Water underground flows and collects in areas called aquifers. Bores (or sometimes referred to as “wells”) are used to access this groundwater from the aquifers.
While the design of individual bores can vary, most include the following components:
Wellhead and concrete apron: The top of the bore has a wellhead, which should be surrounded by a concrete apron that slopes away. This prevents surface water and contaminants from getting into the bore.
Casing: The bore hole commonly has a casing lining it to prevent it from collapsing and acts as additional protection against external contaminants.
Screened intake section: Below the casing is the open section of the bore where water enters. This area typically has a screen, which allows water to flow through from the aquifer but minimises other material, such as sand and gravel, from getting into the bore. Having a screen also helps stabilise the bore.
Pump and riser: A pump (usually submersible) is used to deliver water to the surface through a riser pipe, which may be rigid or flexible.
Bores can range widely in depth, with some reaching hundreds of metres below the surface, depending on the local geology and the depth of the water table. The depth from the ground surface down to the water table, when the pump is switched off and the water is at rest, is known as the static water level. It indicates where the water naturally sits in the bore.
When applying for a consent to take ground, the council may ask for information about the bore, including its depth, casing depth, and static water level. This helps ensure that groundwater is extracted responsibly and that the bore does not negatively impact the surrounding aquifer or other users.
Sue Clark
Environmental Consultant