Landscape Irrigation Auditing

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Landscape Irrigation Auditing Management Program
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Landscape Irrigation Auditing and Management
Training

• Developed byTexas Cooperative Extension
• Supported by Lower Colorado River
  AuthorityTexas Water Development Board

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Goal Good Water Management

• Save water
• Save money
• Improve appearance

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How Is This Goal Achieved?

• Identify and fix equipment problems (licensed
  irrigator?)
• Test the performance of the irrigation system
• Schedule irrigations to match demand

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LIAM Results Mobile Lab
Description 99 acres, 3 sites Pre-Audit water
use 154,529 ccf (43.0 in) Post-Audit use
125,066 ccf (34.8 in) Water save 29,463 ccf
(8.2 in)
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Mobile Lab - Cont.
Value of water saved Cost of audits
Net savings Benefit/cost

29,463 ccf x 0.96/ccf 99 acres x
50/acre 28,284 - 4,950 28,284 / 4,950
28,284 4,950 23,334 5.7
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LIAM Results Golf Course
Description 43 acres, 9 holes Pre-Audit water
use 69,000 ccf (44.4 in) Post Audit us
41,382 ccf (26.5 in) Water saved
27,878 ccf (17.9 in)
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Golf Course Cont.
Value of water saved Cost of audits Net
savings Benefit/cost
27,878 ccf 0.71/ccf 43 acres x 216/acre 19,793
- 9,288 19,793 / 9,288
19,793 9,288 10,505 2.1
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LIAM Results Water District
Description 152 acres, 7 sites
Pre-audit water use
825,418 ccf (149.6in) Post-audit water use
694,695 ccf (125.9in) Water saved 130,723
ccf (23.7in)
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Water District Cont.
Value of water saved Cost of audits Net
savings Benefit/cost
130,723 ccf x 0.46/ccf 152 acres x
50/acre 60,132 - 7,600 60,132 / 7,600
60,132 7,600 52,532 7.9
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Today You Will

• Review contents of the Training Manual
• Learn landscape audit procedures
• Perform your first audit

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Tomorrow You Should Be Able To

• Review LIAM terms/concepts
• Master LIAM calculations
• Review LIAM computer software
• SoAsk lots of questions!

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Learning the Audit Procedures

• First -We will observe a mini-audit
• Then -We will review
• -the eight steps
• -sample worksheets
• -sample field work
• -the computer software
• Finally -You will perform an audit

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LIAM Training Manual

• Preface and procedure chapters
• Theory chapters
• Appendices

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Base Irrigation Schedule

• Run time for station
• The number (or days) per week for each station
• Average weather conditions

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Precipitation Rate (in/hr)

• How fast does the system apply water?
• Varies from station to station
• Even varies within a station
• May exceed soil infiltration rate

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Distribution Uniformity (DU) ()

• Ratio dry vs. wet areas
• Based on irrigation system hardware
• Easy to measure using catch devices
• Limiting factor when producing good schedules

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Catch Device

• Catches water while sprinklers run
• Known area, volume and testing run time produces
  precipitation rate
• Avoid splashout, adjust to slopes
• Conical graduated cylinder (16.61 sq in)

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Key Water Management Actions

• Check and fix equipment (licensed irrigator?)
• Adjust station run times independently
• Change run times according to season
• Fine tune the system by trimming back

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Key Actions of Irrigation Auditor
Before Audit
After Audit
First- Balance delivery by each station
Then- Adjust irrigation throughout the year
Water Applied Turf Water Required
Jan.
Dec.
Jan.
Dec.
Finally- Trim back to save more water
100
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Water Applied
Jan.
Dec.
Jan.
Dec.
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Where does water savings come from?

• Adjusting station run times independently
• Changing run times throughout the season
• Trimming back irrigation schedule

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LIAM Training Procedures

• Procedures for Site Selection, Field Work,
  Follow-up
• Use worksheets to collect data
• All calculations performed by computer software
• Step-by-step sequence its easy!

