For garden bed areas there is a couple of main different irrigation options, landscape dripline or micro-sprinklers/sprays. While micro-sprinklers are good for vege gardens where the soil will be cultivated we strongly recommend landscape dripline for any shrub garden beds for the following reasons.
Firstly dripline lasts for years, this is different to micro-sprinkler systems, micro sprinklers are subject to damage by pets and animals and are also subject to damage by frosts, we continually see garden micro-sprinkler systems only a few years old that are damaged beyond use.
Secondly dripline is out of site and puts water directly into the soil and to the roots of the plants, buried beneath the garden mulch dripline is an invisible super effective irrigation system. Micro-sprinklers put out large sprays of water that are subject to drift if windy, another common problem is the sprinklers are blocked by plant growth and create dry ‘shadow’ areas throughout the garden bed.
Thirdy dripline is a lot cheaper to buy and install and uses a lot less water. This means you can create an irrigation system with less zones thus making it a lot more cost effective and simple and also save on installation costs.
We recommend drip line irrigation for your garden areas as it lasts longer, waters more effectively, is out of site and range of pets, uses less water and is less expensive.
Watermark generally use the Rivulus 13mm landscape dripline with pressure compensating drippers, this means the same amount of water is emitted out of the first dripper in the line as the last. We recommend this method for watering your shrub garden areas. For vege gardens or if you particularly want mirco-sprays in your shrub gardens we install quality micro-spray systems and position the sprinklers in the most effective way, we recommend you drain the zones and turn off prior to winter.
An irrigation system generally has several different zones that run at different times, different zones are required for two main purposes.
Firstly the system is subject to the available water flow at your property, for example a typical residential property will have water flow rate of between 20-40 litres per minute, if your irrigation system is using say 50 lpm the system will not function, there will not be sufficient flow to be emitted out of all the sprinklers at once. By dividing the system into several zones that run at different times you can water your entire property in different areas over a period of time.
The second reason different zones are required is because of the aspects of the site, i.e sunny areas and shady areas are divided into different zones that can be set to run for different lengths of time depending on the requirement. Garden beds are also broken into separate zones to lawn zones as shrubs have different water requirements and exposure to lawn areas.
Watermark designs our plans bearing all these factors in mind so you get a functional and effective watering system.
Below are links to download manuals for a wide range of controllers and sprinklers that we supply and install.
*One common mistake that is made on controllers is setting more than one start time, once a start time is set it will sequentially run through all the programmed zones, you do not need to set a start time for each zone unless you want the system to start multiple times in one day.
*Different programs within the controller allow you to separate out certain zones from others. For example a system with 4 zones could have zones 1,2,3 on program A with one start time set to operate on Mon, Wednesday and Friday, zone 4 could be on program B with 3 start times each day if you were trying to establish new grass in this zone.
*Most controllers have seasonal adjustment, by default this is set at 100%, you can reduce this to 50% for example in the autumn which automatically reduces the run times on all the zones to 50% of the setting. The available range is typically between 25-150%
*With rotor sprinklers it is important to note that with there being one stream of water a rotor set for 90 degrees will apply twice as much water as a rotor set for 180 degrees unless a different nozzle is installed. MP rotator sprinklers apply the same precipitation of water from 90-360 degrees.
As the pressure requirement increases through a pipe system the flow decreases. When we test your water flow at your property we test it at a pressure of about 2.5 bar or 36 psi, this is the optimum pressure that works well for sprinklers, dripline systems require a lot less pressure (around 0.5 bar or 8 psi). If you have a flow rate of 40lpm with no pressure this may drop to 30lpm to produce a 2.5 bar pressure. It is important to test the water source properly before designing an irrigation system.
We also measure static pressure (pressure in the line at no flow rate) if this exceeds about 3-4 bar we generally install a pressure reducing unit to avoid excess pressure in the irrigation system which can cause unnecessary leaks.
Flow rate is mainly influenced by pipe size, for example a 25mm pipe at 5 bar static pressure could produce around 40lpm while a 63mm pipe at the same pressure could produce around 400-500lpm. Supply pipes for residential properties are generally 20-25mm which reduces flow rate.
As the water makes it’s way through the pipe system the flow rates reduces because of friction. Below is a case study we did on an irrigation system to give you an example. When designing our irrigation systems we create a suitable buffer between the tested water flow and the required water flow at the emitters.
Friction loss case study – (based on pressure of 2.5 bar)
25mm MD mains pipe at water source tested at 42lpm
Waterflow tested at exit of manifold (start of zone pipe) the water had now travelled through 20m of 25mm ldpe pipe, 1 amiad 25mm 130 screen filter, 1 BCV backflow preventor, 2 corners and 2 (fully open) nyglass ball valves. Waterflow 31lpm
Waterflow tested at end of zone pipe, the water had now passed through an additional 40m of 19mm hi pol lateral & 2 corners. Waterflow 27lpm.
This shows how the flow rate decreases through the pipe system and the importance of designing a system that takes these factors into account. If the sprinkler water requirement in the zone mentioned above was over 27lpm the sprinklers would struggle to even pop-up or at best have a small arc of water being emitted rather than the required high pressure spray arc.
Pop-up lawn sprinklers, although designed and tested to create even precipitation throughout the arc are not always perfect. Imperfections can be caused by wind, near the sprinkler head the droplets are finer than on the outer perimeters of the arc, if there is a breeze blowing these smaller particles can be blown away while the outer perimeter is still being watered by the larger droplets.
Wind also significantly reduces the total arc of a sprinkler, if two sprinklers are just overlapping and you get a certain prevailing wind you can have the consequence of dry patches in your lawns. By designing a system that has head to head coverage (the perimeter of the arc of one sprinkler reaching the head of the next sprinkler) you minimise the chances of imperfections in the evenness of cover.
MP rotators are a revolutionary design and typically have the most even precipitation and wind resistant characteristics.
The primary purpose of a pop-up sprinkler system, rather than to wet the top of the grass, is to create and maintain suitable ground water so you have a nice evenly moist growing medium for your lawns and gardens.
We love creating amazing watering systems and seeing our customer enjoy green lawns and lush
gardens, please be in touch to discuss your requirements.