A dam illegally constructed in an Auckland Council reserve is set to be lowered before Christmas, but not removed
The impact of an illegally-constructed dam has been described by the Environment Court as “critical” for New Zealand’s most endangered bird but its removal will be a slow process, with the company which built it unlawfully setting most of the terms.
Since an Environment Court decision recommending the dam be removed, the company has suggested that placing more rocks in it could temporarily improve the chance of fish making their way upstream.
It has since applied for and been granted consent for just a bit of the dam to come down now, with a watch and wait approach before another half metre reduction.
A break in the weather needs to happen before now and Christmas for work to commence. The company says complete removal will occur after June 2020 if it receives the necessary approvals to build a bridge in the council reserve.
The dam, which was illegally constructed on public land by the Tara Iti golf course development company associated with US billionaire Ric Kayne, blocks the passage of inanga to upstream spawning grounds.
This reduced a food source for the critically-endangered fairy tern but ensured salt-free water remained above the dam where the exclusive golf course’s water intake is located. The company has consent to take up to 146,000 cubic metres of water – the equivalent of 58.4 olympic-sized swimming pools – from the stream each year until 2034.
Only 37 breeding-age pairs of fairy tern remain. The last breeding season was the worst ever, with only two chicks surviving. A lack of food was one suggested reason for the poor results.
Auckland Council initially issued two abatement notices to the company after the dam was built, but then later issued a certificate of compliance. This was based on seeing photographs of a fish passage. No monitoring of the effectiveness of the fish passage was undertaken.
The New Zealand Fairy Tern Charitable Trust took Auckland Council to court earlier this year after unsuccessfully trying to get the issue addressed.
Judge Jeff Smith’s decision expressed surprise the trust had to take the issue to the court to get action.
“Given the critical nature of the fairy tern population and related inanga breeding at Mangawhai, we are surprised that none of these departments have taken action.”
The dam is located in an Auckland Council reserve, the stream banks are part of a marginal strip under the management of the Department of Conservation, and the bed of the stream is managed by Land Information New Zealand.
The court case was borne out of frustration of concerns being ignored, said the fairy tern trust convenor Heather Rogan when the case was lodged.
“Nothing else has worked.”
The trust lost its case for an enforcement order against Auckland Council, but the Environment Court decision made it clear a solution needed to be found quickly by Auckland Council, the Department of Conservation, and Land Information New Zealand.
“Given the situation has now arguably continued for something in the order of five years, we agree with the trust that the matter has now become critical. We have already expressed our concern that the relevant government departments and the council have not acted sooner to investigate and monitor the situation and devise appropriate solutions.”
Why the delay in total removal?
A week after the court decision, the golf club developer, Te Arai North Limited (TANL), updated the court with news fairy tern were nesting at the mouth of the stream. Its ecologist advised removing the dam could cause a rush of sediment downstream, muddying the stream and affecting foraging.
TANL suggested removal be postponed and a few rocks be hand-placed in the existing fish passage:
“The ecological advice received by TANL is to therefore defer any lowering of the structure at this present time. As an alternative interim measure, TANL is seeking ecological advice on any improvements that it might carry out on the existing fish passage. Such work, which TANL is optimistic could be sensitively carried out by careful hand placement of additional rock material within the existing fish passage, would not require a resource consent as it would be covered by the terms of the Certificate of Compliance and the permitted activity conditions in the Auckland Unitary Plan.”
It’s not clear how a couple of rocks were thought to improve the situation. In the court hearing, Judge Smith expressed concern the volume of water coming through the fish pass was too great for inanga to climb. The court estimated the water through the fish passage was around a metre per second, and felt 0.3 metres per second a more suitable speed for inanga.
However, concern around sediment and debris behind the illegal dam was backed by Department of Conservation staff. Lowering it in stages was suggested, timed carefully with tides and rainfall to ensure any sediment released would be flushed through the stream.
The trust favours complete but careful removal, starting immediately, before water levels drop during summer. By late January, several tern use the stream mouth for feeding. The trust is concerned parts of the stream could close in low flow, reducing fish for these tern. It wants the dam lowered to its 2013 height. At that stage it was described as a ford made by gravel deposited on the stream bed. In its original form, inanga could swim over it easily.
Following the suggestion of adding more rocks to the dam, TANL has since applied for resource consent to lower the dam by 500 millimetres and install a floating fish pass. It has also applied to lower access roads to the dam to make it easier to drive over once it is lowered. This has been granted by Auckland Council.
After ecological monitoring by the company and the Department of Conservation, the dam may be lowered further by 500mm if fish passage is not satisfactory. Other options listed in the conditions of the consent are for further modifications to be made to the fish passage, or the full removal of the dam.
From discussion notes following the court decision that were shared by the trust, TANL’s willingness to completely remove the structure it built illegally is linked to approval to build a bridge in the reserve to cross the stream. The bridge has been approved by Auckland Council, but also needs approval from the Department of Conservation and Land Information New Zealand. Once this is in place the company said:
“… TANL undertakes to completely remove the structure and reinstate the stream banks by June 2020 with any removal works not commencing until professional ecological advice has been obtained that the fairy terns have vacated Te Arai.”
The initial lowering of the dam will require three to four days of suitable weather. Staff from the Department of Conservation will supervise the work. Land Information New Zealand had initially given permission for the work to be carried out up to December 24. Newsroom has asked if extending this date is problematic and has been told by Land Information New Zealand’s deputy chief executive, crown property, Jerome Sheppard it is happy to extend permission until January 2020 if required.
Trust members are worried about two key dates: the late January period when several tern feed at the stream mouth, and March, when inanga are likely to spawn and will need to get upstream of the dam. It is willing to undertake the removal of the dam itself.
As well as raising the dam illegally, altering the configuration of the stream and installing rocks on the stream bank without permission, it appears TANL put a shipping container and generator on the banks of the stream to house and power its water pump. This strip of land is administered by the Department of Conservation and it appears the appropriate permission was not sought. The generator has been removed and a concession application for the shipping container is pending.
The Environment Court has asked for a report to be filed by April 5, 2020, detailing the lowering of the dam and any remaining concerns.