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sembled" system is capable of monitoring both instanta- <br />neous and cumulative discharge and features a low -cost <br />( —$100) programmable logic controller equipped with <br />a 4 X 20 LCD display and a 4 X 4 keypad. This unit is <br />installed in a NEMA 4 enclosure and runs on 12 volt DC <br />solar charged power. It is compatible with a wide range <br />of water level sensors that output an analog (voltage or <br />current) signal. Programming for the units has been devel- <br />oped at the WRRL. After a period of demonstration/field <br />testing with these units, an instructional aid for component <br />acquisition and system assembly as well as the program <br />code will be available from the WRRL website. <br />A low -cost flow measurement device using pres- <br />sure differences on the inside and outside of a <br />pipe elbow bend to determine flow rate. <br />agricultural water systems. An example proj- <br />ect supported by the S &T program involves <br />development of an improved calibration <br />methodology for using radial gates as flow <br />measurement structures. This capability can <br />enable districts to measure flows with suit- <br />able accuracy for monitoring canal operations <br />using existing radial gate control structures. <br />The calibration method is being coded into a <br />software package that will soon be available <br />for download from the WRRL website. <br />A "self- assembled" electronic flow monitor- <br />ing system known as the Continuous Flow <br />Meter (CFM) has been developed by re- <br />searchers at the WRRL. Demonstration sites <br />for this concept are being established for the <br />upcoming irrigation season on the Pioneer <br />Ditch (in cooperation with the Nebraska <br />Kansas Area Office), at the Angostura district <br />(in cooperation with the Dakota Area Office), <br />and at the Yuma Mesa district (in cooperation <br />with The Yuma Area Office). The "self -as- <br />tial pressure can be observed and <br />measured using water columns on a <br />manometer. A CFM installed at this <br />site utilizes an electronic pressure <br />transducer (seen at the bottom of <br />the manometer) to sense the pres- <br />sure differential. This information <br />Venturi flumes <br />such as this one can <br />also measure flow. <br />is processed to calculate differential <br />head, discharge, and totalized volume which are shown on <br />the CFM display. <br />In other ongoing studies, WRRL staff members are looking <br />at using a Venturi flume for measuring flows under condi- <br />tions of high submergence. A Venturi flume as referred to <br />in this study is a flat bottomed structure with a prismatic <br />upstream section, a gradual contraction to a prismatic <br />throat section and a gradual expansion back to the down- <br />stream channel. Flow is determined by measuring flow <br />depth at both the upstream and throat sections, then using <br />this information to simultaneously solve the energy and <br />continuity equations. In a laboratory test flume (shown <br />