Irrigation systems
Designing and installing the system
Prepare a plan
Draw a plan of the garden to a scale of 1:100, which means that one centimetre on the plan equals one metre of garden. Using the spacings recommended by the manufacturer, the position of each sprinkler may be determined on the plan. The principles are similar for both microsprays and pop-up lawn sprinklers.
Plot each spray at half its spray diameter to allow complete coverage. Use half and quarter sprays along the edges of the garden and in the corners, while sprays are also available for narrow beds.
Pop-up lawn sprinklers, micro-sprays and drip irrigation all require different operating pressures and should not be mixed on the same lines.
Plot each spray at half its spray diameter to allow complete coverage. Use half and quarter sprays along the edges of the garden and in the corners, while sprays are also available for narrow beds.
Pop-up lawn sprinklers, micro-sprays and drip irrigation all require different operating pressures and should not be mixed on the same lines.
Calculating the water flow rate
Measure the time it takes to fill a 9 litre bucket directly from the tap you intend using, with all other taps turned off. Divide the container size in litres by the time taken to fill the bucket in seconds and multiply by 60.
For example, if it takes 20 seconds to fill a 9 litre bucket, the calculation is …
9 ÷ 20 x 60 = 27 litres per minute
The result is your maximum flow rate in litres per minute.
Sprinklers and drippers are rated by their flow rate, and knowing the flow rate of the water supply allows us to easily calculate how many sprinklers may be operated on the water supply at any one time.
The sprinklers required to irrigate a typical family block with average water needs will often exceed the flow rate available, so the load has to be divided between several separate lines.
Sprinklers, micro-sprays and drippers should not be operated on the same irrigation lines as their pressure requirements differ, but they can be operated on separate lines simultaneously, so long as the overall flow rate is adequate.
For example, if it takes 20 seconds to fill a 9 litre bucket, the calculation is …
9 ÷ 20 x 60 = 27 litres per minute
The result is your maximum flow rate in litres per minute.
Sprinklers and drippers are rated by their flow rate, and knowing the flow rate of the water supply allows us to easily calculate how many sprinklers may be operated on the water supply at any one time.
The sprinklers required to irrigate a typical family block with average water needs will often exceed the flow rate available, so the load has to be divided between several separate lines.
Sprinklers, micro-sprays and drippers should not be operated on the same irrigation lines as their pressure requirements differ, but they can be operated on separate lines simultaneously, so long as the overall flow rate is adequate.
Installation
All of the components necessary for a home garden irrigation system are readily available at most hardware stores and garden centres, along with brochures which provide detailed instructions and the flow rates needed for designing the system.
Micro-irrigation involves laying the 13mm polytube lines as required and inserting risers, drippers or sprays as required.
The installation of pop-up lawn sprinklers is more complex but still within the grasp of the average handyman. The sprinkler units are forced to ‘pop’ up above ground level by the water pressure, and are linked by rigid PVC pipes dug into trenches cut into the lawn surface. A most critical factor is to ensure that the sprinklers are flush with the lawn surface once installed to avoid damage to the units when mowing.
Micro-irrigation involves laying the 13mm polytube lines as required and inserting risers, drippers or sprays as required.
The installation of pop-up lawn sprinklers is more complex but still within the grasp of the average handyman. The sprinkler units are forced to ‘pop’ up above ground level by the water pressure, and are linked by rigid PVC pipes dug into trenches cut into the lawn surface. A most critical factor is to ensure that the sprinklers are flush with the lawn surface once installed to avoid damage to the units when mowing.