choosing the right irrigation equipment, scheduling and audit requirements · 2017. 6. 30. ·...
TRANSCRIPT
![Page 1: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/1.jpg)
www.sonomacountywater.org
Kris Loomis CLIA,CID W.A Programs Specialist [email protected]
Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements
![Page 2: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/2.jpg)
MWELO Ordinance Sections Covered
• 492.7 Irrigation Design Plan• 492.10 Irrigation Scheduling• 492.12 Audit, Scheduling and
Analysis• 492.13 Efficiency
![Page 3: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/3.jpg)
492.7 Irrigation Design Plan A to V
Irrigation components and requirements
a) Metersb) Controllersc) PSI Regulators, boosterd) Sensorse) Manual shut off valvesf) Backflow preventiong) Flow sensorsh) Master valvesi) Runoff preventionj) Soil Infiltration ratesk) Hydrozones
l) Minimum efficiencym) ASABE/ICC802-2014n) Operating demands/restrictionso) Mulch = low flowp) Matched precipitation ratesq) Head to head coverager) Swing joints/riser protections) Check valvest) Areas with a dimension <10’u) 24” hardscape setbackv) Slopes and application rates
![Page 4: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/4.jpg)
Landscape Water Meters
• Non-residential • 1000 Sf or greater
• Residential • 5000 Sf or greater
Either provided by waterpurveyor or privately owned
I’m not a meter
Courtesy of Rain Bird
![Page 5: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/5.jpg)
Selection and Installation Considerations
Courtesy of Netafim Irrigation
Choose the correct meter by design flow range & minimal psi loss
Follow manufacturer’s upstream and downstream installation recommendations
Courtesy of Rain Bird
![Page 6: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/6.jpg)
Irrigation Controllers
Must utilize data from either • Evapotranspiration Or• Soil moisture sensing And• Non volatile memory
Courtesy of Hunter Industries
Courtesy of Hunter Industries Courtesy of Rain BirdCourtesy of Weathermatic
Courtesy of Toro / Irritrol
Courtesy of Rachio
![Page 7: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/7.jpg)
Pressure Regulation up or down
If water pressure is below or exceeds the recommended psi of the irrigation devices.Too high or too low?
• Excess psi must be addressed by usingeither a set psi or adjustable regulator
• Low psi can be addressedby installing a booster pump
Courtesy of Rain Bird
Courtesy of Hunter Industries
![Page 8: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/8.jpg)
Sensors
• Rain• Freeze• Wind Must be able to suspend or alter irrigation during unfavorable weather conditions
Courtesy of Hunter Industries
Courtesy of Hunter Industries
Courtesy of Rain Bird
Courtesy of Weathermatic
Courtesy of Toro / Irritro l
![Page 9: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/9.jpg)
Manual Shut-off Valves
Required close to point of connection • Gate• Ball• Butterfly ValveCan you use the valve on your backflow preventer? No!
IN CASE OF EMERGENCY
![Page 10: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/10.jpg)
Backflow Prevention Devices
Refer to applicable local agency code for requirements
Electric anti-siphon
Double Check R.P. Device
![Page 11: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/11.jpg)
Flow Sensors
Have the ability to detect high flow conditions.
• All commercial applications
• Residential over 5000 Sf
• Size by flow range
• Installation considerations
Courtesy of Rain Bird
![Page 12: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/12.jpg)
Master Shut-off Valves
A Love-Hate relationship • Required on all systems*• What they do• Why they do it• Problems they solve• Issues they create• How to get around the issues
Courtesy of Rain Bird
Courtesy of Weathermatic
Courtesy of Hunter Industries
Using a quick coupler can be a challenge with master valves
A remote valve controller may be your new best friend
Courtesy of Hunter Industries
![Page 13: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/13.jpg)
Prevent Runoff
• Run-off• Overspray• Low head drainage• What is a “similar condition”?
Avoid on hardscapes, adjacent property, non irrigated areas, roadways or structures
Courtesy of Rain Bird
Courtesy of Hunter Industries Courtesy of WUCOLS
![Page 14: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/14.jpg)
Soil Type and Infiltration Rates
Soil type dictates:• Water holding capacity • Irrigation frequency
Infiltration rate dictates:• How fast to apply water• Maximum zone run time• Number of cycle start times
Don’t bite off more than you can chew!
