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How to: Design an Irrigation System

It is not a good idea to try to water your gardens and your lawns as one zone. Gardens and lawns require different amounts of water and generally do not require watering with the same frequency. The best option is to divide your gardens and lawns up into zones where each zone will require about the same amount of water at about the same frequency.

Below we're going to give you a run through of everything you'll need to know to get you started on designing a basic irrigation system for your home.

If you don't feel like tackling the job, our experienced design team are here to help. Click here for more information, fill in the form and receive an information pack via email detailing all the information we need from you to get started, at absolutely no charge! We cater clients Australia wide!

For those up for the task, any good design for an irrigation system will begin with two things:

1. A Plan - Drawn to scale with as much information as possible. For this you can use graph paper or download our Design Planner and draw out the design at a scale of 1:100. Show all garden and lawn areas, any paths or driveways, retaining walls and location of water source e.g. garden taps / water tank.

2. Your flow rate - A flow test is important as it dictates how many sprinklers you can run at once. Click here to see our formula for performing a simple "bucket flow test". Alternatively you can hire our water flow and pressure tester for a hire fee of $100.

    Things to remember when designing a system:

    1. All irrigation methods require different operating pressures to work efficiently.

    Roughly, most pop-up sprinklers require a pressure of at least 300kpa, garden sprinklers require at least 200kpa and dripline at least 100kpa. In order to determine how many pop ups, garden sprinklers or dripline can be run per zone, it is important to know the flow rate at the desired operating pressure.

    2. It is not a good idea to try to water your gardens and your lawns as one zone.

    Gardens and lawns require different amounts of water at different frequencies. When designing, divide your gardens and lawns up into separate zones, where all areas within each zone will require about the same amount of water, at about the same frequency.

    3. For your garden zones, avoid putting drippers / dripline and garden sprayers on the same zone.

    Drippers generally range from 1 to 24 litres per hour, whereas garden sprayers range from about 50 to 200 litres per hour. This means that you will get a very different precipitation rate across the zone, based on how long you water for, resulting in very uneven water coverage and inefficient water use.

    Lets start the lesson off with popup sprinklers for your lawns.

    Lawn Irrigation System with Popup Sprinklers:

    Head to Head" coverage - sprinklers should be installed so that one sprinkler sprays onto the adjacent sprinkler. The drawings below which show a 10m x 5m lawn area with 6 sprinkler heads (figure I.1) and one with 2 sprinklers (figure I.2).

    1. The first configuration means that there are no dry spots and that due to the overlapping of each sprinklers wetted area the run time for the zone can be reduced.

    2.The second has dry spots and so the area needs to be watered for excessive durations to provide water to these dry spots.

    It is better to spray from the edge of lawn and garden areas into the middle. So, it is better to position your sprinklers around the edge (see figure I.1). If the area is wider than the radius of the sprinklers used then more sprinklers should be placed in the middle.

     Figure I.1 - Efficient Installation Figure 1.2 - Inefficient Installation

    Your lawn and garden areas will probably not be uniform rectangles or squares. So, when you are designing a system, wherever possible, break the areas up into rectangles and squares.

    Gear driven pop up sprinklers and fan popup sprinklers should not be used within one zone.

    Fan sprays put down approximately 4 times the amount of water as gear drives in the same amount of time.

    This means that the area that is watered by the gear drives, will not receive enough water in the time it takes to water the area with the fan sprays, or the area with the fan sprays will be over-watered by the time it takes to water the area with the gear drives.

    Garden Irrigation System with Micro Sprays or Dripline:

    For garden areas we recommend micro-spray sprinklers or dripline.

    Micro-spray sprinklers

    With some variation due to your flow rate and pressure micro-spays generally throw a 2m radius and need between 50-70L/hr for each sprinkler.

    This means that they need to be installed every 2m and your flow rate in litres per hour divided by 70 will give you the maximum number of sprinklers that can be installed on each zone. Micro-sprays should also be installed 'head to head'.

    Dripline

    There are many different configurations of in-line drip tube. One example is a flow rate of 2L/hr at 30cm spacing. As a general rule of thumb this dripline should be spaced at 40cm.

    This means that a run of dripline should be placed in your garden every 40cm. This effectively creates a grid pattern of 30x40cm rectangles with a dripper at each corner.

    • Your soil type will determine the correct spacing with sandy soil requiring closer and clay soil wider spacing.
    • Once the amount of dripline necessary is determined the flow rate can be worked out and the number of zones can be determined.
    • Divide the area by the spacing and then multiply this by the drip rate, then divide this number by the dripper spacing to get the flow rate required for the entire system. Then divide that number by the flow rate of your tap and you will have the number of zones necessary (see the following example for your calculations).
     Flow rate from your tap: Area to be watered: Run Spacing: Dripper Spacing Drip Emitter Rate:
    3000 L/hr 500 m2 40cm = 0.4m 30cm = 0.3m 2 L/hr
    500m2 ÷ 0.4m So, 1250m of drip line is needed for the area. 1250m x 2 L/hr ÷ 0.3m So, the entire system needs 8334 L/hr. We have 3000L/hr at the tap
    =1250m =8333.33 L/hr 8334 ÷ 3000 = 2.78

    So, the system needs to be divided into 3 zones. For more information about drip irrigation please see our 'Installing Drip Irrigation' Guide.

