4. What is dam?
Dam is a solid barrier constructed at a
suitable location across a river valley to store
flowing water.
Or
The arrangement made for systematic
control of water flow for better optimum
utilization of available water.
Humanity control over Natural resources
5. What is the purpose of dam?
The purpose (requirement) of dam is following
Drinking water
Navigation
Flood control
Recreational purposes
Irrigation
Hydropower
6. Requirement of dam (world wide %)
48.60%
17.40%
12.70%
10.00%
5.30%
0.60% 5.40%
Irrigation
Hydropower
Water Supply
Flood Control
Recreation
Navigation and
Fishing
Others
Source: International Commission on Large Dams (ICOLD)
7. Parts of a dam
Dam body: Body forms the main part of a dam as an
impervious barrier
Reservoir: It is the artificial lake behind a dam body
Spillway: is that part of a dam to evacuate the flood water from
reservoir.
Water intake structures: is a facility to withdraw water from
a reservoir.
Sluiceway: Gerektiğinde baraj gölünü tamamen boşaltmak,
dolusavak kapasitesini azaltmak, akarsu mansabına bırakılacak
suyu salmak amacına yönelik tesisler.
Diversion facilities: To redirect the streamflow from
construction area
9. Types of dam?
ACCORDING to the SIZE of the DAM
1. Large (Big) dam
2. Small dam
International Commision on Large Dams, (ICOLD) assumes a
dam as big when its height is bigger than 15m.
If the height of the dam is between 10m and 15m and matches
the following criteria, then ICOLD accepts the dam as big:
If the crest length is bigger than 500m
If the reservoir capacity is larger than 1 million m3
If the flood discharge is more than 2000 m3/s
If there are some difficulties in the construction of
foundation
10. ACCORDING to HEIGHT of DAM
High Dam or Large Dam
If the height of the dam is bigger than 100m
Medium Dam
If the height of the dam is between 50m and 100m
Low Dam or Small Dam
If the height of the dam is lower than 50m
11. ACCORDING to the STATICAL DESIGN of
DAM BODY
Gravity Dams
Arch Dams
Butress Dams
Embankment(Earth) Dams
Composite Dams
12. GRAVITY DAM
These dams are heavy and
massive wall-like structures of
concrete in which the whole
weight acts vertically
downwards
As the entire load is transmitted on the small area of foundation, such dams
are constructed where rocks are competent and stable.
13. Structure of Gravity Dam
Heel
Gallery
Toe
Spillway
(inside dam)
Crest
NWL
Normal
water level
MWL
Max. level
Free board
Sluice way
Upstream Down stream
14. Example of gravity dam.
• Bhakra Dam is the
highest Concrete Gravity
dam in Asia and Second
Highest in the world.
15. Buttress Dam – Is a
gravity dam reinforced
by structural supports
Buttress - a support that
transmits a force from a
roof or wall to another
supporting structure
This type of structure can be considered even if the foundation rocks are little
weaker
19. Earth Dams:
They are trapezoidal in
shape
Earth dams are constructed
where the foundation or the
underlying material or rocks
are weak to support the
masonry dam or where the
suitable competent rocks are
at greater depth.
Earthen dams are relatively
smaller in height and broad
at the base
They are mainly built with
clay, sand and gravel, hence
they are also known as Earth
fill dam or Rock fill dam
20. ADVANTAGE OF DAM
40 % Of world food production comes from Irrigated
forming out of which 16% is contributed due to
dams.
30-40% of 268 million hectares of irrigated land is
watered from dams
19% of world energy comes from hydro-electric
power ( which includes 150 countries)
90% of 24 countries
50% in 63 countries
21. DISADVANTAGE OF DAM
FLOOD
NOT ECONOMICAL
TIME
CULTURAL DAMAGE
Loss of forests , wildlife habitat, the degradation of
upstream catchments
Disruption of fishing and waterway traffic
The fragmentation and physical transformation
of rivers
