Fig. 2. Normalized surface elevation and penetration measurements from five field soils in order of decreasing penetration results. The solid line with circle symbols represents a spline fit through surface elevations and the solid line with the triangle symbols represents a spline fit through penetration depths. In (A) and (C), the solid line represents a spline fit through wetting front measurements made after dismantling, and in (B), (D), and (E), the penetration depth was very similar (<1 mm) to the wetting front depth.