Created in 1956, the Kaituna Cut diverted the flow of water away from the Maketū estuary so surrounding areas could be farmed. But, it didn't go as planned.
Aroha Wilkinson is the last remaining member of the Maketū Action Group. Formed in the 1970s, the group tirelessly campaigned to return the Kaituna river to the Maketū estuary.
"The diversion didn't work. It was not what we were expecting," Wilkinson said. "From 14 culverts we were told in the beginning, to four. They ran out of money because they spent it on a study again, which had been done time and time again ... studies."
It didn't take locals long to notice something was wrong with the estuary.
"The estuary was gradually deteriorating. It was getting shallower and shallower and we were losing the natural runoffs. We only had one left and that's when my husband said we've got to do something."
But getting the locals motivated proved impossible.
"All of them said that they weren't interested in the river ... it was Maketū's river to look after, not theirs. Even the local people, had enough by then, just told us to do what we're going to do ... that it probably won't happen.
"They were disheartened, absolutely disheartened."
It took the group five years before it got the opportunity to make its case to the Government in 1984.
"We went into Parliament and everybody threw questions at us, we answered them. And we were taken to dinner and they said that it was all finished, the questioning.
"We went back in and that's when they said to us 'we have to come to Maketū and find out what the river is like. We don't know anything just by questions and answers – we've got to come and see it for ourselves. Is there anywhere you can put us up?' I said if you can sleep on a floor you can stay on the marae and we'll feed you. They said 'done'. So they came."
After being shown around the river and hearing about its history, the Government agreed to a re-diversion - it was 1988. A letter announced the regional council would begin the work the following Monday.
"They'd been allocated so much," Wilkinson said. "And unbeknown to us they started doing research work again. Then we were told after a while, when they'd spent quite a bit of money, that they were going through the money and it wasn't on the river, it was on studies.
The Maketū Action Group rang the Government and told it.
"And that's when they put an injunction on the money, and they said 'do the actual job, that's what it was for, the money was allocated to put the river back, not for studies'."
It was about the same time the regional council finished its study of the river and presented it to the group, who were shocked.
"All wrong. There was hardly anything that was right. They described an island - it wasn't an island it was mangroves. Where they got all that from?"
The study presented a huge obstacle to getting the Kaituna Cut rectified. If it was published, it could have completely destroyed the group's argument.
"We told our anthropologist 'we're not even going to bother going to the meeting. How do we stop that book from being published?'
"He said 'you've got to go to the meeting. Sit there, listen to the meeting, let them finish, and when they ask for questions, you walk out. All of you.'
"What happens then? He said 'the book doesn't get recognised and it doesn't become fact' and that's exactly what we did.
"Then the Bay of Plenty Times started helping us ... and then we got the culverts."
Looking back, Wilkinson says the hardest part to deal with was the lack of support from some of the locals.
"They were really negative, our own people. They weren't interested," she said. "Now, I can walk into a meeting ... all those people that are sitting in the marae are the very ones that never ever wanted anything to do with the return of the river. And now they've got a cheek to stand there and start talking about the river and that to me is ..."
"That part hurts because none of these ones see it now," she said pointing to her fellow Maketū Action Group members.
But a happy ending is within reach, with the first stage of the re-diversion due to open in the coming months.
"It is happy now. Probably the opening will be shortly, well before time. So yes, it is... it is a happy ending."