2007 Annual Report
Analysis of new laboratory data on submerged radial gates has been completed. A correction procedure was developed for submerged flow conditions that is more accurate than prior methods under the tested conditions, using data from the Bureau of Reclamation. A few computational difficulties still need to be resolved to account for complex flow conditions observed in the field. User-friendly gate calibration software still is under development.
Irrigation-induced erosion and subsequent transport of soil particles are inherently unsteady phenomena; hence, unsteady simulation of the process is more correct than assuming a succession of steady states, as is done in other erosion simulation software (WEPP, SRFR). The entrainment and advection of sand, silt, and clay particles and fitted with a smooth distribution across size classes, has been programmed and is being complemented by incorporating the unsteady nature of the phenomena. Thorough tests to correct errors will complete the program.
Simulation studies conducted in 2006 suggested the possibility of developing a cutoff criteria for surface irrigation systems in the Yuma-Mesa area of Arizona based on the time of advance to the middle of the field. Drs. Charles Sanchez and Dawit Zerihun, of the University of Arizona-Yuma Agricultural Center (YAC), field tested this concept in 2007. Preliminary results suggest the method may be too sensitive to uncertain input data for practical implementation. A formal agreement was established in 2007 with the Yuma Agricultural Center to further analyze these issues through additional simulation studies and field tests.
Field studies on level basins in Concordia Parrish, Louisiana have been completed. We still need better recommendations on the area that can be efficiently irrigated with a given flow rate. The flow rates for rice irrigation are very low, which makes them very inefficient for soy beans, corn or cotton. We have proposed an extension bulletin to combine what collective knowledge we have obtained. This would be a combined effort from ARS in Maricopa and Missouri, and extension in Louisiana, Arkansas and Mississippi.
The USALARC is evaluating the Arizona Department of Water Resources’ Best Management Practices program for agricultural water conservation. Background information was compiled to establish baseline conditions needed to contrast participants with the general farmer population. Incentives for participation, program-induced changes in cropping and water use patterns, and overall program implementation and enforcement are being investigated through interviews with a sample of farmers. Questionnaires were developed during the summer of 2007 and interviews are scheduled to be completed by the late fall.
SCADA Operator Training Software Irrigation delivery systems are under pressure to improve the accuracy and flexibility of water deliveries to farmers while reducing operational losses and improving overall water accountability. Sophisticated control approaches and operator training are needed to achieve this objective, however, irrigation projects in the U.S. and other parts of the world are still implementing manual centralized remote control on their canals with the help of Supervisory Control And Data Acquisition (SCADA) technology. Engineers from the USALARC have developed a novel system for training operators on canal supervisory control, SCADA systems, and for testing canal automation using special software, which replaces the physical link to the canal system’s communication hardware (usually radios), and thus to the canal gates, with a link to a simulation model of the canal. This software system allows users to learn how to interact with the SCADA interface and test operational strategies, including canal automation, using scenarios that might prove dangerous on the real canal. West Consultants, Tempe , AZ , adapted the software for use with HEC-RAS , a public-domain software product developed by the U.S. Army Corp of Engineers, and is marketing the software with water districts. Several irrigation and water conservancy districts have expressed interest in using the software. NP211 Water Availability and Watershed Management, Managing Irrigation for Effective Water Use
Clemmens, A.J. 2007. Simple approach to surface irrigation design: theory. Land and Water. (1)1-19. Available: http://www.sakia.org/ejlw_2007_01_01_i
Clemmens, A.J. 2007. Simple approach to surface irrigation design: application. Land and Water. (1)20-43. Available: http://www.sakia.org/ejlw_2007_01_02_i
Clemmens, A.J., Molden, D.J. 2007. Water uses and productivity of irrigation systems. Irrigation Science. 25:(3)247-261
Strelkoff, T., Clemmens, A.J., Perea-Estrada, H. 2006. Calculation of non-reactive chemical distribution in surface fertigation. Agricultural Water Management. 86:93-101