When we moved to the Rock Farm, our garden was irrigated by dam water, pumped by a petrol pump. To water the garden, we would have to walk down to the dam with a can of petrol, and try to start the pump. More often than not, the pump would be hard to start and our garden would be left parched and dry for another day.
The first step was to give the petrol pump a service, and to build a small shelter or pump house for the pump. This helped considerably, and the pump is now far easier to start. But it was still a long way from the house, and turning a tap on to water the garden required a considerable effort.
Something had to be done, and we decided on a two-phase approach. The first phase was to install a header tank up near the house, with an electric pump on it that could water the garden on demand. The second phase was to replace the petrol pump with a solar pump and ball valve that would keep the header tank full at all times.
The most cost-effective tank for its size is the 5 000 gallon / 22 500 litre poly tank, and we ordered one from our local rural supplier. It arrived a week or so later and was carefully placed (dropped) from the truck on my leveled site. Thankfully I was able to move the tank into the right position with a couple of ropes and the four-wheel drive.
The plan was for the existing piping system to remain largely unchanged. A short extension was added from the 2 inch feeder pipe to allow the tank to be filled by the existing petrol pump. I needed a mechanism to bypass the new electric pump, so I added a few valves to allow me to fill the tank, and then run the electric pump from the tank back into the piping system.
It took a while and a few attempts to get the piping installed and checked for leaks. In the configuration below, the petrol pump on the dam can be run to fill the tank. Once the tank is filled, I can then switch two valves and use the electric pump to irrigate the garden.
The fittings I used are good quality, but decidedly expensive. The pump is a cheap one, but easily replaced should I need to. I have found cheap fittings don’t last, but have had good luck with the cheaper pumps. To give the pump a bit of protection from the weather, I also built a small shelter for it.
We leave the power switched off and the tank isolated when not in use, as we have a few leaks in the irrigation system that I am still working through. That said, it is much easier for us to open a valve and turn on the power to have water on demand in our garden.
During the peak of summer, we were able to water our garden every couple of days, without the difficulties of starting the old petrol pump. We found that because we could use the water easily, we did use the water, and we were able to nurse new fruit trees through the worst of the summer without loss.
The second phase of our plan – the solar pump on the dam – has been relegated to the bottom of the priority list for the next few years. The little Honda pump keeps working away without fault, and now I am only running it once or twice a month, my tolerance and patience with it is much less likely to wear out. It also provides a good redundancy in case of bush fire.