Walking through a quiet forest of snow gums, passing scar trees, there is the sense that we are entering a hallowed and ancient ground. The forest opens into a clearing, and Uncle Max starts calling out to the ancestors to make them aware of our approach.

The Yuin elder has gathered Koori elders and clans in the Walgalu high country, the birthplace of Australia’s major rivers high in NSW’s Kosciuszko National Park.

Traditional owners and locals are concerned about the effect of feral horses in a NSW national park, which are now protected under new a new law.

They are here to perform a Narjong - a water ceremony - to invoke the sacred duty of caring for the river systems, a tribal responsibility for thousands of years.

"We’ve visited the source of several rivers which are holy to us," says Indigenous author Bruce Pascoe. "I’ll never forget Uncle Max taking us to the source of the Nepean, which rises in a peat bog."

Uncle Max and local guide Richard Swain have organised the ceremony to show the damage done to Kosciuszko’s delicate alpine wetland by feral horses.

But they also want to expose the myth around brumbies that resulted in the NSW government passing a law that recognised the heritage value of an animal that has only been in the Snowy Mountains for about 180 years.

Swain wants people to understand the reality of feral horses in the park, compared to the myth. The reality, which is backed by scientific studies, says that the horses destroy sensitive and important alpine ecosystems at the origin of our rivers.

Walking the land: clans on their way to a Narjong ceremony in Kosciuszko National Park. Justin McManus

The myth of the brumby in popular culture portrays them only as majestic wild horses. But in reality many are in poor health and show signs of abnormalities that are almost certainly the result of inbreeding.

As he walks, Uncle Max feels the hardness of the bare ground underfoot, pockmarked with horse hoofprints. “There is no give in it,” he says.

“The horse is much heavier than us, so when they tread on this, they are turning the taps off on the Murrumbidgee River.”

ACT Parks manager Brett McNamara shows how the sphagnum moss at the source of the Cotter River retains and cleans water. Justin McManus

Uncle Max is referring to is the hydrology of the sphagnum bogs and the river which forks through the mountains.

The wetlands house sphagnum moss that can retain water for up to seven years. Textured like a sponge, it naturally filters the water and slowly releases it down into the river systems and helps prevent the low-flow systems which favour growth of blue-green algae.

Algal blooms deplete oxygen in the water, and were the major cause of the massive fish kills in the Darling River in recent months.

Just across the border in Canberra’s Namadgi National Park, ACT Parks manager Brett McNamara and his rangers are working to control and monitor feral animals.

He’s concerned an unchecked feral horse population in northern Kosciuszko will soon set up shop in Namadgi’s delicate alpine wetlands, which feed the Cotter River, which in turn gives the nation's capital 80 per cent of its drinking water.

“I’m yet to meet a feral horse that can recognise a border,” McNamara says.

The wetlands were recently declared endangered and news that NSW park rangers removed zero horses from Kosciuszko was slammed as “irresponsible” by ACT Environment Minister Mick Gentleman.

McNamara says as far back as the 1900s, newspapers were reporting on the plight of pastoralists pitted against the pillaging feral mobs of wild horses. Only decades after Banjo Paterson’s 1890 poem "The Man From Snowy River" the Sydney Morning Herald was referring to brumbies as a “scourge” in 1913.

An alpine sphagnum bog at the source of the Cotter River in the Namadgi National Park, a fragile source of Canberra's water supply. Justin McManus

Feral horses got so out of control that in the 1940s, farmers were asking to use machine guns to thin out their numbers.

When Canberra was founded, one of the first laws passed was the Cotter River Act to protect the quality of the river’s water, at risk of damage by a then-strong feral horse population in Namadgi. Upholding the act was one of the first jobs of McNamara’s predecessor.

But pastoralists took it upon themselves to brutally cull the horses in NSW. They corralled them through V-shaped fencelines where, through the gap at the bottom of the V, they would hold out a knife and slit the horse's throat as it ran past.

A far cry from the dreamy, wistful image conjured by Paterson’s romantic ballad - though perhaps we would do better to remember the movie, where the brumbies are rounded up and removed from the high country by the daring young stockman Jim Craig.

Horses next to a headwater for the Murrumbidgee River on Currango Plain in Kosciuszko National Park. Justin McManus

Protections for the horses were spearheaded by NSW deputy premier and Nationals MP John Barilaro. He holds the state seat of Monaro, an electorate that covers 22,000 square kilometres in the state’s south, including the Snowy Mountains.

His so-called Brumby Bill passed NSW parliament in June last year and will see a new horse management plan drafted allowing only non-lethal methods to control their numbers, including re-homing.

Conservative estimates currently put Kosciuszko's feral horse population, stretching from south of the ACT’s borders to the Victorian border, at about 8000.

The bill saw the NSW government ditch the proposed plan from its own independent reference group, which in 2016 recommended bringing horse numbers down to 600 within two decades.

For a time, the deputy premier lauded the cultural values of the brumby and refused to be drawn on the damage an unchecked population could cause. But Barilaro’s recent comments at a public forum in Jindabyne have given some hope to anti-brumby advocates.

“Let’s get it clear, the Brumby Bill recognises the cultural connection. That’s why we have over decades, over decades, struggled to manage horse numbers in Kosciuszko,” Barilaro told the forum.

“What it does put in place, for the first time, it got all stakeholders at the table where we all agree we need a 50 per cent reduction immediately.”

