riprap:
Layer or facing of rock or broken concrete which is dumped
or placed to protect a structure or embankment from erosion;
also the rock or broken concrete suitable for such use. Riprap
has also been applied to almost all kinds of armor, including
wire-enclosed riprap, grouted riprap, sacked concrete, and
concrete slabs.
river training:
Engineering works with or without the construction of
embankment, built along a stream or reach of stream to direct
or to lead the flow into a prescribed channel. Also, any
structure configuration constructed in a stream or placed on,
adjacent to, or in the vicinity of a streambank that is intended to
deflect currents, induce sediment deposition, induce scour, or
in some other way alter the flow and sediment regimes of the
stream.
rock-and-wire mattress:
A flat wire cage or basket filled with stone or other suitable
material and placed as protection against erosion.
roughness coefficient:
Numerical measure of the frictional resistance to flow in
a channel, as in the Manning's or Chezy's formulas.
rubble:
Rough, irregular fragments of materials of random size used to
retard erosion. The fragments may consist of broken concrete
slabs, masonry, or other suitable refuse.
runoff:
That part of precipitation which appears in surface streams of
either perennial or intermittent form.
sack revetment:
Sacks (e.g., burlap, paper, or nylon) filled with mortar,
concrete, sand, stone or other available material used as
protection against erosion.
saltation load:
Sediment bounced along the streambed by energy and
turbulence of flow, and by other moving particles.
sand:
A rock fragment whose diameter is in the range of 0.062 to 2.0
mm.
scour:
Erosion of streambed or bank material due to flowing water;
often considered as being localized (see local scour,
contraction scour, total scour).
sediment or fluvial
Fragmental material transported, suspended, or deposited by
sediment:
water.
sediment
Weight or volume of sediment relative to the quantity of
concentration:
transporting (or suspending) fluid.
sediment discharge:
The quantity of sediment that is carried past any cross section
of a stream in a unit of time. Discharge may be limited to
certain sizes of sediment or to a specific part of the cross
section.
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