    Keep it manual, or automate my system?

    Choosing between automated or manual system is entirely up to your preference. You can spend as much or as little as you like and you can set up the system at a variety of automation levels.

    • Manual System - this is obviously the cheapest option and as a result it requires the most input from you on a day-to-day basis. You turn the tap on when you want to water and you turn it off when you think the area has had enough water. You will most likely need to build a manifold to allow different zones to be watered individually, if each zone is not connected to a separate tap.
    • Tap Timer - these are the "egg timer" style timers that most people are quite familiar with. They are inexpensive but they will reduce the flow rate to your system and may require you to reduce the number of spray heads you can use within a zone on your system. Again you will need to build a manifold to allow multiple zones from one tap.
    • Automatic system - this system will be more expensive but it allows you to water your lawns and gardens at any time of the day whether you are at home or not. It is better to water late in the evening or early in the morning and an automated system allows you to do this with ease. It also allows you to fit a rain sensor which will not allow the system to come on if it is, or has recently been, raining. An automatic system will require a controller and solenoid valves with multi-core cable joining the controller to the valves.

    For more information on automating an irrigation system, see our blog "How to: Install a Multi-Station Automatic Irrigation System".

    If you require any further information regarding designing or installing irrigation systems, please do not hesitate to contact our friendly sales staff at Dural Irrigation by phone on 1800 244 389 or contact us

    You can now go ahead and design and install an efficient drip irrigation system and more importantly gain maximum enjoyment from your garden.

    Planning to design and install your own irrigation system? Buy yours now! Free shipping Australia wide!


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    A smart irrigation system is controlled by a device that is programmed to automatically adjust your watering patterns depending on changes in weather and/or water demand.  The system will usually consist of an automatic controller with a rain, moisture or solar sensor or a WiFi controller with built in weather sensor software.

    Dural Irrigation offers a free design and quotation service for domestic residential solutions. Our qualified design specialists have many years of experience and will provide you with a design and quotation suited to your individual budget and requirements. Unfortunately we currently do not offer installation services, but you will receive expert advice and support to guide you through the whole process.

    The length of drip line should not exceed 60 meters from the point the water enters the line. Thus you could have 120 meters of lateral drip line if the water enters in the middle.  We recommend using a main feeder pipe and having your drip line laid in a grid pattern.

    The amount of sprinkler heads you can run at any one time, on one valve, is dictated by the pressure and flow rate of your water supply. Each sprinkler head has a required operating pressure and flow. Once you have calculated your flow rate at pressure from your water source, you can then determine the total number of sprinklers you can run efficiently at once.

    No, unless you are tapping into your mains water supply.  Most irrigation systems are quite easy to install and Dural Irrigation are here to give you expert advice and support to guide you through the whole process, from choosing the right products and fittings to after installation support.

    Gravity-fed irrigation is only an option for low pressure applications, such as drippers and dripline.  For a gravity feed system to perform well, we recommend installing your holding tank at least 10 meters in elevation and use the least amount of fittings as possible. The main feeder pipe should not be any less than 25mm.

    Let us guide you through your next project

    What is a smart irrigation system?

    A smart irrigation system is controlled by a device that is programmed to automatically adjust your watering patterns depending on changes in weather and/or water demand.  The system will usually consist of an automatic controller with a rain, moisture or solar sensor or a WiFi controller with built in weather sensor software.

    Do you provide design and installation services?

    Dural Irrigation offers a free design and quotation service for domestic residential solutions. Our qualified design specialists have many years of experience and will provide you with a design and quotation suited to your individual budget and requirements. Unfortunately we currently do not offer installation services, but you will receive expert advice and support to guide you through the whole process.

    How much dripline can I run at the same time?

    The length of drip line should not exceed 60 meters from the point the water enters the line. Thus you could have 120 meters of lateral drip line if the water enters in the middle.  We recommend using a main feeder pipe and having your drip line laid in a grid pattern.

    How many sprinklers can I run on one zone?

    The amount of sprinkler heads you can run at any one time, on one valve, is dictated by the pressure and flow rate of your water supply. Each sprinkler head has a required operating pressure and flow. Once you have calculated your flow rate at pressure from your water source, you can then determine the total number of sprinklers you can run efficiently at once.

    Do I need a plumber to install my irrigation system?

    No, unless you are tapping into your mains water supply.  Most irrigation systems are quite easy to install and Dural Irrigation are here to give you expert advice and support to guide you through the whole process, from choosing the right products and fittings to after installation support.

    Is gravity-fed irrigation an option?

    Gravity-fed irrigation is only an option for low pressure applications, such as drippers and dripline.  For a gravity feed system to perform well, we recommend installing your holding tank at least 10 meters in elevation and use the least amount of fittings as possible. The main feeder pipe should not be any less than 25mm.

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