FIG. 4. . Vertical cross-sectional images of water flow simulation results obtained with a two-dimensional dual-permeability model (2D-DPERM) for a nonequilibrium situation at Day 97.74 (i.e., directly after the first irrigation) showing (top) pressure head distribution in the soil matrix (SM) (top left) and preferential flow (PF) domain (top right) with velocity vectors, and (bottom) 2D water transfer rate distribution. Darcian flow velocities in cm d^–1 are indicated by the color of the arrows.