Distribution Uniformity (DU) is the cornerstone to irrigation management, because is allows for even application of water across all plants in the field. Once distribution uniformity is achieved, precision management of the application of irrigation water can follow. The concepts of DU can be misunderstood and multiple visits and follow up are recommended to gain full organizational acceptance and ongoing implementation. Planning to conduct initial meetings separately with the farm manager and the technical irrigation staff is an important first step for establishing a relationship and an information exchange based on what is relevant to each. Follow up and verification that practices are still in place after a time period can help accomplish the oversight and maintenance requirements to sustain even DU. We recommended working with the farm organization through several phases: Outreach > Assessment > Report > Follow Up Consultation > Implementation > Verification . We have compiled resource materials to assist with these phases. We have also compiled references to assist you in creating understanding and motivation for irrigation assessments.
- Why Do an Assessment?
- Assessment
- Report
- Follow Up Consultation
- Implementation
- Verification
- References
- Calculators/Data Sheets
Why Do an Assessment?
Outreach involves presenting an overview of irrigation assessment and achieving understanding of why good distribution uniformity is important for correct water application and for cost savings on water and electricity.
Irrigation System Evaluation Brochure for Coastal San Luis RCD
Source: Coastal San Luis RCD |Read about the mobile lab from the Coastal RCD and get contact information to set up an appointment.
Irrigation System Evaluation Brochure for Monterey Co. RCD
Source: Monterey Co. RCD | Brochure for an irrigation system distribution uniformity evaluation with illustrations of different types of irrigation systems (drip, linear move, sprinkler) and a descriptive explanation of the purpose, objectives and how one is done.
Irrigation System Evaluation Brochure for Mission RCD
Source: Mission RCD | Brochure for an irrigation system evaluation with illustrations of soil moisture and chart of water irrigation needs in avocado.
Irrigation System Evaluation Brochure for Cachuma RCD
Source: Cachuma RCD | Brochure for an irrigation system evaluation highlighting savings and benefits that can be achieved by implementing recommendations.
Distribution Uniformity Graphic
Source: Cachuma RCD | This picture displays the concept of over and underwatering based on distribution uniformity
Initial Consultation Questionnaire
Source: Cachuma RCD | Initial questions to cover with the grower when preparing for a distribution uniformity. Excel Download
Irrigation Water Management Makes Cents
Source: NRCS | A graphic display of how improving distribution uniformity can save money on pumping costs.
Distribution Uniformity for Sprinkler Irrigation
Source: Rain Bird | Explanation of distribution uniformity and economic comparison of good and poor DU.
Hands-On Irrigation Training for Nursery Growers
Source: UC Davis | Read about the factors that effect irrigation efficiency in nurseries and how to manage these.
Assessment
Doing an irrigation assessment involves field observations of the irrigation system as well as taking pressure and water measurements. We have guidance links for two different approaches. The first is the Cal Poly Irrigation and Training Research Center (ITRC) approach, which is used by engineers and trained professionals. This approach is quicker for someone with the expertise needed to understand the system implications and develop their own report. A second approach is to use Standard Operating Procedures (SOP) and to keep detailed records of the information and measurements from the assessment. This SOP approach can be accomplished by a field technician and the recorded information can be evaluated by an engineer or professional for the development of the report and recommendations.
ITRC Approach
Irrigation System Evaluation Short Courses
Source: Cal Poly ITRC | Methods for evaluating irrigation performance can be learned through online education, classroom and field experience.
Ag. Irrigation Evaluation & Distribution Uniformity Software
Source: Cal Poly ITRC | Purchase DU software, catch cans, and irrigation publications
SOP Approach
The SOP approach allows for complete data entry of important field variables that can later be evaluated. Excel sheets for data entry accompany most SOPs.
Distribution Uniformity Evaluation for Surface Drip in Vineyards SOP
Source: UCCE |Procedure for performing a distribution uniformity evaluation includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Fertigation Uniformity Evaluation for Surface Drip SOP
Source: UCCE | Procedure for performing a fertigation evaluation includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Distribution Uniformity Evaluation for Solid Set Sprinklers SOP
Source: UCCE | Procedure for performing a distribution uniformity evaluation includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Evaluation of Design and Operation of a Surface Drip System SOP
Source: UCCE | Procedure for evaluating the design and performance includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Distribution Uniformity Evaluation for Surface Drip SOP
Source: UCCE |Procedure for performing a distribution uniformity evaluation includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Distribution Uniformity Evaluation for Subsurface Drip SOP
Source: UCCE |Procedure for performing a distribution uniformity evaluation includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Evaluation of Design and Operation of Overhead Sprinklers SOP
Source: UCCE |Procedure for evaluating the design and performance includes the materials, procedures, estimated time, and data collection sheets. Data Entry Excel Sheet.
Distribution uniformity evaluation for micro-sprinklers SOP
Source: UCCE | Procedure for performing a distribution uniformity evaluation includes the materials, procedures, and calculation sheets. Accompanying Excel Sheet for data entry. Data Entry Excel Sheet.
Distribution uniformity evaluation for greenhouse pot micro-irrigation system SOP
Source: UCCE | Procedure for performing a distribution uniformity evaluation includes the materials, procedures, and calculations. Accompanying Excel Sheet available for data entry. Data Entry Excel Sheet.
