Waterwise Irrigation Systems are designed and installed to make the most efficient use of available water. WWLP members are encouraged to design and install to Irrigation Australia standards.
Irrigation Australia Limited (WA region) and Water Corporation have compiled a workbook for the Waterwise Garden Irrigation Program (WGIP), which includes comprehensive specifications and installation advice for waterwise irrigation systems. Members of the Waterwise Landscaper Program who are interested in becoming Waterwise Garden Irrigators can contact Irrigation Australia (WA Region) at https://www.irrigation.com.au
For the purposes of the Waterwise Landscaper Program please refer to the WGIP ‘Systems specifications’ for your assessment. https://www.irrigation.org.au/assets/pages/6E9E6203-1708-51EB-A65470E3F41123EB/Good wateringLR.pdf
Note: Pay particular attention to garden bed irrigation, irrigation for turf and control systems.
The WGI Program covers:
- Smart watermark approved products
- Mains water connection
- Mainline
- Control valves
- Control wiring
- Cable connections
- Garden bed irrigation
- Irrigation on turf
- Control systems
- System handover
- Standards for domestic irrigation installation
Smart Approved WaterMark Products
The Smart Approved Watermark was established as a labelling scheme to promote water saving products and services and to reduce water use around the home. Some examples of Smart Approved Watermark products include selected brands of Mulches, Pool covers, and irrigation products. Preference should be given to products, which have been granted ‘Smart Approved Watermark Certification’ (SAWM).
These products, when installed and operated to the manufacturer’s specification, have been demonstrated to offer significant water savings.
Refer to www.smartwatermark.info to keep up to date with products certified.
A selection of the following certified products are listed in the WGIP:
- Drip irrigation
- Rain sensors
- Soil moisture monitors
- Sprinkler systems
Guidelines for waterwise irrigation systems
- Use separate stations for distinct hydrozones e.g. lawn and garden beds
- Each station should use sprinklers/emitters of the same type
- Design and install to minimize variations in rate of output between identical emitters in the system (system should not operate at more than 10% variation)
- All emitters should work at the manufacturer’s recommended operating pressure
Sprinkler systems
- Use sprays with coarse or heavier precipitation microsprays are not recommended due to misting.
- Sprinklers should be spaced at no more than the radius of throw specified by the manufacturer’s recommendations.
- Part circle sprinklers should be used where appropriate to prevent wasteful overspray in garden beds.
- Pop up heights should be suited to the planting or shrub adaptors fitted on fixed polyrisers above planting to minimize ‘shadowing’ of plants at their mature height
- In narrow beds less than 3m wide, irrigation may be installed on one side of the bed with sprinklers of a radius of throw of between 1/4 and 1/3 greater than the width of the bed providing that overspray is against a solid object or a turfed area.
Drip Systems
In line dripper and row spacing should be appropriate to the soil type, for example:
- Sandy soils – 0.3m dripper spacing, 0.3m rows
- medium/loamy soils – 0.4m dripper spacing, 0.4m rows
- heavy/clay soils – 0.5m dripper spacing, 0.5m rows
- Use appropriate layout techniques for the planting scheme e.g. grid format for dense planting and ‘lite’ layout of dripline where the line is woven throughout a planting area for more sparse planting schemes.
- For very sparse planting low-density poly and individual drippers may be more efficient.
- Drip systems should be protected by the installation of a minimum 120 mesh filter to prevent clogging of emitters.
- As subsurface drip systems (under lawn) require the introduction intrusion inhibitor at approved dosages, the mains water supply must be protected at the point of connection by a reduced pressure zone backflow device by a licensed plumber. Use only Anti Siphon (AS) dripline sub surface (turf).
- A vacuum breaker/air release valve should be installed at high point/points in the drip system to prevent ‘suck back’.
- An automatic line flushing valve should be installed for each station on the collection manifold at the furthest point in the system.
Benefits of drip irrigation
Landscape architects, contractors, nurseries, designers and consultants recognise the benefits of using low volume drip irrigation because of its accelerated plant growth compared to overhead sprays. The combination of rapid growth and dramatic water savings are the major benefits of drip systems. They are ideal for sloping areas, minimising run off.