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The Eight Steps of an Audit
Site Selection Field Work Follow-up
Step 1 Obtain site dataStep 2 Rank the
sites Step 3 Inspect the siteStep 4 Prepare
for the irrigation system tests

Step 5 Perform
irrigations system testsStep 6 Calculate base
irrigation scheduleStep 7 Prepare reports,
adjust scheduleStep 8 Review performance

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Step 1 Obtain Site Data

• Obtain list of sites
• - parks, cemeteries, golf courses
  residential, and commercial properties
• Assign site priority factors (Top, Normal)
• Determine irrigated acreage at sites
• Obtain water use records for sites

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Site Priority Factors

• Park A is at edge of town, low attendance
  (Normal)
• Park B is downtown, highly visible (top)
• Park C is like many other parks in town (Normal)

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Obtain Acreage, Water Use of Sites

• Acreage from maps Water use (1000 gallons, 100
  ccf)
• Park A 20 acres - 26,097 ccf
• Park B 5.0 acres - 6,500 ccf
• Park C 3.9 acres 4,323 ccf

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Step 2 Rank the Site

• Computer calculates (Water Budget)
• - irrigation requirements
• - potential water savings
• You group by site priority factors
• You then compare the monetary benefits

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Net Benefits (3 Years)

• Assume gt(3 x saved) audit cost net
  benefits - Park A (3 x 6,495) - 2,600
  16,885
• - Park B (3 x 1,600) - 800
  4,000
• - Park C (3 x 501) - 668 835

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Rank Sites Before Performing Audits

• Park B done immediately Top
• Park A done soon Normal, highest benefits
• Park C audited after Park A
• Park C to be congratulated Close to goal!!

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Metered and Un-metered Sites

• Metered sites may need adjustment
• - other water uses (bathrooms)
• Un-metered sites need estimates
• - use watering rate average

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Site Selection Worksheet (1/2)
Page 1 of 1
Date
6/9/91 Site Name South Elm Park
Phone [phone]
Organization North Texas Park District
Auditor Jane Smith Site
Manager John Doe
Best time to call 9-11am
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Site Selection Worksheet (2/2)
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Step 3 Inspect the Site

• Use site maps to identify hardware, problem areas
• Site inspection checklist gt List of items to be
  fixed
• Performed by???

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Site Inspection Worksheet
Page 1 of 1
Date 12/14/91Site name South Elm
Park Site Manager John
DoeOrganization North Texas Park District
Phone [phone]Auditor Jane Smith
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Use of Site Map
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Step 4 Prepare for Irrigation Systems Test

• Review site maps
• Formulate audit plan, prepare field data
  worksheet
• Enter basic site data into computer
• Have items been fixed at site?
• Schedule audit

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Irrigation Audit Areas

• Audits consist of stand-alone and
  over-lapping stations

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Develop an Audit Plan

• Cover critical areas
• Cover most of area
• Work along longest possible dimensions

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Audit Plan Linking Stations

• To reduce field time, link stations if possible
• Untested station uses results from a tested
  station
• Link ONLY if the following are similar
• Equipment - Plant Material
• Spacing - root zone depth
• Pressures - soil type
• Plant Type
• Soil conditions

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Step 5 Perform Irrigation System Tests

• At site, modify audit plan if needed
• Briefly run each station to be tested
• flag the heads of stations being tested
• upwind/downwind ratio less than 0.6?
• determine rotation rate gt testing run time
• Place devices and collect data

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Testing Run Times (minutes)

• How long the station runs for test affects
  quantity of water in catch devices
• Spray heads 5 10 minutes
• Sprinklers 12 16 minutes

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Collect Other Data During Station Test

• Spacing of sprinklers head-to-head, row to row
  (or line-to-line)
• Determine pressures in each station
• Determine soil type and rootzone depth

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Spacing Measurement
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Field Work Hints

