Engineering Commons^™

A New Approach To Vfd System Specifications And Rebates, Kyle Feist, Randall Cole, Charles M. Burt

BioResource and Agricultural Engineering

Variable frequency drives (VFDs) are used to provide flexibility and efficiency enhancements for agricultural pressurized irrigation systems. Standard 6-pulse VFDs commonly used for agricultural pumps can also create real problems with the pump motor and nearby electrical systems, unless mitigated by special equipment.

With support by the California Polytechnic State University (Cal Poly) Irrigation Training and Research Center (ITRC), Pacific Gas and Electric Company (PG&E) recently began a new rebate program for installing VFD systems for pressurized irrigation. A major component of the new rebate program is the requirement to comply with a detailed set of minimum VFD system design …

Case Study: Modernization Of The Walker River Irrigation District, Stuart Styles, Robert C. Bryan, Sierra Layous

BioResource and Agricultural Engineering

The Irrigation Training and Research Center (ITRC) and Walker River Irrigation District (WRID) collaborated on the modernization of WRID with support from the Bureau of Reclamation, U.S. Department of Interior in Carson City, Nevada. This paper presents an update to the USCID case study that was presented in 2014 on the initial proposed plan for improving water gauges throughout WRID. There has been phased implementation of the initial proposed plan as well as modification and expansion of that plan. The initial scope of work for system improvements was developed by ITRC in 2009 following field investigations and engineering analyses of …

Improving Flow Measurement Accuracy Using A Portable Irrigation Turnout Calibration Unit, Stuart Styles, Kyle Feist, Charles M. Burt

BioResource and Agricultural Engineering

Relatively accurate flow measurement at irrigation district water delivery points is an important component of volumetric billing and equitable service. In California, this has often occurred with conversions to pressurized irrigation systems which commonly include the installation of pipeline flow meters as part of the on-farm system. However, a large portion of irrigation turnouts in the western US continue to operate via gravity and fall into one of the following categories: (a) a metergate, or similar structure was installed without adherence to standard construction requirements or (b) the structure was never intended for flow measurement.

For these and other scenarios, …

Using Electricity Consumption To Estimate Water Volumes Pumped From Wells, Charles M. Burt

BioResource and Agricultural Engineering

The Sustainable Groundwater Management Act (SGMA) of California has led some organizations to want access to documentation of the volumes of groundwater pumped by individual wells. Many well pumps already have flow meters installed that provide an accurate measurement of both instantaneous flow rate and the cumulative volume pumped. For wells that do not have flow meters, it has been proposed for many years that pumped volumes can be accurately estimated by simply using the total power consumption, measured in kilowatt-hours (kWh).

Influence Of Supply-Channel Velocity On Farm Delivery Meter Gate Flow Measurement, Daniel J. Howes, Charles M. Burt, John M. Thorburn

BioResource and Agricultural Engineering

The work presented here is an extension of previous papers that updated the calibration of round (Armco-type) meter gates (three sizes: 0.30, 0.46, and 0.61 m), developed ratings for rectangular gates (two sizes: 0.46 and 0.61 m) on round pipes, and examined errors and uncertainty related to using these devices for water discharge measurement. Previous works examined gate discharge ratings under low supply-channel flow velocity perpendicular to the gate discharge pipeline. Here, additional testing was conducted to test the hypothesis that higher velocities in the supply channel would show decreased meter gate flow compared to the low-velocity ratings, but that …

Managing Drip Filter Backflush Water, Charles M. Burt

BioResource and Agricultural Engineering

The paper discusses the principles of backflushing different types of filters, as well as pressure and flow requirements for proper backflushing of various filters. Additionally, it discusses options for what to do with the backflush water. A prototype ITRC design for cleaning and recycling backflush water is presented.

Reconstructing The Natural Hydrology Of The San Francisco Bay - Delta Watershed, P. Fox, P.H. Hutton, D.J. Howes, A.J. Draper, L. Sears

BioResource and Agricultural Engineering

We evaluated the impact of landscape changes on the amount of delta outflow reaching San Francisco Bay. The natural landscape was reconstructed and water balances were used to estimate the long-term annual average delta outflow that would have occurred under natural landscape conditions if the climate from 1922 to 2009 were to repeat itself. These outflows are referred to as natural delta outflows and are the first published estimate of natural delta outflow. These natural delta outflows were then compared with current delta outflows for the same climate and existing landscape, including its re-engineered system of reservoirs, canals, aqueducts, and …

Rating Rectangular Farm Delivery Meter Gates For Flow Measurement, Daniel J. Howes, Charles M. Burt

