How irrigation for Field of Play works
Irrigation. It’s vital for maintaining a healthy turfgrass sward and a crucial part of a turf manager's toolkit. Irrigation is not just applied to keep the grass alive but also used to wash in fertilisers or chemicals and applied to high-wear areas to accelerate turf repair. We get asked a lot of questions about irrigation when we’re going through the design process with clients, so we’ve put together an entire series on irrigation.
Part 1 consists of quick-fire blog posts that will answer the ten most common questions we get asked. Part 2 busts a few myths about how irrigation systems are designed.
Question 1: where does irrigation water come from?
This is a very common question and not surprising when the world is becoming more conscious about water usage. The answer does vary, but typically the irrigation system will connect into the site's water main and take potable (i.e. drinking water) from the town supply and apply it to the sports field via the irrigation system.
The connection to the water main is an important one; the pipes are large, the water is under a lot of pressure and the regulatory authority wants to ensure that water once is taken, does not pass back into the main as it could contaminate the drinking water supply. This work is done by a structure called a Headworks and sometimes called a Meter Pit. Most local governments have rules about what is required as part of the headworks, but typically, it would include:
• A water meter;
• A backflow prevention device (also called a check valve);
• A master valve for stopping supply to the entire irrigation system;
• A filter, and;
• Dedicated fittings for testing pressure and reducing pressure if necessary.
These pits are located near the property boundary at the connection with the mains.
Alternatively, irrigation water can be sourced from a nearby creek or a borehole. Taking surface water (i.e. from a nearby creek) is controlled by the Water Act 2000 and a water licence will be required. Taking underground water from a bore, or installing a new bore for irrigation on the property, may require approval under Water Regulation 2016 if it is to be located within a groundwater management area, and then a local approval may be necessary to confirm extraction quantities and the equipment, particularly if the borehole is deep.
Another option is to collect rainwater and stormwater into tanks for re-use on fields. How to calculate the volume of water a field need is the subject of another blog post, but if we need to apply 25mm of water per week over 10,000m2 that’s 250m3 of water, or 250,000 litres, per week. During Queensland's’ dry season, for example, it can go months without rain and so the size of the tank required to provide irrigation resilience during prolonged dry weather would be enormous as the source of water is so unreliable. Tanks (also the subject of a future blog post) are best used as a buffer for the irrigation system, used to provide temporary storage of water from a more reliable source before being applied to the field at the appropriate flow rate and pressure.
Potable water is the most reliable water source in terms of availability and quality but the most expensive. If you wish to use an alternative source, you’ll need to understand how much you are likely to use (in case you need a permit) and the quality of that water and how it might impact on grass health.
We hope you’ve enjoyed reading our irrigation blog. Check out our other posts and if you’d like to discuss anything covered in this irrigation series in more detail, contact us.
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