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Irrigation - Efficiency

Tuesday 08, Dec 2020

In the second part of this edition’s look at irrigation and water management, Bruce Macphee outlines ways turf managers can improve their irrigation system’s efficiency.

More than ever, turfgrass sporting surfaces are under greater scrutiny to be more environmentally responsible with the vital resources they have, in particular water.  The common misconception, particularly during periods of drought, is that anything green is environmentally irresponsible, irrespective of the water source. 

Improving water use efficiency must be a priority for all turf managers in this current climate to ensure we can continue to maintain sports surfaces at the high standard user groups have come to enjoy.  Maximising irrigation efficiency will reduce the volume of water required to maintain a quality sports turf surface.

The effective use of available water resources for irrigating all turf areas is a combination of the following;

  • A good system design with a high degree of delivery uniformity;
  • Flexible control (e.g.: valve in head); 
  • Regular maintenance and auditing of  the rrigation system;
  • A good understanding of plant water use; and
  • Appropriate turf management.


While we can’t always address all of the above points, significant improvements can be made without complete system replacement.  In most situations turf managers are not dealing with the latest state-of-the-art system and have to deal with infrastructure which is often old, outdated and nursed through each season just to keep the turf alive.

Something that should not be underestimated is the level of stress this can place on the turf manager, with sleepless nights spent worrying if the system is going to make it through the evening irrigation cycle.  Bores, transfer pumps, tank levels, old wiring, glue joints, stuck valves and broken sprinklers are just a sample of the possible failures.

Most turf managers get to know their system intimately and understand all the little idiosyncrasies that need attention just to keep the system going.  Replacement of an irrigation system, including pumps and controllers, can be a hard pill to swallow for many clubs and budgets don’t often allow for major upgrades to be completed.  While this problem won’t be solved overnight, completing a full assessment of your system and its weaknesses can help you make significant adjustments for the time being and help build a case for replacement down the line.

HOW OLD IS YOUR SYSTEM?

A good starting point is to review the ageof the various components of your irrigation system – sprinklers, pipes, valves, fittings pumps and controllers.  As an irrigation system ages, more frequent breakdowns are experienced.  Irrigation heads have many moving parts that can wear over time, gear rotors, impellers and nozzles also wear over time and rotation times can start to vary which greatly affects water distribution and uniformity.

Pipe work has a limited serviceable life with glue joints usually being the first to give way.  Over time, leaks in the pipe network can become frustrating and time-consuming to repair. Valves and wiring also become less reliable over time, particularly if valve boxes become full of soil or water.  The length of irrigation seasons also has an impact on the life expectancy of an irrigation system (i.e.: with a longer irrigation season there tends to be a shorter life expectancy).

With every irrigation system there comes a time when the cost of maintenance and down time lost to repairs outweigh the risk to the club of lost turf.  Keeping detailed records of your maintenance costs in relation to repairs can also help build a case for system replacement.  It is important to include system down time and costs for labour and components to provide the full picture.

The American Society of Golf Course Architects summarises the expected life cycle of an irrigation system as follows;

  • Irrigation system – 10-30 years;
  • Irrigation control system – 10-15 years;
  • PVC pipe (under pressure) – 10-30 years;
  • Pump station – 15-20 years.
     

CLICK HERE to read the full article. 

CLICK HERE to read the first part in the irrigation series. 

This article was originally published in Volume 22.5 of the Australian Turgrass Management Journal.