be careful of gurus, page-7

Here is an interesting read on aquifers and the mentioned website is a great source of knowledge about groundwater.
An extract....

4. Drilling of bores can crack an aquifer
Myth: Concerns over drilling test bores and exploration bores commonly suggest that an aquifer can be cracked. The idea that an aquifer can be cracked like a piece of china has perhaps come from images of geological materials that have been fractured during movement of the earth.

Reality: Alluvial aquifers comprised of sand and gravel cannot crack. Moist clay sediments cannot crack. Fracturing or cracking can occur in swelling clay sediments due to moisture changes or in rock aquifers in response to changes in pressures or stresses. Over the past decades thousands of bores have been drilled through alluvial sediments into underlying rock in NSW. There is no evidence that drilling of any type (whether for water, testing or mineral resources) could damage aquifers, provided that sealing procedures in the Australian Standard and NSW DPI standards are adopted*. However, old corroded bores and water bores that have been gravel packed to the surface have caused leakage of shallow saline groundwater. The risk of impacts on groundwater levels or quality due to monitoring test holes or exploration drilling is negligible compared with other potential risks to the sustainability of groundwater resources.
AWA (2007). Water in Australia - Facts and Figures, Myths and Ideas. Published by Australian Water Association, Sydney.
Obtained from The University Of NSW website ?connected waters?.