About the earthen dam

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Fundamentals of Soil and Water Conservation
Engineering
(AGL308)
Mr. Rohitashv Nagar
Assistant Professor
Department of Agronomy
School of Agricultural Sciences
Career Point University, Kota (Raj.)

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Lecture-2
Earthen Dam

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Earthen 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
 Low cost

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 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.

5. Career Point CaresA Typical Layout
Heel
Gallery
Toe
Spillway
(inside dam)
Crest
NWL
Normal
water level
MWL
Max. water level
Free board
Sluice way
Upstream Down stream

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EarthDams
soil
reservoir
clay core
shell
Earthen Dam Lala I.P. Ray

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Heel: Contact with the ground on the upstream side.
Face: Exposed surface of the structure.
Crest: Top of the dam.
Toe: Contact on the downstream side.
COMPONENTS

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Galleries: Small rooms like structure left within the dam for checking
operations. ( GENERALLY FOUND IN CONCRETE DAMS).
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.

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Types of earthen dam
1.Homogenous embankment type:
homogenous material available economically and locally
Here sometimes a blanket of relatively impervious material is
provided at u/s.
Earthen Dam Lala I.P. Ray

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Types of earthen dam
2.Zoned embankment type: Central impervious core is provided
with a pervious transition zone covered by a much more
pervious outer zone.

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Types of earthen dam
3.Diaphragm type: Thin impervious core known as diaphragm is
provided to prevent seepage base Length of core is less than the
height (b<h) or b< 10 m thickness of diaphragm at any elevation is <
10 m or less than height of embankment above corresponding
elevation
Earthen Dam Lala I.P. Ray

12. Career Point CaresEarthen Dam Lala I.P. Ray
 Water supply
 Drought & Flood control
 Irrigation
 Recreation
 Navigation
 Fisheries
 Hydro-power generation
Usage of a Dam

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