Drip Line Irrigation: All You Need To Know
I’m pretty sure you’ve seen it by now. The brown irrigation pipes used on gardens these days. It’s called drip line irrigation.
I wonder how many people understand how it works. How it’s supposed to work, that is. How the designer intended it to be used, and what components are necessary inclusions in the system for it to operate as it was designed.
On many occasions, I have seen single runs of this brown pipe running through gardens for as long as 25 to 30 metres, turning around trees and returning to where it started. I think this is because of our understanding of the old black poly pipe. You know, where we just jab a hole and insert a dripper. Many use this thinking, assuming the only difference is that the dripper is inside the pipe.
This thinking in incorrect. Why?
This brown drip line is very different to the old system and if installed and used correctly, it can operate effectively for 20 to 30 years without any substantial maintenance. Wow. That’s longevity for you. And of course, it is the most effective way to water a garden.
So where do I start?
Drip Line Irrigation Installation
Firstly, start at your water source, either a tap or solenoid valve. You will need to fit a dual check valve if it is not already fitted to your tap or solenoid valve assembly. This prevents water from your drip line system flowing back into the water supply. This is a legal requirement.
Secondly, you’ll need to reduce the water pressure, and install a filter to the irrigation line. You see, the drip line system is designed to run as a low-pressure system and requires a mesh filter to stop large foreign matter entering the pipework.
Thirdly, you’ll need to construct a manifold system from the delivery point, to start your pipework, and one at the other end on the garden, to receive the pipework.
Drip Irrigation System: Flushing
One of the important design aspects of a drip irrigation system, is the ability to totally flush it out. If the system is designed correctly with the recommended amount of pipework, the system should be able to flush automatically when it starts up and when it shuts down.
Flushing is a very important function of a drip line system, as it helps to prevent build-up of salts in the pipework that will eventually reduce flow in the pipe or cause blockages. Flushing will also prevent pathogens living in the pipework, that often get caught up in pipework.
How does the system do this?
I am glad you asked, as I quite often see this missing from a system. In some cases, the system is designed so badly it could never occur.
Firstly, you will need to fit a flushing valve to the lowest point of the line. We normally fit it below the network of piping, at the end of the receiving manifold, in a small square valve box. Next, we fit a vacuum breaker to the highest point of the line.
This configuration will allow flushing to occur when you start up the system. As the water fills the pipework, you will hear a high-pitched sound as air is pushed out of the drip line drippers. When the system has reached the correct pressure, both the flushing valve and the vacuum breaker will close, and the system is now running optimally.
Please Note: It is normal to see water coming from both the vacuum breaker and flushing valve until the system has reached the running pressure.
When the system has been switched off and the pressure drops below the running pressure, the vacuum breaker will open as will the flushing valve. This is important. Why? As the water drains from the system, if the vacuum is not broken, the pipe may be flattened under the pressure of the vacuum—created by the water exiting the system.
A system that is designed in this way, will run for years with the minimum of fuss, and will only require some seasonal cleaning or minor repairs.
Drip Line Irrigation: Getting it Right
It goes without saying, getting your drip line irrigation right from the get-go will not only save you money down the track, but it will also save you time and save you from headaches too.
Yes, you can give it a go yourself applying the advice offered in this article. Or you can give us a call, and we can set you on the right foundation. (We use Weathermatic Smartline Controllers).