Harnessing Your Own Water

It was a long winding ascent up dirt road, and I confess to walking my bike up most of it. According to the person who put me on to this place though: hills equal gravity and gravity is my friend for the thing I’ve come to see. It also started to rain, which seems appropriate and auspicious.

I eventually wheeled my bike along a rough driveway, past a small lake and to the entrance of a remarkable straw bale house. Two storeys high, it’s a mix of smooth-contoured white render and rustic wooden beams.

I’m welcomed at the door by a dog Jack and his owner Joyce, who kindly offered me a cup of tea. Joyce’s husband Ken arrived home a short while later and we sat down for lunch together. I’d come to see a special apparatus that I’d heard talked about but never seen before.

This is the first of two unique homes I was visiting, both off-the-grid and using an interesting method to get their energy.

Later that afternoon I’m walking my bike up another long, hilly, dirt road, past another small lake, and up a steep incline to another remarkable house. It’s been a long day and I arrive very hot, sweaty and worn out. The owners Peter and Robyn are warm and welcoming, and they soon lead me inside.

They immediately take me to the guest bathroom, which is immaculate and wouldn’t look out of place in some fancy hotel, and they show me how to use the composting toilet. This wasn’t the kind of water harvesting I’d come here to see, and I think I’d already sweated out any excess fluids coming up their hill, but it’s interesting nonetheless.

When you sit on the seat it presses down on a button that opens the flap covering the hole. Next to the toilet is a bucket of wood chips and a scoop, which you use to cover your business when you’re done. A small extractor fan in the tank keeps it odour free. Eventually it will all end up fertilising their orchard, with the composting process having killed any pathogens. It’s nice to know that my output will end up as something nutritious.

Peter and Robyn’s have kindly offered me their guest room for the night, and I feel like I’m in a luxurious resort. It’s wonderful to be showered again, with my clothes in the washing machine.

Over dinner I learn that Peter is a retired engineer and Robyn was a scientist but now works as a counsellor. They moved to Tasmania for the scenery and a slower pace of life, but also wanted to have a smaller environmental footprint. Their whole house is overflowing with sustainability features, while also being a very comfortable, attractive and spacious home.

The stone and timber that makes up their walls and ceiling comes from their land. Rainwater is harvested from their roof to meet all their water needs. Their greywater is passed through a series of grease traps and reed beds, from which it comes out clean and is used to water the orchard. Big north-facing windows allow passive solar heating in winter, with eaves to block the higher summer sun, along with outdoor blinds if necessary. The concrete floor and big stone fireplace provide thermal mass to soak up the heat and keep the house warm. It gets down to 7 degrees outside while I’m there, but inside it’s a comfortable 20 degrees, even with no heating. They have a wood heater, but they hardly use it.

They’re not connected to the electricity grid; instead an array of solar panels down the hill produces most of the electricity for the house, which gets stored in a large battery bank in a shed. All the household appliances have been selected for their energy efficiency, and any excess electricity can be used to charge their second-hand electric car — a small Mitsubishi iMiEV.

The challenge comes in winter, when their solar panels don’t produce enough.

In the morning Peter takes me for a walk. As we stride down the hill through large cleared fields that aren’t used for anything, I remember the question I asked them the night before over dinner. If they were wanting a low environmental footprint, wouldn’t it be better if all the trees on these fields hadn’t been cleared? They replied that the fields had been cleared generations ago for livestock grazing. Since they’ve owned the land a lot of it is reverting to native forest, and the rest has become grassland used by native wildlife. They’ve also put a ‘covenant’ on most of the forest; a legally binding requirement, attached to the land title, that the forest stay protected into the future.

We reach the small lake that I’d cycled past on my way in, which is actually a dam, and Peter takes me to the far corner. There a culvert allows the water to pass under the driveway into a small collection pond, before continuing as a small stream flowing into the forest. This is where their special system starts. But it’s the end of summer and unfortunately the water level in the collection pond is too low for the system to run.

To see a system that runs all year round I needed to go to Ken and Joyce’s place in Gordon, which is where I went the morning before. Let’s rewind to then.

I learnt that Ken and Joyce moved here for similar reasons to Peter and Robyn: for the scenery and slower pace of life. Their house also has a lot in common with Peter and Robyn’s. They’re both off-grid, with solar panels, micro hydro and battery storage; a passive solar design; energy efficient appliances; rainwater harvesting; greywater recycling; a vege garden; and an orchard. And they’re both gorgeous and comfortable homes, surrounded by hills and forest.

After lunch, Ken took me for a walk around his property. It was raining, so we wore raincoats. I feel sorry for the dog Jack, but he doesn’t seem to mind getting wet. Ken’s a soft-spoken and reserved man, and we started off walking in silence. Steep slopes dropped away to the side of the track we were following, and I kept expecting the tennis ball that Ken threw for Jack to bounce down into a gully, with Jack tumbling after it.

