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Scientific Irrigation Scheduling Subcommittee. Tuesday, July 9 2013 1pm – 3pm, PDT. Agenda. Introductions [10 minutes] Objectives [5 minutes] Measure overview and history [5 minutes] Review of Quantec study [15 minutes] Measure appropriateness for RTF Standard Protocol [15 minutes]

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Scientific irrigation scheduling subcommittee

Scientific Irrigation SchedulingSubcommittee

Tuesday, July 9 2013

1pm – 3pm, PDT


  • Introductions [10 minutes]

  • Objectives [5 minutes]

  • Measure overview and history [5 minutes]

  • Review of Quantec study [15 minutes]

  • Measure appropriateness for RTF Standard Protocol [15 minutes]

  • Proposed Methodology for estimating savings [15 minutes]

  • USDA Farm and Ranch Irrigation Survey for estimating baseline practices [15 minutes]

  • Adjustments to baseline for program activity [15 minutes]

  • Additional issues [10 minutes]

  • Next steps [5 minutes]

Subcommittee objectives
Subcommittee Objectives

  • Determine whether or not there is sufficient knowledge and data to support a Scientific Irrigation Scheduling (SIS) standard protocol in compliance with the RTF Guidelines.

  • If there is, then support RTF staff in measure development

    • Provide expert opinion on uncertain parameters

    • Review methodology

    • Discuss the impact of incentive programs on measure adoption

Overview of measure
Overview of Measure

  • “Scientific irrigation scheduling is a process growers of agricultural products can use to improve irrigation water management. When used properly, scientific irrigation scheduling provides information on when to irrigate, how much water to apply, and how to apply water to satisfy crop water requirements and avoid plant moisture stress. When used appropriately, irrigation scheduling saves water, energy, labor, and fertilizer, and in many cases improves crop yields and crop quality.”

    • (emphasis added)

  • Uses soil moisture monitors, and modeling specific to crop type, soil type, and local meteorology to determine when/how much to water.

  • Traditional methods rely more on look/feel of soil and crops, predetermined watering calendars, and water availability.

History of measure
History of Measure


  • 2006 - Deemed Calculator approved, still in use

  • 2012 - Cascade contracted to update measure to comply with guidelines for standard protocol

  • Nov. 2012 – Cascade presentation to RTF

    • Meeting minutes:

    • Excerpts:

      “Jones made a motion that the RTF approve the Scientific Irrigation Scheduling Standard Protocol and move it to the “Proven” category with a sunset date of November 2017. Harris seconded the measure. Hadley said he would vote against the motion because it does not comply with the guidelines. We are using the 10 percent savings value within the best practice method, and we can’t test that number, he stated.

      “Lauren Gage also expressed concerns about the calculator and said she would vote against the motion. Hope said he agreed with Hadley and would vote against the motion. The RTF discussed the data and concerns about whether it conforms to the guidelines.

      “Hadley made a motion to table a decision on the SIS protocol until the RTF adopts new guidelines that address data source requirements for parameters used within standard protocols. Jones seconded the motion, which passed with 20 votes in favor and none against.”

      • April 2013 – RTF approved changes to Guidelines, including the use of “Diligent Review” as an acceptable source of Standard Protocol parameters.

Quantec study
Quantec Study

Current savings estimates are based on research conducted by Quantec from 2003 - 2005

  • Quantec, “A Study of Irrigation Scheduling Practices in the Northwest” December 2003, for BPA.

  • Quantec, “Phase II: Measurement of Water and Electricity Impacts”, June 2005, for BPA, NEEA, Pac. NW Generating Cooperative

Quantec study phase 1 baseline practices
Quantec Study – Phase 1. Baseline Practices

43% of irrigated acres are irrigated efficiently

  • Survey of 776 farms across the PNW

  • Quanteccategorized farms according to irrigation decision-making practices

  • “Examination of reported water use and their deviations from known irrigation requirements indicated that, by and large, farms in practice level I tend to use less water than farms that use less sophisticated practices. Comparison of mean water use derived from a regression model of water use showed that application of the combination of methods used in practice levels I and II are likely to result in water savings of approximately 12% and 10%, respectively.”

Quantec study phase 2 impact study
Quantec Study – Phase 2. Impact Study

The impact study compared growers known to use outside SIS services to growers known not to practice water management. I.e. – compare the best to the worst.

“It was therefore decided to select the treatment group from among growers who received water management services through GWMA or IRZ Consulting, and to select the control group from farms in close proximity to the treatment farms. The main advantage of this approach was that it offered a more consistent basis for defining water management practices among the treatment group and significantly helped the recruitment and data collection processes.