Evaluation of design and operation of a micro-sprinkler system SOP
Source: UCCE | Procedure for performing a system evaluation that includes the materials, procedures, estimated time, and data needed. Accompanying excel sheet for data entry available. Data Entry Excel Sheet.
Evaluation of design and operation of a micro –irrigation system for potted plants SOP
Source: UCCE | Procedure for performing a system evaluation that includes the materials, procedures, estimated time, and data needed. Data Entry Excel Sheet.
Report
Reports are developed for growers and field irrigation specialists to bring about understanding of their irrigation system efficiency and to recommend improvements. These reports may be accompanied by spreadsheets that are used by the professional in evaluating the system and developing the report.
Coastal San Luis RCD Irrigation System Evaluation Report template
Source: CSLRCD | Report template
Water destination diagram
Source: CSLRCD | Water destination diagram
Micro scheduling check
Source: CSLRCD | Micro scheduling check
Ventura County RCD Low Volume Irrigation System Evaluation Template
Source: VCRCD | Report template
Summary Irrigation System Evaluation for SIP certification by Cachuma RCD
Source: Cachuma RCD | Example report (not identifying the owner) of a SIP summary irrigation system evaluation by Cachuma RCD.
Irrigation System Evaluation by Cachuma RCD (excel format)
Source: Cachuma RCD | Example of data and results of an irrigation evaluation from an excel sheet. Excel Download
Example Irrigation Evaluation Report
Source: UCCE | Example of an Irrigation Evaluation Report that would be provided to a Grower
Follow Up Consultation
After you have provided a report with suggestions for improving distribution uniformity, plan a follow-up visit to address questions and to reinforce the reasons DU is important. You can also address the ongoing maintenance of the system and suggest any field training that is needed for irrigation operators and ranch managers.
Maintenance of Micro-irrigation Systems
Source: UC ANR | Instructions and answers to common questions about maintaining, evaluating and unclogging microirrigation systems.
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Implementation
Implementation of the technical improvements that you recommended. NRCS funding may be available for some implementation or the local RCD may have grant money.
Equipment List for Mobile Lab and common maintain & improve equipment
Source: RCD Santa Cruz County | List of Mobile Lab Equipment
List of Equipment and Cost associated with irrigation system maintenance and improvement
Source: Cachuma RCD | Common Equipment needed to maintain and improve irrigation systems, with associated cost.
DripTips & AquaFlow 4.0
Source: Toro | Information on the design & value of drip systems, plus free design assist software.
Space Pro – Sprinkler Profile and Coverage Evaluation
Source: Fresno State CIT | An analytical tool for irrigation system design that allows comparison and evaluation of different designs, layouts, sprinkler types, etc..
Verification
After a period of time (6 months – a year), verifying that proper irrigation practices and changes made are still being properly operated and maintained is important. It is easy for field personnel to fall back to old habits or not to understand what is needed to continue to have a reliable irrigation system that provides good DU.
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References
Efficiency via Irrigation Toolkit
Source: FarmsReach | View a variety of additional toolkits for irrigation assessments and improving water use efficiency.
Irrigation Performance Measures: Efficiency and Uniformity
Source: Cal Poly ITRC | Standardized definitions and approaches to irrigation performance measures
Identification and Quantification of Efficiency and Uniformity Components
Source: Cal Poly ITRC | Concepts, definitions, equations, and sources of inaccuracy for water efficiency and distribution uniformity.
Irrigation Efficiency is the Key to Controlling Runoff in Nurseries
Source: UC Davis | Guidance on how to determine plant needs in nurseries based on uniformity, salinity, and crop type.
Irrigation Webinar Archive
Source: Grange Network | Archived webinars include drip irrigation operation and maintenance, overcoming distribution uniformity challenges, investing in a wireless irrigation network, and maximizing the longevity of irrigation tubing.
How Irrigation Uniformity and Management Affects Plant Health (recorded webinar)
Source: Dellavalle Lab | View this webinar about the importance of proper water application & how crops, trees and vines can suffer from improper moisture situations.
Calculators & Data Sheets
Sprinkler Irrigation Calculator
Source: Rain Bird | Calculate the precipitation rate/nozzle discharge, pipe friction loss and velocity, pump break horsepower and more.
Micro Irrigation Calculator
Source: Rain Bird |Calculate tree and vine daily requirements/precipitation rate, drip line friction loss and manifold pressure loss and diameter.
Irrigation Conversion Calculator
Source: Rain Bird | Calculate pressure, flow, length, area, volume, precipitation rate, and water temperature.
Sprinkler and Micro Irrigation Engineering Formulas – U.S. Units
Source: Rain Bird |Chart of formulas and conversion rates, including emitter discharge, precipitation rate and friction loss.
Water Use Tracking Tool for Grower
Source: RCD Santa Cruz County | Fill-in sheet in Spanish for tracking daily water use by noting the start and stop times or gauge readings for irrigation.
The development of this toolkit was funded by a grant from the Western Sustainable Agriculture Research and Education Program. Programs and projects supported by Western SARE are equally open to all people.