EP 1110-2-13
28 Jun 96
B-2. Terms
Bedrock
The consolidated body of natural solid mineral matter
which underlies the overburden soils.
That part of the valley side against which the dam is
constructed. An artificial abutment is sometimes con-
Berm
structed as a concrete gravity section to take the thrust
A nearly horizontal step in the sloping profile of an
of an arch dam where there is no suitable natural
embankment dam. Also a step in a rock or earth cut.
abutment. The left and right abutments of dams are
defined with the observer viewing the dam looking in
Borrow area
the downstream direction, unless otherwise indicated.
The area from which material for an embankment is
excavated.
Acre-foot
A unit of volumetric measure that would cover 1 acre
Breach
to a depth of 1 foot. It is equal to 43,560 cubic feet.
An eroded opening through a dam which drains the
reservoir. A controlled breach is a constructed
opening. An uncontrolled breach is an unintentional
Adit
A nearly horizontal underground excavation in an
opening which allows uncontrolled discharge from
abutment having an opening in only one end. An
the reservoir.
opening in the face of a dam for access to galleries or
operating chambers.
Catastrophe
A sudden and great disaster causing misfortune,
destruction, or irreplaceable loss extensive enough to
Appurtenant structure
Ancillary features of a dam such as inlet and outlet
cripple activities in an area.
works, spillways, tunnels, or powerplants.
Channel
A general term for any natural or artificial facility for
Axis of dam
The vertical plane or curved surface, chosen by a
conveying water.
designer, appearing as a line, in plan, or in
cross-section, to which the horizontal dimensions of
Cofferdam
the dam are referenced.
A temporary structure enclosing all or part of the con-
struction area so that construction can proceed in the
dry. A diversion cofferdam diverts a river into a pipe,
Baffle block
A block, usually of concrete, constructed in a channel
channel, or tunnel.
or stilling basin to dissipate the energy of water
flowing at high velocity.
Compaction
Mechanical action which increases the density by
reducing the voids in a material.
Base thickness
Also referred to as base width. The maximum
thickness or width of the dam measured horizontally
Conduit
between upstream and downstream faces and normal
A closed channel to convey water through, around, or
to the axis of the dam, but excluding projections for
under a dam.
outlets, or other appurtenant structures.
Construction joint
The interface between two successive placings or
Batter
Angle of inclination from the vertical.
pours of concrete where bond, and not permanent
separation, is intended.
B-2
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