Scour is the main cause of bridge failures. Monitoring of bridge scour is an essential method to control the damages caused by flood events. In this study, a large-scale tube consisting of heating and temperature-sensing elements was developed, and its application for detecting saturated soil and water was analyzed. Laboratory experiments confirmed the applicability of the thermal sensor for scour-monitoring purposes. Three methods are proposed in this article for analyzing the data obtained from a heat probe. A linear relationship between temperature increase from the initial to the secondary time and heat production in the probe was observed, and a line that can be used to determine scour was introduced. This method is simple and can be used for low-cost, large-diameter heat probes that are easy to fabricate.