Water Resources Engineering types of wells with figuresOpen wells (Dug wells) Tube wells Wells and Tube Wells Irrigation in India Merit & Wells with Impervious lining CLASSIFICATION OF OPEN WELL BASED ON TYPE OF Lining  Well with pervious lining : These type of wells are suitable in coarse formations these are constructed by masonry of dry bricks or stones without any binding materials. So the water supply enters from the wall of well therefore the flow is radial. Such wells are provided with bottom plug so the flow is not combination of radial and spherical.well with pervious lining CLASSIFICATION OF TUBE WELL BASED ON SUPPLY SYSTEM Strainer type tube well Cavity tube well Slotted Type Tube well

1. Subject- Water Resources Engineering
By
Denish Jangid
Assistant Professor
Civil Engineering Department
WELLS,
TYPES OF WELLS

2. Overview of lecture
1. Introduction
2. Wells and Tube Wells Irrigation in
India : Merit & demerits
3. Open well and classification of
open well
4. Tube well and classification of tube
well

3. INTRODUCTION
Well: It is a vertical structure dug in ground for purpose
of bringing ground water to the earth’s surface
Basically wells are classified as follows :
 Open wells (Dug wells)
 Tube wells

4. There were about 5 million wells in 1950-51 and their
number has now increased to about 12 million.
Uttar Pradesh has the largest area of 93-84 lakh
hectares under well irrigation which accounts for
about 28-19 per cent of the well irrigated area of
India.
This is followed by Rajasthan (10-44%), Punjab (8-
65%), Madhya Pradesh (7-97%), and Gujarat (7-34%)
Bihar (6-29%), Andhra Pradesh (5-87%), Maharashtra
(5-75%), Haryana (4-41%), Tamil Nadu (4-35%), West
Bengal (4 19%) and Karnataka (3.06%).

5. Wells and Tube Wells Irrigation in India :
Merit
1. Well is simplest and cheapest source of irrigation
and the poor Indian farmer can easily afford it.
2 Well is an independent source of irrigation and can
be used as and when the necessity arises. Canal
irrigation, on the other hand, is controlled by other
agencies and cannot be used at will.
3. Excessive irrigation by canal leads to the problem of
reh which is not the case with well irrigation.

7. 4. There is a limit to the extent of canal irrigation
beyond the tail end of the canal while a well can be
dug at any convenient place.
5 Several chemicals such as nitrate, chloride,
sulphate, etc. are generally found mixed in well
water. They add to the fertility of soil when they
reach the agricultural field along with well water.
6. The farmer has to pay regularly for canal irrigation
which is not the case with well irrigation.

8. Wells & Tube Wells Irrigation in India :Demerits
1.Only limited area can be irrigated. Normally, a well can
irrigate 1 to 8 hectares of land.
2. The well may dry up and may be rendered useless for
irrigation if excessive water is taken out
3. In the event of a drought, the ground water level falls and
enough water is not available in the well when it is needed
the most.
4. Tube wells can draw a lot of groundwater from its
neighbouring areas and make the ground dry and unfit for
agriculture.
5. Well and tube well irrigation is not possible in areas of
brackish groundwater.

9. OPEN WELL
These are the wells which have comparatively
large diameters and lower discharges
Usually they have discharge of 20 m³/hr but if
constructed by efficient planning it gives
discharge of 200-300 m³/hr
They are constructed of diameter of about 1-10 m
and have depth of about 2-20m
They are constructed by digging therefore they
are also known as dug wells

10. CLASSIFICATION OF OPEN WELL BASED ON DEPTH
1. Shallow open well : These are the wells resting
on the water bearing strata and gets their supplies
from the surrounding materials
2. Deep open well : These are the wells resting on
the impervious layer known as mota layer beneath
which lies water bearing pervious layer and gets
their supply from this layer

11. CLASSIFICATION OF OPEN WELL BASED ON DEPTH

12. CLASSIFICATION OF OPEN WELL BASED ON
TYPE OF Lining/Walls
Kachha wells : These type of wells are only
constructed when water table is high as these type
of wells sometimes collapses.
It has no lining. The well sides are unprotected. Also
called unlined well. It is limited depth well. Like 6
Meter

13. CLASSIFICATION OF OPEN WELL BASED ON TYPE
OF Lining
Wells with Impervious lining : These are most
suitable and stable type of open well. These are
constructed by first digging a pit then a curb which
is a circular ring with sharp bottom is inserted .
Then a masonry wall up to some distance above
ground is constructed , then as excavation proceeds
it sinks blow and then masonry is further extended
and well is constructed. As water enters from the
bottom type of flow is spherical.

15. CLASSIFICATION OF OPEN WELL BASED ON TYPE
OF Lining
Well with pervious lining : These type of wells are
suitable in coarse formations these are constructed
by masonry of dry bricks or stones without any
binding materials. So the water supply enters from
the wall of well therefore the flow is radial. Such
wells are provided with bottom plug so the flow is
not combination of radial and spherical.

