1. DAMS Dept. Of Civil Engineering
Jyothi Engineering College, Cheruthuruthy

2. Dams
Dam is a solid barrier constructed at a suitable location across a river to store flowing water.
Storage of water is utilized for following objectives:
Hydropower
Irrigation
Water for domestic consumption
Drought and flood control
For navigational facilities
Other additional utilization is to develop fisheries
In some cases more than one purpose may be served by a single dam. Such a dam is known as a multipurpose dam

4. Structure of Dam Down stream Upstream Gallery Heel Toe Road way Crest
Spillway
(inside dam)
MWL
Max. level
NWL
Normal
water level
Free board
Sluice way
Gallery
Heel
Toe

5. Heel: contact with the ground on the upstream side
Toe: contact on the downstream side
Abutment: Sides of the valley on which the structure of the dam rest
Galleries: small rooms like structure left within the dam for checking operations.
Diversion tunnel: Tunnels are constructed for diverting water before the construction of dam. This helps in keeping the river bed dry.
Spillways: It is the arrangement near the top to release the excess water of the reservoir to downstream side
Sluice way: An opening in the dam near the ground level, which is used to clear the silt accumulation in the reservoir side.

6. CLASSIFICATION OF DAMS
According to use
Storage dam
Gravity dam, Earth dam, Rock fill dam, Arch dam
Diversion dam
Weir, Barrage
Detention dam
Water spreading dam, Debris dam

7. According to hydraulic design Over flow dam
Spill ways
Non-over flow dam
Gravity dam, Earth dam, Rock fill dam

8. According to materials of construction Rigid dams
Gravity dam, Arch dam, Buttress dam, Steel dam
Non-rigid dam
Earth dam, Rock fill dam

9. Gravity Dams
Gravity dam is the one in which the external forces (water pressure, wave pressure, silt pressure) are resisted by the weight of the dam itself
These dams are heavy and massive wall-like structures of concrete in which the whole weight acts vertically downwards
Reservoir
Force
Self weight
As the entire load is transmitted on the small area of foundation, such dams are constructed where rocks are competent and stable.

10. Bhakra Dam is across river Sutlej in Himachal Pradesh
Bhakra Dam is the highest Concrete Gravity dam in Asia and Second Highest in the world.
Bhakra Dam is across river Sutlej in Himachal Pradesh
The construction of this project was started in the year 1948 and was completed in
It is 740 ft. high above the deepest foundation as straight concrete dam being more than three times the height of Qutab Minar.
Length at top m (1700 feet); Width at base m (625 feet), and at the top is 9.14 m (30 feet)
Bhakra Dam is the highest Concrete Gravity dam in Asia and Second Highest in the world.

12. Buttress Dam:
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

13. Arch Dams:
These type of dams are concrete or masonry dams which are curved or convex upstream in plan
This shape helps to transmit the major part of the water load to the abutments
Arch dams are built across narrow, deep river gorges, but now in recent years they have been considered even for little wider valleys.

15. 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

17. Rock fill dam
The term Rock fill dam usually represents a dam that contains more than 50% of compacted or dumped pervious fill.
The dam is dependent for water tightness on an impervious upstream blanket or an impervious core.
"Like an earth dam it is composed of fragmental materials, with each particle independent of the others.
The mass stability is developed by the friction and inter-reaction of one particle on another rather than by any cementing agent that binds the particles together.