A BAND of Celts wander north into new lands and discover a broad river sweeping through forests. They are in awe of the river because it is deep and powerful. They give it a name, and the name is Esk. To later generations this possesses magical, almost ethereal, qualities. The name resonates so strongly it survives several waves of migration: Romans, Anglo Saxons, Scots, Vikings, Normans. Thousands of years after those Celts peered through the rushes, that river is still called Esk. That’s fascinating.

I’m pondering this as I wander up the Rio Sucio on the outskirts of Orgiva, in Andalucia, many damp miles south of the River Esk. Thought processes fork and spill over stones like the branches of a stream. I pass a woman walking her dogs. She might be thinking about cooking dinner or the benefits of qigong. I’m thinking about river names.

Did you know that the river names Esk (of which there are several in England and Scotland), Usk, Axe and Exe share a common origin? The names stem from the ancient Celtic isca, meaning “water”. Simple as that. Those Celts peered through the rushes and said: “Huh. Water.” And it stuck.

The Rio Sucio is flowing for the first time since June. Two days of heavy rain have brought life to its thirsty runnel. Snow lies white and inaccessible above its source in the Sierra Nevada mountains.

Rio Sucio means “dirty river”. Little romance there, either; but at least there’s an adjective and a smattering of imagination. The dirty river is tainted with grey clays washed down from the folds of Cerrillo Redondo – slippery Andalucian clays the locals use for waterproofing the flat roofs of their homes.

When you dredge the silted depths of river etymology you recognise that names such as Yellow River and Red River aren’t so bland after all. They are basic and functional, but to non-English-speaking travellers they probably sound romantic.

River names of my Lakeland childhood include Brathay (Old Norse for broad river); Calder (Celtic for rapid or rocky river); Caldew (Anglo Saxon for cold river); Cocker (Celtic, crooked river); Derwent (Celtic, river abounding in oaks); Ehen (Celtic, cold river); Gilpin (Anglo Saxon, gushing river); Greta (Old Norse, rocky river); Irt (Celtic, possibly fresh or green river); Kent (Celtic, sacred river); Liza (Old Norse, shining river); Lowther (Old Norse, foaming river); Mint (Celtic, noisy river); Rothay (Old Norse, trout river); Sprint (Old Norse, gushing river).

My favourite is the River Mite, which flows into the Irish Sea at Ravenglass along with the Irt and one of the many Esks. The consensus is that Mite has its source in the Celtic word “meigh” – which means to urinate. Incidentally, the River Piddle, in Dorset, may or may not rejoice in similar origins. The Victorians altered the spelling to Puddle because that’s the sort of thing they were good at.

So I wander up the Rio Sucio pondering over stuff like this. Perhaps I should take up qigong. Perhaps I should find out what it is first.

FOOTNOTE: I have owned a copy of the Dalesman publication Lake District Place-Names, by Robert Gambles, since it was published in 1980. I nearly gave it away when I moved to Spain. So glad I didn’t. Incidentally, there is an alternative theory that the river names Esk, Usk, Axe and Exe mean “abounding with fish”. The scales of justice have yet to weigh on that one.