Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: chris on 30/04/2009 12:10:04

Title: How do geologists locate underground water?
Post by: chris on 30/04/2009 12:10:04

If we assume that water divining or "dowsing" (sp?) has no evidence to support it (which we probably can without much difficulty) what scientific methods are available to enable people to locate underground water reserves or to identify the best position for a bore-hole?

Chris

Title: How do geologists locate underground water?
Post by: JimBob on 30/04/2009 17:48:04

Having good geologic and topographic maps is probably the best place to start. As most water wells are not very deep, 500 feet or so, the stream drainage and the placement of surface sands is of great importance in finding the best location. If the well to be drilled is deeper than 1,000 feet, then the surrounding wells are of great importance, more than if you drill a shallower well. 

However, most people who drill a water well just go out and drill a hole wherever the client wants a well. If there is an aquifer in the area, they will know how deep and what aquifer produces best - and is suited for the client. They don't think they are doing geology, they just have a bit of knowledge gained from experience so they apply their experience. But it is geology even if they don't realize they are doing it.

For the most part, locating a well doesn't necessarily require geology. Managing an aquifer system does. Draw-down and recharge are quantifiable and discernible parameters that can be evaluated in a geologic system to produce regional plans for use. As the population density grows, over-use can be a very big problem.