Tuesday, 6 October 2009
I have been fairly excited in recent days. I feel liberated from one of the great worries of farmers. And that worry is, when will it rain? While there is no replacing natural rain, having a water source which can be used for irrigation is absolutely fantastic.
The primary purpose of the new pond was for irrigation of the property. We are extremely fortunate that this is a spring-fed pond. So it just keeps filling and overflowing.
I was also very fortunate that the previous owners happened to put the waste treatment plant a short distance away from where I wanted to locate the pump. To me, electric was the only choice to power the pump. While solar might have been a distant second option as well, it is simply more efficient to put larger scale solar panels on the roof, than it is to have a small solar panel only driving a pump. So I have been able to run a temporary extension cord from the power point at the waste treatment plant to the pump.
After extensive research and comparison of Davey, Onga, and Grundfos pumps, I decided that the Grundfos JPB 4 PC15 was the best option. I was only looking for about 30 L/min and it can deliver up to 60 L/min. Moreover it takes much less power to do so than its Australian counter parts. Not to mention it was significantly cheaper even with a recent price rise. So while I would have like to support the Australian pump manufacturers, the simple fact was their engineering did not match my requirements without additional cost and, most importantly, additional power consumption. Power was my foremost consideration due to the existing power requirements of the waste treatment system.
For the piping, I chose 1-1/4 inch rural piping. This is also known as green line. It is an economical pipe with reasonably priced fittings. While it obviously has greater resistance than 1-1/2 inch and 2 inch pipe, the pump is able to still provide the required flow rate through this diameter of pipe. The longest run will be about 100+ meters with about an 8-meter delivery line static head and a 2-meter supply line static head. We have not fixed the pipe in place at this stage, as I wanted to see how well it worked at various locations on the property. So there is still some work to be done for the final fixed set up.
In the meantime, I have been able to lug the pipe around and get water back into the subsoil. How to I know that? Well, I put in 5 Jakfruit Blackgold seedlings into the chook free range area. I intensively watered the ground before I planted and the soil sucked it all up, including the clay subsoil (the green in the grass is thanks to the irrigation). However I did find that for the final planting hole, I had not watered the ground sufficiently. The soil which a shovel was able to shift in the other holes, required a mattock. Even then it was hard going. When I reached the clay layer, I had to stop. I filled the hole with water and let it soak in over night. The next day I was able to resume the planting which included working gypsum and organic matter into the clay layer.
So I look forward to being able to continue with an aggressive planting schedule as are in the driest time of the year for the SEQ area. Next stop, swale-ville.
Oh yes, I should also mention that the pump enclosure was made almost entirely out of recycled materials, with the exception of the roofing screws.