Electrical resistivity imaging of field-scale solute transport in the unsat
urated zone of the Chalk in East Yorkshire is described. The study involved
application of an electrically conductive tracer to the surface of an 18 m
(2) plot at a rate of 49 mmd(-1) for two days (representative of very heavy
rainfall). The resistivity response of the upper 25 m over the following t
en months is reported. These results are interpreted together with geologic
al and hydrological data. The hydrogeological interpretation is that rapid
bypass flow occurs along steeply inclined joints during high intensity rain
fall in autumn and winter, but not usually during the summer. Joint saturat
ion occurs locally, progressing upwards from horizons rich in thin marl lay
ers.