hydrograph:
The graph of stage or discharge against time.
hydrology:
The science concerned with the occurrence, distribution, and
circulation of water on the earth.
imbricated:
In reference to stream bed sediment particles, having an
overlapping or shingled pattern.
icing:
Masses or sheets of ice formed on the frozen surface of a river
or floodplain. When shoals in the river are frozen to the bottom
or otherwise dammed, water under hydrostatic pressure is
forced to the surface where it freezes.
incised reach:
A stretch of stream with an incised channel that only rarely
overflows its banks.
incised stream:
A stream which has deepened its channel through the bed of
the valley floor, so that the floodplain is a terrace.
invert:
The lowest point in the channel cross section or at flow control
devices such as weirs, culverts, or dams.
island:
A permanently vegetated area, emergent at normal stage, that
divides the flow of a stream. Islands originate by establishment
of vegetation on a bar, by channel avulsion, or at the junction
of minor tributary with a larger stream.
jack:
A device for flow control and protection of banks against lateral
erosion consisting of three mutually perpendicular arms rigidly
fixed at the center. Kellner jacks are made of steel struts
strung with wire, and concrete jacks are made of reinforced
concrete beams.
jack field:
Rows of jacks tied together with cables, some rows generally
parallel with the banks and some perpendicular thereto or at an
angle. Jack fields may be placed outside or within a channel.
jetty:
(a) An obstruction built of piles, rock, or other material
extending from a bank into a stream, so placed as to induce
bank building, or to protect against erosion; (b) A similar
obstruction to influence stream, lake, or tidal currents, or to
protect a harbor (also spur).
lateral erosion:
Erosion in which the removal of material is extended
horizontally as contrasted with degradation and scour in a
vertical direction.
launching:
Release of undercut material (stone riprap, rubble, slag, etc.)
downslope or into a scoured area.
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