Detail in pipeline application ‘staggeringly deficient’

There’s concern the Department of Conservation’s assessment of proposed changes to a yet-to-be-constructed hydro scheme underestimates their potential impact

A West Coast small hydro scheme’s proposed new pipeline path could require over 1000 native trees be felled on public conservation land.

What was supposed to be a thin pipe lying on top of the conservation forest land and zig-zagging around large trees has morphed into a proposal for a one kilometre long trench dug for a much larger pipe to be buried. To do the earthworks, a 6m-wide corridor of native bush would be felled.

The Department of Conservation (DoC) has said the change is “nil to minor” and it’s not something the public needs to be notified about.

Conservationists are concerned and say there are holes and inaccuracies in the application. A survey conducted by the Federated Mountain Clubs (FMC) after learning of the proposal estimates 1175 large native trees could face chainsaws. The applicant’s survey lists 101 trees which could be affected. 

The proposed 1.2m diameter pipe from Griffin Creek to the scheme’s powerhouse allows for a volume of water 16 times greater than the applicant currently has permission to take.

The yellow dotted lined is the approximate path of the pipe. Image: Supplied

The FMC’s assessment of the proposal describes the changes as: “... considerably different from the current granted scheme, with an environmental footprint that is many times greater in terms of effects.”

It also points out there are a large number of potential issues that haven't been considered and documentation expected to accompany this sort of application is absent.

“Differences between the current scheme and proposed changes, such as heavy earthworks needed, use of machinery, blasting, and even the light vehicle access route, are not mentioned in the applications for the variation of supporting documents.”

FMC president Jan Finlayson called it a “staggeringly deficient application” which lacks an assessment of environmental effects, a recreational effects assessment or a geotechnical assessment for a pipeline that crosses the Alpine Fault. 

“The preposterousness of this application is really only outdone by DoC’s response.”

The club wants the proposed changes declined, or at least publicly notified.

Newsroom approached Griffin Creek Hydro's director Rhys Morgan with a number of queries and was told: “At this stage in the process I am unable to answer your questions.”

Project creep

The Griffin Creek hydro project near Hokitika gained DoC permission in 2011. It aims to create 1.3MW of power and is classed as a small hydro project. 

The project DoC gave permission for almost a decade ago had a small footprint. A water intake at Griffin Creek would feed into a flexible 30cm diameter pipe which would snake its way for around 1km of conservation land before reaching a powerhouse on private land. 

Equipment would be helicoptered in and pipe would be winched up hills. A narrow 30cm walking track through the forest would provide foot access to the water intake.. 

Only trees with a trunk diameter smaller than 20cm were allowed to be felled. The new application asks for permission to cut trees with trunks up to 50cm in diameter. 

A 1km, 1m-wide swath of forest in a 3m-wide easement where trees can be felled is requested to be increased to 6m wide within a 30m-wide easement corridor.

A DoC field officer’s report from a 2018 site visit with a company representative points to misplaced optimism in the original application for the hydro scheme as the reason for the changes. 

“The intended footprint was optimistically narrow. The parts of the track so far constructed are often wider than those approved...

“As with the intended footprint, it is likely that the 20cm DBH (diameter at breast height) was optimistically small and that inevitably, larger trees would have been affected.”

The new proposal suggests removing the need for a 30cm-wide walking track and placing a 3m-wide gravelled track on top of the buried pipe.

In order to use DoC-managed land for activities like mining, bee-keeping, tourist operations, or hydro schemes requires a concession. 

Once a concession is gained it’s possible to seek variations to it. If these are considered to be small, DoC can decide not to notify the public of the changes.

In theory, this means a series of small variations could result in an outcome quite different to what was initially approved.

The project has already applied for one variation to its concession. This was to double the amount of water it was allowed to take. It withdrew the request after DoC said it would need to be publicly notified.

For this application, DoC has so far opted not to notify the public, but did seek input from interested parties to help “inform the decision on the variation application”.

Initially it gave these parties a bullet-point list of proposed changes, and five days to respond. 

Where are the details?

The NZ Canyoning Association is still waiting for additional material from DoC in order to respond to the proposal. It’s been told these documents will be provided in July, and it will now be given 10 days to submit a response once these are supplied.

The canyoners rate the creek highly for its recreational value and are concerned any increase in water taken above what is currently allowed would have negative impacts. 

Like others, this group has noted the mention of the larger pipe and is perplexed why this would be needed in the absence of permission to take more water. 

Forest & Bird Canterbury West Coast regional manager Nicky Snoyink said there’s ambiguity about what’s been proposed based on the information she received from DoC through an Official Information Act request.

She said what she’s received doesn’t make it clear what size the pipe will be, and whether it will be 1.2m in diameter. The change to 1.2m is mentioned in a field officer's report and in a report of visual effects prepared on behalf of the applicant but wasn't included in the bullet-pointed list supplied by DoC.

“If it’s going to remain at 0.3m as I have been told, then I would be concerned why they need to cut such a wide swath of vegetation - a 6m swath - over a kilometre. That’s really concerning for us because it’s a significant disruption to the ecosystem.”

Without knowing the exact nature of what is being sought by the company, she said it’s impossible to know the effects.

“I think the department needs to go back and get more information to be able to determine what the effect is more, then it needs to be publicly notified again because it’s a big departure from what’s originally there.”

In contrast, other hydro schemes such as the McCullough’s Scheme devoted hundreds of pages to assessing the environmental impact. 

Some trees in the area where the pipeline would go are well-established older trees. Photo: Neil Silverwood

Counting the trees

FMC went to the area and conducted a vegetation survey. Its results differ from the survey supplied by the applicant.

One of the reasons could be the method of counting used in the applicants' survey, which counted trees of a certain size in a 10 to 15m radius.

FMC vice president Neil Silverwood said the applicant only measured trees over 30cm in diameter, not 20cm. That wasn’t the only issue though.

“The main thing is when they would get to five plus trees, they would record that as five plus and give it a weight of five in the final tally. That’s where I think it went wrong.”

This means there could have been 10 large trees in a 10 to 15m radius, but only five were included in the total number the applicant supplied to DoC.

About half of the forest in the area is old growth podocarp forest. Silverwood said only 3 percent of this type of forest remains. 

DoC Hokitika district operations manager Nicole Kunzmann said there's no set timeline for a decision on the application.

"The next step is to ensure that the decision-maker has all of the information required to inform a decision. The department is awaiting on input from key stakeholders, including recreationalists, West Coast Conservation Board and Iwi. Once all input is received and the department considers it has all the information to inform the decision, a report will be completed for a decision."

She said a geotechnical assessment was not submitted by the applicant and has not yet been requested. 

DoC said the applicant did not supply an assessment of environmental effects but did include information related to these.

“ ... which is effectively an AEE for the variation and this was deemed by DoC staff to be sufficient.”

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