Engineering Commons^™

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.

Juxtaposing Nasa’S Aeronet Aod With Carb Pm Data Over The San Joaquin Valley To Facilitate Multi-Angle Imaging Spectroradiometer (Misr) Pm Pollution Research, John Kanemoto

STAR Program Research Presentations

Airborne particulate matter (PM) has been shown to increase the risk for asthma, chronic bronchitis, cardiopulmonary complications, and respiratory cell membrane damage/infection/leakage. PM levels are currently analyzed from two perspectives: stationary land-based monitoring (LBM) sites and total Aerosol Optical Depth (AOD) atmospheric column measurements. Both perspectives often leave miles of space between measuring locations and will have a continually increasing cost from introducing/maintaining sites. The Multi-angle Imaging SpectroRadiometer (MISR) satellite team hopes to begin investigating/archiving PM levels comprehensively via inputting MISR AOD measurements into a function/model which predicts the amount of ground level PM.

In the future, multivariable spatial correlations …

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 …