THE ORIGINS OF OUR ECO FOLLY can be dated to an early spring morning when I took the dogs for a walk up on the hillside behind the house. I noticed the slight figure of a man, high above me, picking his way down through the scrub. He stopped and began waving and jabbing an arm in the direction of the gorge as if he wanted me to look at something, but I couldn’t make out what it might be. It was one of those days with barely a whisper of wind and only the odd tutubía dipping its way across a cloudless sky. Then I saw it: a surge of water was rolling down the Cádiar river, roaring as it came. Within minutes the whole riverbed was a pinkish-brown flood, dotted with clumps of bushes and trees that had been torn from the hills. Then, almost as soon as it had begun, the torrent subsided and the river returned to its normal steady sussuration.

I had heard about the awesome erosion of flash floods before but had never seen it in action. There must have been a violent and sudden rainstorm up in the hills of the Contraviesa, as the river was coloured by the red earth washed off its steep slopes. The water had been so thick with earth and sand that it had moved almost in slow motion, like a river of treacle, rearranging the topography of our riverbed.

I turned to look up the hill and saw the man who had been waving, approaching along the path. He was wearing a purple tracksuit and hopped over the stones with an agility that seemed at odds with his mop of curly grey hair. I noticed that he was carrying a stylish-looking retractable umbrella.

‘Hallo,’ the man said in English.

‘Hallo,’ I replied, looking with curiosity at the umbrella.

‘Oh yes, it’s a Japanese design, very compact…’ he offered, marking my interest. ‘I had an idea a storm might break, but I hadn’t expected it to happen so far up.’ And he talked at length about the phenomenon of flash-flooding, pointing out just why he thought the river had taken the course that it had.

I was fascinated by this display of hydrographical knowlege and stood there, nodding and putting in the odd question. ‘Where are you going?’ I asked eventually.

‘I’m going back to my van. I’ve parked it about two kilometres up river – beyond that cortijo there,’ and he pointed towards El Valero. ‘It’s Chris and Ana’s place, if you know them…?’

‘I do, I do… indeed I am them, or one of them.’

‘Really? That’s most felicitous,’ he paused, savouring the word. ‘I’d been intending to come over and introduce myself to you.’

‘Felicitous indeed,’ I said. ‘Who are you, then?’

‘I’m Trev,’ he said, extending his hand. ‘Not Trevor. Trev.’

I said I was pleased to meet him and suggested we walk back to the farm together. I was anxious to see what damage the flood had done to the river terrace. As we walked, Trev told me about his work as an itinerant ecological engineer and how he thought it possible that we might be in need of his services. I told him I wasn’t sure exactly what an ecological engineer did – but if he could help me improve the efficiency of my solar power panels or improve on the shaky functioning of the chumbo – well, we could certainly use some help. Trev nodded at this but said that he preferred to put his mind to something more concrete – metaphorically speaking, he added hastily. He’d tell me what was possible when we’d had a look over the land.

We stopped at the house, where I made Trev a cup of herbal tea. When I carried it out onto the patio, I saw that he had walked down to the terrace by Ana’s vegetable patch and was pacing slowly to and fro. Every now and again he would stop, look up at the sun and rub the side of his nose with his index finger; this, it appeared, was his preferred mode of thinking. Porca, who likes to keep an eye on his territory, was flitting between the branches of a large fig tree and studying the intruder.

‘I’ve had a good look at your solar panels and your water systems,’ Trev announced as I joined him. ‘And I can see what you mean about the chumbo. It’s a bit honky down there, isn’t it? What you need is a reed-bed to clean up your waste.’ Then, reaching out for his cup, he peered up into the branches of the fig: ‘Ah – a Quaker Parakeet, I do like those,’ he said, before resuming his flow. ‘I reckon we’re going to have to think laterally about fusing alternative and traditional technology in this place. It’s a great spot to do it, mind – really very promising for the right sort of project.’

