A probe for measuring wetting front migration in rocks

To facilitate investigations of flow dynamics in unsaturated fractured rock s, we have designed a probe to qualitatively monitor saturation changes in borehole environments. This flexible probe is able to fit the cylindrical s hape of boreholes and requires no backfill. Field results suggest that the design of this electrical resistivity probe (ERP) is suitable for determini ng changes in relative wetness along boreholes in unsaturated fractured roc k environments. The performance of these probes was compared with that of p sychrometers under a variety of tests; these probes were found to be signif icantly cheaper in addition to providing data that had a greater spatial an d temporal resolution.