Borewell
http://www.prashantborewell.com/support.html
(18.10.2013)
What
is a borewell?
A bore well is a well of
4 ½, to 12″ in diameter drilled into the earth for retrieving water. In
this 4 ½ ” and 5 ½ Bore wells are commonly for Domestic purposes while 6
½ and more are for Commercial / Industrial purposes. A bore well is cased in
the region of loose subsoil strata open in hard rock or in crystalline rock.
High grade PVC pipes are used for Casing in bore wells. The depth of a bore
well can vary from 50 feet to 1500 feet.
How
do we find-out the availability of water in the land?
The best way to find out whether water is available in your land is to
investigate using any geophysical techniques adopted by a qualified hydro
geologist. Buy the service of Experienced Senior Ground Water
Surveyor’s crew for finding most
suitable site using the latest Computerized Sound Survey Systems. Their
findings are 90% accurate.
What
is the difference between a bore well and a tube well?
A bore well is drilled with casing pipe put only up to the soil-rock boundary
and this is done normally for shallow depths in hard rock or in crystalline
rock. But in a tube well, the casing pipes are put up to the bottom of the bore
wells, with perforation in the pipes in some level. Normally the Tube wells are
drilled in sand and gravel where the availability of water is much below the
ground level.
Techniques
used in drilling of a Bore well?
Ancient techniques utilized driving of tubes inside the earth to drill well
using mud or water as a liquid media. Then after the invention of diesel
engines, rotary drilling was used to remove cores out of the earth. This was
called calyx method. There are several methods used for drilling Bore well.
Most commonly used are Compressor Drilling, Manual Drilling and Rotary Drilling. Compressor Drilling is done with the vehicle
fitted with High Power Hydraulic Air Compressor Machine. It is commonly used to
drill on soil surface and hard rock. Another method is by manual Drilling or
Hand Bore. This is most suited for lands with Clay or Sand. All these drillings
will be at 4 ½”, 5″, 6 ½”, 7″ & 8
½” Dia. Air compressors and pneumatic drilling equipments are used to
drill bore wells up to 3000 feet. The rates for drilling a bore well depend on
the location, nature of soil and availability of water.
What
care must be done while drilling a bore well?
While drilling a bore well we have to insert pipes called Casing pipes. It can
be PVC/GI. This is done to prevent the Surface water with Sand from entering
inside the bore well. These Pipes are fixed inside the hard rock under the
soil. Casing pipes are of 4 – 8 Kgs. Some of the contractors compromise with
this casing pipe to reduce drilling cost. We discourage it. Because it will
lead to future problems like bore silting, muddy water etc. Filtering can also
be done to prevent muddy water and for getting surface yield. Bore wells must
be kept closed to prevent something to fall inside it and block the bore. Pumps
must be installed as soon as possible to avoid bore silting and damage.
Periodical cleaning must be done to retain yield and quality of water.
We recommend using high quality ISI mark casing pipes with correct
measurement & thickness for long life of bore wells.
Did all bore well yield water?
According to us most of the bore wells yield water. Only a few of them were
dry. We had drilled 85% of bore well with high yield 10% with good yield &
5% with no yield. Our Water divining success rate is 90% – 95%.
We recommend clean/flush your bore well on every 5 year to retain
the yield & quality of water.
Why the bore well fails?
All the locations indicated by a geophysical survey at their respective
locations are interpreted from the resistivity values which are far better than
those obtained from the surrounding regions of the area surveyed , these
locations contrarily have resistivity values indicative of massive hard rock
with absolutely no fractures or seepages of water within them. Under the
conditions of crystallization of basalt, innumerable vesicles are formed, thus
creating air pockets within the mass of hard rock, The resistively of these
vesicular crystals remain in a similar range as those of soft weathered rock
through which seepage of water is likely. Hence, in case pockets of these are
encountered a probability of a decrease in yield of the aquifer bodies in the
boreholes is possible. Thus all results are interpreted from a complex natural
system of heterogeneous nature. Hence, variations in the results cannot be
totally ruled out.
What
types of Pumps are used in bore wells?
Most commonly used pumps for bore wells are Submersible pumps, Hand pumps and
Compressor pumps. All types of pumping systems from 0.25 monoblocks to 50 HP
Submersible pumps, Monoblocks, Centrifugal jet, Bore well submersible,
Compressor pumps, Hand pumps, Solar Submersibles, Pressure boosters, Piston
Pumps, Turbine pumps etc. can also be used. It depends upon the availability of
water & the depth of bore well. Testing can be done for checking the
discharge quantity of water from the bore well. We have professional geologists
for testing and they will recommend the pump suitable for your bore well.
Is bore well water pure for domestic use?
The bore well water is purer than fresh river or lake water. It will still have
dissolved solids and salts and minerals. Some of the bore well water will be
hard water. It is advisable to test the bore well water before drinking, if you
have any doubts on its freshness.