17. TUBE WELLS
A tube well is a long pipe sunk in ground
intercepting one or more water bearing strata.
As compared to open well there diameter is less
about 80-600 mm. Tube well is a type of water well in which a
long 100–200 millimetres stainless steel tube or pipe is bored
into an underground aquifer. The lower end is fitted with a
strainer, and a pump at the top lifts water for irrigation.
A tube well is a deeper well from which water is lifted with
the help of a pumping set operated by an electric motor or a
diesel engine. Obviously, a tube well cannot be constructed
everywhere and requires some geographical conditions
favouring its installation.

18. The first tube well of India was sunk in Uttar Pradesh
in 1930. Till 1951 India had just 2,500 tube wells. The
central and the state governments are helping the
farmers by distributing pumping sets, granting loans
and giving subsidies.
The number of electrical pump sets/tube wells
increased from 2 lakh in 1960 to over 4 million in 1995-
96 while the dieselized pump sets increased from 2 3
lakh to about 3 million during the same period.

20. The main factors for installing the tube well:
(i) There should be sufficient quantity of ground water because a tube well
can generally irrigate 2 hectares per day against 0.2 hectares per day
irrigated by an ordinary well.
(ii) The water level should be nearly 15 metres. If the water table is more
than 50 metres deep the cost of pumping out water from the tube well
becomes uneconomic.
(iii) There should be regular supply of cheap electricity or diesel so that
water from the tube well can be taken out at the hour of need.
(iv) The soil in the immediate neighbourhood of the tube-well should be
fertile so that there is demand for irrigation and the cost involved in the
construction and operation of the tube well can be recovered by the
increased farm production.

21. CLASSIFICATION OF TUBE WELL BASED ON DEPTH
Shallow tube well : These are the tube which has
depth limited to 30 meters and maximum have
discharge of 20 m³/hr
Deep tube well : These are the tube wells which
have maximum depth of about 600 m and may give
discharge more then 800 m³/hr

22. CLASSIFICATION OF TUBE WELL BASED ON SUPPLY SYSTEM
Strainer type tube well : These is
most commonly used tube such that in
general a tube well means strainer
tube well. In this type of well a
strainer which a wire mesh with
small openings is wrapped around
the main pipe which also has large
openings such that area of opening
in strainer and main pipe remains
same. Annual space is left between
two strainer so that the open area of
pipe perforations is not reduced.
The type of flow is radial.

23. In tube wells the metal pipe driven in ground is perforated to
allow only clear water to enter the hole. It is obvious that if no
other means is adopted the perforations in the metal tube will
have to be made very fine. It is very costly process.
As an alternative wire net may be wrapped on the cylindrical
frame of small diameter but it is liable to break as it is very
delicate. So the best and most commonly adopted practice is to
provide a pipe with fairly big perforations and surrounding that
is a wire net or a strainer with smaller openings.
Normally the mesh size of the wire net or strainer is kept equal
to D to D of the surrounding soil. This type of well derives water
from one aquifer of unlimited extent or from a confined aquifer
or from number of aquifers.

24. CLASSIFICATION OF TUBE WELL BASED ON SUPPLY SYSTEM
Cavity tube well : A cavity type tube well
consists of a pipe sunk in ground up to the hard
clay layer . It draws water from the bottom of
well . In initial stages fine sand is also pumped
with water and in such manner a cavity is
formed at the bottom so the water enters from
the aquifer into the well through this cavity
. It is an empty space within a solid object.
A cavity type tube well draws water from
bottom of the well and not from the sides and is
drilled in alluvial formation.
The flow in a cavity well is spherical.
The area of flow is increased by enlarging the
size of cavity.

25. HOW IS THE CAVITY FORMED?
The tube well is taken down till it penetrates the
impervious or (mota) layer and reaches the water
bearing layer. In the initial stages when the water is
pumped out fine sand comes in the tube well with
the water and consequently a hollow or cavity is
formed at the bottom.

26. After the cavity formation only clear water enters the
tube well. Since the rate of pumping is more, the
velocity of water entering the coarse sand layer is
critical but when it comes in the hollow the velocity
is reduced. Finally the water enters the tube well at
the bottom with a velocity lower than the critical
velocity.
Developing a cavity:
1) A centrifugal pump is generally adopted for
developing a cavity well.
2) Generally the depth of cavity is small (in
centimetres).

27. 3. Slotted Type Tube well:
CLASSIFICATION OF TUBE WELL BASED ON SUPPLY SYSTEM
Sometimes the nature of subsoil
formation is not anticipated correctly.
Obviously bore hole driven for
constructing strainer well will be a
failure. If a mota formation is present
cavity well may be resorted to.
But if neither of the conditions are
existing the slotted tube well can be
rightly constructed. There should be of
course an aquifer present at the bottom.
In the bore hole (say 36 cm diameter) a 15
cm diameter education pipe is lowered till
it reaches the bottom. The bottom of the
education pipe is slotted as shown in Fig.
The size of the slots may be 25 mm x 3
mm with 12 mm spacing