• Set up ahead of current station
• Always be running a station
• Get major areas done first
• Remote communication device
• Assistance of site staff

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Step 6 Calculate Base Irrigation Schedule

• Enter field data into computer from worksheet
• Computer performs all calculations
• Computer prints base irrigation schedule

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Details of Schedule Calculation
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Base Irrigation Schedule
Audit Area ID 1Site Trim Factor 1Rainfall
Used
Client City of Dallas Site Park 1
Run Time (minutes)
indicates a linked station
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Set Controller Using Base Schedule

• Review results with site manager
• Set controller using base schedule
• Put schedule inside controller cover for
  reference

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Step 7 Prepare Reports and Adjust Schedule

• Deliver audit report to site manager
• Confirm implementation of base schedule
• Discuss need for equipment changes

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Audit Report

• Letter format for management review
• Presents base schedule and potential savings
• Document hardware changes to consider
• Appendix contains
• - base schedule and raw data
• - technical information and references

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Encourage Site Manager to Trim Back

• Reduce site trim factor until mild stress appears
• Repair/replace hardware where stress occurs
• Increase station trim factor if it cant be
  repaired
• Implement adjusted schedule after trimming

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Step 8 Review Performance

• Periodic performance review of all sites
• - Un-audited sites may now need audits
• Estimate water savings due to audits
• Discuss possible improvements, site trimming

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The Eight Steps of an Audit
Site Selection Field Work Follow-up
Step 1 Obtain site dataStep 2 Rank the
sites Step 3 Inspect the siteStep 4 Prepare
for the irrigation system tests

Step 5 Perform
irrigations system testsStep 6 Calculate base
irrigation scheduleStep 7 Prepare reports,
adjust scheduleStep 8 Review performance

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LIAM terms

• Vocabulary of water used and field evaluation
• Described throughout the manual

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Key Water Auditor Actions

• Check and fix equipment (licensed irrigator?)
• Adjust station times independently
• Change run times according to season
• Fine tune the system by trimming back

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Evapotranspiration ET (in/day)

• Water evaporated from soil
• Water transpired through the plant

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Potential Evapotranspiration PET (in/day)

• Different locations have different PET
• Based on a hypothetical grass reference crop

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Crop (Plant) Coefficient Kc ()

• Percentage of plant water use of PET
• Different value for each plant type
• Warm season turf less than cool season

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Adjustment Factor A ()

• Percentage of plant water used of PET under
  allowed stress
• As little as 60 of Kc
• Other adjustments due to micro-climate and site
  conditions

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Plant Water Use

• PET temperature, humidity, wind, solar
  radiation
• Kc or AKc plant material, level of stress
• Daily Water Use PET x Kc or AKc

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Effective Rainfall (inches)

• Rainfall stored in rootzone
• Less than actual due to runoff and evaporation
• Generally 67 of average rainfall

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Effective Rootzone

• Depth of soil containing 80 of the root mass
• Is the potential rootzone may be deeper than
  actual?
• Can root zone be manipulate with irrigation?
• Tighter soil restricts root depth

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Available Soil Water Holding Capacity (in/ft)

• Amount of water held (or stored) in the soil
• Amount of water that can be stored varies by
  soil texture (or type)
• Excess water drains below roots
• Deep soils permit infrequent irrigation

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Managed Allowable Depletion (MAD) ()

• Percentage of available soil water capacity
• How dry the soil is permitted to become before
  irrigating
• Influence irrigation frequency

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Infiltration Rate (in/hr)

• Rate at which water moves into soil surface
• Sandy soils accept water rapidly
• Heavy soils accept water slowly
• Decrease during irrigation

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Runoff

• Precipitation rate exceeds soil infiltration rate
• Compaction and thatch contribute
• Multiple-cycle to achieve moisture depth

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Landscape Irrigation Auditor Training
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Today You Will

• Review yesterdays results
• Conduct an audit
• Review technical concepts
• Review software features/calculations

