It’s obviously pretty standard in quarry applications to leave at least 1m above the maximum groundwater level when there is any risk to surrounding water supplies - here and here are just two examples of many.
Aggregate Industries would dearly like to reduce this unquarried metre to nothing, if given half a chance; it obviously couldn’t care less about peoples' drinking water supplies.
But AI should count itself lucky that stiffer groundwater restrictions have not been specified by the Environment Agency. In the quarry extension in Kent, referenced in the post below, Condition 37:
No mineral extraction shall take place... within 2 metres of the maximum recorded depth of groundwater... Reason: To minimise the risk of pollution of the public water supply.
Two metres have also been specified here and here, and also Switzerland, home to AI's parent:
The Swiss federal government has banned the extraction of sand and gravel from areas where drinking water is sourced.
permits shall not be granted in groundwater protection zones, including designated drinking water sources;
In a limited number of exceptions, gravel may be removed from above the groundwater level "provided a protective layer of material is left above the maximum groundwater level possible".
During quarrying the protective layer of material is required to be [at] least two metres above the highest maximum 10-year groundwater level.
For surrounding residents relying on Straitgate for their drinking water, the matter is important; AI made claims about 'dry working' at Venn Ottery.
