RESEARCH PLAN – SCIENTIFIC IRRIGATION
SCHEDULING
BONNEVILLE POWER ADMINISTRATION
Draft – September, 2014
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Provisional Research Plan Template
TABLE OF CONTENTS
1. INTRODUCTION ................................................................................................................1
1.1. Measure Specification .......................................................................................................................... 1
1.2. Research Objectives .............................................................................................................................. 2
1.3. Limitations of Proposed Research .................................................................................................. 3
2. SAMPLE DESIGN AND DATA COLLECTION PLAN .............................................................4
2.1. Sample Design ......................................................................................................................................... 4
2.2. Data Collection ........................................................................................................................................ 5
3. ANALYSIS PLAN ...............................................................................................................5
4. RECOMMENDATIONS FOR COLLABORATION ...................................................................6
5. BUDGET ...........................................................................................................................6
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1. INTRODUCTION
The research objective is to inform and validate a simple and reliable approach to estimating
energy savings due to scientific irrigation scheduling (SIS). Historically, the RTF has estimated
SIS savings as 10% of efficient-case energy consumption, but the empirical basis for this
approach is not sufficient to meet the reliability standard for a proven standard protocol.
Generally, this research is focused on developing an estimate of the “Average Percent Deviation
from Water Requirement” (1reference Quantec study for definition). This will be used to
estimate savings in the following way:
Savings = (Baseline Water Application - Actual water applied)* Water to Energy conversion
Where:

Water to energy conversion = Conversion from water use to energy use using the
regional calculator, including factors for lift, discharge pressure, pumping plant
efficiency, etc.

Actual water applied = water applied by crop, as measured by SIS water consultants

Baseline water application = Water Requirement * Average percent increase over Water
Requirement, where:
o Water requirement = specific water requirement for the crop, as determined by
the SIS consultant
o Average percent deviation from Water Requirement = Amount of water above
water requirement for average of all farms.
1.1. Measure Specification
Scientific irrigation scheduling uses a combination of soil moisture monitoring, climatic data,
field specific data, and water measurements to optimize the timing and volume of irrigation.
Relative to current irrigation practices, SIS reduces electric use by reducing the amount of water
used for irrigation, which in turn reduces the work required to pump this water.
Market Sector
Agriculture
Measure Specifications
None specified.
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http://www.bpa.gov/EE/Utility/research-archive/Documents/200354_Phase_II_25JUL05_final.pdf
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Research Plan Template
(Utility program managers assess SIS provider qualifications)
Baseline
Current Practice
Estimation Method
Standard Protocol
Category
Provisional
Estimation Procedure
Statistical
Sunset Date
12/30/2019
Sunset Factors
Completion schedule for research plan.
Number of Measure
Applications
One
(The RTF does not define multiple types of SIS participation)
The simplest reliable method is described in detail in the provisional standard protocol. The
method seeks to estimate an SIS application’s energy savings in two steps:
1. Estimate water savings as a fixed percentage of the actual water requirement2 for the
acreage served by the affected pump station, then
2. Convert water savings to energy savings based on the pump station’s efficiency and
total dynamic head (TDH).
The main research objective is to inform Step 1 above by estimating the average percent
deviation from the water requirement. Step 2 is conducted in the current calculator and
outlined in the standard protocol.
1.2. Research Objectives
The main research objective is to estimate the baseline for SIS. This baseline is the average
percent deviation from water requirement.
Using a percent deviation simplifies the baseline calculation and accurately reflects the
measure’s objectives. The measure aims to help growers irrigate the appropriate amount for
that field based on multiple variables, including evapotranspiration, length of growing season,
crop type, precipitation, irrigation sprinkler system efficacy and antecedent soil moisture. These
varying field-specific conditions could mean that a field treated by SIS is appropriately irrigated
but uses more absolute water than another field which is not treated by SIS and is overirrigated yet uses less absolute water. In other words, the absolute water applied is not
reflective of the appropriate amount of water that should be applied, which is determined by
many factors.
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The water requirement is the annual gross water requirement for the crop over the season accounting for evapotranspiration,
length of growing season, crop type, precipitation, and antecedent soil moisture. This is the calculated amount of water that
would be pumped. The water requirement is the “ideal” water amount applied to the crop.
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Provisional Research Plan Template
This focus on the percent deviation from water requirement simplifies the sampling strategy
and provides a basis to allow comparison across the region’s irrigated acreage.
The water requirement will be measured by water consultants using the same methods used
when developing the recommendations on SIS treated fields. This requires using soil moisture
measurement devices (like the Neutron probe), actual water applied (like a rain gauge) and
crop specific ET data from the appropriate weather station (like AgriMet or others)
Actual consumption will be based on measured water application. The research will use
multiple methods to estimate the actual water flow. These can include a water-applied method
(center pivot sprinkler package flow rating) and measured pivot irrigation run-time.
One complicating factor in the research is the weather and seasonal water restrictions. An
unusually dry or wet growing season will impact the final results in unknown ways. As the
research is implemented, the consideration of drought conditions and water restrictions will be
reviewed and the research may adapt to these changing conditions. Drought conditions could
affect what fields are included in the analysis and the timeline of the research. For instance, if
summer of 2015 is a drought year, then the study might continue for an additional growing
season of summer of 2016 or fields might be excluded from the final analysis.
1.3. Limitations of Proposed Research
Methodological issues will be determined throughout the research implementation. These
include:

Defining the SIS-eligible population. There are around six million acres of pressureirrigated acreage in the Pacific Northwest. However, not all of these acres are a prime
candidate for SIS because of the water source, water availability, crop type, growing
season, and the pumping energy required. See section 2.1 for detail.

