In an unconfined aquifer, the flow area varies with the saturated thickness because the water table itself forms the upper boundary, so under the Dupuit assumptions (streamline curvature is negligible and the hydraulic gradient equals the water-table slope, invariant with depth) the governing continuity equation is expressed in terms of the square of the saturated thickness (h²) rather than head (h) directly, distinguishing it from confined-aquifer flow theory. This mass-balance formulation, incorporating recharge and specific yield, yields steady-state solutions for one-dimensional flow between water bodies (including the location of a groundwater divide as a function of recharge rate) and for radial flow toward a pumping well, with drawdown-based approximations used to estimate aquifer transmissivity.
In an unconfined aquifer, the flow area varies with the saturated thickness because the water table itself forms the upper boundary, so under the Dupuit assumptions (streamline curvature is negligibl…