A water well is a vertical shaft dug into the ground to access groundwater. There are several methods for constructing wells depending on factors like depth to groundwater, site geology, and water needs. Dug wells are excavated by hand tools or machinery and lined permanently. Bored wells are dug using hand or powered earth augers in diameters up to 1 meter and depths over 30 meters. Driven wells involve driving connected pipes into the ground. Jetted wells use high-pressure water jets to cut holes up to 15 meters deep.

1. D. Naresh Kumar
Assistant Professor
Civil Engineering Department

2.  A water well is a hole or shaft, usually vertical
excavated in the earth for bringing groundwater
to the surface. For constructing wells; selection
of a particular method depends on the purpose
of well.
 Many methods exist for constructing wells,
selection of a particular method depends on the
purpose of the well, the quantity of water
required, depth to groundwater, geologic
conditions, and economic factors.

3.  Depths range up to 20m or more, depending on
the position of the water table, while diameters are
usually 1 to 10m.
 A pick and shovel are the basic implements. Loose
material is hauled to the surface in a container by
means of suitable pulleys and lines. Large dug
wells can be constructed rapidly with portable
excavating equipment such as clamshell and
orange-peel buckets. For safety and to prevent
caving lining of wood or sheet piling should be
placed in the hole to brace the wells.
 A modern dug well is permanently lined with a
casing of wood staves, brick, rock, concrete or
metal.

4. pick
shovel
clamshell orange-
peel
bucket

6.  Bored wells are constructed with hand
operated or power driven earth augers.
 Hand augers are available in several shapes
and sizes, all operating with cutting blades at
the bottom that bore into the ground with a
rotary motion. These wells are seldom exceed
20cm in diameter and 15m depth.

7. Hand auger
Borehole drilling
using hand
auger

8.  Power driven augers will bore holes up to 1m
in diameter and under favourable conditions,
to depths exceeding 30m
Augers for boring wells
Hollow stem auger drilling

9. A driven well consists of a series of connected
lengths of pipe driven by repeated impacts
into the ground to below the water table.
Diameters of driven wells are small, most
falling in the range of 3 to 10cm.
Advantages of driven wells are that they can be
constructed in a short time, at minimum cost

10. A driven well with driving
mechanism

11.  Jetted wells are constructed by the cutting
action of a downward-direction stream of
water. The high velocity stream washes the
earth away, while the casting, which is
lowered into the deepening hole, conducts
the water and cutting up and out of the well.
Small diameters holes of 3 to 10 cm are
formed in this manner to depths greater than
15m.

12. Various designs of
jetting drill bits
Jetted well with self
jetting well point

13.  Cable tool method
Wells drilled by the cable tool method are
constructed with a standard well drilling rig,
percussion, tools and a bailer. The method is
cable of drilling holes of 8 to 60 cm in
diameter through consolidated rock materials
to depths of 600m

14. Basic well drilling tools for the
cable tool method

15. Drilled shafts
Cutting shoe for
segmental casing
Temporary casing
Oscillator/Rotator
method

16. Drilling mud

17.  Rotary drilling can also be accomplished with
compressed air in place of drilling mud. The
technique is rapid and convenient for small
diameter holes in consolidated formations
where a clay lining is unnecessary to support
the walls against caving. Large diameter holes
can be drilled by employing foams and other
air additives. Drilling depths can exceed
150m depth favourable circumstances.

19.  After a well has been drilled, it must be
completed. This can involve placement of
casing , cementing of casing, placement of
well screens, and gravel packing.

21. Gravel Packing