Segmentation Plan. Prior to implementing this research, a segmentation plan will be
developed to provide a balance between number of fields that will need to be included
in the sample and granularity to account for meaningful market segments. See section
2.2 for detail.

Measurement plan. Refinement of the methods to determine actual water applied and
the water requirement will be developed and methods to account for any bias
developed. See section 2.4 for detail.

Field recruitment. Incentives or a value proposition for fields that are outside of the SIS
treated fields will need to be developed as well as protocol for research on-site to
minimize end-user disruption. See section 2.3 for detail.
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2. SAMPLE DESIGN AND DATA COLLECTION PLAN
The following describes the research plan steps. Section 2.1 describes defining the population;
Section 2.2 the segmentation design; Section 2.3 the data collection and Section 2.4 the
analysis.
2.1. Defining the Population
There are approximately six million acres of pressure-irrigated acreage in the Pacific Northwest.
However, not all of these acres are a prime candidate for SIS because of the water source ,
water availability, crop type, growing season, and the pumping energy required to get the
water to the field. The research will use USDA data to develop population estimates and then
present these population estimates to stakeholders. Agricultural and energy efficiency experts
in the region will help refine and improve these definitions such that the final population
definition reflects an accurate baseline. The following will be considered at a minimum: (1)
whether an irrigated field is a likely SIS candidate based on crop type and irrigation type; (2)
crop type and (3) regional variations. BPA envisions a working meeting in December 2014 to
review BPA’s initial analysis.
2.2. Sample Design
At a minimum, we seek to estimate a single percentage deviation from the water requirement
for all crops and sites. However, due to variations in irrigation practices, segmenting the
sample will likely provide more accuracy. That said, each sample cell will require an increased
number of sites, so balancing the desire for segmentation with the cost of increased sites will
be important for the feasibility of the field work.
It is likely that the segmentation will consider: Crop type, region, and system type. Additional
considerations include: Soil type, Cutting, Climate zone, Grower size, Farm size, Sophistication,
Water constraints. The segmentation plan will determine which of these factors are accounted
for in the water requirements calculation and which are needed for segmentation for the
program’s implementation.
Within the sample design, a sample frame will be determined. It is important that the research
is based on an unbiased, random sample of farms. The most feasible method will be
determined to develop a sample list or choose farms.
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2.3. Data Collection
The data will be collected on fields using experienced water consultants. The data collection will
have to begin in order to be in the field for the growing season in March.
Critical components that could affect data collection in the field include recruiting nonparticipating fields, drought conditions and continuous QC of data throughout the data
collection period.
The plan to recruit non-participating fields will be developed in coordination with utility
stakeholders. Possible methods to help recruit fields could include participation of utility staff,
paying for the SIS information and providing it at the end of the growing season, or the use of
financial incentives for growers.
In the event of an unusual water year, the research team will meet with the SIS subcommittee,
engaged experts and RTF/Council staff to develop a contingency plan. The research team will
monitor climate forecasts regularly.
Once in the field, monthly QC checks by the analysts will be performed to address any problems
with data quality or equipment. A QC checklist will be developed early within the project so
that data problems can be identified quickly and resolved.
Once the fields are identified, we will use one or both of the following estimates to calculate
water applied by field:

Measurement of water applied. This is conducted by a consultant on a field using a
catch can/rain gauge and soil moisture probes. This can be used for pivots and
hand/wheel lines, but not for orchards and vineyards. Measurement will adjust for
water balance (soil moisture before and after season) and adjusted for rainfall.

Irrigation run-time. This method can be used on pivots and on orchards/vineyards, by
zone. It will use a data logger and a pressure sensor on the pressure gauge.
Measurement will adjust for water balance (soil moisture before and after season).
Prior to implementation, BPA will refine which applications will be appropriate for one or both
to measure water applied.
The water consultants will use the methods used via SIS ( weekly reports of moisture
measurements and weather information and irrigation recommendations) to help determine
the appropriate level of irrigatation for that particular field. The details of this approach and
how data will be provided for analysis will be further refined before the fieldwork commences.
3. ANALYSIS PLAN
The analysis will be ongoing, as QC of field data and weather monitoring will occur throughout
the field data collection. Once the field data are completely collected, each site will have an
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Research Plan Template
water requirement and an amount irrigated. The two combined will develop a percent
deviation from the water requirement.
One analytical decision that will need to be determined is the treatment of outliers. The 2005
BPA study found that the savings were inconsistent, with a few farms accounting for most of
the deviation above the water requirement. Sites may need to be weighted to the population
depending upon the sample segmentation.
4. RECOMMENDATIONS FOR COLLABORATION
This research would require support and collaboration between multiple entities. BPA will be
the project manager of this project, including coordination, analysis and funding. This project
will require support by public and investor owned utilities to working with growers in the
sample. Sites in IOU territories will need to funded by those utilities. Additionally, coordination
with SIS consultants will be required, as this is the method to gather most of the data.
5. BUDGET
The government estimate of cost cannot be shared publicly due to BPA federal contracting
guidelines.
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