EP 1110-2-13
28 Jun 96
held in its raised position by the water pressure in a
flotation chamber beneath the dam.
Any fabric or textile (natural or synthetic) when used
as an engineering material in conjunction with soil,
e.
Emergency gate. A standby or auxiliary
foundations, or rock. Geotextiles have the following
gate used when the normal means of water control is
uses: drainage, filtration, separation of materials,
not available. Sometimes referred to as guard gate.
reinforcement, moisture barriers, and erosion
protection.
f.
Fixed wheel gate (fixed roller gate or fixed
axle gate). A gate having wheels or rollers mounted
Groin
on the end posts of the gate. The wheels bear against
The area along the contact (or intersection) of the face
rails fixed in side grooves or gate guides.
of a dam with the abutments.
g. Flap gate. A gate hinged along one edge,
Grout
usually either the top or bottom edge. Examples of
A fluidized material that is injected into soil, rock,
bottom-hinged flap gates are tilting gates and fish
concrete, or other construction material to seal
belly gates so called from their shape in cross section.
openings and to lower the permeability and/or
provide additional structural strength. There are four
h. Flood gate. A gate to control flood release
major types of grouting materials: chemical, cement,
from a reservoir.
clay, and bitumen.
i.
Outlet gate. A gate controlling the flow of
Grout curtain
water through a reservoir outlet.
One or more zones, usually thin, in the foundation
into which grout is injected to reduce seepage under
j.
Radial gate (tainter gate). A gate with a
or around a dam.
curved upstream plate and radial arms hinged to piers
or other supporting structure.
Grout blanket
An area of the foundation systematically grouted to a
k.
Regulating gate (regulating valve). A gate
uniform shallow depth.
or valve that operates under full pressure flow
conditions to regulate the rate of discharge.
Grout cap
A concrete pad constructed to facilitate subsequent
l.
Roller drum gate. See drum gate.
pressure grouting of the grout curtain.
m. Roller gate (stoney gate). A gate for large
Hazard classification
openings that bears on a train of rollers in each gate
The rating for a dam based on the potential
guide.
consequences of failure. The rating is based on
potential for loss of life and damage to property that
n. Skimmer gate. A gate at the spillway crest
failure of that dam could cause. Such classification is
whose prime purpose is to control the release of
related to the amount of development downstream of
debris and logs with a limited amount of water. It is
a dam.
usually a bottom hinged flap or Bascule gate.
Head, static
o. Slide gate (sluice gate). A gate that can be
The vertical distance between two points in a fluid.
opened or closed by sliding in supporting guides.
Head, velocity
The vertical distance that would statically result from
Gate chamber
Also called valve chamber. A room from which a
the velocity of a moving fluid.
gate or valve can be operated, or sometimes in which
the gate is located.
Headrace
B-8
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