Meeting irrigation demands in a water-challenged environment

Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.Includes bibliographical references.Delivering water efficiently through distribution networks is a priority for irrigation districts but often is a difficult goal to achieve. SCADA shows promise of improving operational efficiency, increasing flexibility in the amount and timing of water deliveries, and reducing spills and other losses in distribution networks. However, implementing SCADA in a district for the first time is a difficult process. Districts often do not understand or are distrustful of the technology. They often do not know or understand how their system actually operates, thus making it difficult to design SCADA systems and to determine operational parameters and control algorithms. Selecting equipment that is easy to integrate into district operations is not a simple decision. Simple tasks such as selection of sensors and communication hardware become time consuming because of the need to explain advantages and disadvantages of each component. District boards of directors are normally reluctant to spend money, which further complicates the process. Once SCADA is installed, district personnel have to be trained on how to use the equipment to perform daily operations. In this paper we discuss the process of implementing SCADA projects for the first time in a district that had no previous experience with such technology or control systems. The paper will cover both hardware aspects as well as human consideration, and discuss some of the many lessons learned

Meeting irrigation demands in a water-challenged environment

Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.Includes bibliographical references.Increasing demands on limited water supplies will require maximizing crop production per unit water. Field studies are being carried out near Greeley, Colorado to develop water production functions for crops grown in the Great Plains. These yield per unit water relationships can be used to determine if deficit irrigation is economically desirable and how to best manage limited water supplies. A field facility, the Limited Irrigation Research Farm, was developed specifically to carry out limited irrigation research. Irrigation water is applied through drip irrigation systems; precipitation and reference evapotranspiration (ET) is measured with a weather station; soil water content is measured with time-domain reflectometry (TDR) and neutron probes; canopy temperatures are monitored; and growth, ground cover, biomass, and yields are measured. Yields are related to irrigation applications, crop ET, and crop transpiration. Initial results with corn, sunflower, wheat, and dry beans show linear relationships between yield and crop ET and transpiration

Evaluation of Canal Lining Projects in the Lower Rio Grande Valley

Since 1999, seven (7) irrigation districts in the Lower Rio Grande Valley of Texas have installed six (6) different types of synthetic canal lining materials, totaling approximately 21 miles. In 2005, we began a program to track the long‐term effectiveness and durability of these lining projects and to document the damage caused by such factors as UV, animal traffic, intentional and unintentional vandalism, and normal irrigation district operational and maintenance activities. Each project was evaluated using a visual inspection process during which performance/condition ratings were assigned. Without question, the best lining system is a synthetic liner with a protective barrier of shotcrete. The synthetic liner significantly reduces seepage, while the shotcrete protects it from damage. This lining system needs little to no maintenance. There were two types of liners used: PVC and polyester. Each performed equally as well. The performance of synthetic liners without a protective barrier varied dramatically. One important factor was the location of the project. Liners located in high traffic areas (people and animals) showed significantly more damage than those installed in remote areas. Damage was also common which appeared to be caused by mowing and canal cleaning operations. The PVC alloy is the toughest of the 4 liners installed without a protective barrier, is more difficult to cut and less likely to be damaged by unintentional vandalism. We also observed that liners carelessly or improperly installed were more susceptible to intentional and/or unintentional damage. For example, liners which are not properly stretched leave folds which can easily be caught by machinery or pulled by children swimming in the canals. Additional details are provided in this report, along with suggested considerations when planning a lining project. A summary of the findings for each individual lining project is presented in the Appendix B of this report which is published separately

Meeting irrigation demands in a water-challenged environment

Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.Includes bibliographical references.Irrigation districts in the Lower Rio Grande Valley of Texas have been experimenting with an assortment of synthetic canal lining materials, looking for more cost-effective methods for rehabilitating old, deteriorating canals. The synthetic canal lining materials are showing promise, but little information exists on the relative performance between different products. In 2005, we initiated a program to track the long-term effectiveness and durability of these lining projects and to document the damage caused by such factors as UV damage, animal traffic, intentional and unintentional vandalism. A summary of our results from the first four years of inspections are presented. Inspections for the linings are currently being updated for 2009-2010. Additionally, this paper provides documentation on canal lining installation and maintenance procedures, along with suggested considerations when planning a lining project. This paper also discusses future collaborative efforts underway for the testing and evaluation of synthetic canal liners. The best performers were the two types of synthetic liners (PVC and polyester) with a protective barrier of shotcrete, which have shown no problems to‐date. The noticeable difference between the two types of liners was the ability of the polyester to hold the shotcrete in place on the canal sidewalls. The PVC liner required an additional support system using a wire mesh overlay serving as the attachment between the material and the shotcrete. The performance of synthetic liners without a protective barrier varied dramatically. One important factor was the location of the project. Liners located in high traffic areas (people and animals) showed significantly more damage than those installed in remote areas. The PVC alloy is the toughest of the 4 liners installed without a protective barrier, is more difficult to cut and less likely to be damaged by unintentional vandalism. We also observed that liners carelessly or improperly installed were more susceptible to intentional and/or unintentional damage

Meeting irrigation demands in a water-challenged environment

Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.Includes bibliographical references.In an effort to improve the management of the Bryan Canal, the United Irrigation District in South Texas installed a radial gate in place of a pre-existing vertical slide gate structure with the objectives of establishing telemetry and remote control capabilities, and providing the District the ability to control the gates based on flow. This paper discusses the calibration of the radial gate for flow based on the head differential and gate opening. Details are provided on the equipment and instrumentation used, which included pressure transducers for upstream and downstream water levels, gate opening sensor, and doppler and velocity flow meters. The calibration of the doppler flow meter will be discussed along with the methods used to determine actual radial gate opening from sensor data and the problems caused by hysteresis. Flow rate was calculated from the head differential across the gate and gate opening using a submerged orifice equation. By adjusting the discharge coefficient, the equation was calibrated in such a way that total calculated flow matched the total measured flow. The flow data was further analyzed for individual flow events. Data was collected continuously over three months. This paper discusses the process of analyzing data and determining the conditions for which the equation is valid