Glossary Related to Sediment Transport - Sediment Transport in Irrigation Canals: A New Approach - page 276

Eddy A vortex type of water motion, partly flowing opposite to the main current;

small whirlpool; movement of flowing water in a circular direction, caused
by irregularities or obstructions in canals, rivers or streams.

Eddy viscosity Name for the momentum exchange coefficient; also called 'eddy

coefficient'.

Elevation head The vertical distance to a point above a reference level.

Energy (grade) line Plot of the total energy head in the flow direction.

Energy gradient Difference in total energy per unit of horizontal distance in the flow

direction.

Energy head, Total- Sum of the elevation of the free water surface above a horizontal datum in

a section and the velocity head at that section.

Energy loss/head loss Difference in total energy between two cross-sections.

Energy, Specific- Sum of the elevation of the free water surface above the bed and the

velocity head at that section.

Equity Criterion of the share for each individual or group that is considered fair

by all system members; the measure can be defined as the delivery of a
fair share of water to users throughout a system; the spatial uniformity of
the ratio of the delivered amount of water to the required (or scheduled)
amount.

Erodible Used for the material (soil) prone to erosion.

Erosion The process by which soil is washed or otherwise moved by natural factors

from one place to another; the gradual wearing away of canal beds by
flowing water.

Erosion and scour The detachment and transport of sediment particles because of flowing

water. The processes can occur over land or within rivers and canals and
ultimately result in the deposition of transported sediment at downstream
locations. The movement of sediment can lead to the loss of significant soil
volumes, the instability of canal beds and banks, the undercutting of bridge
pier and abutment foundations, the reduction of conveyance and storage
capacity, and the damaging of aquatic habitat.

Erosive Used for the mechanism causing erosion.

Error The difference of a measured value from its known true or correct value

(or sometimes from its predicted value).

Euler Leonhard Euler (1707-1783) - Swiss mathematician and physicist.

Event An occurrence, which meets specified conditions, e.g. damage, a threshold

rainfall, water level or discharge.

Extreme A value expected to be exceeded once, on average, in a given (long) period

of time.

Fall A sudden drop in bed level of a stream.

Fixed-bed channel The bed and sidewalls are non-erodible; neither erosion nor accretion

occurs.

Flow Movement of a volume of water; not to be confused with 'rate of flow' or

'discharge'.