Thermal Image displays the main channel as blue and the warmer yellow

Figure 2. Thermal image displayed as an inset of a true-color photograph taken in the field. The cooler water (blue) of the main creek channel flows in from the upper right. Warmer spring water (yellow) flows in from the lower right. At this location, the creek is about 40-feet wide. The temperature scale is in degrees Celsius. Image courtesy Kurt McCoy/USGS Virginia Water Science Center.