An improvement on Hvorslev's shape factors

The shape factors listed by Hvorslev (1951) are widely used to measure in situ hydraulic conductivity (e.g. discussion in Ratnam et al, 2001). The shape factor F [L] is defined by the general equation

where Q [L³T^-1] is the flow rate of water from a piezo-meter, K [LT^-1] is the hydraulic conductivity of the aquifer, and H [L] is the constant applied head-difference between the piezometer and the unperturbed aquifer.

Lowther (1978) commented that the table of shape factors provided by Hvorslev (1951, fig. 12)...