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Bore Drilling Advice

The decision to drill a groundwater bore and drought-proof a farm will be determined by:

Requirements

The depth to be drilled for the required groundwater volumes and quality, and the associated budget considerations.

The selection of the driller

…including their capability to successfully drill to the required depth and their cost per metre.

After-drilling assessments

This may include a pump-test to assess water flow volumes and quality, and an immersed camera assessment to check rock fracture inflows at each level of flow.

Groundwater Quality

The mineral and chemical composition of groundwater affects its suitability for different uses and this quality varies with depth from the surface.  For example, water quality in the shallow groundwater systems to 200m can be affected by salinity, hardness (accumulation of carbonates) and chemicals (contaminants) used in agriculture and other land or industrial uses.

However, the groundwater in the zone from 300-500m is generally of a spring water (potable) quality, with excellent mineral and chemical (pH/ORP) values.  Much of this deep, confined groundwater has never reached the Earth’s surface and the age of the water may be millions of years old. Most of this deep water is confined below rock systems and bore flows can range from 50,000L per hour to 250,000L per hour.

Improving Groundwater Quality

It is critical for domestic water supplies (household drinking, stock water and water for vegetable production) that the water is of the highest quality.  Often water from the shallow water rock fractures can be saline (salty) and hard (high in carbonates). Phi’on has developed and patented several devices to fit bore water pipelines to overcome water quality issues. See www.meawater.com

These devices are unique in that they entrain a permanent negative (-mV) charge to the water (the natural state of flowing water in a pristine stream) and have been proven to reduce the saline taste and remove calcite build-up in pipes.

Common mistakes

  • Selecting a drill hole location without proper assessment of the groundwater sources.
  • Not having the site professionally mapped and the bores located by an experienced consultant.
  • Locating the bore based on proximity to electrical power.
  • Not setting aside a budget to drill to a greater depth to obtain water or a greater flow of water, ie. a Plan B. Consideration needs to be given to drilling up to and beyond 200m and often below 300m to obtain the water volumes and quality required to drought-proof a farm.
  • Not engaging the most capable drilling company for the job.   Always obtain a guarantee from the driller to drill to the depth you require.
  • Not supervising and testing water depths and quality during the drilling operation.  A simple EC meter can give you a quick test result for salinity levels.  Remember, the deeper you drill, the fresher the water
  • A driller can often give good advice about the potential for more water based on the changes in rock materials.  However, your consultant’s advice should be sought during the drilling, if required. Also, share your consultant’s bore hole analysis with the driller. Remember, the driller may not understand the local hydrology or the science of deep groundwater sources.
  • Hydrological maps of the groundwater sources are often hopelessly inadequate.  In some cases, the maps show no groundwater below say, 160m when significant volumes exist at 200-300m.  This can occur because most hydrologists or hydrogeologists have limited knowledge or experience with deep groundwater mapping and bore location.