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Base Irrigation Schedule
Audit Area ID 1Site Trim Factor 1Rainfall
Used
Client City of Dallas Site Park 1
Run Time (minutes)
indicates a linked station
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Station and Audit Area Statistics
Audit Area 1
Dominant turf type Warm Season
Managed Allowable Depletion 0.50
Overall DU(decimal) 0.77
Station Prec. Rate DU
Root Zone Soil Type
(in/hr) (decimal) (inches)
1 0.75 0.78
6 Loam 2
0.70 0.75
6 Loam 3
0.75 0.78
6 Loam
Recommended Irrigation Days Per Week Jan Feb
Mar Apr May Jun Jul Aug Sep
Oct Nov Dec 0 0 1
1 2 3 4 3
2 0 0 0
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Goal Good Water Management

• Save water
• Save money
• Improve appearance

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Key Water Management Actions

• Check and fix equipment (licensed irrigator?)
• Adjust station run times independently
• Change run times according to season
• Fine tune the system by trimming back

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Key Actions of Irrigation Auditor
Before Audit
After Audit
First- Balance delivery by each staion
Then- Adjust irrigation throughout the year
Water Applied Turf Water Required
Jan.
Dec.
Jan.
Dec.
Finally- Trim back to save more water
100
80
Water Applied
Jan.
Dec.
Jan.
Dec.
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Fine Tune the System Trim Back

• Observe of shade, orientation during inspection
• In operation look for unusual dry or wet spots
• Repair hardware if possible then
• Trim back individual stations

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Additional LIAM Terms

• Auditing Terms in Chapter 2
• Scheduling Terms in Chapter 3
• Appendix Calculation guide

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The Eight Steps of an Audit
Site Selection Field Work Follow-up
Step 1 Obtain site dataStep 2 Rank the
sites Step 3 Inspect the siteStep 4 Prepare
for the irrigation system tests

Step 5 Perform
irrigation system testsStep 6 Calculate base
irrigation scheduleStep 7 Prepare reports,
adjust scheduleStep 8 Review performance

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Site Inspection Worksheet
Page 1 of 1
Date 12/14/91Site name South Elm
Park Site Manager John
DoeOrganization North Texas Park District
Phone [phone]Auditor Jane Smith
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Audit Data Sheet (1/3)
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Precipitation Rate Test Worksheet (2/3)
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Precipitation Rate Test Worksheet (3/3)
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Catch Device Placement Stand-Alone
SAMPLECatch DevicePlacementStand Alone
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Catch Device Placement - Triangular
SAMPLECatch DevicePlacementTriangular Spacing
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Catch Device Placement - Rectangular
SAMPLECatch DevicePlacementRectangular Spacing
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Evapotranspiration ET (in/day)

• Water evaporated from soil
• Water transpired through the plant
• Refers to the total water needed by crops and
  plants

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Potential Evapotranspiration PET (in/day)

• Different locations have different PET because
  the climate is different (not soils!!)
• Based on a hypothetical (perfect) cool season
  grass, 4 inches tall under well-watered conditions

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Crop Coefficient Kc ()

• Percentage of plant water use of PET
• Different value for each plant type
• Warm season turf (60 or 0.6) - cool season
  turf (80 or 0.8)

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Adjustment Factor A ()

• Supplying less than the maximum amount of water
  plants will use (allowed stress)
• As little as 60 of Kc for turf grasses

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Available Water Holding Capacity (AWHC) (in/ft)

• Water storage (per foot of soil) varies by
  texture or soil type
• Excess water drains below rootzone or runs off
• The amount of water that is stored in soil
  between irrigations
• AWHC x rootzone inches of available water

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Effective Root Zone

• Depth of soil containing active roots or 80 of
  the total root mass
• Potential rootzone may be deeper than actual?
• Can manipulate with irrigation?
• Rootzone x AWHC inches of available water

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Managed Allowable Depletion (MAD) ()

