Overall the time-series of the hydraulic gradients display the steep increase at the time of bore arrival. For both beaches hydraulic gradients gradually decrease with time, as the saturated zone above the wetting front becomes thicker. Moreover, hydraulic gradients are significantly reduced by the build-up of pore-air pressure in the unsaturated region of the 1.5 mm beach (Steenhauer et al., 2011a). This pressure build-up is discussed in Section 3.3.
beach
1.5 mm
mm