a Low Carbon Capital plan that aims for a 40% reduction in carbon emissions by 2030. Investing in the GHW, particularly by fixing the P2N gap that separates the Hutt from the Wellington CBD, will play a part in achieving that target.

New water fountain on the GHW

Councillor Sarah Free and friend, and Russell Tregonning (GHW) at the opening of the GHW drinking fountain

It may seem odd that a route that runs continually by the water needs a water fountain, but walkers and cyclists on the Great Harbour Way/Te Aranui o Pōneke will be grateful for a new water fountain installed at Chaffers Marina on the Wellington Waterfront section of the GHW. You can refill your plastic water bottle or drink directly. Canine companions have a special water bowl at the base of the fountain.

Te Aranui o Pōneke – a place for penguins

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Little Blue Penguin coming ashore

When you’re travelling the GHW, you might be lucky enough to see a little blue penguin, or kororā,. On shore, they’re vulnerable, and keep out of sight. But you may see one swimming off shore, where they feel more confident, or at dusk see them scurrying to their nests.

Unfortunately in many places along the GHW, humans have built roads between the shore and the penguin nests, and kororā end up as road kill. Places for Penguins provides safely located nesting boxes for kororā. Volunteers check the boxes every few weeks to monitor the progress of penguins. From June to December, they’re raising chicks, and from January to March the boxes are a safe haven for the annual moult, when they can’t swim or feed for a couple of weeks until their new coat grows back.

Another hazard for kororā are dogs – while your canine companion will enjoy an outing on the GHW, make sure it’s under control and not tempted to disturb our precious penguins.

Seaward Petone to Ngauranga route to go ahead

Visualisation of Petone to Ngauranga cycle/walkway

Visualisation of Petone to Ngauranga cycle/walkway

NZTA has confirmed that a shared cycling and walking path will be built on the seaward side of the Railway between Petone and Ngauranga (P2N). Construction is expected to begin by 2019. This is great news for solving the P2N “gap” in the Great Harbour Way Te Aranui o Pōneke, making it safe and comfortable for walkers and cyclists to complete the circuit around Wellington’s harbour, Te Whanganui-a-Tara.

The proposed 3m wide path will have 1m shoulders allowing for a wider path if demand warrants. The path will protect the railway line from storms, such as the 2013 event which affected commuters for six days, and had economic impacts of up to $43 million. Wellington Mayor Celia Wade-Brown points out that the path will make the 10km from Petone to Wellington a straightforward option for commuters and recreational users. It will also provide access for fishers to a significant part of the harbour shoreline.

Related projects to be funded under the Urban Cycleways Programme will connect the path to Melling and Lower Hutt in the north, and to Thorndon and the Wellington Waterfront in the south.

The history of the Petone to Ngauranga path is a long one. In 1900 “large numbers of cyclists were induced by the beauty of the day to ride to the Hutt district. Between Ngahauranga and Petone a narrow path in the centre of the mud had been beaten hard by horses hoofs and hundreds of bicycles, enabling riders to remain in the saddle from town to their destination”. In 1901 Hansard reported Wellington MP Mr Wilford’s proposal that cyclists contribute 5 shillings (about $45) a year to build a cycle track from Wellington to the Hutt, despite parliamentary doubts about the future of transport – another MP opined that “there is not such a a craze for cycling now as there was five or six years ago. Many young men are abandoning the cycle and going back to the horse, and then, the motorcar is going to take the place of the cycle. We have a dozen of these in Canterbury at the present time”. A foot and cycleway was built between the railway line and the road, but a 1911 letter reported that “already there have been several narrow escapes” with motor cyclists using the path. In 1927 the track had been “repeatedly dug up…for the purpose of laying water mains, drains, etc.” A 1929  Cyclists Touring Club ride picked up 1843 nails from the path. In 1930 the track had been damaged by storm and motor lorries crossing to repair the railway line. In 1933 the Lower Hutt Borough Council rejected proposals to repair the cycle track for a cost of around £1800 (about $200 000), even though £600 would have been paid by the Public Works and Railways Departments as compensation for damage done to the track.  In the 1980s the road was widened, reducing the cycleway to an unmaintainable width.

Intrepid reporter navigates the P2N in 1980

Intrepid reporter Karen Brown rides the P2N in 1978

Today we’ve learned the lesson that private motor cars are not sustainable transport, and the P2N project will be a big advance in Wellington’s active transport and recreation network, connecting the Wellington CBD to the Hutt Valley and the Rimutaka Cycle Trail.

Ciclovia demonstrates demand for cycling and walking route around harbour

Miramar Ciclovia 2015

The 2015 summer has seen three Ciclovia on the Miramar Peninsula section of the GHW. For each Ciclovia, the road between Shelly Bay and Scorching bay was motor free for a day, allowing people of all ages and abilities to walk and cycle along the coast without cars. The fact that up to 2300 people participated in each Ciclovia shows a strong demand for cycling and walking routes around Wellington Harbour, which is the aim of the GHW project.