Scientific Irrigation Scheduling Subcommittee Thursday, August pm – 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] 2

Introductions 3

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 4

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 5 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 6

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. 7

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 8

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 9

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 10

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 11

Discussion and Next Steps 12