A field testing device usable to determine the scour-depth potential of soils relied upon to support structural foundations placed in flowing water is disclosed. The device measures the scour potential in-situ, in relative terms, to the scour potential of fine sand using a columnar containment vessel driven into the soil to be tested. Within the columnar containment vessel is a cutting head as an aid in directing a water flow in a generally horizontal direction across the surface of the soil to be tested. Additionally, the cutting head serves to aid in the evacuation of eroded soil from with the containment vessel through an exhaust port. The exhaust port is part of a continuous closed loop water system which provides water for the scour testing and then removes the used water along with eroded soil particulates.