Detecting Water Loss Sink Points in Shallow Flooded Agricultural Environments Using a Visual Technique Based on Infrared Thermography: Laboratory Testing

This study presents a new visual-based method that uses a thermal tracer and infrared thermography to detect sink points in shallow flooded areas. Laboratory experiments were conducted in a 2 × 2 m2 soil flume where different scenarios with varying sink characteristics (e.g., permeability) were examined. To detect the sink point, hot water was continuously applied to create a temperature gradient across the flooded area, and multiple tracer discharges were tested. A portable infrared video camera was used to obtain high-resolution thermal imaging. The sink detection method was based on tracking the leading edge of the tracer’s plume over time. This method successfully identified water sink points in most experimental scenarios and provided valuable insights into surface flow processes. Specific combinations of tracer discharge and sink characteristics (e.g., location and saturated hydraulic conductivity) could influence the method’s effectiveness in detecting the sink location.