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Irrigation

by editor

Irrigation is all about the useful things we do with water in the landscape. Water can be sourced from a mains tap or a water tank or indeed the best of both worlds, a combination of both.

Water storage tanks can be located underground or aboveground and come in all different colours, shapes and sizes and are made from different materials such as plastics and metal.

What are the water collection points for water in the landscape
Besides coming off the roof of a building when it rains or after seeping through soil profiles; we can also use what’s termed grey water. Grey water is all the wastewater that a home produces such as from the bathroom and laundry. Grey water systems can be retro fitted to existing facilities. A licensed plumber must install these systems.

Once the water storage question is sorted you need to consider what type of irrigation system to install. This is recommended to be installed by a licensed plumber and drainer to ensure your project meets certain criteria, which can differ from State to State. The system to install will depend on aesthetics, the clients’ budget, the runoff area, garden size, water pressure and the desired outcomes from managing all this water.

There are two main types of irrigation systems:
• Sprinkler systems
• Drip irrigation

Sprinkler systems
The dimensions, size of lawns and gardens, and water pressure will determine the type and number of sprinklers that will need to be used. Consider local authority water restrictions too. If water use is not a consideration and large amounts of water need to be applied in a short time frame or large lawn areas need to be maintained, then this is the type of system to install.

Try to link the sprinklers into different zones, if possible, as some areas of the garden will need to be watered more often than others. For example, vegetable gardens will need more water than native plants. It may also be that you want the lawn to be watered at different times and rates to the garden.

The Hunter Solar Sync allows users to upgrade to a smart controller, providing daily automatic adjustments to a controller’s watering schedules based upon changing weather conditions.

Visit https://www.hunterindustries.com/ for more information on this.

Flow rates
The simplest method I know to test the flow rate in litres per minute from your mains water source is this:

  1. You need to time in seconds how long it takes to fill a standard bucket with water from the tap you will connect the system to
  2. Then divide that into 60 (seconds in a minute)
  3. Then multiply by bucket size in litres

For example, if it takes ten seconds to fill the bucket, then divide that into sixty (seconds in a minute) which is six and multiply six by nine (bucket size in litres) equals 54 litres per minute flow rate. The usable water available to you is 80 per cent of that total.

Specialist irrigation shops can work it all out for you.

Water pressure and pumps
Line lengths and number of sprinkler heads from the source also work against water pressure. Another way to combat water pressure or more precisely a lack of it, is to install a pump. Different pumps are used for different situations.

For instance, to pump water long distances, up steep slopes and in big volumes. There are:
• Floating pumps
• Submersible or turbine pumps
• Booster pumps
• End suction centrifugal pumps
• Displacement pumps
You might find it easier to contact Toro. Toro has been in Australia for over 40 years now and has expanded to become the largest single supplier of irrigation products to the landscape, agricultural, turf care and domestic household garden markets. For more information visit www.toro.com.au.

Drip or micro irrigation
The second type of irrigation system is drip or micro irrigation, and it is extremely water efficient. Drip irrigation:
• Uses much less water
• Minimizes evaporation
• Eliminates wind drift and overspray
• Reduces run off
• Delivers water directly to the roots of the plants which is the healthiest way to deliver nutrients to a plant

There are three main types of drip systems –
• Water weeping hose
• In-line drip tube
• Plug in drippers

Water weeping hoses weep water at a rate of approximately two litres per fifteen metres per minute along their entire length. They are designed to run at a low pressure and each hose can be up to thirty metres long.

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