Assessing soil water repellency spatial variability using a thermographic technique: An exploratory study using a small-scale laboratory soil flume

- A technique to assesss soil water repellency spatial variability, based on infrared thermography, was studied.
- Small-scale laboratory tests were carried out using a soil flume and a portable infrared video camera.
- The thermographic technique allowed mapping soil water repellency spatial distribution.
- The thermographic technique distinguished different classes of soil water repellency severity.
- The thermographic technique could not identify areas with low soil water repellency severity.

This exploratory study presents a technique to assess soil water repellency (SWR) spatial variability based on infrared thermography. Small-scale laboratory tests were carried out using a soil flume and a loamy-sand soil, where SWR was induced on soil surface with waterproofing spray and repellent areas were mapped through thermal imaging, using a portable infrared video camera. Cold water was used to create a temperature gradient on the soil surface in order to assess SWR. The technique was, in overall terms, successful in mapping SWR spatial variability, distinguishing repellent from wettable areas as well as distinguishing between areas with different levels of SWR severity, in particular, between areas with extreme as opposed to low to medium SWR. The proposed technique appears to have high potential to contribute to a better understanding of the hydrological impacts of different spatial patterns of SWR due to its capacity to monitor in real time the dynamics of these impacts.