Reviving dry bore-wells
Hydro-fracturing is one way of cleaning the blockage in the fissure and releasing water back into the bore wells
Possibilities: Hydro-fracturing can also open up the bore well to new fissures in the immediate vicinity.
Many of these bore wells have yielded well in the past but now are dry. This is true of almost all the Southern states. When these life providing bore wells fail they cause great trouble as alternative sources of water are sought.
The cause of the drying up of bore wells may be many but one of the causes can be the blockage of the fissure/s leading water into the bore well. This blockage can be due to mineralisation effects or due to the clogging of the fissure with silt. Hydro-fracturing is one way of cleaning the blockage in the fissure and releasing water back into the bore wells.
Hydro-fracturing can also open up the bore well to new fissures in the immediate vicinity not previously tapped by the bore well.
What is hydro-fracturing?
As the terms suggest, it is applying water under high pressure for the creation, propagation and cleaning of fractures and fissures deep in the rocky layer of the earth.
The creation or extension of the fractures is done using very high pressure water pumped into the bore well with pressures reaching as high as 3000 PSI (pounds per square inch). Mr. Ganesh of Ayyapas Aqua Solutions, Bangalore, who manufactures hydro-fracturing equipment and conducts hydro fracturing with his team, explains the procedure.
First an indigenously developed camera is introduced into the bore well to observe the correct depth of the casing, the presence of horizontal and vertical fissures at various depths and the total depth of the bore well itself.
With the camera observation it is possible to come to a conclusion as to whether hydro-fracturing is needed and the probability of its success. After determining the true depth of the fissures the team then introduces a top plug or a packer consisting of rubber gaskets into the bore well, which is then made to swell like a balloon using an oil pump. This expanded balloon like plug then prevents the upper transfer of pressure.
Through a pipe inside the packer, high pressure water is introduced using a specialised pump. The pressure gauge is monitored to note the impact. In a typical successful scenario the pressure increases and then rapidly falls indicating the cleaning up and widening of the fissures.
Two or three such pressure operations can be carried out depending on the depth of the bore well and the number of fissures present. Once hydro-fracturing is done the yield in the bore wells increase. This can be confirmed through a pump test by noting the volume of water pumped out in a given time.
Mr. Ganesh and team have noted a success rate of over 90 per cent with yields increasing by over 200 per cent in certain cases. Defunct bore wells can be brought back into life thus reducing sunk costs in such infrastructure.
Ganesh also insists on rainwater harvesting and artificial recharge to go hand in hand with hydro-fracturing as this is the only source of groundwater. Customers and clients who have seen a bore well fail understand the scarcity value of groundwater and the need to preserve and use it judiciously and the need for groundwater recharge too.
The typical response of sinking a new deeper bore well with huge costs and less chance of success can be avoided by hydro-fracturing.
Bore well owners and the nation at large have to understand the science of hydro-geology and preserve this precious resource for themselves and for the future generation. Participation in this scientific understanding, using water judiciously and harvesting and recharging groundwater is the path to water wisdom. India with its hard rock terrain and its huge dependence on groundwater has to lead the way.
S.Vishwanath, Bangalore www.rainwaterclub.org www.arghyam.org E-mail: firstname.lastname@example.org
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