How groundwater works and why water divining is often successful
Groundwater (water beneath the ground surface) moves very slowly through bodies of rock/sediment called aquifers. The pore spaces in these aquifers are usually voids in either sand/gravel beds beneath streams, or extensive, sheet-like bodies of sandstone. Boreholes drilled in either of these situations will find groundwater no matter where they are drilled, so water divining in these cases will always be successful.
Groundwater also flows through fractures in rocks like basalt and granite. Boreholes drilled in these aquifers have less likelihood of success; whether water divining increases the probability has not been unequivocally demonstrated.
Groundwater flow in caves can occur as groundwater streams, equivalent to surface streams; groundwater streams do not occur in other aquifer types, because the flow is too slow and/or uniform across the aquifer. Boreholes drilled to intercept water-filled caves are almost never successful, whether using water divining or not, but if a bore hits a cave stream, the flow rate can be extraordinary.
John Webb (PhD UQ 1982) is Emeritus Professor of Environmental Geoscience at La Trobe University. He specialises in groundwater geochemistry, including at contaminated sites, and is involved in research projects on improving treatment procedures for acid mine drainage, and on the origin of springs in central Queensland. He also works in geomorphology, particularly landscape evolution and karst geomorphology, and geoarchaeology, including artefact and ochre sourcing. He has supervised over 100 honours students and 30 PhD students, and published over 150 papers.
Skeptics Café will be held in the Function Room at The Stolberg Hotel, 197 Plenty Road Preston. The 86 tram route is close, and Bell train station – situated on the Epping line – is a short walk away. It will also be a virtual event accessible via Zoom, as per the details above.
Start Time: 6:00pm for dinner and a chat. 7:30pm for beginning of the talk.
We aim to wrap up after 9:00pm.
Donation appreciated: $5.00