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Why NZTA road would wreck Takapu Valley

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The 700 hectare Takapu Valley is a pristine steep narrow rural valley with abundant native birdlife and bush remnants. Rare native falcons visit to hunt. Kereru use the valley as a link between Belmont Regional Park and Porirua Reserves. The loss of Takapu Valley to a motorway link road would be one of the largest green space losses in Wellington for a long time.

Since last Thursday, Takapu Valley residents have been sending us their many reasons for opposing the NZ Transport Agency’s plan to build a new road through their valley. Their reasons, to be considered for a second time by Wellington City Councillors at a meeting tomorrow morning, are more than persuasive.

Here are some of them.

Porirua Harbour Recovery

Takapu Stream is the last un-developed headwaters of the Porirua Harbour System. The valley teems with native fish and eels, reseeding the neglected Porirua Stream. Takapu Valley has over 50 natural springs feeding clean water into the Porirua Stream. A motorway link road would cut across most of these, spilling run toxic run off and sediment into the upper reaches with impacts on the health of the catchment, and breeding grounds for native fish and eels.

Sports and Recreation

The biggest Northern Wellington sports ground complex at Grenada North will be lost under the motorway (option D). There is nowhere else to put this sports ground.

Takapu Valley has the only two western accesses to Belmont Regional Park. Transmission Gully compromises one, and the motorway link road compromises that further, and destroys the other. This will affect many bikers, walkers and horse riders, as it’s a major recreation site 15mins from the CBD. A big loss for Wellington.

Heritage

When early settlers purchased 1 acre of land on The Terrace, they were given 100 acres in Takapu Valley. It’s one of the first rural areas in Wellington, and several families still farm there from the mid 1800s. The motorway link road destroys two of these large farms.

Loss of a Rural Community

The motorway link road through Takapu Valley will destroy homes, but more importantly it will destroy a close knit rural community that has existed since the 1850s. It will cut all eastern properties in half, and no promises have been made to provide access or clean water. It will also impact livelihoods. There are few communities like this left in Wellington.

Rural, nature and solitude experience

Many people use the valley to get away from the urban environment, so close to Wellington. Schools such as Scots College and the local primary schools such as Redwood use Takapu Stream as an educational tool for biology classes. Runners, walkers and cyclists use the valley for a quiet green space experience.

Commissioner for the Environment

The Parliamentary Commissioner for the Environment stopped the Transmission Gully Road going down Takapu Road in 1992 because of environmental concerns. Now NZTA are trying to build it again by another name. But nothing has changed. Except for the Transport Agency’s changing justifications for wanting to build a road through the valley:

Heavy Commercial Vehicles

NZTA say: Option D through Takapu Valley (via Petone to Grenada Road) would be better for heavy trucks heading north. Making things cheaper for trucks will save money on things you buy in the shops.

Reality: Trucks won’t use it; they’ll use SH2/SH58 (and NZTA knows it).
NZTA has only ever compared trucks coming from Petone to Transmission Gully (TG) via Option C or D or the long way around Ngauranga. It will almost certainly be cheaper from trucks to take SH2 to SH58 (there’s 50% less climbing), but NZTA has never modelled this (because they know it will sink their logic).
NZTA *has* agreed that from everywhere else in the Hutt except Petone, SH2 to SH58 is already better than Petone to Grenada Road
NZTA models show that between Ngauranga and TG, SH1 is faster than Takapu (so no one will use Takapu)
NZTA models expect 59 trucks northbound and 104 southbound to use the link. (compare > 400 on SH58, > 800 on SH1/SH2)

Resilience

NZTA say: Option D (Takapu Valley) would be great, would let you bypass SH1 through Tawa, would give Wellington another link to Transmission Gully

Reality: Option D doesn’t offer a bypass due to one direction ramps; is far more likely to fail in an event than the part of SH1 it’s supposed to bypass; it bypasses only 3km of SH1 – but you can’t use it for that because of one-way ramps at TG; it runs along an active, unstudied fault; it features medium-height cuts into steep, fault-fractured hill faces that could close the road for weeks; SH1 through Tawa is expected to be usable immediately after an earthquake; the new road can’t avoid the fault due to pylons, which themselves are a hazard; Gully link is too close to Linden, Tawa to make a difference

Congestion, travel times, etc.

NZTA say: Increases in traffic through Tawa will mean a lot of congestion by 2031, so we need to build extra road between P2G and TG.
Reality: It won’t, so we don’t, and even if we did, the Takapu Valley link road would help so little that it would be practically pointless – so few people would use it.

 People are driving less, not more.
 GRWC, Opus, and NZTA (Transmission Gully) models say the existing four lanes through Tawa are enough.
 NZTA models show increase travel times of 10-170 seconds. That’s within the error bars.
 NZTA and GWRC models show that most Hutt traffic will take SH2/SH58 instead of P2G, and most Wellington traffic will stay on SH1 and not use the Takapu “shortcut” – because it would be slower. Porirua traffic can’t use it at all.
 Level of Service modelling shows that widening the motorway through Tawa results in a massive improvement in service levels. The Takapu link has a tiny effect: service is worse than not building P2G at all.
 “Option A (Option D is Takapu Valley) provided the best network wide performance results … the highest increase in average network speeds; 11% in the AM peak and 7% in the PM peak. … With the increase in speed, there are the associated large drops in network travel time, delay and queuing time.”

Environment

NZTA say: Option D has environmental effects that can be mitigated.

Reality: Out of three options with identical BCRs, NZTA is promoting the most environmentally damaging option possible. “Mitigation” is unlikely.

 Takapu Stream is listed in Table 16 of the Regional Policy Statement as “a stream requiring protection due to it meeting criteria as a significant indigenous ecosystem.”
 Second-largest catchment for Porirua Stream, and the only part of the Porirua Stream catchment not yet heavily developed.
 Local bodies have signed on to protect freshwater catchments in general and to rehabilitate Porirua Stream and Harbour in particular.
 Takapu has thriving native fish stocks, no introduced trout – it’s a nursery for all the rehabilitation efforts.
 The road’s alignment would fill every gully on the east flank of catchment and pipe, culvert, or divert the Takapu headwaters and all tributaries.
 The visual interruption of landform, vegetation, visible from the Belmont Regional Park and surrounding residential areas, and the noise effects on the park and the surrounding residential areas can’t acceptably be mitigated, because there’s a “high degree of intervisibility”.

Other options are far less damaging, are cheaper, and more effective that building a road through the Takapu Valley.

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