I t took Kurt Jackson five years to fulfil his mission to paint the Bristol Avon from source to sea – and now the successful project is being marked in style.

Images from the second half of his journey, from Bath to Avonmouth, are on show at the Victoria Art Gallery in the spa city. And a new book tells the full story, with all 120 of his paintings and many of his sketches reproduced.

The Victoria gallery showed his first set of paintings two years ago. Since then he has continued his journey through two cities, various suburbs, and a spectacular gorge that was being painted generations before Kurt Jackson came along.

From the green water meadows of Wiltshire to city wharves and the M5 bridge at Avonmouth, it sounds very much like a journey of two halves.

"It certainly was," Kurt replies. "The first part was very tranquil, green, beautiful, quiet, English. But when the Avon gets tidal, it's a different matter altogether – still striking in parts but also man-made, modern, muddy and noisy with traffic.

"I don't often paint in the middle of cities. I am far more at home in the countryside.

"In Bristol I chose to follow the floating harbour rather than literally the river. I enjoyed all the different craft, and the history of the place up to a certain extent.

"I still remember the scene from Temple Bridge, with the other bridges, the river traffic, churches and buildings ranging from yuppy office blocks to Victorian warehouses.

"And I remember that at one point in the city, on the opposite bank, two men were drilling in a warehouse conversion, next to me a chap caught a massive fish, and two blokes were getting drunk on a bench. All those strands of life coming together...

"I can well imagine why people who knew the city docks half a century ago have fond memories of the busy scene back then. On the other hand, we know that the Bristol slave trade centred around those docks, and we have to remember these things as well.

"Working down from the city centre, I painted the ss Great Britain, and, of course, the suspension bridge. How do you do that in a way it hasn't been done a thousand times before?

"In my case, I stayed with my wife Caroline at the Avon Gorge Hotel and painted it at night. I paid no attention to anything that had been done before.

"I work either totally plein air or in the studio, from sketchbooks or a little from photographs. Avonmouth was so different. I took photographs, printed them on canvas and then painted over them with oils.

"I felt it was a scene that demanded a different response, but so did the working conditions. I was not allowed in the docks , so I found myself up on the cycle path of the M5 bridge, looking down on the scene.

"I've never worked in conditions like that before, with the road noise and fumes. I must confess that end of the river is not my favourite part of world."

Kurt, who is 48, sells his paintings for anything from £900 to £50,000 in galleries, and continued working on other projects throughout his Avon years. Born in Blandford in Dorset, he has lived in Cornwall since 1984, and has an exhibition of paintings of islands off that county opening at the Lemon Street Gallery in Truro next month.

The new Avon book will be followed by a major retrospective study of his work, contributors to which include his great admirer the Bristol author Helen Dunmore. This will be launched at Tate St Ives next spring.

Another book, and one of the surprise hits of the summer, is Caught by the River, by Jeff Barrett (Cassell, £17.99), which includes a section by Kurt on his Avon experience, in particular at Bristol city council's Eastwood Farm nature reserve in Brislington. And the project has also been the subject of a short film by his daughter Zinzi, as part of her finals for a media degree at Swansea University.

Paintings in his current show are in sizes ranging up to 8ft x 12ft, and when we spoke, Kurt was looking forward to viewing them together on a gallery wall for the first time. About 20,000 visitors saw the first part of the Avon exhibition in Bath in 2007.

As was the case two years ago, he is still not afraid to write directly on to his canvases – words and phrases that spring to his mind while painting. It's an entertaining eccentricity, but many of his admirers find it unnecessary. His paintings say quite enough to the viewer – and that viewer does not need to be an art boffin to admire and understand them.

"The Avon project has been the highspot of my career," he says. "Every time I'm working it's an experience I think I'm so fortunate and privileged to be able to have."

It's been a venture in which he has injected mystery and magic into pleasingly recognisable landscapes, some of which have been familiar to him for a long time.

"When I was a kid I used to spend weekends with my grandparents on the Somerset- Wiltshire border," Kurt says. "One of the highlights was early on the Sunday morning before the rest of the family were awake, when my father and I would creep out of the house to walk across the misty, dew-covered fields towards Bradford on Avon. This is my first memory of this fine English river.

"Over the past few years I've completed several projects about rivers, in this country and on the Continent. To follow a river from its source as it grows and changes, erodes and meanders, evolving itself and the land, is not just a journey to get to know the river.

"It's also about discovering and understanding the host countryside – its history, people, culture and wildlife.

"The river becomes a metaphor for life itself. The Avon – 'the river' in Celtic – is very English and quite beautiful – some of it pristine, some of it abused, much of it used for industry, transport, fishing and agriculture."

The artist has always had a fascination with nature and studied zoology at St Peter's College, Oxford, during which time he also went to art courses at the Ruskin College of Art. After graduating, he travelled and painted extensively – visiting the Arctic alone, and hitching across Africa with Caroline.

At home in Penwith, they and their three children live in a carbon-neutral home, one of just a handful in the country, with a wind turbine in the garden generating all their energy and a heat-exchange pump buried deep under the house. Excess power is fed back into the National Grid. They grow most of their own vegetables – he is a vegan – and have built an eco-friendly freshwater pond near by.

He is equally enthusiastic about certain ecological and other charities, and Oxfam will benefit from the sale of three works in the current show – Below Weston Lock in Bath, Magpie Chatter at Holm Head and Autumn Dusk off Avonmouth.

"I want to ensure my way of living and working does as little damage as possible to the landscape," he says. "I see myself as an environmentalist. It's the fundamental issue and springboard for everything else in my life."

It's also an insight into his life that puts into perspective his distaste for some of what he saw towards the mouth of the Avon.

Kurt Jackson: The Avon, Bath to Avonmouth runs at the Victoria Art Gallery at Pulteney Bridge, Bath until October 4. The gallery is open Tuesday to Saturday 10am-5pm and Sunday 1.30pm-5pm, admission free. There will be a free exhibition tour with the gallery's Jon Benington on September 18, noon-12.45pm.