Explicit infiltration function for boreholes under constant head conditions

Infiltration per unit area of the source region from discs, strips and furrows has previously been shown to be the sum of the one-dimensional infiltration and an edge effect term. Here we apply the same approach to examine infiltration under a constant head from boreholes (both lined and unlined). A critical empirical parameter (gamma) in the edge effect term is related to the radius of the borehole, soil hydraulic properties, boundary and initial conditions. For lined boreholes, gamma has a narrow range and for the examples investigated, a constant value of 1.06 introduces less than 5% error compared to using the case-specific gamma value. For unlined boreholes, gamma is larger, ranging between 1.02 and 3.16 for the examples investigated, and should be estimated for specific conditions.