A borehole is a vertical capture engineered structure used to exploit the water from a water table held in the interstices or in the cracks in a rock in the sub-soil known as an aquifer.
The water can be raised to ground level either very simply using a receptacle or more easily using a manual or motor-driven pump.
Boreholes vary tremendously, be it in-depth, the volume of water, the cost or the purity of the water, whether or not treatment is justified before it can be consumed (and should also be checked regularly, not just when the structures are completed).
Boreholes Come In Three Categories:1. Dynamic.
1. A Dynamic Borehole: As the drill hits a break, water is ejected out from the hole in a pressurised spray.
2. An Average Borehole: As the operator removes samples of soil or rock drilled -water is evident.
3. A Residual Borehole: A residual borehole is more difficult to determine. The operator can drill past or through one or several "dry" breaks until he reaches the allocated depth with samples not showing any sign of water evident.
To the driller this might be viewed as a dry hole. With our experience in the borehole drilling industry and with our work with site surveyors ... we have realised that this conclusion is in most cases not correct.
We have done assessments within a week (at least 10 days) and have found reasonable amounts of water (ie. 70%) full.
The explanation for this is based on the actions of the drilling or blowing of the rig - which can actually block breaks temporarily and which eventually open with the pressure from the breaks releasing water.
At the time the drilling may appear as a dry hole, however, our experience has shown that given time the breaks will open release water.
Have Faith In Your Site Surveyor: If the surveyor advises you to drill to a certain depth he is doing it through many years of experience.