But when asked why NSW needed to bin the 2016 independent report and form a new scientific committee, Barilaro says they needed to organise a recount of the horse population.

Damage caused by feral horses to the headwaters of the Murrumbidgee River in the Kosciuszko National Park. Justin McManus

“We cannot put a final number on it until we follow the process, identify the parts of the park that are suitable, and know how many horses there currently are,” he says.

One of the scientists who was on that independent reference group was botanist Professor Geoff Hope. He says a 50 per cent reduction would not be enough and the group agreed a population of 600 was the most sustainable.

“Our view was the park could tolerate a few out in the harder, lower parts,” he says.

While a fresh count is necessary, the count doesn’t need to happen before horses are removed, he says.

The higher wetlands are home to the critically endangered Northern Corroboree Frog, no bigger than a thumbnail, and the Broad-toothed Rat.

Degradation of the soil caused by feral horses. Justin McManus

But Hope says the biggest concern is once the wetlands and grasslands are gone, Kosciuszko’s insect and invertebrate biodiversity plummets.

“We’ve got a pretty unusual park. From a scientific perspective it’s also remarkable,” Hope says.

The horses are eating up and ‘pugging’ - stomping - the riverbeds, making them wider and shallower and muddying their flow.

Pascoe says that sheep are also incredibly destructive of soil. "The first Europeans found soils so friable you could run your fingers through them but after only a year of grazing by sheep, all the Aboriginal crops were gone and the soil had been beaten into a water-resistant pan. We have soft-footed animals already grazing on Australian farms, we should eat them and keep the horses to the race track and the house paddock."

Just on the Victorian border, the difference between untamed Kosciuszko and paddock Kosciuszko is clear. Fenced-off sections to keep horses out are flourishing with tussock. The rest of the plain by Wombat Trail is muddy, with a brown creek running at a gurgle.

But the horses have other supporters besides Barilaro.

Snowy Mountains local Peter Cochran has been a passionate advocate for allowing feral horses in Kosciuszko since he entered politics in 1988.

Many of the brumbies are in poor health and show signs of inbreeding. Justin McManus

Now, 20 years after leaving parliament, Cochran runs horseback tours through the Snowys with the chance to see feral horses a key selling point of his packages.

He and his wife made separate $5000 donations to Barilaro’s election campaign in 2011 but haven’t made donations since.

Cochran is quite open about his hands-on involvement in putting together the Brumby Bill with Barilaro in 2017. “Now is that a crime? Everybody has a vested interest,” he says.

His family has been in the Snowys for generations and he says brumbies are part of their cultural heritage.

When it comes to scientists who are concerned about the impact of horses on Kosciuszko: “Wouldn’t trust ’em as far as I can kick ’em.”

When it comes to the concerns Canberra has about the future of its water supply: “Bullshit.”

A pro-brumby activist from the Brumby Sustainability and Management Group follows the dancers to the Narjong ceremony ground. Justin McManus

And the fenced-off areas to protect grasslands from horses on the Victoria-NSW border? “A concocted scientific experiment.”

Back on the plains, Narjong performers from different parts of the river system paint up for ceremony: Ngarrindjeri from the the Murray mouth in South Australia, Barkindji from the Darling River, and Ngaran from the headwaters. A good crowd has gathered to show support for the ailing river systems, and hear the call to take responsibility for protecting country.

There are also people from the Snowy Mountains Brumby Sustainability and Management Group present. They have been camped next to the Narjong campers with their horses for a few days, in something of a standoff that reflects the polarisation around this issue.

The group's president, Alan Lanyon, denies the horses have had an impact on high country eco-systems, and describes this impact instead as “evidence of existence”.

Making fire for the smoking ceremony. Justin McManus

The scientists, whose studies say otherwise, are dismissed as being tied to a particular cluster of environmental groups that promote the complete removal of horses from the high country.

The ceremony begins with dancers circling the corroboree ground in full voice to the percussion of clap sticks, each group and river system singing up its name - “Indi”(Upper Murray river), “Murrumbidgee”, “Galari”(Lachlan River), “Barka” (Darling River) and then they merge into the “Murrundi”(Murray River).

The fire stick dance then follows, with the rhythmic chant of “Shulumun Baba” to call up the fire spirit.

Author Bruce Pascoe (foreground) and other participants in the ceremony wash ochre from their bodies in the Murrumbidgee River. Justin McManus

The fire makers spin their fire-making sticks with increased fervor. The chant and movement of dancers quickens, culminating in a crescendo of clap sticks as the fire sparks and takes hold.

Coolaman smoking fires are then lit from the one sacred spark, and all those gathered pass through the smoke - including the brumby advocates.

The smoking ritual is to encourage people to focus their energy on caring for the rivers and the landscape.

After the smoking is completed, the ashes from the fire are dug into the bank of the Murrumbidgee, giving ceremonial energy to the river. Dancers then proceed to bathe and wash off their ceremonial ochre into the river, also giving the river the power of the ceremony.

After the ceremony, Ngarrindjeri elder Major “Moogy” Sumner says he’s come from Coorong in South Australia, at the mouth of the Murray.

Pro-brumby activists go through the smoke at the ceremony, held on March 6. Justin McManus

“Without water, like everything else, we will just die,” he says. “Like the fish that died the other week [in the Murray], that water was dirty. That water was poison.”

“So if the fish die, and the little animals and plants that rely on the water die ... when is it our turn that we’ll be dying, that we’ll be missing from this country?”