A dam is a structure built across a river or stream to retain water. Dams have several purposes including water supply, flood control, irrigation, hydroelectric power generation, navigation, and recreation. Dams are classified based on their structure as arch dams, gravity dams, buttress dams, or embankment dams. While dams provide many benefits, they can also fail due to construction or geological issues, causing downstream flooding. Dams also have disadvantages like displacing communities and damaging natural environments.

1. HERITAGE INSTITUTE OF TECHNOLOGY
Department - CIVIL
Presented by- Abhijit Pal
TOPIC - DAM

2. OUTLINE
 What is a Dam
 Structure of Dam
 Purposes of Dam
 Selection of Dam sites
 Classification of Dam
 On structure
 Dam failure
 Disadvantages of Dams
 Conclusion
 Bibliography

3. WHAT IS A DAM
 A Dam is an obstruction
or barrier built across a
steam or river
 It is a structure built to
retain water

4. STRUCTURE OF DAM
 Heel- contact with
the ground on the
upstream side
 Toe– contact on the
downstream side
 Sluiceway- An
opening in the dam near
the ground level, which
is used to clear the silt
accumulation in the
reservoir side

5. STRUCTURE OF DAM
 Spillway– It is the
arrangement near the top to
release the excess water of the
reservoir to downstream side
 Gallery- Small rooms like
structure left within the dam
for checking operations
 Abutment- Sides of the
valley on which the structure
of the dam rest

6. PURPOSES OF DAM
 Water supply- Dams gather drinking water for people
 Flood control- Dams keep areas from flooding
 Irrigation- Dams help farmers bring water to their farms
 Hydroelectric- Dams help create power and electricity
from water
 Navigation- Dams create lakes for people to sail on from
one part to another
 Recreation- Dams can be used for swimming

7. PURPOSES OF DAM

8. SELECTION OF DAM SITES
 Topography
 Geology
 Material availability
 Spillway size and location
 Communication
 Locality land and population

9. CLASSIFICATION OF DAM
ON STRUCTURE
 Arch Dam
 Gravity Dam
 Buttress Dam
 Embankment Dam

10. ARCH DAM
 An Arch Dam is a curved
dam built where access to
materials is limited
 Ex- Idukki Dam in Kerala
 Arch Dams are thinner and
therefore require less
material than any other
type of dam
 These are dependent upon
arch action for its strength

11. ARC DAM

12. GRAVITY DAM
 Gravity Dams resist the
horizontal thrust of the
water entirely by their own
weight
 Ex- Dworshak Dam in
Idaho
 Gravity Dams are typically
used to block streams
through narrow gorges

13. GRAVITY DAM

14. BUTTRESS DAM
• Buttress Dams are dams
in which the face is held
up by a series of supports
• Ex- Bartlett Dam in
Arizona
• Most Buttress Dams are
made of reinforced
concrete and are heavy,
pushing the dam into the
ground

15. BUTTRESS DAM

16. EMBANKMENT DAM
 Embankment Dams are
massive dams made of
earth or rock
 Ex- Tataragi Dam in Japan
 Typically created by the
placement and
compaction of a complex
mound of various
compositions of soil,
sand, clay and/or rock

17. EMBANKMENT DAM

18. DAM FAILURE
 Faults in construction
methods eg-Teton Dam in
Idaho, USA in 1976
 Geological problems with the
dam foundation eg- St.Francis
dam
 Landslides which fall into the
storage reservoir eg- Vaiont
Dam in Italy in 1963

19. DAM FAILURE
 Earthquakes can certainly
cause damage to dams eg-
Lower San Fernando Dam
 Dangerous alterations to the
operation of the dam and/or
its structure may lead to
failure eg- South Fork
Dam (Johnstown) in 1889

20. DISADVANTAGES OF DAMS
The natural environment
is destroyed
The building of large dams
can cause serious
geological damage
Dams have endangered
some species of fish,
inhibited the seasonal
migration of fish
Displaces people

21. CONCLUSION
 Dams support 30%-40% of the irrigated area and 12%-
16% of the global food production
 Thus dams can be a source of huge profit both in terms
of fresh water resource and generation of electric
power
 Therefore construction of dams should be made
keeping in mind its long terms of service

22. BIBLIOGRAPHY
 Engineering Geology by Parbin Singh
 www.dams.com
 www.google.com/dams