We reached the entrance to their property where there’s a small stream flowing through a culvert under the driveway, similar to at Peter’s house. Here Ken shows me the inlet. It’s a small metal tray covered by a mesh screen, over which the water flows as it comes out of the culvert. Connected to the tray is a plastic pipe about as wide as my forearm. The water that passes through the screen falls into the tray and enters the pipe.

I’m amazed at how small the stream is and how thin the pipe is, and find it hard to believe this can power their home. But of course, what’s most important is the change in elevation or ‘head’ — how far down the water is dropped. Hence why I needed to cycle up such a big hill to see this. We set off again, following the pipe down the hill.

Ken soon starts talking about water and the way it moves across his land. Previous farmers who cultivated this area had just been concerned with having the water reach the bottom of the valleys as soon as possible. He shows me a section of slope where the ground looks unstable with large cracks in it — an example of where old practices have led to erosion.

So much of what Ken does is about slowing the movement of water down the slopes. He’s carved out numerous long trenches, or “swales”, along the contours of the slopes, to allow the water to collect and soak in to the soil. He’s also dug ponds in many places, again to collect and slow the water. In winter the flow of water can become torrential, and as one swale overflows, the water runs into the next, and then the next after that; each one catching and slowing the torrent. Once it’s soaked in, the water keeps flowing but moving under the soil. Ken has researched this in depth and seems to understand his land intimately. You almost get the sense that he can see the flow of water under the ground.

Finally we reached a place where two small streams converge, and where the pipe we’d been following attached to a small housing. I could hear the splashing and whirring sound before I saw it. This was the micro hydro generator, and there were actually two of them, with another pipe coming from high up the other small stream. The whole apparatus was gushing with water.

Ken explained to me how it works. The pipe we’d been following had carried the water down a drop of about 45 metres, so it was now at high pressure. It was directed onto the rim of a small turbine called a ‘pelton wheel’, causing it to spin and turn a small generator (really just a small motor run in reverse). The generated electricity then entered a couple of cables and was carried through conduits buried in a long trench that led back up the hill to the house. These two small hydro systems were enough to power their home year round.

Joyce told me a story that speaks to the long history of hydro power in Tasmania. When they were digging the trench for the conduits, the young guy they’d hired to do the digging couldn’t understand why he was being made to dig it down the hill when he could see that the mains grid power lines were up the hill in the other direction. He was a timid lad though, and didn’t say anything, but he was confused and spent the night stewing over it. The next day he had to ask: what was going on?

The problem was that for many generations large-scale hydro power, using big reservoirs and dams, had supplied most of the electricity in Tasmania. To him, and to many Tasmanians, the mains power supply was the hydro; the two had become synonymous, and Tasmanians still often refer to power and electricity as “the hydro”. So when he was excavating the trench for Ken and Joyce, he understood that it was to connect the house to the hydro, but he assumed that meant the mains power grid.

After returning to the house with Ken, Joyce offered to take me to for another walk. We headed off past steep terraced slopes and down through a lush section of forest to another small stream. Here she showed me the inlet pipe for the second generator that I’d seen down the valley with Ken. The inlet screen was slightly different, apparently to protect against silt, and the pipe for this one was about as wide as my fist, but otherwise it’s very similar. We then enjoyed a nice walk through the forest following the pipe.

Fast forward again to the next morning over at Peter and Robyn’s place. Peter and I are looking at the collection pond where there’s currently not enough water to enter the inlet pipe. From there we follow the pipe as it snakes through woodland and into moist forest carpeted in moss.

As we walk Peter tells me about the challenges of laying the thick pipe, which originally came to them in large stiff coils. Together he and Robyn had the arduous job of stretching it out, painstakingly unwinding each coil along their driveway. They’d leave it for a few days to settle into its new shape, before then dragging each length down into the forest.

We arrive at a lush grotto surrounded by tree ferns. Here the pipe connects to the pelton wheel and generator, and the water is reunited with the stream. Because the generator isn’t running I’m able to see into the housing and the cupped blades of the turbine. It’s like a mini version of those big water wheels used by old-fashioned grain mills. It’s a beautiful setting for this elegant piece of technology.

Peter tells me that the water has dropped 45 metres in elevation, and can generate over 800 watts, enough to power their home in winter when their solar panels don’t get much sun. And unlike solar, it runs continually day and night.

Afterwards we follow the power conduit up another forested hillside and back towards the house. Threading the cable through the metal conduit was apparently another long, slow and repetitive job that they did themselves. It eventually enters a trench and travels underground the last few hundred metres to the house.

It’s been a special couple of days, and I’m touched and deeply grateful for the time that Ken, Joyce, Peter and Robyn have spent with me, showing me their slice of the world and how they’ve harnessed their water to meet their needs.

To cap it all off, Peter helps me load my bike and bags into the boot of their electric car and drives me all the way down the long hill. It occurs to me that I’m in a vehicle that can be powered by the water from their small stream.

Thank you so much Ken, Joyce, Peter and Robyn for hosting me and being so patient and hospitable. A huge thanks also to Paul Coull who built their micro hydro systems and who put me in contact with Ken and Peter.