‘Yes, you’re right,’ I said slowly. I noticed how he had said we and indeed this seemed like good innovative talk. ‘So what eco-scheme do you think we should go for?’

‘Well, it won’t be easy and it won’t be cheap, but I could help you build something bold and experimental – something that would really enhance as well as interact with the environment. If you’re interested, of course.’

‘Sounds interesting,’ I said. ‘So, what is it?!’

‘A swimming pool,’ he replied.

I looked at Trev incredulously.

‘Are you crazy?’ I said. ‘What in hell would I want with one of those? If I want to swim, I can swim in the river, for Heaven’s sake.’

He met my gaze with a quizzical look.‘That’s not such a great prospect today,’ he said, indicating with a nod of his head the devastation in the riverbed below.

It was true. The flood and its sludge had carried away all trace of our swimming-hole, created with a bit of tractor-shovelling from Manolo and a precarious dam of boulders. It would take a long, hot day’s work to collect the boulders for another.

Trev folded an arm across his stomach, rested the other elbow in the cup of his hand and resumed fondling his nose. ‘I think maybe there’s a bit of confusion as to what I mean by the term swimming pool.’

It turned out that ‘swimming pool’ was in fact entirely the wrong term for the concept Trev had in mind for El Valero. ‘I’m not thinking of digging a rectangular hole in the ground…’ he explained, ‘…painting it turquoise and filling it full of chemicals. Oh no, I’m not into that at all. I’m thinking of bringing water closer to your home, creating an eco-sphere – one that you can swim in, mind – that will be natural and clean and yet not have a drop of chlorine in it.’

And Trev went on to explain why chlorine was the very bane of the planet; how aerosols and fridges and bovine flatulence were good for the ozone layer compared to what the chlorine in people’s swimming pools was doing. Then he began to sketch the idea that he had been developing for just such a client as myself, who appreciated ecology, who treated his farm and landscape as a kind of garden, who had notions about leaving the earth enriched rather than denuded and impoverished.

There was a real beauty about Trev’s ideas and it all sounded a long way from swimming pool salesmanship. He imagined our eco-sphere (for swimming) as a pool of crystalline water, filtered by secondary pools filled with a cleansing jungle of lilies, reeds, rushes and water-mints. Schools of delicious fish, later to be harvested for the household, would cruise to and fro devouring the organisms and micro-organisms inimical to the purity of our pond. A great bolster of raw untreated sheep’s wool would float upon the surface of the reed-pool to suck up all the gunk that fouled the water from sunburn oil and other unguents. And any organism or clod of muck that escaped this formidable net was to be lofted by a solar-powered waterwheel up to an immense stone bottle filled with selected sands and sifted earths from long before the dawn of man. (You could buy this stuff, apparently, in bags from swimming pool shops.)

From the great bottle the filtered water would meander along stone runnels where the action of the sun’s rays upon the thinly spread flow would knock any surviving bacteria on the head. Then the pure water would cascade over a fall of sun-baked stones back into the main pool. The whole was to be constructed using natural and locally-occurring materials; the shapes were to be organic and uplifting; the landscaping with stone and plants indigenous and exotic; and the project could be completed with an unpretentious pavilion of pisé and thatch.

It was clearly a mad, ludicrously complex scheme, and one based on a whole rake of optimistic assumptions. No one in their right mind would ever commision such a project.

I engaged Trev and his scheme on the spot.

I whiled away the rest of the morning in vainglorious thoughts of El Valero as a showpiece of eco-technology. Sitting on the terrace beside the vegetable patch – an auspicious spot according to Trev – I pictured Ana, Chloë and me floating happily among the lilies and gazing out across the mountains and rivers, while carp darted in the depths beneath.

My pleasant daydream was dispelled by the hoot of the car and the sound of dogs barking. Ana and Chloë were back from Orgiva. Jaime and Manolo had also come up to the house to collect some tools, and we all sat down on the terrace to have a drink in the shade. I could hardly contain myself and burst at once into an account of the flood, my meeting with Trev, and our bold new plans for reshaping the landscape of El Valero.

