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