If local hapu have a gripe, it's not about the power station per se, this churning beast that a century ago caused a river to be turned from its natural course before pumping out the used water into the old river bed, hundreds of metres downstream from where a canal steals the river.
That loop in the flow of things has had repercussions. It is part of a long-building perfect storm with several fronts which has conspired to adversely affect the wider network of fresh waterways over many, many years.
It is why kaitiaki insist they need unencumbered access to the Wairua River at a point about 50 metres below the hydro station. That location is on DoC reserve, not Northpower land. But a locked Northpower gate prevents anyone without a key, ie anyone not on power-company business, getting into that reserve.
Another debate is also underway to get DoC to tighten up on grazing cattle degrading the public Wairua Reserve, as well as freeing up access to people.
The Whatitiri Māori Reserve Trust, representing the three Te Uriroroi, Te Parawhau and Te Mahurehure hapu of Whatitiri, says that since their ancestors first settled, the area was used for gardens, eel fishing, transport and was part of a route between the Far North and points south.
War parties, inter-iwi marriage brokers, traders, despots and diplomats traversed that route, and local hapu went through centuries of upheaval, loss, fragile peace, deals, alliances and sheer determination to dig in to their rohe.
The wedge of land with its valleys, forests, flats, rivers and cliffs hold the remains of those times — physically, historically, spiritually, in law and lore.
And its waters are intrinsically linked to the Hikurangi Swamp and the Mangakahia, Wairua and (Northern) Wairoa Rivers.
Four Māori reserves and the adjacent DoC reserve contain stands of untouched native forest, regenerating bush, rapids and deep pools in a network of the Wairua and tributaries. Around and between the reserves are also grazed blocks.
The river and its banks are of interest in the fields of conservation, botany, archaeology, indigenous study and history. It is already a quiet attraction to kayakers, freshwater fishers, walkers and others in the know. If they can find their way in.
The area is being investigated — just not fast enough, say the Whatitiri trustees — by the Walking Commission, which is charged with ensuring public access to reserves and esplanade-strip water bodies throughout New Zealand. There is at least one paper road leading to this stretch of the Wairua.
Sitting just upstream from the power station is small, low Motutere Island, one of the hapu reserves. It was once the site of a large garden, between seasonal floods. Older locals remember a pātaka, or vegetable storage house on stilts, on the island. Another hapu reserve can be accessed from Motutere without feet even getting wet most of the year as the island, once in the middle of the river, is now circled by a dry moat, except after heavy rain.
But first visitors, most often hapu members, have to get to the island and other reserves without going on to Northpower land at the hydro station. A catwalk around the front of the power station used to enable access the reserves upriver, then a hop, skip and jump across the stream to the island. The catwalk has long gone.
So as not to trespass on Northpower land, getting to Motutere and the adjacent reserve can mean paddling a kayak across the river from just below the turbine outlets, across rapids and a fast flow of water, line up an angle to hit the opposite bank, then walking upriver through the DoC reserve (which spans both sides of the river).
For kaitiaki to access the river to carry out cultural inspections, elver translocations and eel surveys, involves another obstacle course — getting permission from Northpower to go through the gates it keeps locked at the top of the drive.
Northpower quite reasonably says people can't just have free access to a working power station. It is plain, simple logic, not just Health and Safety rules.
Millan Ruka's name probably makes Northland bureaucrats and their downstream staff curse.
He is a Whatitiri trustee, of Te Uriroroi, and a Northland rivers campaigner who was made a Member of the New Zealand Order of Merit in this year's Queens Birthday Honours.
Ruka has written thousands of submissions, requests, complaints, reports, survey summaries, you name it, to nearly every local and central government or public department relating to freshwater quality and tuna (eel) fisheries.
Throughout, Ruka remains mild mannered, humble, a quietly spoken quiet achiever who is quick to say he is only doing what is right, he is backed by the three hapu, and is only one of several trustees on the reserves management team.
In his role as Environment River Patrol-Aotearoa, searching out riverbank and water degradation from unfenced riparian zones, taking water samples and checking on eel and other wildlife numbers, Ruka would drop his kayak or other patrol craft into the water from DoC's Wairua Reserve.
The long-way-downstream detour he's had to take since the gate went up more than two years ago is a nuisance to him and impractical for others who will help with the upcoming summer survey of eel and elver numbers the Whatitiri trust has been asked to undertake.
Logistical planning needs to be done yesterday, but can't progress until access issues are sorted out.
A letter Ruka sent DoC operations manager Louisa Gritt on October this year (one of several on the same subject sent to all stakeholders over more than a year) points out the shared hapu reserves are places of cultural and spiritual significance. Te Uriroroi can only get to one reserve, but it's not practical for those not agile and fit who have to climb over two fences to get to it.