Chloë was thrilled. ‘Our very own swimming pool,’ she cheered, hopping around in excitement and setting the dogs off again. Bathing in the river, apparently, held no great charm for an eight-year-old. She pointed out that it wasn’t easy to practise your strokes on a sludgy river bottom with water barely reaching the top of your knees, and as the riverbed is quite wide, it means you get hot and dusty again before you’ve made it back to your towel hanging in the willow tree, let alone the house. Her only concern about Trev’s eco-scheme was whether the pool would be ready in time for her friend Hannah’s visit the next weekend.

Ana, once she’d digested the fact that I was serious about the project, and had indeed good as commissioned it, was also inclined to be positive, particularly about its botanical aspect. ‘It does sound beautiful,’ she conceded, ‘and I’ve always liked the idea of El Valero having its own grand folly. But how do you know it will work? You seem to be taking an awful lot on trust. And what do you actually know about this man Trevor and his earthly works?’

I had to concede that I didn’t know much. Trev and I had talked a little that morning about his previous projects and his chosen life. He had, for the past five years, been dividing his time between England, the Pyrenees and the Alpujarras, moving from one to the other in a customised van-cum-home-cum-office, stopping for however long a project involved. For the last couple of months he had been working at Cortijo Romero, an alternative therapy centre just outside Orgiva. The centre specialised in personal development courses, rebirthing, yoga, circle-dances and the like. Trev had designed and installed a complex underfloor heating system for the therapy rooms. ‘And what could be more important?’ I asked rhetorically, ‘if you’re casting off the shackles of your hidebound ego, than a nice, warm floor to do it on?’

Ana seemed to agree but said she’d be keen to hear how the system worked when winter arrived and it was actually switched on. However, Jaime was straightforwardly enthusiastic. He seemed to understand the workings of the project better than any of us and was keen to see how it all pieced together. ‘I doubt I’ll be here to take a dip in it, though, man,’ he said. ‘This is going to be a tricky project to get right; it could take months.’

Manolo, who’d been smiling to himself throughout these discussions, looked stunned. ‘Months?’ he spluttered. ‘It’s only a swimming pool.’ Manolo had orthodox views about how pools were built, having worked on a few in his time. The one unassailable rule was that they took no longer than six weeks. More than that and the workmen were either incompetent or robbing you blind, or both.

I explained yet again how this was going to be very different from your average chemical pool, and that we were going to create a whole new eco-sphere with cunning contrivances to keep the water clean and pure.

Manolo heard me out and then, resuming his habitual smile, asked: ‘So, no chlorine, then?’

‘No, Manolo,’ I answered. ‘No chlorine.’

Over the next fortnight, Trev hurled himself into calculations, diagrams and settings like a man possessed. The floodgates that had too often held back his visionary schemes now opened wide under our patronage, and the ideas came bursting forth. He lived the project, breathed it, slept it, drank it and ate it. The eating took the form of odd bits of greenery stuffed artlessly into a wholemeal bun: an odd diet that turned out to be an attempt to regain the affections of his girlfriend. She had, apparently, given him the boot (by email), because what she was after was a full-blooded vegan partner, and Trev’s half-baked vegetarianism fell way below the mark. We knew there was some justice in this, as when Trev came to eat with us he would hunker down to a plate of roast chicken like a proper trencherman.

From time to time, in order to see computer projections of the project, I would pay a visit to Trev’s van. This was parked in the shade of an olive tree on the far side of the river. From the outside it looked ordinary enough, the sort of van you might hire to load up a market stall, except that it had two large solar panels propped beside it on a rock, with a cord trailing back into the engine. On sunny days these panels provided more than enough electricity to run his computer and domestic appliances and on dull ones he could always charge up his solar batteries with a drive. He had also managed to find the nearest spot to El Valero where you could use a mobile phone and I would often come across him sitting on the hill with his laptop, surfing the Internet.

