PREPARED FOR WATER RESTRICTIONS?
AN EFFICIENT IRRIGATION SYSTEM IS THE ANSWER
BACK in September 2018, you may recall one of my articles dedicated to helping gardeners drought-proof their gardens through a number of strategies, one of which was installing an efficient irrigation system.
With the ongoing drought we have experienced over the last 12 to 18 months, one of the worst ever, it may not be long before our watering practices are more closely scrutinised by our region’s councils, and, in particular, their spin on what constitutes an “efficient” irrigation system as dictated by harsher water restrictions.
This may take the form of inspections of irrigation systems to make sure they comply with their rather convoluted and confusing efficiency guidelines.
So what style of irrigation system will be more likely to comply with these laws, and which will deliver water exactly where you want it in your garden?
If you take a long, hard look at the pros and cons of both sprinkler and drip irrigation, you’ll soon conclude that a drip system is better suited for irrigating most, if not all garden beds, be they vegies, annuals and perennials, or tree and shrub plots.
Sprinklers are still the chosen method of water delivery to lawns and other grassed areas.
I should point out that a drip system can take on one of two major forms, that of a continuous pipe with cleverly
engineered drippers installed internally at fixed intervals (usually 30, 40 or 50cm) along the pipe, or individual drippers (fixed or adjustable) attached externally, either directly to a pipe or via a small, flexible water delivery tube.
Why are drip systems better for the planted areas mentioned earlier?
Well, water savings alone can be up to 60% of that used by sprinklers for similar areas.
A well-planned drip system will put water only where it’s needed, reducing wastage and weed growth as well.
If matched to the soil texture, there’ll be no runoff (as sprinklers can cause on heavier soils), and excellent penetration of moisture down through the soil profile, which encourages deep, drought resistant root systems.
If the drip system is installed under garden mulch, evaporation is reduced to virtually nothing (sprinklers can lose up to one third their volume before the water hits the ground), and ALL water is applied to the soil, whereas some mulches, particularly those with finer textures, can absorb up to 50mm of irrigation from sprinklers before the soil begins to take on moisture.
And as plants grow taller, there’s no reduction in application effectiveness as would happen when taller plants and close foliage blocks the stream from a sprinkler.
Convinced yet?
There can be some drawbacks to using drip irrigation.
It’s difficult to see if there’s any
problems like blockages or leaks, as they’re usually hidden under mulch.
Some older systems can easily suck dirty water back into the dripper when the system is turned off and water drains to low points, but many newer types have anti-siphon features built in or recommend a vacuum breaker be installed at a high point.
Some readers with older systems may have also encountered roots growing into and blocking part-buried drippers.
Modern systems have clever root-intrusion prevention in the form of either a renewable filter that slowly releases root-discouraging chemicals (no harm to plant growth) or permanent copper-oxide coated emitters that roots hate to touch!
So there’s really no good reason why you shouldn’t toss that leaky, wasteful and highly modified sprinkler system and replace it with a sleek, shiny (and very quiet) drip system soon.
A few pointers just before you rush out to your nearest irrigation store and spend your hard-earned cash on the latest whizz-bang drip system.
Work out the flow rate of your water source.
If you’re connecting to a garden tap, whack a 10L (standard two gallon) bucket under it at full flow and time how long, in seconds, it takes to fill to the brim.
If it takes, say, 10 seconds to fill, then the flow rate will be 60L/min, or 3600L/hr.
This will be more than enough water to supply to a residential system.
(Email me if you need assistance working this out.)
You also need to know your water pressure, as this will dictate the parts required for installation.
Most garden taps in Toowoomba, for example, have too much pressure for many drip systems (they operate effectively between 40-300kPa), so the irrigation store may recommend a fixed pressure reducer to be included in the system.
Measuring water pressure requires an adaptor with a pressure gauge and an on-off valve for accurate readings.
There are also restrictions on the length of a drip system which is determined by your water pressure and how many (and what output) drippers per metre, as you can have too many for efficient operation.
There are a number of excellent local and regional irrigation stores with competent and qualified staff who can help the novice irrigator get the most (efficiency and effectiveness) out of their irrigation system.