Glossary Related to Sediment Transport - Sediment Transport in Irrigation Canals: A New Approach - page 272

Automatic system System that starts and stops without human intervention in response to

control, such as a switch, or a valve.

Backwater Flow profile controlled by downstream flow conditions in a subcritical

flow: e.g. a structure, change of cross-section; is commonly used for both
supercritical and subcritical flow. Term backwater calculation or profile
refers to the calculation of the flow profile.

Backwater calculation Calculation of the free-surface profile in open channels.

Backwater curve Longitudinal profile of the water surface in an open channel where the

flow depth has been increased by e.g. an obstruction, increase in channel
roughness, decrease in channel width or bottom slope. The water surface
slope is less than the bottom slope; the curve is upstream of the obstacle
that raises the water level and is concave upwards. Occasionally the term
is used for other non-uniform profiles, upstream or downstream.

Bagnold Ralph Alger Bagnold (1896-1990) - British geologist and expert on the

physics of sediment transport by wind and water.

Bakhmeteff Boris Alexandrovitch Bakhmeteff (1880-1951) - Russian expert on

hydraulics, who developed the concept of specific energy and an energy
diagram for open channel flows (1912).

Bank protection the process by which the bank is protected from erosion by lining or by

retarding the velocity along the bank; device to reduce scour by flowing
water e.g. mattresses, groynes, revetments.

Bank, left/right- bank to the left/right of an observer looking downstream.

Barré de Saint-Venant Adhémar Jean Claude Barré de Saint-Venant (1797-1886), French

engineer, who developed the equation of motion of a fluid particle in
terms of the shear and normal forces exerted on it.

Bazin Henri Emile Bazin: French scientist (1829-1917) and engineer, worked as

an assistant of Henri P.G. Darcy.

Bed erosion Deepening of a channel by the gradual wearing away of bed material,

mainly due to the forces of flowing water.

Bed forms Channel bed irregularity that is related to the flow conditions; features

on a channel bed resulting from the movement of sediment over it.
Characteristic bed forms include ripples, dunes and anti-dunes.

Bed load Sediment transport mode in which individual particles either roll, slide

or hop along the bed as a shallow, mobile layer a few particle diameters
deep; mass (or volume) of course sediment (silt, sand, gravel) in almost
continuous contact with the bed and transported in unit time.

Bed material Material with particle sizes that are found in significant quantities in that

part of the bed affected by transport.

Bed material load Part of the total sediment transport, which consists of the bed material and

whose rate of movement is governed by the transporting capacity of the
channel.

Bed or bottom slope Difference in bed elevation per unit horizontal distance in the flow direction.

Bed profile Shape of the bed in a vertical plane; longitudinally or transversely, which

should be stated.