Accuracy of an Abrasion Measurement Method for Agricultural Irrigation Canal Surface Using a Depth Gauge

Abstract

We propose a simple measurement method employing a depth gauge as a quantitative abrasion measurement technique for agricultural irrigation canal surfaces. As the first step in this method, anchors are installed at two locations on the surface to serve as reference points. A measuring plate is placed on the top of the two anchors and the distance from the measuring plate surface to the surface is measured in 5 places with a depth gauge. The average distance to the surface is obtained as the average of 5 measurement values. By determining the difference between two values at different times, it is possible to estimate the progress of the average abrasion amount during that period.

In order to clarify the influence of each factor on the measured values, we conducted laboratory tests and field measurements on a channel with coated surfaces using a high-precision laser displacement meter and we compared the average distance to the coated surface using the laser displacement meter and the depth gauge.

As a result, the error of the abrasion measurement value using the depth gauge was estimated to be 0.4 mm for the laser measurement value of a channel with coated surface. The accuracy of a single measurement of the average abrasion depth estimated by the field measurement results was the laser measurement value ± 0.4 mm. When the average value of three iterations is used, the measurement accuracy is improved to ± 0.3 mm for the laser measurement value.