Recently a team from the University of Strathclyde, BGS Corporate Member Drilcorp and Water for People successfully sealed capped and controlled the flow from an artesian borehole in Chikhabado Village, Chikwawa District, Southern Malawi. This is believed to be the first successful control of such flow from a borehole in Malawi. Work on the borehole was set up as an open training session, to inform others working in groundwater supply in Malawi of problems associated with artesian water flows and demonstrate how to successfully control them. A total of 34 people from 10 organisations took part in the training.
If water flows naturally from a borehole without the assistance of a pump, this flow is described as ‘Artesian’. These flows occur when borehole drilling encounters groundwater in a confined unit under pressure. Artesian flows are often celebrated; it appears an unlimited supply of water is available without the need to buy and power pumping equipment.
However, there are significant problems with allowing artesian boreholes to flow uncontrolled. To control the flow, the borehole must be sealed just above the level of the artesian water flow and water directed up through a rising main pipe. At the top of this rising main a valve can be fitted to control the flow at surface. Sealing the borehole is usually done using a packer, a device which can be inflated against the walls of the borehole or casing to stop upwards water flow.
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