Dissolved radon concentration in fractured rock aquifers

摘要

Dissolved radon concentrations are used to estimate groundwater flow rates and fracture apertures sizes. Groundwater radon concentrations have been measured both before and after purging nested piezometers, and radon emanation from aquifer matrix materials has been measured on samples obtained during drilling. The paper shows how the ratio of radon concentration before purging to that after purging can be used to quantify the groundwater flow rate. The ratio of radon concentration in groundwater after purging, to radon emanation rate is related to the fracture aeprture size. These results show that both groundwater flow rate and fracture aperture decrease with depth in fractured shales in the Clare Valley, South Australia.