Courtesy of Rain Bird
Courtesy of Rain Bird
![Page 15: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/15.jpg)
Hydrozones
Hydrozones need to be irrigated according to their unique needs Considerations• Plant type• Plant factor• Soil type• Microclimate• Irrigation method• Precipitation rates
Courtesy of Hunter Industries
![Page 16: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/16.jpg)
Irrigation Efficiency 492.13
System must be designed and installed to meet, at minimum, the irrigation efficiency…regarding the Maximum Applied Water Allowance
Considerations Spray Efficiency ≥ .75 Drip Efficiency ≥ .81Choose quality irrigation products that have:• In-head pressure regulation• Matched precipitation rate nozzles• Larger droplet size• Pressure compensating drip emittersIf audit proves otherwise, improvements should be madeCourtesy of Hunter Industries
Courtesy of Netafim
![Page 17: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/17.jpg)
Efficient vs. Inefficient
Inefficient
Efficient
Inefficient Inefficient
Efficient Efficient
Lack of adequate pressure Excessive system pressure
Larger droplet size
![Page 18: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/18.jpg)
American National Standards Institute (ANSI) / American Society of Agricultural and Biological Engineers’/International Code Council (ASABE/ICC)
Quality tested products • .65 Distribution Uniformity Lower Quarter (DULQ) or higher • Search ASABE/ICC 802-2014 on manufacturer's website• Less flexibility on equipment choices…that’s a good thing• Limited knowledge about compliant products
![Page 19: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/19.jpg)
Operating Demands / Restrictions
Operating demand considerations • Pressure fluctuations due to demand • Reclaimed water availability
Restrictions • # of days per week limitations• Watering window limitations
![Page 20: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/20.jpg)
Mulch = Low Flow
The use of low volume irrigation is required to maximize water infiltration in the root zone
• Drip irrigation with online emitters
• Drip irrigation with inline emitter tubing
![Page 21: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/21.jpg)
Matched Precipitation Rates
Sprinkler heads and other emission devices
• Sprinklers…stick with one brand nozzle per zone• Drip Irrigation…use appropriate and consistent flow• Inline …use the same flow rate per outlet per zone
0
4
0 0
MPR
360 Degree = 4 GPM 0
1
1
2
0MPR
90 degree = 1 GPM 90 degree = 1 GPM 180 degree = 2 GPM
![Page 22: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/22.jpg)
Consistent Flow is the Key for MPR
Pressure compensating = more consistent flow
Non-Pressure compensating = less consistent flow
Courtesy of Netafim Irrigation
![Page 23: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/23.jpg)
Consistent Grid = Easier Calculations
Calculating precipitation rate and eventually run time can be less complicated when using this method
Courtesy of Netafim Irrigation
![Page 24: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/24.jpg)
Head to Head Coverage
• Goal, to achieve the highest distribution uniformity possible• Even Head to head coverage isn’t perfect • Follow manufacturer’s recommendations
No such thing as 100% DU
Poor coverage
![Page 25: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/25.jpg)
Swing Joints or Other Riser Protection
Courtesy of Hunter Industries
Courtesy of Rain Bird
Courtesy of Hunter Industries
• Static pressure devices need higher psi rated support
• Dynamic pressure devices can use lower psi rated support
• Above ground options
![Page 26: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/26.jpg)
Check Valves / Anti Drain Valves
• Low head drainage• Run-off• Water hammer• Erosion / surface problems• Water loss- guess how much?
Check valves and/or anti drain valves are required where low head drainage may occur. They help prevent
Courtesy of Rain Bird
Courtesy of Hunter Industries Courtesy of WUCOLS
![Page 27: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/27.jpg)
Areas Less than 10’ = No Spray
Irregular shaped areas are generally less efficient and are more susceptible to runoff
Short radius nozzles generally have high precipitation rates of 3” per hour +/- which soil infiltration rates can not match.
Here’s why:
What to do?......
Courtesy of Rain Bird
![Page 28: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/28.jpg)
Areas Less than 10’ = No Spray
What you can do: • Inline emitter tubing
offers a variety of application rates to better match your soil infiltration rates.
• Unusual size areas can be designed in a more efficient way.
• Using a tubing with a built in check valves helps to prevent low head drainage on slopes.
Courtesy of Rain Bird
![Page 29: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/29.jpg)
24” SetbackThese restrictions may be modified if:• The landscape area is
adjacent to permeable surfacing and no runoff occurs.
• The non-permeable surfaces are designed and constructed to drain entirely to landscaping.
• An alternative is specified that must be approved and prevent runoff. Confirmed in audit.
• No overhead irrigation within 24” of any non-permeable surface.
• May include drip, dripline, or other low flow non-spray technology.
• Can be planted or not planted.
• May be mulch, gravel, or other porous material.