“To ensure comparability with the treatment group, each treatment field was matched with a local control field with the same crop grown by a farmer known not to practice water management.”

Quantec study impact study
Quantec Study – Impact Study

  • Analysis

    • Meter irrigation water use - indirect measurement: log line pressure at point of delivery, multiply by sprinkler design flow rate

    • Estimate “ideal” water use – use water balance model specific to county-level weather, field soil type, crop type (evapotranspiration rates)

    • Ideal water use is the normalizing factor for all fields (control and treatment)

  • Findings

    • Control group used 12% more water than ideal

    • Treatment group used 2% more water than ideal

    • Based on this, a 10% water savings for SIS is proposed

Quantec study impact data
Quantec Study – Impact Data

  • Note:

  • Small sample size

  • Limited crop type

  • High variance

Quantec study impact data1
Quantec Study – Impact Data

Impact appears to be on the least efficient irrigators.

Variance = ( [actual] – [ideal] ) / [ideal]

Quantec study limitations of analysis
Quantec Study – Limitations of Analysis

  • Small sample size – 19 treatment, 19 control

  • Limited geography and crop type

  • Dated – study conducted 2003 – 2005

  • Baseline only represents a subset of the population (non-SIS users)

  • Does not examine takeback – (i.e., use of saved water elsewhere on farm)

Rtf standard protocol
RTF Standard Protocol

Complete Guidelines:

Sections to review:


-Section 2. Measure Classification (PDF page 6-7)

-Section 7.1 Creating a New Measure (PDF page 19- 20)


-Section 3. Standard Protocols (PDF page 42 – 49)

For two methods (UES and standard protocol),the RTF approves measures within three categories:

  • Proven. Proven savings estimation methods are those that the RTF considers reliable.

  • Provisional. Provisional savings estimation methods are those that the RTF approves with special conditions requiring the collection of data from all or a sample of specific measure applications. The RTF uses these data to improve the reliability of the savings estimation method.

  • Small Saver. The RTF may determine that the likely savings from a measure are too small to warrant the resources needed to meet the quality standards defined for provisional or proven measures. Such measures are categorized as small saver.

Rtf standard protocol1
RTF Standard Protocol

  • Savings, Section 3.4 Quality Standards

    • Section 3.4.1 Provisional

      • “ the best practice method may rely on parameter values obtained from studies performed by other agencies, if after a diligent review of these studies the RTF determines that the values are sufficiently reliable.”’

    • Section 3.4.2 Proven

      • “One of the requirements for a standard protocol is that it be the simplest reliable method for estimating savings for a measure. A precise definition of reliability is difficult to enforce across all standard protocols, but in general, any method that produces savings estimates within +/- 20 percent of the best practice method (across a representative sample of best practice examples) should be considered sufficiently reliable. Alternatively, a method is sufficiently reliable if the combined sampling and measurement error for the representative sample is less than +/- 10 % with a confidence interval of 90%. “

    • Section 3.4.3 Small Saver

      • The RTF may determine that the likely savings from a measure are too small to warrant the resources needed to meet the quality standards for a proven standard protocol. In making this determination, the RTF will consider the size of the regional end use that is affected by the measure or the magnitude of the likely savings. A standard protocol in the small saver category is reliable if it satisfies the following criteria:

        • The measure is applicable in the region.

        • Sound engineering and statistical analyses are used in estimating savings

Rtf standard protocol2
RTF Standard Protocol

  • “Input parameter values for models used to estimate savings may be derived from sources other than data collected at an end user site. These sources must be cited and accessible. Such sources may be used in estimating savings, if after a diligent review, the RTF determines that they are sufficiently reliable.”

    -RTF Guidelines for the Estimation of RTF Savings, Section 3.3

  • “Diligent Review - The RTF uses estimates of parameters, e.g., average length of a residential shower or heat/cool interaction factors, from studies performed by other agencies in estimating measure savings. The RTF must diligently review a study before approving the use of these values in the estimation of measure savings. A diligent review will include, but is not limited to understanding the characteristics of the sample studied, the study’s data collection methods and analysis methods, and the variability of the parameter estimates across the study sample. A diligent review will consider whether the sample is applicable to measures delivered in this region and if not whether it is feasible to normalize the results for application to this region.”

    -Roadmap for the Assessment of Energy Efficiency Measures, Section 1.3.7

Rtf standard protocol questions
RTF Standard Protocol Questions

  • The Quantec study provides insufficient information to be used as the basis for a standard protocol.

