SWCE and Irrigation and Drainage Engineering Terminology

Rate of evapotranspiration equal to or smaller than predicted crop evapotranspiration as affected by the level of available soil water, salinity, field size or other causes.

• Actual Crop Evapotranspiration

• Reference Crop Evapotranspiration

• Crop water Requirement

• Crop Efficiency

Structure or weir provided across the river or creek to raise its water level and divert

the water into the main canal to facilitate irrigation by gravity

• Check Dam

• Ogee Dam

• Diversion Dam

• Gabion Dam

Amount of water used in producing crops which is the sum of evapotranspiration or consumptive use plus seepage and percolation losses

• Crop Use

• Crop Water Requirement

• Crop Coefficient

• Farm Water Requirement

Rate of evapotranspiration of a disease-free crop growing in a large field (one or more

ha) under optimal soil conditions, including sufficient water and fertilizer and

achieving full production potential of that crop under the given growing environment;

• Crop coefficient

• Penman coefficient

• Blaney-Criddle

• Crop Evapotranspiration

Sequence of different crops grown in regular order on any particular field or fields

• Crop rotation

• Cropping Pattern

• Relay Cropping

• Regular Cropping

Any barrier constructed to store water

• Weir

• Dam

• Reservoir

• Embankment

Volume below the intake structure; sediment volume based on 25 years of accumulation in the reservoir

• Intake Volume

• 25yrs Reservoir

• Dead Storage

• Active Storage

Numerical value on the uniformity of application for agricultural irrigation systems

• Distribution Uniformity

• Coefficient of Uniformity

• Unimodal pattern

• Christiansen's uniformity Coefficient

The total quantity of water diverted from a stream, lake, or reservoir, or removed from the ground in order to irrigate a crop.

• Crop Water Requirement

• Farm Water Requirement

• Diversion Water Requirement

• Head Works

Ratio of the particle size at 60% passing to that at 10% passing

• Apparent Specific Gravity

• Relative Density

• Sieve Efficiency

• Uniformity coefficient