BioResource and Agricultural Engineering

Traditional meter gates for farm delivery flow measurement from an open channel conveyance have traditionally incorporated round canal gates (Armco type) for control. In recent years, some irrigation water agencies (i.e., irrigation districts) have replaced deteriorating round gates with lower-cost rectangular gates that cover round holes. Similar to the situation described in a companion paper, where round gates were examined, there have been no investigations into flow measurement uncertainty using the existing rating tables for these gates. In this study, two commonly used rectangular gate sizes, 0.46 m (18-in.) and 0.61 m (24-in.), were tested under scenarios of various gate …

Accuracy Of Round Meter Gates For On-Farm Deliveries, Daniel J. Howes, Charles M. Burt

BioResource and Agricultural Engineering

Recent California legislation requires irrigation water agencies larger than 25,000 acres to measure volumetric water deliveries within specified levels of relative uncertainty. Although the meter gate is one of the most widely used flow measurement devices in California, little investigation has been conducted into the accuracy, limitations, and uncertainties of the rating tables developed over 60 years ago. A meter gate testing facility was constructed at the Cal Poly Irrigation Training and Research Center’s Water Resources Facility capable of testing gates up to 0.76 m (30 in.). The facility was constructed with gates oriented perpendicular to the supply channel flow …

Improving Flow Measurement Accuracy At Farm Delivery Gates In California, Charles M. Burt, Daniel J. Howes

BioResource and Agricultural Engineering

ITRC, through a CSU ARI grant, constructed a meter gate testing facility and tested five gates of various sizes and designs. The gate testing was conducted by varying the multiple parameters including upstream and downstream head, supply channel velocity, gate opening, and head above the gate. Data was also collected at various locations on the downstream side of the gate. In total, ITRC staff collected over 10,000 points of data during this evaluation. Using the new rating tables for the three gates examined, the relative uncertainty is less than ±5 to ±7% at the 95% confidence level with the new …

Evapotranspiration From Natural Vegetation In The Central Valley Of California: Monthly Grass Reference-Based Vegetation Coefficients And The Dual Crop Coefficient Approach, Daniel J. Howes, Phyllis Fox, Paul H. Hutton

BioResource and Agricultural Engineering

Restoration activities in the Central Valley of California and elsewhere require accurate evapotranspiration information, which can then be used for a wide variety of surface and subsurface hydrologic evaluations. However, directly measuring evapotranspiration can be difficult or impossible depending on the evaluation’s time frame. Transferability of measured evapotranspiration in time and space is also necessary but typically requires a weather-based reference. For nonagricultural vegetation, there is at present time no standard reference, which makes the evaluation of a variety of vegetation types from different sources difficult and time-consuming. This paper examines several methods used to estimate evapotranspiration from native vegetation, …

Practical Guide For Metergates, Charles M. Burt, Daniel J. Howes

BioResource and Agricultural Engineering

This document contains brief instructions on the use of special round canal gates called “metergates” for flow measurement.

Center Pivot Sprinkler Distribution Uniformity Impacts On The Spatial Variability Of Evapotranspiration, Daniel Howes, Sean Ellenson, Lucas Hoffmann, Franklin Gaudi

BioResource and Agricultural Engineering

Understanding variable evapotranspiration (ET) throughout a field can help maximize yield on a per-acre basis, as well as assist with proper irrigation scheduling. The results from this study indicate that irrigation system distribution uniformity (DU) has a significant effect on the uniformity of ET during water-stressed periods. The study site involved intensely managed forage (alfalfa and winter grain hay) irrigated by center pivots being supplied with reclaimed water near Palmdale, California. During spring and early summer 2007 the center pivots were operating under deficit irrigation. In 2010, after the installation of reservoirs, water was applied to meet full evapotranspiration (ETc) …

Modernization Of The Walker River Irrigation District Water Gauges, Stuart Styles, Robert C. Bryan, Kenneth C. Spooner

BioResource and Agricultural Engineering

The Irrigation Training and Research Center (ITRC) and Walker River Irrigation District (WRID) collaborated on WRID’s Water Gauge Improvement Project with support from the Bureau of Reclamation, U.S. Department of Interior in Carson City, Nevada. This paper presents a summary of the proposed plan and implementation for improving water gauges in WRID with strategic engineering recommendations for new hardware and control equipment; water management strategies; flow measurement devices; and integration of a new district-wide SCADA system. Field investigations and engineering analyses were carried out by the ITRC in 2009 to inspect existing WRID infrastructure, to review current operational procedures, and …

Integrating Remote Sensing Of Evapotranspiration With Applied Water To Target Potential Water Conservation Projects In Watersheds, Daniel J. Howes, Stuart Styles

BioResource and Agricultural Engineering

The overall purpose of the project is to develop a methodology for watershed managers to successfully target and release recommendations to growers that could benefit from improved on-farm irrigation management. Initially it was thought that the methodology could rely on remote sensing of actual crop evapotranspiration, effective rainfall estimates, and water application information (pumped volumes and surface water deliveries) to simply evaluate if fields and farms that applied significantly more water than plants needed could be identified. However, it became clear that, in this region specifically, additional information on water quality, crop sensitivity to salinity, and an assumed good irrigation …