    • Small sample size

    • Limited geography, crop type

    • Dated study

    • Baseline different than what RTF would use

  • Are there additional data sources that could be used to increase the certainty in savings estimates?

  • Could expert opinion of the subcommittee increase the certainty in savings estimates?

Rtf standard protocol questions1
RTF Standard Protocol Questions

  • What category of standard protocol is most appropriate?

    • Small Saver – Is this measure too prevalent to qualify as a small saver?

    • Provisional –

      • What information could be collected that could be used to validate the current savings approach?

      • Would metered data be useful?

      • Could irrigation systems be logged?

    • Proven – This would require the RTF to approve a savings estimate that currently cannot be verified.

Rtf standard protocol questions2
RTF Standard Protocol Questions

  • Takeback – Is water saved used elsewhere on the farm or region?

    • If we can’t verify the water saved isn’t used elsewhere, then we can’t verify there are energy savings.

    • Should the measure be limited to irrigation districts without water constraints?

  • How to account for interactive measures: Irrigation hardware, Pump VFD?

    • Pump VFD

      • Installed before SIS, or simultaneously – Adjust pump system efficiency in SIS calculator?

      • Installed after SIS – Account for in Pump VFD Calculator: Reduce pre-VFD annual energy consumption by % savings of SIS

    • Irrigation Hardware – subtract irrigation hardware if installed through an incentive programs

      • This is consistent with the Pump VFD approach.

Proposed savings approach
Proposed Savings Approach

  • Savings =

    [energy intensity of water]

    x [ideal water demand]

    x [% savings from SIS]

    x [1 - % baseline SIS-like saturation]

  • Energy intensity of water (kWh/acre foot) – determined by onsite data collection on irrigation system

  • Ideal water demand (acre feet) – ex ante estimate developed by consultants providing SIS service

  • % savings from SIS – expected average savings for farms going from simple irrigation strategies (i.e., Quantec Level III) to SIS or similar methods

    • Our current best estimate is 10%

    • Should this value vary by crop type or other parameters?

  • % baseline SIS-like saturation – Percentage of measure eligible acres that already use SIS or comparably efficient irrigation strategies (i.e, Quantec Level I and II).

    • This should vary by crop type, geographic area, farm size.

    • It could also vary by water source (off-site, well, surface)

    • The USDA Farm and Ranch Irrigation Survey (FRIS) could be used to develop these baseline estimates.

Using fris to estimate sis like practice
Using FRIS to Estimate SIS-like practice

  • Quantec characterized irrigation practice into three levels.

  • Quantec estimated that

    • Level I was roughly 12% more efficient than Level III

    • Level II was roughly 10% more efficient than Level III

  • FRIS does not collect enough detail to recreate Quantec’s three Practice Levels.

    • However, it can be used to approximate a Level I/II vs. Level III dichotomy.

    • Furthermore, FRIS can provide this dichotomy as a function of several relevant variables:

      • Geographic location

      • Crop type

      • Water source

      • Farm size

      • Irrigation system type

Adjustments to baseline for program activity
Adjustments to Baseline for Program Activity

  • “Savings is defined as the difference in energy use between the baseline (see section 3.2) and post (after measure delivery) periods, which is caused by the delivery of a measure. The terms “net” or “gross” are intentionally not used to modify the term “savings,” as they may conflict with the definition of “baseline,” provided in section 3.2. The current practice baseline defines directly the conditions that would prevail in the absence of the program (the counterfactual), as dictated by codes and standards or the current practices of the market.”

    • Roadmap, Section 1.3.2 (page 5 of the PDF), emphasis added

  • Would SIS be less prevalent if programs were pulled?

  • Baseline Options

    • FRIS 2003

    • FRIS 2008

    • Quantec 2003

    • One of the above, adjusted to account for program activity

Additional issues
Additional Issues

  • [Subcommittee members discuss additional concerns in developing savings methodology]

Checklist of topics
Checklist of Topics

  • Is there sufficient data to develop an RTF Standard Protocol?

    If so…

  • Proven, Provisional, or Small Saver?

  • Baseline

    • What data source(s) should we use to characterize the baseline?

    • What adjustments should be made for program activity?

    • What adjustments should be made for areas with significant takeback?

  • Savings as a percentage of ideal

    • Is the 10% estimate appropriate?

Next steps
Next Steps

  • Revise SP document and calculator to reflect today’s discussion

  • [If called for] submit custom query to USDA for FRIS data

  • Conduct analysis of FRIS data to develop categories (e.g. crop type, farm size) and baseline estimates for each category.

  • Circulate SP document and calculator to subcommittee for review