1 © 2014 Regents of the University of Minnesota. All rights reserved. 11 Auditing home lawn irrigation systems Sam Bauer, University of Minnesota Extension

2 © 2014 Regents of the University of Minnesota. All rights reserved.

3 REASONS FOR AUDITING YOUR IRRIGATION SYSTEM  Every system will have a different precipitation rate –We need to convert minutes to depth  To ensure that the irrigation system is operating as designed  To identify any issues with irrigation uniformity and/or broken components  To reset arcs and angles of sprinklers

4 © 2014 Regents of the University of Minnesota. All rights reserved. Caroline Calcote

5 © 2014 Regents of the University of Minnesota. All rights reserved. IRRIGATION SYSTEMS  Key components of irrigation systems include: 1.Design (engineering) 2.Equipment: pipes, valves, controllers, etc 3.Installation 4.Water management: when and how much 5.Maintenance If not done correctly, any item will have a negative impact on water use efficiency

6 © 2014 Regents of the University of Minnesota. All rights reserved. IRRIGATION HEAD TYPES  3 primary types –Fixed spray- horizontal flat fan pattern –Impact rotor- single or multiple nozzles –Gear rotor- single or multiple nozzles –Rotors may have multiple stream designs, from 2 to 8 nozzles –Generally more efficient than single stream because of better water placement

7 © 2014 Regents of the University of Minnesota. All rights reserved. FIXED SPRAY NOZZLE Residential applications, 3-18ft spacing, high precipitation rates (up to 10”/hr), low DU compared to rotors, low operating pressures

8 © 2014 Regents of the University of Minnesota. All rights reserved. MATCHED PRECIPITATION RATE NOZZLES

9 © 2014 Regents of the University of Minnesota. All rights reserved. GEAR AND IMPACT ROTORS Radius of 18 to 100 ft, lower precipitation rates (under 1” per hour), geared rotors more common, higher operating pressures

10 © 2014 Regents of the University of Minnesota. All rights reserved. Beard and Kenna, 2008

11 © 2014 Regents of the University of Minnesota. All rights reserved. SPRINKLER SPACING

12 © 2014 Regents of the University of Minnesota. All rights reserved. OLD – VS – NEW SPRINKLER OR NOZZLE Coefficient of uniformity of an individual sprinkler

13 © 2014 Regents of the University of Minnesota. All rights reserved. IRRIGATION UNIFORMITY  Basic concept behind irrigation uniformity is to apply water as evenly as possible –Most irrigation scheduling is driven by dry spots –Applying more water to dry spots over-irrigates everything else  How can this be achieved? –Uniformity adjustments –Soil improvement- aeration, topdressing –Tolerate a few dry areas

14 Irrigation Uniformity Good Poor © Irrigation Association

15 © 2014 Regents of the University of Minnesota. All rights reserved.

16 © 2014 Regents of the University of Minnesota. All rights reserved. CONTROLLER TECHNOLOGIES Smart controllers: –Store historical data –Onsite sensors for calculating real time ET –Actual weather station utilization for ET adjustment –Rainfall, temperature, and moisture sensors

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18 © 2014 Regents of the University of Minnesota. All rights reserved. ADD-ONS  Soil moisture sensors  Rain sensors –The bare minimum

19 © 2014 Regents of the University of Minnesota. All rights reserved. Paul Eckholm

20 © 2014 Regents of the University of Minnesota. All rights reserved. CHEAP ALTERNATIVE TO AN IRRIGATION SYSTEM

21 © 2014 Regents of the University of Minnesota. All rights reserved. IRRIGATION AUDITING PROCEDURES 1.Site inspection –Check irrigation components, arcs and angles, programs 2.Performance testing –Catch cans. Longer test times = greater accuracy –Calculate precipitation rate and distribution uniformity 3.Scheduling –Set specific run times for each zone

22 © 2014 Regents of the University of Minnesota. All rights reserved. DISTRIBUTION UNIFORMITY (DU)  Measure by setting out several water collection cups on a grid  DU = avg of lower 25% divided by overall average of collection cups Ohio Irrigation Association

hour run time Overall average = Lowest 25% average = / * 100 = 74.4% Distribution uniformity = 74.4% Precipitation rate = 0.812”/hr Catch can depth (in)

24 © 2014 Regents of the University of Minnesota. All rights reserved. IRRIGATION ZONE ADJUSTMENTS Zone run time (min) Targeted irrigation depth (in.) Zone precip rate (in./hr) x 60 Zone run time (min) 0.5 inches 0.81 inch/hr x minutes to apply 0.5 inches of irrigation = =

25 © 2014 Regents of the University of Minnesota. All rights reserved. Precipitation and Infiltration Rates Precip. Rate < Infiltration Rate Precip. Rate > Infiltration Rate Turgeon, 2005

26 © 2014 Regents of the University of Minnesota. All rights reserved. SOIL WATER INFILTRATION Soil Infiltration Rates (in/hour) Coarse sand1.0 and up Fine sand0.5 to 3.1 Sandy loam0.4 to 2.6 Loam0.08 to 1.0 Clay loam0.04 to 0.6 Clay0.01 to.10 Adapted from: Kopec, 1995

27 © 2014 Regents of the University of Minnesota. All rights reserved. INFILTRATION TEST  Materials: water, stopwatch, ruler, wooden board, rubber mallet  Procedure: Double ring infiltrometer 1.Insert both rings into the soil to a depth of 2” 2.Fill both rings with water to a minimum depth of 4”, start clock 3.Record water level drop over 30 minutes 4.Repeat until infiltration stabilizes 5.Record stabilized infiltration rate

28 © 2014 Regents of the University of Minnesota. All rights reserved.  Once a day or once a week? –As infrequent as possible while still maintaining the health desired –Wet the soil to sufficient depths with each irrigation  Possibly 0.5 to 1” to reach soil depths of 6” and greater (soil type dependent) –Utilize multiple cycles per night for soils with low infiltration –Increase frequency and reduce volume in summer, or let lawns go dormant IRRIGATION FREQUENCY

29 © 2014 Regents of the University of Minnesota. All rights reserved. IRRIGATION TIMING  Irrigate in early morning if possible. During breakfast or before you leave for work. –Daytime irrigation is less efficient  Evaporation losses  Wind –Late afternoon to late evening irrigation can increase the incidence of certain turfgrass diseases, weeds, and promote succulence

30 © 2014 Regents of the University of Minnesota. All rights reserved. DETERMINING WHEN TO WATER  Soil moisture probe

31 © 2014 Regents of the University of Minnesota. All rights reserved. Dr. Aaron Patton, Purdue Dr. Dave Gardner, Ohio State

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33 © 2014 Regents of the University of Minnesota. All rights reserved. ADDITIONAL INFORMATION  UMN Turfgrass Science Website:  UMN Extension Turfgrass Management Website:  Sustainable Urban Landscape Information Series: Yard and Garden Info:  Facebook: “University of Minnesota Yard and Garden”   Blog: Smart Gardens Radio Show WCCO AM830, Saturdays 8-9am Sam contact: , twitter =