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Scientific Irrigation Scheduling Subcommittee. Thursday, August 8 2013 1pm – 3pm, PDT. Agenda. Introductions [10 minutes] Subcommittee objectives [5 minutes] Summary of last meeting and subsequent RTF staff work [10 minutes] Proposal for provisional standard protocol [20 minutes]
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Scientific Irrigation SchedulingSubcommittee Thursday, August 8 2013 1pm – 3pm, PDT
Agenda • Introductions [10 minutes] • Subcommittee objectives [5 minutes] • Summary of last meeting and subsequent RTF staff work [10 minutes] • Proposal for provisional standard protocol [20 minutes] • Discussion and next steps [20 minutes]
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
Summary of Last Meeting and Subsequent RTF Staff Work [slide 1] • Quantec study from 2003 to 2005 remains the best study we have on SIS impacts • Issues with baseline, small sample size, limited geographic range • Subcommittee agreed that the 10% savings (from inefficient irrigation to SIS) was reasonable, but could not confirm that is was reliable for the region. • Baseline - many farms are already using efficient irrigation practices, but this varies considerably by • Geographic location • Crop type (and variety) • Farm size Savings may be greater than 20% or may be negative
Summary of Last Meeting and Subsequent RTF Staff Work [slide 2] • Baseline can be estimated from analysis of Farm and Ranch Irrigation Survey (2003 and or 2008), but further adjustment would need to be made for the influence program activity. • Subcommittee was not sure of how to adjust baseline to reflect program activity • Programs have been active for decades, and re-participation is significant. • We don’t know what growers would do in the absence of programs
Summary of Last Meeting and Subsequent RTF Staff Work [slide 3] RTF staff conclusion: • We don’t have enough information to reliably estimate the savings from SIS, as required for a proven RTF measure. • Our estimates of savings from inefficient irrigation to SIS is considerably uncertainty • Because of the significant levels of re-participation, most savings are based on an assumption about what previous participants would reverts to if the program were removed. We have no data to support these assumptions.
RTF Staff Proposal • A provisional measure could be developed with a data collection plan that supports an eventual proven measure. • The provisional measure would require explicitly excluding re-participation, so that the baseline (no SIS incentives) irrigation levels could be observed. • For existing participants, observe irrigation levels (relative to “ideal”) during program and after (couple with crop type and ET data) (“post-pre”) • For new participant, observe irrigation levels before program and during program (“pre-post”) • Persistence of efficient irrigation practices would argue for a longer measure life
Proposed Provisional Approach [slide 1] Proposed Simplest Reliable Method Water savings = [ideal water consumption] x [SIS savings %] x [ 1 – baseline SIS saturation] • Ideal water consumption: consultant reported water consumption during program year • SIS savings %: 10% • Baseline SIS saturation: unadjusted saturation of efficient irrigation practices, as determined by analysis of FRIS data Best Practice Method Water savings = [ideal water consumption]x[Program savings %] • Ideal water consumption: ET-based water-balance model (using AgriMet or other), specific to crop type, soil type, location • The method for estimating ideal water consumption must be applicable to all years, not just years of participation. This is why consultant-reported consumption would not work here. • Program savings % • For new participants, savings is the difference in expected normalized irrigation levels pre-program and during-program • “Normalized”: expressed as a % of ideal consumption level • Expected level: as a function of crop type, location, farm size, [other variables], based on data collected as part of provisional protocol • For re-participants, savings is the difference in expected normalized irrigation levels post-program and during program
Proposed Provisional Approach [slide 2] Required data collection • Irrigation system specifications (see draft Calculator) • Geographic location (same categorization as ET data) • Farm size (total acres and irrigated acres) • Annual data: for 2 years pre-program (if available), program year(s), and 2 years post-program • Crop type and variety • Annual pump kWh • Any modifications made to system: EE measures, equipment replacement, change in # of irrigated acres • Location-based ET data • Participation year data: consultant reported volume of water consumption and ET model data Eligibility • Farm that has not received an SIS incentive in the past three years [NEW CRITERIA] • Must be in area with excess water capacity
Proposed Provisional Approach [slide 3] Provisional data collection will allow us to answer several questions: • Impact of SIS-program on previously non-participants • What participants revert to in the absence of program incentives • How closely measured water consumption (consultant report) matches kWh-based estimates • How closely measured water consumption (consultant report) matches ET-based modeled estimates