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Groundwater the forgotten resource
‘In today’s world no water anywhere is cooler, clearer, or less polluted or contaminated than the water which exists underground. Nor is any other supply of fresh water as plentiful or so widely distributed over the surface of the Earth.
It is a fact that we over-use and mis-use our surface water supplies at staggering annual costs, which in many cases, could have been avoided by properly developing and using our groundwater resources.
Groundwater exists simply because the surface of the Earth is not sealed tight, large areas are porous.
The water that does not ‘runoff’ during a storm, evaporates back into the atmosphere, or becomes trapped as soil moisture gradually penetrates downwards and becomes groundwater.
This water moves through the ‘pores’ or open spaces of the different materials beneath the surface and may even appear again o the surface at a point lower than that at which it entered the ground water reservoir. This re-appearance may be in the form of a spring, or it may simply seep into a stream, thus maintaining stream flow during dry periods.
Water that is contained within the lower saturated zone is called ‘groundwater’, and if this stored water is removable in useful quantities, the formation within which it is stored is called an ‘aquifer’.
There are two main types of aquifers. The first type is called a ‘water table aquifer’ and occurs when the top of the zone of saturation is the top of the aquifer. The second type of aquifer is called an ‘artesian aquifer’ and occurs when a permeable layer is sandwiched between tow impermeable formations.
Both consolidated materials, that is, rock formations, and unconsolidated materials, such as sands, gravels or weathered rocks, may be aquifers.
Some consolidated rocks, such as granites, basalts, hard sandstones, etc, may contain water in joints and fractures within the rock. Other rocks, such as limestones, and dolomites, may have quite large channels or cavities within them where water has worn away the softer or broken sections of the rock. Some of these channels become large caves and even have underground streams flowing through them.
Unconsolidated materials, particularly buried sand and gravel formations deposited by pre-historic rivers, often are extremely good aquifers, and many of the worlds highest capacity bores are located in such formations.
Today, in mans ever increasing search for groundwater, we have developed new drilling machines and equipment to make sure that once the water has been located, it can be developed and brought to the surface with the minimum of trouble and expense.
Test bores are to obtain an accurate sample of the various formations encountered; water samples for quality analysis and final production bore designs.
The most remarkable fact about Groundwater is that it is to be found almost everywhere beneath the surface of the Earth; below deserts, along river valleys, high on the slopes of hills and mountains, even, in some places, below the oceans.
To ensure the best possible results in obtaining an adequate, properly constructed ground water supply it is obvious that great care should be taken in the selection of competent, skilled personnel to undertake the investigation and construction of a bore.”