General Irrigation Terminologies Flashcards
PNS-BAFS-PAES-216_2017
areas open for public entry such as golf course, public and private parks, playgrounds, schoolyards, and playing fields, residential landscapes and industrial park landscapes
access areas
volume of water stored in reservior between the minimum water level and normal water level
active storage
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
rise in maximum flood level from the original unobstructed flood level which result after an obstruction to the flow such as a dam, has been introduced
afflux elevation
overgrowths of algae in water producing dangerous toxins in fresh or marine
water
algal bloom
ratio of the average depth of irrigation water infiltrated and stored in the root zone to the average depth of irrigation water applied
application efficiency
geologic formation which contains water and transmits it at a rate sufficient to
be economically developed for pumping artificially developed well
acquifer
cross-sectional area of the flow which is measured perpendicular to the direction
of flow
area
field that is level in all directions, encompassed by a dike to prevent runoff, and
provides an undirected flow of water onto the field
basin
type of surface irrigation where water is applied to the basin through a gap in the perimeter dike or adjacent ditch; water is retained until it infiltrates into the soil or the excess is drained off
basin irrigation
maximum average contact pressure between the foundation and the soil which
should not produce shear failure in the soil
bearing capacity
method of irrigation which makes use of parallel border strips where the water
flows down the slope at a nearly uniform depth
border irrigation
area of land bounded by two border ridges or dikes that guide the irrigation stream from the inlet point of application to the ends of the strip
border strip
inclination or elevation drop per unit length of the channel bottom
channel bed slope
groundwater that is confined by relatively impermeable layer
confined aquifer
introduction of substances not found in the natural composition of water that make the water less desirable or unfit for intended use
contamination
ratio between water received at the inlet for a block of fields to that released at the project’s headwork
conveyance efficiency
loss of water from a channel during transport due to seepage and percolation
conveyance loss
depth of water flow where the energy content is at minimum hence, no other backwater forces are involved
critical depth
ratio of actual crop evapotranspiration to its potential evapotranspiration rate is
crop coefficient
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; includes water loss through transpiration by the vegetation, and
vaporation from the soil surface and wet leaves
crop evapotranspiration
sequence of different crops grown in regular order on any particular field or
fields
cropping pattern
amount of water used in producing crops which is the sum of evapotranspiration or consumptive use plus seepage and percolation losses
crop water requirements
any barrier constructed to store water
dam
vertical distance from lowest point of the ground line to the dam crest
dam height
volume below the intake structure; sediment volume based on 25 years of
accumulation in the reservoir
dead storage
