Nerves Of Steel For Pipe Touch Down!
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They oversaw the careful lowering of a 39-metre-long (128ft) steel pipe, lifted in sections by a 120 tonne crane and then fixed together, into a 42 metre deep (126ft) underground borehole – with just 13 millimeters to spare.
The £270,000 scheme to “reline” two of the company’s boreholes has been carried out at South East Water’s water treatment works in Deptford Road, Greywell, Hampshire.
The scheme is needed following an increase in the number of incidents of “cloudy” water being abstracted from the underground boreholes - effectively wells that have been drilled down into the chalk aquifer, which in turn stores rainfall that has percolated down through the ground.
The new steel liners will help protect the quality of drinking water that is abstracted from the boreholes, and will also ensure there is a safe, secure supply of water in the future.
Trevor Muten, Water Resources Manager, said: “The underground boreholes at Greywell form an integral part of our water supply network, helping produce up to seven million litres of water every day for our customers in north Hampshire.
“Over recent months the water quality has not been as good as it needs to be for our customers, and so we immediately started investigations. The cloudy water appears to have been caused by flooding during the very wet winter of 2006/07 getting through the original well liners, as their condition has deteriorated.
“By installing new, more robust steel liners, we can protect drinking water quality and ensure this source is able to continue to provide vital water supplies for years to come.”
Once the steel pipe was installed in the borehole, the gap between the existing wall and the new liner will be filled with an expanding concrete grout. This ensures there is a tight fit with no leaks or cloudy water being able to get through the liner to reach vital water supplies.