Yet with his gaze fixed downstream while steering his tinny along the reach known as the Seaham Weir Pool, Digby Rayward sees not just the beauty but the threats to this waterway.

"This has deteriorated so much in 20 years," Mr Rayward says. "What's it going to be like in 20 years' time?"

Digby Rayward has had a close-up view of that deterioration. His 16-hectare farm is on the river bank. Rayward says he has seen banks being eroded, trees falling into the river, and thicker weeds and more algal blooms because of an increase in nutrients in the water.

"I think we're almost at a tipping point," Mr Rayward says. "The river then becomes an unhealthy river."

Digby Rayward is the chairman of the Williams River Care Association, a group that has been battling for the best part of three decades to protect the waterway.

Much of their focus has been on the Seaham Weir Pool. It is a 20-kilometre stretch from Clarence Town downstream to Seaham Weir.

In the middle of this stretch is an area for wakeboarders, and it is also popular with water skiers.

Transport for NSW has a boating traffic management plan, with speed limits and usage restrictions along the weir pool, which is designed "to protect the environment of the Williams River".

However, the Williams River Care Association's members argue the water-skiing and wakeboarding boats are a major cause of damage along this reach.

To back their argument, they cite studies and reports stretching back to the 1990s, and they recount what they have seen play out on the water and along the banks.

"What we could see was a beautiful clear weir pool in the mornings, and the first boat comes past, second boat, and within five or six boats, it's turned into a turbid, murky river," says association member Brian Ness. "This is what we're physically seeing, seeing the wave action."

In response to the erosion and the sediment pouring into the river, property owners and environmental groups planted vegetation along the banks.

"We did all this work and we just watched it getting destroyed every summer," Brian Ness says. "It was a skiing problem. Then wakeboarding came in, and that made it even worse. A high-energy impact on the banks just destroyed whatever we put up."

The sediment is rich in nutrients. When the sediment is stirred up, Mr Ness argues, it provides food for weeds and algal blooms, including potentially toxic blue-green algae.

"It's growing and growing and growing as an issue," Brian Ness says of blue-green algae.

According to a Water NSW report in December, high levels of blue-green algae were detected in the Williams River at Clarence Town's caravan park, prompting a "red alert". In other words, avoid the water for recreational use, which doesn't exactly entice visitors to stay.

"They come for pristine 'green and clean', not green and 'blue-green'," says Digby Rayward, who is also a Dungog Shire councillor.

"We're getting more blue-green algae outbreaks, and they're starting to happen earlier."

In Clarence Town live other river lovers who are also boating enthusiasts. Mick Godfrey moved here in the early 1990s because of the river. He ran a ski school for about 15 years, and he and his family are still regularly out on the water.

"I love the river," Mr Godfrey says. "We fish in it, we ski in it, we paddle in it, we use it as a lifestyle."

He acknowledges some boats cause wave action. But at the moment, Mr Godfrey argues, with low water levels, there are more beaches and sediment benches along the banks, stopping the waves and preventing erosion. He questions whether boating activity in the river is affecting water quality.

"They need to show we're degrading the quality of the water," Mr Godfrey says.

To see the changes to the river, the State MP for Port Stephens and Shadow Minister for the Environment, Kate Washington, has headed out on the water this week.

First, Ms Washington kayaks upstream from Clarence Town's caravan park. She is guided by long-time locals Ron Elliott and John Ellis.

Ron Elliott, a renowned kayak maker, says he has no argument with the boats; he just cares about the river. Ron Elliott points out a carpet of duckweed and a trail on the surface that he says is the start of a blue-green algal bloom.

"It's the worst I've ever known it in 50 years," Mr Elliott says of the river.

"Unfortunately we're in a drought, and that is contributing somewhat to the state, but the growth of [duckweed] and the blue-green algae, never seen it like it before in my life. It's amazing."

Cattle are standing in the water. However, John Ellis doesn't believe cattle are a major problem for the river, whereas "the boats will stir up the mud and just keep that nutrient cycle going and going and going".

However, ski boats don't operate up here. Mick Godfrey says there is no algae issue downstream where he and others water ski and ride wakeboards.

Kate Washington heads down to that part of the river in the tinny, accompanied by Digby Rayward and Brian Ness. They point out the retreating banks, arguing that fences are creeping closer to the edge, and trees threaten to topple into the water.

"It's just like a slow cancer," Digby Rayward says.

To Kate Washington, this is more than a local environmental issue, with some landholders worried about what is happening in their backyard. The issue literally flows much further and deeper than that.

"This is a water security issue, a water quality and quantity issue," the MP says.

"Newcastle should care, and the whole of the Hunter should care, because this is about the Hunter's drinking water supply. This is ground zero for Hunter water security."

The weir pool is a crucial part of the Lower Hunter's drinking water supply.

Hunter Water says about half of the water in Grahamstown Dam is pumped from the Williams River at the Seaham Weir Pool.

The corporation says it has treatment processes to ensure the safety of drinking water. But it is concerned about ongoing deterioration in water quality as a result of erosion along the river.

"A failure to adequately address erosion would significantly increase the cost of producing drinking water at Grahamstown Water Treatment Plant, which is why we have recommended action to prevent further deterioration," a Hunter Water spokesperson says.

The Williams River Care Association members believe for this part of the waterway's future to clear up, the wake-producing boats have to go.

A 2015 study into erosion along the river recommended temporary boating restrictions, as one measure to prevent further damage to the river's banks. The report had identified other factors causing damage, including poor land management practices and floods.

After the study was released, Kate Washington said she was briefed by Hunter Water and was told there would be boating restrictions - "and then nothing happened".

In late 2016, a management working group, including government agencies and local councils, was formed to deal with the erosion issue. Hunter Water is a member of that group, and its spokesman says the corporation has been "working with Transport for NSW to identify solutions to address erosion caused by wake-generating boating activities".

Transport for NSW, which is the lead agency in the group, didn't directly answer a question about a boating ban. However, its spokesperson responded, "Transport for NSW's goal continues to be to work with other agencies and stakeholders to find a prgramtic, shared solution to a complex issue".

Mick Godfrey says a boating ban would hurt Clarence Town economically, and it would prompt him to sell up and leave.

"If they [government authorities] take it from us, it would be a significant dent on how we live," he said.

Former world champion barefoot skier Greg Adams, who has used the river for years, says it would be very disappointing if there was a general boating ban. However, he says those boats that produce waves causing damage along the river "have to go".

"I think we need to look at the size of the wake and the size of the waterway," Mr Adams says.

"There's only a certain size wave that can be on a skinny river."

Kate Washington says she will be seeking talks with Hunter Water, along with Environment Minister Matt Kean and Water Minister Melinda Pavey, for more to be done to protect the river.

"We can't just sit here once again and do nothing," Ms Washington says.

"If we don't make water security a priority now, we are being entirely irresponsible and we are dooming our future generations."

This story first appeared on The Herald.