Figure 1.

(a) Structure of anecic earthworm burrows as reported in Shipitalo & Butt (1999, fig. 3); (b) preferential flow in a worm burrow observed during a dye tracer experiment in the Weiherbach catchment; (c) exemplary generation of earthworm channels of high conductivity for 1.5 m× 1 m model domain for case n_b = 10, l_b = 1.1 ± 0.1 m and p_lat = 0.1.