Borehole Tests and Drillings

It is Time to Think About Borehole Tests and Drilling

In the wake of the near-catastrophic drought in the Western Cape and the continuing hikes in the price of municipal water, a growing number of suburban homeowners are choosing to follow the example of their country cousins by relying, instead, on water drawn from subterranean sources beneath their properties. Even if used only for topping up the pool and watering the lawn, over the course of a year, the savings can be substantial. In addition, it is an option that can help relieve the pressure on the dwindling reserves available to service providers. In short, maybe we should all consider arranging some borehole tests and, if satisfactory, drilling.

Rain falling on the land percolates through the soil until it reaches a layer of rock that is sufficiently permeable to support its flow, whereupon it forms underground streams known as aquifers. If a shaft of sufficient depth is drilled from above and protected from soil contamination with a suitable liner, water can then be extracted from the aquifer with a pump. For maximum efficiency, the pump should be designed to operate submerged, pushing water upwards rather than drawing it upwards from the surface.

Before proceeding, a hydrological survey will be necessary to determine the best site for the borehole drilling, and a number of tests will also need to be performed in order to check the quality of water and to estimate the likely yield. The survey should be conducted by an experienced hydrologist who will combine data based upon the surrounding terrain with that obtained from specialised survey maps to determine where to and the approximate depth of the hole needed to intersect the aquifer. Based upon these findings, it is then possible to provide a quotation.

The quote should include all equipment and labour, including any walling that may need to be removed and replaced to provide access for the borehole drilling equipment, and the cost of any tests. It is important to note that the quote will normally stipulate a maximum depth to which the company agrees to drill. Should this prove to be insufficient to intersect the aquifer, be aware that any additional drilling necessary will incur added expenses and will normally be calculated at a fixed cost per metre.

The importance of the testing component of the operation should not be underestimated. The contractor will, of course, ensure that every precaution is taken to ensure the source is not contaminated as a result of the borehole drilling process. Nevertheless, traces of chemicals and microorganisms can occur, and tests should be conducted to determine what treatment, if any, might be necessary to provide the desired quality of water. In addition, step-drawdown, yield, and recovery testing serves to provide valuable insight into the operating efficiency and the likely long-term performance of the new installation.

Even though not all regions of South Africa may be officially designated as semi-arid, it has become clear, in recent years, that the country as a whole is now faced with an impending water crisis. While municipalities are taking what action they can to avert it, consumers need to play a more active role in water conservation. Why not contact the Water Pump Group and inquire about borehole tests and drilling on your property?



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