By Michael D. Vogt, CGCS, CGIA
There remains no simple way or shortcut to arrive at a method to manage irrigation water, especially given the inherent inefficiencies or water application with a circular pattern with designed overlaps along with single head coverage. However, the increase use of handheld moisture meters and in-ground moisture sensors have brought about many changes in water management and hand water applications particularly on greens surfaces. The superintendent must quantify the use of the current irrigation system by using the steps above and making adjustments to time at individual heads on a constant basis, which remains our best practice of today. Without the baseline numbers from an audit it remains a guessing game on what areas of the course are receiving quality coverage. Out of all information attained from irrigation audits the most important number to attain remains Distribution Uniformity; that percentage is the broad report card of the irrigation systems ability to apply water evenly over a give area.
When a superintendent designs a schedule for water distribution that schedule must be modified to accommodate changes in weather or evapotranspiration (ET0) which can change the turfs need for water. An audit provides the tools necessary to meet these requirements.
Our modern irrigation systems become less efficient with time and even the most advanced systems were never designed or intended to be a “set it and forget it” water distribution tool. The recommended schedule resulting from an audit is based on the field results; inspections, distribution uniformity, precipitation rate, soil intake amounts, turf water use, root zone depth and soil water holding capacity. Further adjustments to scheduling must be made to accommodate the limits of the control system used to operate the system.
An added benefit to an irrigation audit or multiple audits is to identify trends in system maintenance or other system needs. Typical maintenance activities that may be identified by an audit include:
• Adjusting sprinkler heads to level;
• Adjusting arcs for proper pattern coverage;
• Ensuring that there is nozzle and sprinkler uniformity;
• Clearing clogged nozzles;
• Replacing drive mechanisms or irregular rotating heads.
Also, an audit may alert superintendents to more significant problems, such as:
• Moving heads to more appropriate spacing;
• Adjusting pressures at pumping source;
• Adding pressure regulating devises in field;
• Upgrading to different system components (sprinklers, valves, pressure regulating valves, screens, filters, etc.).
Money saving examples of a properly maintained and scheduled system (an irrigation audit will supply these numbers to calculate your savings):
Once field data is gathered an illustration of saving can become clear and a return on investment can be communicated to club or course leaders.
Water savings will look like this:
Water will always have a cost, whether its cost is just pumping or you must actually purchase water. In the example above Distribution Uniformity (DQLQ) was collected for a golf course in the east that purchased water by the unit (1,000 gallons) which costs $1.40. Simple math tells us that saving 10% in DQLQ will yield a savings of 4,236,024 gallons per year. The equation would look like this, 4,236,024 / 1,000 = 4,236, 4,236 X $1.40 = $5,930.40.
Power savings would look like this:
Pump station pumps 1,000 gallons per minute, we save 4,236,024 gallons per year or 4,236 minutes of pumping time or 70.6 hours. If your course irrigation power bill was $21,000 per year based on 55,910,086 gallons at 60% DULQ that number would be 0.000376 (55,910,086 / $21,000 = 0.000376) per gallon in electricity or electricity savings of $1,592.00. In addition, saving 70.6 hours over the life of the pump system, that would equate to at least one free year added to the life of the pump station.
Combined savings of $5,930.40 water + $1,592.00 electricity = Total yearly savings $7,522.40.
Audit, $3,000.00 + new nozzles $3,000.00 + labor $1,522.40 = payback - one year
To locate a Golf Irrigation Auditor near you look to the Irrigation Association website;