PowerPoint Presentation
Group MembersAli Asghar 13 C 842Hafiz Zain Akram 13 C
826M.Farhan 13 C 832
DAM & RESERVOIR STRUCTURE
INTRODUCTIONDamA dam is a hydraulic structure of fairly
impervious material built across a river to create a reservoir on
its upstream side for impounding water for various purposes.
ReservoirA reservoir is a man-made lake that is primarily used
for storing water which is located at the back side of Dam.
A dam and a reservoir are complements of each other.
A VIEW OF TARBELA DAM
Purpose of DamsGeneration of hydropower electricityFor
agricultural & irrigation purposesFor fisheryTo prevent the
floodingTo diverse the water
Generation of Hydroelectric Power
Irrigation Purpose
Dam prevents flood
Water Diversion
Components of DAM
Components of DamAbutmentThe part of a valley side (wall)
against which a dam is constructed. An artificial abutment is
sometimes constructed as a concrete gravity section, to take the
thrust of an arch dam where there is no suitable natural abutment.
Right and left abutments are those on respective sides of an
observer looking downstream.
Abutments
Components of DamGalleryA passageway within the body of a dam or
abutment; hence the terms "grouting gallery", "inspection gallery",
and"drainage gallery".
A long and rather narrow hall; hence the following terms for a
power plant: "valve gallery", "transformergallery", and "busbar
gallery
SpillwayA structure over or through which flood flows are
discharged.Controlled SpillwayIf the flow is controlled by gates,
it is called a controlled spillwayUncontrolled SpillwayIf the
elevation of the spillway crest is the only control, it is called
an uncontrolled spillway
Fig - 1Fig - 2
Components of Dam
Types of Spillway
Auxiliary SpillwayBell mouth spillwayFuse Plug SpillwaySiphon
SpillwayComponents of Dam
Auxiliary Spillway
A dam spillway built to carry runoff in excess of that carried
by the principal spillway; a secondary spillway designed to operate
only during exceptionally large floods. Also referred to as
Emergency Spillway
Components of Dam
Bell mouth spillway
Some spillways are designed like aninverted bellso that water
can enter all around the perimeter.Components of Dam
Fuse Plug Spillway
Afuse plugis a collapsible dam installed onspillwaysindamsto
increase the dam's capacity.
Components of Dam
Asiphonmakes use of the difference in the height between the
intake and the outlet to create a pressure difference needed to
remove excess water.Siphon Spillway
Components of Dam
Crest: The top of the Dam. These may in some cases be used for
providing a roadway or walkway over the dam.
Parapet walls: Low Protective walls on either side of the
roadway or walkway on the crest.
Heel: Portion of Dam in contact with ground or river-bed at
upstream side.
Toe: Portion of dam in contact with ground or river-bed at
downstream side.
Components of Dam
Sluice way: Opening in the dam near the base, provided to clear
the silt accumulation in the reservoir.
Free board: The space between the highest level of water in the
reservoir and the top of the dam.
Dead Storage level: Level of permanent storage below which the
water will not be withdrawn.
Components of Dam
Energy Dissipation components + Foundation Treatments of DAM
Components of DamEnergy DissipationStilling BasinA basin
constructed to dissipate the energy of fast-flowing water, e.g.,
from a spillway or outlet, to prevent undercutting of the dam and
to protect the streambed from erosion.In latest techniques some
spillways are design in such a manner that do not required stilling
basin. Example: Ohio Dam USA
Stilling Basin Hydraulic Jump
Downstream of OhioDamSpillway
Components of DamEnergy DissipationStilling Basin
ContinueCertain auxiliary devices are usually provided in stilling
basins to reduce the length of the jump.Chute BlocksBaffle
wallsSillsThese devices also improve the dissipation action of the
basin & stabilize the jump.
Components of DamEnergy DissipationChute BlockInstalled at the
toe of spillwayFurrow the incoming jetBaffle BlockInstalled at the
mid of stilling basinIncrease the turbulenceDentated SillsInstalled
at the end of stilling basinDecrease the velocity of jet
Energy Dissipators
Water striking on Buffle block
Chute spillway with Buffle Blocks
Foundation Treatment Techniques for DamsVarious techniques are
used for foundation treatment of dams, The most common techniques
are as follows:GroutingHoles are drilled at shallow as well as deep
and cement grouting is filled to establish an effective barrier to
seepage under the dam and to consolidate the
foundation.Consolidation GroutingCurtain Grouting
GroutingConsolidation GroutingLow-pressure grouting to fill
voids, fracture zones, and cracks at and below the surface of the
excavated foundation is accomplished by drilling and grouting
relatively shallow holes.
Consolidation Grouting
GroutingCurtain GroutingConstruction of a deep grout curtain
near the heel of the dam to control seepage is accomplished by
drilling deep holes and grouting them using higher pressure.
Curtain Grouting
Why Grouting Important