The only thing at odds with this technological Tardis were the van doors. When Trev first told me they were difficult to open, indicating that I should stand back while he did so, I assumed they must work on some state of the art time-lock device. In fact, they were dented and just needed to be kicked hard in a particular spot and then wrestled open with the handle. It was nice to see an old-fashioned method enduring.

Trev seemed able to turn his hand to almost any mechanical or electronic task, forging solutions with a mixture of science, art and Heath Robinson make-do. As the ecosphere project took shape, he adapted the windscreen-wiper-motor out of our old Land Rover and fitted it up to drive a bank of solar panels that moved with the progress of the sun, lying perpendicular to the sun’s rays all day and winding back at night to the starting position. The capacity of the panels was calculated to drive another motor – lifted from a defunct cement-mixer – that turns the waterwheel, whose lifting capacity is calculated in turn to move the entire volume of water of the pool three times through the filter, using the twelve hours of sunshine that we enjoy on an average summer day.

Throughout proceedings, the aesthetic consideration remained paramount, not least because Trev is also an artist. He shows his art works under the name of Val Dolphin (which has rather more pull in Bohemian circles than Trevor Miller) though the art is apparent in everything he designs. His pool steps, for example, sweep down in a spiral that calls to mind the interlocking leaves inside the aperture of a lens or that masterpiece of Bauhaus aquatic sculpture, the Penguin Pool at London Zoo.

All of this was exactly as I would have had it, except for one small failing – a failing that threatened to engulf our grand endeavour in a fog of rancour. Trev was an absolute perfectionist. He had no toleration whatsoever of errors and viewed even tiny deviations from his plans as jeopardising the entire project. Quite possibly he was right. But it was hard on both the soul and coffers to pull work apart and start all over again because a step, say, was two centimetres out, or the materials were discovered to be not quite up to scratch.

There was also the problem of lost days where we did nothing but wait for new parts to be sourced or materials to arrive, leaving Manolo, Jaime and me to do sporadic stints of labour when the right materials were to hand. And then with summer just around the corner and no swimming pool in sight, I cracked. Manolo and I had been working hard on completing the weir that separated the fish pond and sump. The sump was where the water was gathered for lifting by the waterwheel into the sand filter. For a whole day we’d struggled to get the levels right. It was slow, back-breaking work but we kept at it, knowing that the end was at last in sight and we could soon move on to another task. Then Trev appeared on the scene in his neatly laundered, off-white overalls, watched for a while and shook his head.

‘No, no, that won’t do at all,’ he called. ‘That’s way off.’

‘What do you mean?’ I spluttered.

‘It’s way off. It’s not level. You can see it’s not level, even from here. I’m afraid you’ll have to do it again.’

Manolo shrugged but I was ready for battle. ‘Now look here, Trev,’ I said. ‘What the hell does it matter if it’s a tiny smidgeon out? It’s only a pool for heaven’s sake – it’s not the bloody Hanging Gardens of Babylon.’

Trev wheeled round as if stung.

‘Alright. If you want to botch it up, then just say. It’s your money and you do what you want with it. Me, I want to do a good job and create a thing of real beauty. You think about it, Chris. You give it some good, hard thought.’ And with that he stomped off the site in the direction of his van, one finger rubbing hard at the side of his nose.

Deflated, I sat on a rock. Of course, Trev was being too finickity, but this was no way to handle things. I looked round at Manolo and Jaime but instead of backing my outburst, they both looked as if they thought I was in the wrong and had made a mess of it.

At lunch, I talked it over with Ana.

‘You’ve got this far,’ she said, ‘You might as well finish the thing off properly. It’s a pity to spoil the ship for a ha’porth of tar.’

‘Yes, I know. You’re right.’

That afternoon I strode down to the site and set to with a sledgehammer, demolishing our weir. Trev reappeared towards the end of the day.

‘So we’re going for the thing of beauty,’ he confirmed, looking at my pile of rubble.