PAES 601 Flashcards
General Terms
PAES 601:2016?
General Irrigation Terminologies
areas open for public entry such as golf courses, public and private parks,
playgrounds, schoolyards and playing fields, residential landscapes and industrial
park landscapes
access areas
volume of water stored in reservoir between the minimum water level and normal
water level
active storage
rate of evapotranspiration equal to or smaller than predicted crop evapotranpiration 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
aquifer
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 the actual crop evpotranspiration to its potential evapotranspiration
crop coefficient
ratio of the actual crop evpotranspiration to its potential evapotranspiration
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
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
depth of water in the channel cross-section
depth
actual height of the embankment after settlement
designed height
maximum area which an irrigation project can serve considering the extent of arable
lands and the available water supply
design irrigable area
numerical value on the uniformity of application for agricultural irrigation systems
distribution uniformity
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
diversion dam
the total quantity of water diverted from a stream, lake, or reservoir, or removed from
the ground in order to irrigate a crop
diversion water requirement
trickle irrigation
involves dripping water onto the soil at very low rates (2-20 litres/hour) from the
emitters where water is applied close to plants so that only part of the soil in which
the roots grow is wetted
drip irrigation
in-line canal structure designed to convey canal water from a higher level to a lower
level, duly dissipating the excess energy resulting from the drop in elevation
drop
amount of rainwater that falls directly on the field and is used by the crop for growth
and development excluding deep percolation, surface runoff and interception
effective rainfall
soil depth from which the bulk of the roots of the crop extracts most of the water
needed for evapotranspiration
effective rooting depth
effective size
-particle diameter corresponding to a ____ sieve passing
10%
discharges from known sources which is passed into a body of water or land, or
wastewater flowing out of a manufacturing plant, industrial plant including domestic,
commercial and recreational facilities
effluent
any legal restriction or limitation on quantities, rates, and/or concentrations or any
combination thereof, of physical, chemical or biological parameters of effluent which
a person or point source is allowed to delivery into a body of water or land
effluent standard
water conveying conduit or trough which is supported on abutments by piers
elevated flume
spacing between emitters or emission points along a lateral line
emitter spacing
applicator used in drip, subsurface, or bubbler irrigation designed to disspate pressure
and to discharge a small uniform flow or trickle of water at a constant rate that does
not vary significantly because of minor differences in pressure
emitters
specific energy line
grade line of the water surface profile plus the velocity head in open channels
energy grade line
provision for passing of equipment and small machinery
equipment crossing
combination of water transpired from vegetation and evaporated from the soil, water,
and plant surfaces.
evapotranspiration
channel which conveys irrigation water from the turnout to the paddy field
farm ditch
dam component which prevents migration of small particles and screen off fine
materials that flow with seepage water and prevent piping
filter drain
height of the embankment to be attained during construction
finished height
amount of water to replenish the crop water requirement and losses less the effective
rainfall
farm water requirement
additional height of the dam provided as a safety factor to prevent overtopping by
wave action or other cause
freeboard
small parallel channels, made to carry water in order to irrigate the crop
furrows
method of irrigation where water runs through small parallel channels as it moves
down the slope of the field
furrow irrigation
small channel along one part of a field that is used for distributing water in surface
irrigation
head ditch
supply ditch
dam composed of a single kind of embankment material exclusive for slope protection
homogeneous embankment
ratio of flow area to the wetted top width
hydraulic depth
profile of the free water surface
hydraulic grade line
occurs when a thin sheet of incoming flow moving at high velocity strikes water of
sufficient depth
hydraulic jump
cross-sectional area of flow divided by the wetted perimeter
hydraulic radius
estimation of the chance or likelihood of occurrence of a given event by determining
the frequency curves of best fit to samples of hydrologic data
hydrologic frequency analysis
inside slope
slope of the upstream face of the embankment
inside bottom or sill of t the conduit
invert
closed conduit designed to convey canal water in full and under pressure running
condition, to convey canal water by gravity under roadways, railways, drainage
channels and local depressions
inverted siphon
time required to cover an area with one application of water
irrigation period
