Rock Island stands just the way it did when a single photograph defined wilderness in a new way for Australians. It's still there - a rock as sacred to some as Uluru; an igneous monolith eroded by millenniums of rushing water. Like the Franklin River, it is protected by its stubborn geology.

In 1979, now-retired school principal Peter Marmion stood on the river bank upstream of Rock Island at roughly the spot where photographer Peter Dombrovskis' laboriously set up his big Linhof camera. For Marmion it was a humbling moment. Thirty years ago, the campaign that Marmion joined to save the Franklin from inundation in a hydro-electric scheme reached a turning point. The single promise the newly elected prime minister, Bob Hawke, made on his election night victory speech on March 5, 1983, was ''the dam in Tasmania will not be built''.

It had taken a summer-long blockade for that point to be reached. More than 1200 people had been arrested and nearly 500 jailed. For his part, Marmion, a then newly minted teacher, doorknocked small rural towns of north-west Tasmania and sometimes the hostility was palpable.

In the election, the vote swung against Labor in Tasmania, but on the mainland the party benefited from a strategic Save the Franklin campaign. This climaxed on polling day with reproductions of Dombrovskis' picture Morning Mist, Rock Island Bend, Franklin River in this and other newspapers.

Final victory in the quest to save the Franklin was only ensured after the Hawke government defeated Tasmania in the High Court on July 1. Since then, Australia's best-known wild river has flowed as it continues to flow today - and its legacy has only grown. ''I think it was Australia's Yosemite,'' says the campaign leader and former Greens senator Bob Brown, pointing to America's first national park as a parallel. ''Australia had its real moment of environmental conversion.''

The Franklin's spirit is still evoked in green campaigns around Australia. Advocates of the Tarkine region in north-west Tasmania are the latest to threaten a ''Franklin-style'' blockade. Indeed, as recently as last weekend, Brown recalled the Franklin street rallies as he led a protest against the proposed gas hub at James Price Point in Western Australia.

To some who know the river today, its legacy is much more personal. The reason it flows in their hearts has nothing to do with the politics of saving it. For them, the Franklin is a story of itself.

People who were barely alive at the time of the blockade are now the custodians of the Franklin. Marmion, 56, first showed his infant son Adam the river in 1980. It was raining as he stepped out of a car beside the cross-island Lyell Highway, and walked to a shingle bank with the baby swaddled to his chest.

In 2013, Adam is 32 and an expert in human-powered water craft, a sprint canoeist, a rescue kayaker, and a guide on the rafting trips his father runs on the river.

Today, beside Adam in the raft is his close friend Alex Wilson, 28, an outdoor leadership training manager who went down the river with Adam for the first time at the age of 17. Between them they have done 33 Franklin trips, most as guides. Perhaps as much as anyone today, they are at home here.

''Everything is bigger, larger than life,'' Adam says.

Wilson says his first trip was the start of a career. ''It's such an incredible part of the world. Remote. Pretty significant white water. Different to anything I'd ever done. I felt so comfortable in the wilderness. I was more inspired to see remote places. It really was an eye-opener.''

A journey down the Franklin has become a rite for thousands of Australians; it has meant injury for some, death for others. It is an arduous and dangerous 100 kilometres of total immersion in the natural world. It is a place where it is impossible to do anything else but live in the moment in true wilderness, surviving by skill and by everyone pulling together.

At one minute, the shingle on the riverbed shimmers though the water's tannin tint. At the next, a paddle flails for grip through airy white water. And then there are the long, flat hauls against the wind.

All sounds are decided by the river. The water clatters and churns, drums and booms, or rolls in a near silent tumble. After a few days it becomes mesmerising. Hours might be spent listening to a waterfall cascade.

The vegetation that drapes the Franklin valley is a varied and exuberant green tapestry. There is no forest clearfell, no plantation, no weed. Instead there is old flora. Huon pines hang out over the river like Tolkien's guardian tree giants. Some of these ancients look as if they have been threatening to fall into the river for centuries.

On the edge of the floodline, younger vegetation is blown by the water to always face downstream. Piled into rock crevices are deep tangles of washed-up wood. Fallen logs hidden underwater snare passing rafts.

And then there are the rapids. Here the guides come alive. Is the best route river left, or through that squeeze on river right? Where is the rock ''undercut'' or ''stopper'' hole that will bring a raft to grief? What's changed since last time they were down?

Much of the rock is water-polished quartzite, slick as glass. As these guides ease rafts down more dangerous rapids by line, they step nimbly from rock to raft, and back to rock, as easily as if it were a footpath in the city.

In the Great Ravine, it's possible to sit on a monster boulder that weighs at least 300 tonnes. They feel it being vibrated by the flow. Adam notes that ''it's shifted a few metres to the left''.

At the Cauldron, a guide will look you in the eye and say ''if you fall in there, you will die''. Then they build a raft bridge over boulders beside the pool that holds its victims under by force of rolling water.

It was Adam's sad duty, as a rescue kayaker, to paddle the Great Ravine in 2009 to help find the body of a 26-year-old Indian soldier, Kailash Rana. He fell out of a raft as it glided past the top lip of the Cauldron. It took several days, but they recovered him.

There is a sign at the starting point of the rafting trip. ''Warning! This is not the place to learn whitewater skills. This river system is dangerous … Factors involved in the death of people on this river include entrapment, inexperience, entanglement, equipment failure, overconfidence, flooding.''

When it first became famous, some of the thousands who rafted the Franklin each summer had little grasp of what they were taking on. Paul Dimmick, a river ranger of the 1980s says: ''Extreme adventurers I was able to understand. I've actually done the Franklin on a lilo myself.

''But there was one man, Bruce Heckinger, who got off the bus with a wetsuit and a couple of barrels. I saw there was no raft, so I asked him what he was doing, and he said 'I'm going to be the first person to swim down the Franklin'. And he did. He actually popped out the bottom.''

Others Dimmick saw might have had rafts, but they had little or no comprehension of what they were taking on. ''About 5 per cent were completely unprepared, and I managed to turn them away,'' he says.

Dimmick also saw the environmental effect visitors had on the river. ''There was such a vast number of people that the river couldn't repair itself. The portage tracks and all the tent pegs. Now the numbers are down, and it can.''

Still, he advises people to think twice about making the journey. ''The Franklin is an ideal low-impact pathway through wilderness. You are actually being carried by nature, so it gives you a very strong connection.

''But with the vast number of people on the planet, and such a small number of wilderness areas, I have an ethic that you should only go there once.''

Alex Wilson disagrees. ''I'm a firm believer that you don't get to know a place until you've been a few times. You see the rapids in low, mid or high water, you see the tributaries, pick out the Huon pine stumps, build a picture over time.''

If the campaign had been lost and the Franklin had been dammed, it would have changed everything for him. ''I would have lost access to the most beautiful river in Tasmania, and my life might have taken a different course.''

On the nine-day rafting trip, Peter Marmion revelled in the company, but also spent a good deal of time quietly absorbing his surroundings, and contemplating the victory of 30 years ago. Like other long-time environmentalists he saw it through the prism of the loss of Lake Pedder, the Tasmanian highland jewel inundated for hydro-electricity in the 1970s.

''That was such a terrible experience,'' he says. ''So when the Franklin case was won, I think it was quite a turning point in Australians' thinking about their wild country.

''But the most exciting thing for me is that my grandchildren will have the opportunity to do this trip as well.''

And, indeed, Adam Marmion has taken each of his daughters, aged three and five, out for a test paddle on a kayak.

Andrew Darby is Tasmania correspondent.