Drip systems are flexible and can easily be added to at further stages of development as well as being easily retrofitted to an existing micro spray system. They can be applied in regular and odd- shaped areas and are discreet in high profile landscapes.
Drip applications are sub-surface for turf and sub-mulch for general planting. Drip is also the most efficient method of dispersing wastewater effluent (greywater) into the soil. It is possible to install drip irrigation into existing turf with minimal disturbance using purposedesigned equipment.
Drip irrigation is the only permissible form of water delivery in many states of Australia. It is the most appropriate irrigation system for our climate and strong prevailing winds.
For efficient water use, drip systems are recommended in almost all situations in preference to spray systems for garden beds.
For technical specifications on drip systems and their installation refer to p15 of the WGIP manual.
It is advisable to obtain further training in drip technology to ensure systems are designed and installed for effective application. It is also important to familiarise yourself with basic operational procedures pertaining to dosing, filtration, field flushing and root control intrusion where required.
Manufacturers and suppliers or drip irrigation components can provide further training and LIAWA can be contacted for upcoming Professional Development sessions on waterwise irrigation systems.
Irrigation controller
- Should be a minimum three station controller and be programmable to
- comply with watering guidelines and restrictions.
- Must have a ‘water budgeting’ feature to enable increase/decrease of watering
- times to all stations according to seasonal/prevailing weather requirements.
- Must be able to interface with a ‘Smart Approved WaterMark’ automatic rain sensor and soil moisture sensor.
- The rain sensor should be adjusted to shut off the irrigation automatically following rainfall.
- Where required the controller should be fitted with a back up battery to hold the memory in the controller in the event of power failure.
- Must be programmed in accordance with any existing watering restrictions in force. There is a table on the revers of the Waterwise Irrigation Control Card that gives seasonal adjustments.
The ‘standard drink’
The recommended ‘standard drink’ for Perth is 10mm of rainfall or 10 litres of water per m2 of watered soil. The standard drink is the same for both turf and garden areas.
Seasonal adjustment
| Time of year | Seasonal adjustment |
| January–February | 100% |
| March | 80% |
| April | 60% |
| May | Manual operation of the controller as necessary |
| June–August | System turned off (winter sprinkler ban) |
| September | Manual operation of controller as necessary |
| October | 60% |
| November | 80% |
| December | 90% |
Catch cups have been introduced to calculate the standard drink run time by sampling the precipitation from a system over a particular area. By placing the cups under each section of sprinklers and timing how long it takes to average 10mm depth, the operating time for the standard drink is obtained.
To establish run time follow these steps:
- Set 10 cups mid way between sprinklers and sprays
- Run the station for its ‘usual’ time
- Record all the readings except the lowest and highest
- Average the remaining eight readings (gives the ‘current drink’)
- Scale the run time up or down to give the standard drink
For checks on uniformity of distribution a more extensive test of coverage should be undertaken.
Future technology
New technologies are emerging such as the ‘Capillary Irrigation Sub-Surface Systems’ or ‘KISSS’. This system introduces a new irrigation approach that matches water delivery to the capillary action of the soil. A geotextile fabric allows water to move through the material at a rate that matches the soil’s ability to absorb it. Water is delivered to the root zone where it is available to the plants and held there in a wetting pattern rather than draining away.
Handover and irrigation scheduling
After installation a system ‘handover’ should take place that includes a working demonstration of all functions of the irrigation controller.
The watering program should be compliant with current Water Corporation and Department of Water regulations and recommendations.
Design tips
Advances in irrigation technology are giving greater flexibility in design and efficiency. Landscape designers and irrigation designers are advised to work closely together to ensure maximum effect for minimal water input. Here are ways designers can contribute to designing a waterwise landscape:
- Clearly identifying the types of plants to be irrigated to avoid shadowing/blocking effects as the plants mature.
- Employ hydrozoning i.e. grouping plants with similar watering requirements to ensure that maximum watering efficiency can be maintained.
- Match the system to the watering requirements of plants e.g. a advanced tree may require a larger volume of water than a sprinkler system can provide.
- Identify the soil type of the site, topography and microclimatic influences.
- Identify slopes on the plan to aid choices of irrigation in system design.
- Mark other points of interest that may have a bearing on the system design such as prolonged shade, high wear and tear.
- It is important that when gardens are redesigned, that the meter is left clear and is able to be read.