Evaluating Net Groundwater Use From Remotely Sensed Evapotranspiration And Water Delivery Information, Daniel J. Howes, Charles M. Burt, Lucas Hoffman

BioResource and Agricultural Engineering

A detailed, comprehensive, and accurate identification of groundwater aquifer properties will likely never be fully achieved because of the high degree of variability and costs that testing involves. Furthermore, accurate estimates of boundary conditions are essential for groundwater modeling so that investigations of improved management scenarios can be conducted. The lack of key input values at the ground surface boundary limits the ability to accurately assess aquifer dynamics. Of major importance is actual evapotranspiration (water consumption or the loss of water to the atmosphere through transpiration and evaporation). The Irrigation Training and Research Center (ITRC) modified remotely sensed satellite imagery …

Winegrape Vineyards And Winery Operations: Energy Efficiency/ Sustainability And Expansion, Stuart Styles, Sierra Layous, Sarah Crable

BioResource and Agricultural Engineering

Southern California Edison (SCE) provides utility services to the greater southern California area. Vineyards and wineries exist throughout the region, and historical data suggests that that they largely do not utilize incentive programs offered by the utility.

As the first phase in a larger study, the Irrigation Training & Research Center (ITRC), located at the California Polytechnic State University, San Luis Obispo, completed a characterization of the vineyard and winery sector as it pertains to energy and water usage in SCE’s service area, including the following major tasks:

1. Identification of vineyard and winery demographics in SCE’s service area.
2. Identification of …

Implementation Of New Irrigation Protocols On Strawberry Transplants On The California Central Coast, Stuart Styles, Kerilyn Ambrosini

BioResource and Agricultural Engineering

For the past five growing seasons, the Cal Poly Irrigation Training and Research Center (ITRC) has conducted research on water use, salinity levels and various other factors related to strawberry transplant establishment. This report summarizes research that can be found online: www.itrc.org/projects.htm.

The project’s goal was to develop an analysis of irrigation practices of the strawberry growers on the central coast of California, primarily during the establishment of transplants. From the analysis, sprinkler use reduction methods were developed. These methods conserve water, save pumping costs, and reduce the runoff that can potentially contaminate local waterways. California growers contributed control and …

Pressure Recorders: Low-Cost, Robust, Low-Battery-Use Field Measurement Techniques For Trending Water Pressure, Stuart Styles, Kerilyn Ambrosini

BioResource and Agricultural Engineering

Water users across California need robust, low-cost water level/pressure sensors with integrated data loggers for a high level of precision and accuracy. The Cal Poly Irrigation Training and Research Center (ITRC) has installed Telog Instruments devices in California and Nevada over the last 12 years to provide a performance review of the devices. The two devices focused on were the Telog Instruments WLS-31 Level Tracker and LPR-31i Line Pressure Recorder. Over the study period, ITRC has collected several sets of data in varying situations. After 11 years of use on a reservoir, the two Telog WLS-31 units had a 1% …

Groundwater Challenges, Charles M. Burt

BioResource and Agricultural Engineering

There are some old lessons that continue to repeat themselves throughout the history of irrigation. For example, it has become a common understanding that accumulated salinity from irrigation spelled the doom of some ancient civilizations in the Middle East. Despite this ancient knowledge, today we still have numerous irrigated basins in which there is no outlet for high-salinity drainage flows.

Likewise, groundwater is something that traditionally has not been well understood, and is often treated as an ever-present back-up plan for irrigation. The “water rights” laws in the western US and elsewhere almost exclusively formalized rules about and concentrated on …

Flow Measurement Options For Canal Turnouts, Kyle Feist, Charles M. Burt

BioResource and Agricultural Engineering

Volumetric record-keeping, billing, and allocations at irrigation district delivery points (turnouts) are the norm, rather than the exception for most California irrigation districts. However, many older districts are just beginning these efforts, and other districts are trying to improve existing hardware and procedures. Volumetric accounting with high accuracy and a reasonable price presents unique engineering challenges for irrigation districts because of the variety of existing structures and configurations at irrigation delivery points. Because it is likely that irrigation districts will attempt to utilize existing devices, or slightly modify them, there is a need for standardized installation and/or calibration. This paper …

Irrigation System Regulating (Buffer) Reservoirs, Charles M. Burt

BioResource and Agricultural Engineering

Regulating reservoirs (also known as "balancing" or "buffer" reservoirs) are very commonly used in western US irrigation district modernization projects with canal systems. Some districts have a dozen or more reservoirs within total service areas of 20,000 – 40,000 ha. This paper presents details of sizing and control of flows into and out of the reservoirs.

