including selection of sites and Dam failure

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