What can be better than to follow a river from source to sea? What a privilege – and what a story! But what’s at the root of my fascination? Consider this.

All around the world and in many different cultures, rivers are regarded as metaphors for life. As rivers of life, they are sometimes seen as sacred entities – think of the river Ganges, or closer to home, the river Dee, which is said to get its name from an ancient Gaelic word meaning “goddess”. Having been drawn to rivers for most of my life, I can appreciate why they have this metaphysical appeal.

HeraldScotland: Paul Murton beside the North EskPaul Murton beside the North Esk (Image: BBC)

They can mirror our own lives in a purely elemental way as they flow from their source to the sea. They are like stories in this regard, having a beginning and an end, with many a twist and turn along the way; and like us, they are born mysteriously and almost magically, growing as they flow to their end, being absorbed by the mighty, salty sea. Rivers are ever-changing, with each ripple and wave forming and unforming as they hurry by; but despite this constant flux they remain substantially the same.

The Dee is the Dee, although its waters change by the minute. No doubt ancient peoples reflected on these mysteries and saw something divine in the rivers they often came to depend on.

Making the series Grand Tours of Scotland’s Rivers, I quickly realised how rivers offer a natural narrative structure, which is a huge help when developing a script. With a river, you know where it’s going to start and where it ends. But it’s all in the telling. They are their own stories of course, but they also carry the stories of generations of people who lived along their course.

HeraldScotland: Paul Murton with local historian Maureen Kelly Paul Murton with local historian Maureen Kelly (Image: BBC)

Many of these stories are embedded in the landscape, and in the names of places and geographical features the rivers flow past. Clach nan Tailler (the rock of the tailors) for example, sits beside the Dee, high in the Cairngorms. It marks the spot where a group of tailors died centuries ago trying to shelter from a snowstorm on their way back from a ceilidh. Then there are the numerous cairns and monuments that dot the wooded hills of the Balmoral estate. These were built by Queen Victoria to commemorate the lives of family members or remember happy events.

They transformed the woods around her Highland holiday home into a memorialised landscape. Hidden deep in an oak wood behind Balmoral Castle is a statue of the ghillie John Brown, who became the queen’s very special friend and companion. The relationship caused a family scandal and a rift between the widowed queen and the Prince of Wales. When he acceded to the throne, he had the statue removed to a secluded part of the grounds and destroyed all correspondence between Brown and the queen.

The haunting beauty of our rivers can be enjoyed by anyone who is willing to absorb the atmosphere hanging over still waters, where kingfishers flash blue as they dive, or to breathe in the spray of tumultuous, exhilarating waterfalls and rapids where Atlantic salmon leap against the flow.

But in some places, haunting takes on an otherworldly dimension, in castles and buildings of antiquity, where things are said to go bump in the night. In Fyvie Castle beside the quiet river Ythan, the hairs on the back of my neck rose perceptibly as I was told the story of Lillias Drummond, wife of Alexander Seton, who imprisoned Lillias because she failed to produce a male heir.

As punishment, she was imprisoned in the castle and died of starvation. Seton remarried a younger woman with unseemly haste. But Lillias ruined Alexander’s wedding night by haunting the nuptial bedroom. Terrible wailing and scratching noises were heard. In the morning, Lillias’s name was found, carved into the stone windowsill. It can be seen to this day. A likely tale no doubt – nonetheless, there is a chill atmosphere in the room where these events are said to have taken place.

In making the series, we visited five rivers: the Dee and the Ythan in the north east; the Esk in the Lothians, the Teviot in the Borders, and the river Annan in Dumfries and Galloway. Each of them has a unique character and personality. Some of them are associated with prehistoric river deities. All of them have a spirit of their own.

Occasionally, I can feel the spiritual dimension of a river. One unforgettable day I went in search of the source of the Dee, which rises spontaneously from solid rock close to the summit of the UK’s fourth highest mountain, Braeriach in the Cairngorms.

I had begun my climb wreathed in low cloud, but as I progressed, the clouds dissolved, making giddying patterns as they unfurled themselves from the flanks of the mountains. By the time I reached the summit, some 4,252ft above sea level, I had climbed out of the clouds and into the blue.

Below me, like a vaporous ice sheet, the cloud extended towards the horizon. Only the tops of the highest mountains were visible: Cairngorm, Ben Macdui, Cairn Toul, The Devil’s Peak, and away in the distance – and looking like a lonely desert atoll – dark Lochnagar.

Under a brilliant sun, I dropped off the summit towards a patch of ground marked on my map by small blue circles. These were the Wells of Dee – the ultimate source of the great River Dee. I dipped in my hand, scooped out some of this infant river water and savoured its fresh mountain taste.

Fascinated, I watched the crystal clear water gather into rivulets and become a stream. I followed its progress across the high plateau for about 500 metres and watched as it tumbled over a 700ft cliff edge and disappeared into the cloud-filled hollow of An Garbh Choire. A rainbow hung above the white mist below. It was a visionary experience, putting me in touch with something primal and out of this world.

Grand Tours of Scotland’s Rivers starts on Monday at 8.30pm on BBC One Scotland