Glossary Related to Sediment Transport - Sediment Transport in Irrigation Canals: A New Approach - page 273

Bed shear stress The way in which currents transfer energy to the channel bed.

Berm Horizontal edge on the side of an embankment or channel section, to

intercept earth rolling down the slope, or to add strength to the construction.

Bernoulli Daniel Bernoulli (1700-1782); Swiss mathematician, physicist and

botanist who developed the Bernoulli equation: 'Hydrodynamica, de

viribus et motibus fluidorum' textbook (1st publication in 1738,

Strasbourg).

Bifurcation Location where a river or channel separates in two or more reaches, sections

or branches (opposite of a confluence).

Boundary conditions Physical conditions (hydraulic and/or others) used as boundary input to

physical or numerical models.

Boundary layer The flow region next to a solid boundary where the flow field is affected by

the presence of the boundary and where friction plays an essential part. A
range of velocities characterizes a flow across the boundary layer region;
from zero at the boundary to the free-stream velocity at the outer edge of
the boundary layer.

Boussinesq Joseph Valentin Boussinesq (1842-1929) - French expert on hydro-

dynamics 'Essai sur la théorie des eaux courantes' an outstanding

contribution in hydraulics literature (1877).

Boussinesq coefficient Momentum correction coefficient.

Bresse Jacques Antoine Charles Bresse (1822-1883) - French applied mathe-

matician and hydraulic expert, who made contributions to gradually varied
flows in open channel hydraulics (Bresse 1860).

Bulk density The mass of soil per unit of undisturbed bulk volume.

Canal A man-made or natural channel used to convey and in some cases also to

store water.

Capacity The ability to receive or to hold power; the ability of a stream to

transport water or sediment; the volume of artificial or natural reservoirs,
basins.

Cartesian coordinate One of three coordinates that locate a point in space and measure its distance

from one of three intersecting coordinate planes measured parallel to one
of the three straight-line axes that are the intersections of the other two
planes. It is named after the mathematician René Descartes.

Caving The collapse of a bank caused by undermining due to the wearing away of

the bank by the action of flowing water.

Channel Stream or waterway; 'channel' generally means the deep part of a river or

other waterway.

Channel, open- Longitudinal boundary consisting of the bed and banks or sides forming a

passage for water with a free surface.

Channel, stable- Channel in which the bed and sides remain stable over a significant period

of time in the control reach and in which scour and deposition during
floods is minimal.

Channel, unstable- Channel in which there is frequently and significantly change in the bed

and sides of a control reach.