''The other three [reserves] cannot be visited unless you crash bush and paddle over. Not accessible by 99 per cent of people,'' the letter said.
On an earlier occasion, to Northpower, requesting access to the river for a cultural impact survey, he wrote: ''We seek to drive down the access track with three persons and to use our kayaks to get over to the other side of the Wairua River. We do not have a safe alternative.''
The resulting lectures from Northpower, on paper and on-site, about protocol and compliance were humiliating and unnecessary, suggests Ruka who is also expert in H&S regulations and has even taught the subject.
There are dozens of pages of cross-correspondence on the access issue.
Gritt, from DoC, assured Ruka a meeting was planned with Northpower late this November to discuss shifting the locked gates to the other end of its easement over the DoC managed Wairua Reserve. That didn't happen.
Gritt told the Northern Advocate DoC understood Ruka's concerns and had been working with him and Northpower on this for a number of months. Northpower and DoC have now agreed to meet in December to look at options to improve access, she said.
''This includes [considering] potential pedestrian access in the short term and investigations into improving access to the river along an already partially formed track and the possibility for provision of a small off road area for one or two vehicles, provided it is deemed safe.''
A number of concerns about health and safety include Northpower vehicles coming and going along the easement through the reserve, she said. And fairly unnecessarily considering this is the heart of the problem: ''What we would like to stress is that there is Public Conservation Land (PCL) which DoC manages and the Northpower site which is separate.''
All options involve treaty partner consultation which will take time, DoC said, but the department is committed to finding a solution.
''Other options include involving Whangārei District Council and looking at improving the paper road.''
Ruka has had extensive correspondence with the Walking Commission, and with Whangārei District Council on that matter, too. He is backed in that struggle by New Zealand Fish and Game.
Northpower also said it is continuing to work with DoC on access but has to ensure everybody's safety, including that of the Wairua Power Station personnel.
The gates shutting off the Wairua Reserve are on Northpower-owned land and are required under the Health and Safety at Work Act, and other standards.
''We don't allow members of the public access to any of our electricity assets in Kaipara and Whangārei without supervision, without being fully inducted on our health and safety protocol or without prior notification.
''No electricity generator operator in New Zealand provides open access to gain entry to their assets.''
Northpower is happy to host people at the power station, with reasonable advance notice, and visitors must undertake a health and safety induction and be supervised while on the property.
Trish Allen, chair of the Public Safety Working Group, acknowledged electricity assets across New Zealand reside in some beautiful places and can be of interest to members of the public.
''These areas are high risk and must be kept in a safe state so as not to cause harm to anyone. This is most important for members of the public who are not trained to recognise or understand the risks associated with these assets.
''Fencing, signage and controlled access are key control measures in ensuring safety.
"Sharing our assets with members of the public is under strict, controlled conditions.''
But Northpower is being asked by the Whatitiri trust to facilitate customary access to a hapu's own land via public land, not access to the power station.
The perfect storm has, on one front, led to devastation of eel numbers due to that killer blockage in the river, and similar obstacles in the drained, stopbanked, floodgated, pumped Hikurangi Swamp.
But the wider environment went through a massive change over a century of farming, irrigation take, drainage and land reclamation from swamp. Add to that the degradation of water quality due to decades — mostly no longer legal — of leachate from fertilised and herbicided pastures, animal effluent, carcasses, exotic forestry slash and unplanted, unfenced riparian banks.
Yet the whole area was once part of the largest eel nursery and habitat in Northland, a food supply — which it could be again, recreationally, customarily or commercially — and on the route to the Kaipara and up to the Pacific Ocean breeding grounds.
In 2011, Ruka, Niwa and Northpower installed fish ''ladders'', then later mussel ropes and a water bypass, so native long-fin eels and elvers could climb past the turbines that had minced millions over the years. That was after it was found there was no fish pass despite it being a resource consent condition for Northpower's operation.
That intervention may not alone have been enough to repopulate the vast upper catchment with tuna. So hapu from local Korokota marae and fresh water conservation groups began catching elvers and moving them upstream — thousands upon thousands of them.
The Integrated Kaipara Harbour Management Group (IKHMG), other water quality and tuna repopulation interests are watching. Fonterra sponsored Living Waters and IKHMG, funded largely by the Government, has commissioned the Whatitiri Māori Reserves Trust to survey that translocation success and upstream eel health and numbers. The results will inform other studies and become a vital national as well as local resource.
The trust just needs to sort out how to get into the water to do it.