Measuring rock moisture using different techniques in the sandstone area of Saxony
In the sandstone area of Saxony in eastern Germany ("Saxonian Switzerland"), climbing on wet rock poses a safety problem as the sandstone loses stability when saturated. Visitor guidance measures ('rock traffic lights') were implemented to temporarily stop climbing at rocks that are too wet. To accompany this measure, we carry out a pilot study at the Gohrisch sandstone massif, involving moisture measurements in the four cardinal directions at the rockwall base and near the summit of the massif. We use a combination of (a) electrical resistivity electrodes, combined with wind-driven rain collectors; (b) 2D-electrical resistivity (ERT); (c) microwave sensors (MW) with four sensor heads for different penetration depth, (d) Schmidt Hammer (SH) measurements to assess rock stability and (e) simulation of the temporal moisture distribution using WUFI®. All techniques are accompanied by laboratory measurements at rock samples.