The findings presented here are the continuation of a series of studies begun in 1998 by the Irrigation Training and Research Center (ITRC) at California Polytechnic State University (Cal Poly), San Luis Obispo, California, on behalf of the Mid-Pacific Region of the United States Bureau of Reclamation (USBR) to test water level sensors under a variety of hydraulic conditions. This report is intended as a supplement to the original 1999 report, entitled “Water Level Sensor and Datalogger Testing and Demonstration” (ITRC Report No. R-01010), which describes the testing processes in detail and presents detailed results for the first 17 sensors tested. The 1999 report can be accessed through the ITRC website (www.itrc.org). The 2003 research, summarized in this report, includes the testing of five new sensors.

The goals for the original project were to determine the best way to monitor water level, and to develop a fast method for appraising sensors considered for irrigation district applications. This research addresses the need for water level sensors that are relatively simple to use and are very accurate over a broad range of hydraulic conditions. The use of water level sensor technologies, including ultrasonic sensors, pressure transducers, bubblers, and float sensors, was investigated for applications in a range of canals, reservoirs, and stilling wells. The testing results have been summarized with decision flow charts and rating tables for cross comparison.

During laboratory testing conducted at the Cal Poly Water Delivery Facility, the water level sensors were installed in a portable monitoring demonstration unit built by ITRC. The sensors were tested under different hydraulic conditions and the data gathered was used to evaluate the performance of each of the water level sensors. The characteristics evaluated included long-term trending, time lag, output stability, linearity and hysteresis, drying effects, and the effects of air temperature.


Bioresource and Agricultural Engineering

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URL: https://digitalcommons.calpoly.edu/bae_fac/132