![Page 30: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/30.jpg)
Slopes Greater than 25% = Low Application Rate
Courtesy of Netafim Irrigation
Precipitation rate too high
Precipitation rate ok
Study manufacturer design guidelines for your soil type. Consider:• Emitter flow • Emitter spacing • Lateral spacing• Slope
Precipitation rate cannot exceed .75 inches per hour
Courtesy of Netafim Irrigation
![Page 31: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/31.jpg)
Irrigation scheduling 492.10Schedules shall be developed, managed, and evaluated to utilize the minimum amount of water required to maintain plant health.
Irrigation schedules shall meet the following criteria:
1. Must have automatic irrigation controller.2. Overhead irrigation only between 8:00 pm and 10:00* (unless
weather prevents it) .3. Scheduling should meet ETWU without exceeding MAWA. 4. Continued………..
![Page 32: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/32.jpg)
Irrigation SchedulingIrrigation schedules shall meet the following criteria:
4. Parameters used to set controller shall be developed and submitted for each of the following:
A. Plant establishment period
B. The established landscape
C. Temporarily irrigated areas
![Page 33: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/33.jpg)
Irrigation Scheduling 5. Each irrigation schedule shall consider for each station
all of the following that apply:A. IntervalsB. Run timesC. CyclesD. Amount applied monthlyE. Application rate (PR)F. Root depthG. Plant type H. Soil typeI. Slope factor settingJ. Shade factor settingK. Irrigation uniformity or efficiency setting
![Page 34: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/34.jpg)
Irrigation Scheduling
All things considered:Plant factor, density, microclimate, efficiency, soil type and slope.
How long do you irrigate for ?
Eto(week) x 60 Or What you need x 60PR What you have
Learning how to calculate irrigation run times requires thought, time, a calculator and training.
![Page 35: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/35.jpg)
Irrigation Audit, Irrigation Survey, & Irrigation Water Use Analysis 492.12
a) All irrigation audits must be done by a local agency irrigation auditor or a third party certified landscape irrigation auditor.*
b) In large projects with multiple installations 1 in 7 lots or approximately 15% will satisfy the requirement.
c) For new construction and rehabilitated landscape projects installed after December 1, 2015
1) An irrigation audit report must be completed and turned in with Certificate of Completion that may include but is not limited to:
• Inspection• System tune-up• System test w/ Distribution uniformity• Reporting overspray or runoff• Preparation of an irrigation schedule
![Page 36: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/36.jpg)
Irrigation Audit, Irrigation Survey, & Irrigation Water Use Analysis 492.12
C 1) Continued…• Configuring irrigation controller considering the following:
• Precipitation rate
• Soil types
• Plant factors
• Slope
• Exposure
• Any other factors*
![Page 37: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/37.jpg)
Irrigation Audit, Irrigation Survey, & Irrigation Water Use Analysis 492.12
2) The local agency shall administer programs that may include, but not be limited to:
• Irrigation water use analysis• “irrigation water use analysis” means an analysis of water use data based
on meter readings and billing data.
• Irrigation audits• “irrigation audit” means an in-depth evaluation of the performance of an
irrigation system conducted by a Certified Landscape Irrigation Auditor. An irrigation audit includes, but is not limited to: inspection, system tune-up, system test with distribution uniformity or emission uniformity, reporting overspray or runoff that causes overland flow, and preparation of an irrigation schedule. The audit must be conducted in a manner consistent with the Irrigation Association's Landscape Irrigation Auditor Certification program or other U.S. Environmental Protection Agency “Watersense” labeled auditing program.
• Irrigation surveys for compliance with the MAWA• “irrigation survey” means an evaluation of an irrigation system that is less
detailed than an irrigation audit. An irrigation survey includes, but is not limited to: inspection, system test, and written recommendations to improve performance of the irrigation system.
![Page 38: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/38.jpg)
Irrigation Efficiency
a) For the purpose of determining Estimated Total Water Used, average efficiency is assumed to be 0.75 for overhead spray devices and 0.81 for drip system devices.
No such thing as 100% DU
The spray assumption of 0.75 or 75% efficient means that it is estimated that 75% of the water applied landed evenly across the intended irrigated area.
The drip assumption of 0.81 or 81% efficient means that it is estimated that 81% of the water applied landed evenly across the intended irrigated area.
![Page 39: Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements · 2017. 6. 30. · Courtesy of Netafim Irrigation. Irrigation scheduling 492.10. Schedules shall be developed,](https://reader035.vdocuments.mx/reader035/viewer/2022071501/612060dad1d53f7c7876290a/html5/thumbnails/39.jpg)
www.sonomacountywater.org
Choosing the Right Irrigation Equipment, Scheduling and Audit Requirements
• Kris Loomis CLIA,CID W.A Programs Specialist II