An approximation is presented to rectify situations occurring as part of the three-dimensional simulation of surficial aquifer flows in which surface grid cells become dry (zero saturated thickness) and then cannot readily receive flows that would again partially saturate them. The approximation permits the cells to be rewetted by adjusting dry cell pressures by the same amount as the pressure change computed for the uppermost nondry cells in the vertical column. This is continued in successive timesteps until the dry cells once again become partially or fully saturated. The rewetting procedure was tested in a recent transient simulation of flows in the surficial Biscayne aquifer of Dade County, Florida, which is partly covered by seasonally inundated wetlands. This study demonstrates an empirical approach to the problem of cell rewetting that might prove useful in other models of flow in surficial aquifers.