Groundwater Nitrate In California: What Should Be Done?, Charles M. Burt

BioResource and Agricultural Engineering

Charle's Burt PowerPoint presentation discusses current issues concerning nitrates in groundwater in California, as well as recommendations made to the State Water Board by the Nitrate Task Force.

Grass Referenced Based Vegetation Coefficients For Estimating Evapostranspiration For A Variery Of Natural Vegetation, Daniel J. Howes, Mariana Pasquet

BioResource and Agricultural Engineering

In arid and semi-arid regions, evapotranspiration from vegetation results in the significant utilization of available water. Accurate estimates of evapotranspiration are required for surface and subsurface hydrologic evaluations as well as irrigation district water balance studies. A significant amount of transferable information exists for irrigated agricultural crops through past and current research in the form of grass or alfalfa reference based crop coefficients (Kc) and basal crop coefficients (Kcb). However, transferable evapotranspiration information on natural vegetation is limited. Much of the work was conducted in the early to mid-1900’s and is presented as actual evapotranspiration from the vegetation at the …

Low-Pressure Testing: Pressure Regulating Valves, Charles M. Burt, Kyle Feist

BioResource and Agricultural Engineering

ITRC tested performance characteristics of pressure regulating valves from a variety of manufacturers. The purpose of the testing was to evaluate the ability of different models of valves to regulate the pressure in a low-pressure system. The testing concentrated on three specific valve performance characteristics: minimal variance from the target downstream pressure caused by changes in flow rate or inlet pressure; minimal hysteresis in outlet pressures; minimal pressure loss (at low inlet pressures) across the valve.

Low-Pressure Testing: Microirrigation Emitters, Charles M. Burt, Kyle Feist

BioResource and Agricultural Engineering

ITRC tested 28 different pressure-compensating (PC) models of microirrigation emitting devices from a total of nine manufacturers in order to compare independent laboratory testing with manufacturer specifications. It is the intention of this report to investigate the ability of currently marketed products to operate in a truly low pressure irrigation system where energy inputs, in the form of pump discharge requirements, can be minimized.

Unique Replogle Flume Installations At The Truckee-Carson Irrigation District, Stuart Styles, Brandon Downing, Walter Winder

BioResource and Agricultural Engineering

The Water Measurement Program (WMP) for Truckee-Carson Irrigation District (TCID) began in 1997, when the Irrigation Training and Research Center (ITRC) of Cal Poly State University was asked to develop a volumetric measurement plan for TCID, funded by the U.S. Bureau of Reclamation, Mid-Pacific Region. This program was intended to develop and install reasonably accurate turnout delivery measurement techniques in the district. As part of the WMP, TCID was required to install a number of new open-channel measurement devices. TCID opted for the Replogle flume as its primary flow measurement device using the newly developed WinFlume computer program.

A few …

Pressure Regulating Valve Pilot Characteristics - 2-Way Vs. 3-Way Pilots, Charles M. Burt, Kyle Feist

BioResource and Agricultural Engineering

Pressure regulation valves, with 3” – 6” diameters, are commonly found at the entrance to agricultural irrigation blocks and manifolds. These valves are typical of a “hydraulic” design, in which a chamber above a flexible disc/diaphragm is filled or emptied. As the chamber is filled or emptied, the irrigation water passes through a smaller or larger orifice, and the pressure downstream of the valve is lowered, increased, or maintained at a constant target pressure. The flow in/out of the chamber is controlled by a small “pilot valve”. The characteristics of these pilot valves are discussed here, in general terms. Of …

Pipeline And Canal Downstream Control System For Recirculation - Patterson Id Case Study, John Sweigard, Charles M. Burt, Peter Rietkerk

BioResource and Agricultural Engineering

Patterson ID in Central California has five long, along-the-contour lateral canals that flow northward from a main canal. The main canal operates on downstream control, providing excellent flexibility to heads of the laterals. The lateral canals operate with manual upstream control and have little storage. The classic tail-ender problem existed; spill from the tail end was necessary to avoid under-supplying tail-end customers.

To eliminate the spill and to provide better flexibility, a system was designed and constructed to tie the ends of the five laterals together with pipes and pumps, with one central regulating reservoir. The automatic control system allows …

Sbx7 Flow Rate Measurement Compliance For Agricultural Irrigation Districts, Charles M. Burt, Evan Geer

BioResource and Agricultural Engineering

Senate Bill x7-7 (SBx7-7) requires documented volumetric accounting to individual turnouts for water deliveries. Section 597.3 of the bill lists two very different requirements for devices. This document examines the requirements of SBx7 and the implications for agricultural irrigation districts. The definitions and impacts of flow rate and volumetric accuracy are defined. Example scenarios and solutions are offered, as well as descriptions of applicable devices.