• Calculated as the percentage of available soil
  water
• Determines how dry the soil becomes before
  irrigating
• Influences the frequency of irrigation or the
  number of days between irrigations

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Plant Water Use

• PET reference grass as influenced by climate
  (temperature, humidity, wind, solar radiation)
• Kc or AKc plant coefficent, level of stress
• Daily Water Use PET x Kc or AKc

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Daily Water Use
Evapotranspiration
ET (inches/day)
Allowable
Depletion
0.10
Soil
0.5"
0.10
MAD
Reservoir
0.10
Available
0.10
Water
0.10
1.0"
0.50" (50 MAD)
AWHC
Irrigate When?...After 5 days
How much?....0.5" losses
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Field Measurements

• Precipitation rate
• Distribution Uniformity (DU)

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Distribution Uniformity (DU) ()

• Ratio dry vs. wet areas
• Based on irrigation system hardware
• Easy to measure using catch devices
• Limiting factor when producing good schedules

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Uniformity
Water Depths in Soil After Application
Uniform
Non- Uniform
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Lower Quarter Uniformity ()

• One way of measuring system uniformity
• Ratio of average of lowest 25 of catch divided
  by total of average catch

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Lower Quarter Distribution Uniformity
Catch Can Volumes
Volume (ml)
Can Number
Lower Quarter Ave.

LQDU
Catch Can Volumes Low Quarter
Ave. of all cans
Average of all cans 67
Low Quarter Ave. 46
LQDU 46/67 .69 or 69
Volume (ml)
Can Number
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Irrigation System Efficiency ()

• Percent of applied water that makes it into the
  rootzone
• Depends on many factors
• Combination of application efficiency,
  distribution uniformity and other water losses
  (leeks in pipeline)
• Very difficult to measure
• Cannot be higher than distribution uniformity

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Efficiency
Water Contained in Root Zone
Efficient
Not Efficient
Bottom ofRoot Zone
All water containedin root zone
Some water below root zone
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Irrigation Schedule

• How long?
• How often?
• When?

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How Long (run time per week)

• How much water is needed
• ET, AKc of turf (demand)
• Effective rainfall
• How fast water is applied
• Precipitation rate (in/hr)

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How Often (days/week, starts/day)

• Soil (AWHC, infiltration rate)
• Rootzone depth
• Plant ET
• Managed allowable depletion (MAD)
• Runoff control

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When (days and times of week)

• Which days of the week
• What time of day
• multiple starts

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Details of Schedule Calculation
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Typical Infiltration vs. Precipitation rates
109876543210
Infiltration Rates Sandy
Loamy Clay
2/hr 1/hr .2/hr
PrecipitationRate
Start
8 minutes
18 minutes
10 minutes

20 minutes
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Details of Precipitation Rate Tests

• Catch devices (volume caught in known area, time)
• Sprinkler output as reaches ground
• Desire similar pressures and wind
• Use linking if consistent performance

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Auditing Procedures

• Auditing software is designed for
• one overlap area between two stations
• Suggestions
• Pick longest direction of overlap
• Folded geometry, convoluted geometry
• Treat as separate audit-areas

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Irregular Geometry
Station 1 Station 2 Station 3
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Catch Can Placement Irregular Geometry
Station 1 Station 2 Station 3
Catch Can Station 1
Catch can between station 1 2 (1/2)
Catch Can Station 2
Catch can between station 2 3 (2/3)
Catch Can Station 3
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Irregular Geometry
Station 1 Station 2 Station 3
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Catch Can Placement Irregular Geometry
Station 1 Station 2 Station 3
Catch Can Station 1
Catch can between station 1 2 (1/2)
Catch Can Station 2
Catch can between station 2 3 (2/3)
Catch Can Station 3
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Computer Software

• Water Budget and Audit Costs
• Calculations for irrigation schedules
• Prints site selection, irrigation schedules
  audit reports (future version)

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Landscape Irrigation Auditing and Management
Short Course