PART 2: FARM IRRIGATION ANG DRAINAGE Flashcards
used in the irrigation of row crops with furrows developed between the crop rows in planting and cultivating processes.
furrow irrigation
higher lps, greater furrow width
stream size
commonly used for irrigating non-cultivated, close-growing crops, or in conjunction with border irrigation
corrugation
makes use of parallel ridges to guide a sheet of flowing water as it moves down the slope
border irrigation
simplest and most widely used by all surface irrigation methods
basin irrigation
uncontrolled application of water
flooding
useful in soils having a low-holding capacity and high infiltration rate where surface method cannot be used and sprinkle irrigation is expensive
subsurface irrigation
can’t be applied in saline soil or or soil with high accumulation of salts
perforated pipes
remains at fixed position while irrigating, and in continuous-move systems
sprinkler irrigation
consists of an extensive network of pipes usually of small diameter that filtered water directly to the soil near the plant
trickle/drip irrigation
outlet device in pipe
emitter
located at water source (reservoir) consist of flow-control valve, measuring devices, pressure control and filters
controlled head
recommended operating pressure and nozzle diameter
up to 1/8 in.; 40 psi
graphical picture of how rapidly water moves from the inlet end to the downstream of the field
advance curve
it is a plot of how the furrows drains after application has been cutoff
recession curve
the process intermittently applying water in the surface irrigation
surge flow irrigation
deliver water at low flow rates through various types of water applicators by a distribution system located on the soil surface, beneath the surface, or suspended above the ground
microirrigation systems
water is applied slowly through small emitter openings to the soil surface
surface trickle
water is sprayed over the soil surface to relatively low pressure
spray
a small stream of water is applied to flood the soil surface in localized areas
bubbler
water is applied through small emitter openings below the soil surface
subsurface trickle
consists of water applicators designed directly into or attached to lateral lines that are laid on the soil surface
surface trickle
system components
pump station
filtration and chemical injection
main pipelines; manifold pipes
laterals
water applicators
designed to dissipate pressure while discharging small uniform flows of water at constant rate
emitters
have a long capillary-size tube or channel to dissipate pressure
long-path emitters
rely on an individual opening or a series of orifices
orifice emitters
rely on vortex principle
vortex emitters
line-source tubing common wall thickness
0.008-0.010
constructed of porous material with pores of capillary size that ooze water when under pressure
porous-wall tubing
has orifices punched through the hose wall or emitters fabricated or inserted at fixed intervals along the hose
single-chamber tubing
permit the passage of relatively large particles while operating
continuous-flushing flow emitters
discharge water at a constant rate over a wide range of pressure
compensating emitters
consists of fine gravel and sand of selected sizes placed in graded layers inside a cylindrical tank
media filters
used to remove fine sands or small amount of algae; used where the water is expected to be clean
screen filters
___ and ____ created by bacteria can cause severe clogging
algae, slime
require setting the desired volume of water to be applied
volumetric valves
an important part of starting up the systems after installation and maintaining performance
flushing
the percent of the area wetted compared to the entire crop area
wetted area
two important components of irrigation requirements
peak irrigation WR
seasonal total IR
It represents the irrigation amount required to meet the maximum crop evapotranspiration rate over time period of one to several days
peak irrigation water req
is restricted by water rights or other legal limitations
seasonal total irrigation req
originates from precipitation on the landscape moving down slope to streams and rivers
surface water
precipitation that infiltrates and percolates down through the soil profile
groundwater
zone of saturation in substratum capable of yielding enough water to satisfy a particular demand
aquifer
it recognizes the right of an owner to make reasonable use of the stream’s flow on the riparian land; owners may use their equitable share of the flow
riparian doctrine
it is based upon the priority of development and use; acquired by filing a claim in accordance with state laws
doctrine of prior appropriation
water contaminants from animal and human wastes
biological
geologically, the loose and discontinuous layers of decayed rock debris overlying solid bedrock which is potential storage medium for water
regolith
the uppermost part of the regolith where chemical and physical weathering are the most active
soil
the boundary between the unsaturated and the saturated zones
water table
groundwater confined under pressure between two impervious layers and may create an artisan condition
confined aquifer
holes drilled or dug downward from the soil surface into an aquifer
well
the vertical distance from the static water table to the water level at the well
drawdown
the horizontal dance from the well to where the water table is not noticeably lowered by drawdown
radius of influence
alternately lifts and drops a heavy chisel-shaped steel bit
drilling rig
is fastened to pipe that is rotated by a machine
steel bit
pump is turned on and off to allow water to surge back into the well thereby drawing fine materials into the well to be removed by pumping during a repeat of the surge
surging
allows for complete flexibility on the frequency, and duration of water delivery
demand schedule
requires the user to request the rate and duartion of water delivery in advance
arranged schedule
all flow entering the small canal is delivered to only one field
rotation schedule
mechanical devices for transferring fluids from one place to another
pumps
discharge the same volume of water regardless of the head against which they operate
positive displacement pumps
has inverse relationship between the discharge rate and the pressure head
variable displacement pumps
described as having a to-and-fro motion
reciprocating
- lift pump
- force pump
used primarily as source of fluid power in hydraulic systems
rotary
most commonly used type of VDP for irrigation
centrifugal force acts on a body mpving in a cicular path, trending to force it further away from the axis of rotation
centrifugal pumps
has casing made in the form of a spiral or volute curve; was proportioned to change velocity head into pressure head
volute cp
the impeller is surrounded by diffuser vanes
diffuser or turbine cp
used an impeller which is suspended vertically on a drive shaft within a long discharge pipe
deep well turbine pumps
type of pumps close-coupled with a smaller diameter electric motor and operated under submerged conditions
submersible pump
are used for low head-high discharge operation; can give high eff compared to CP at heads less than a meter
propeller and mixed flow pumps
as used in irrigation consists of a combination of CP a a jet mechanism or ejector
jet pumps
is the process of removing air in the suction line of the water pump, done by filling the suction line with liquid which replaces the air in the suction line
priming
the quantity of water produced and operating conditions of pumps govern the selection
type of pump
the source of available energy for use influences the selection
power
determines the types of impeller
water quality
characteristic curve and pump performance characteristic curves
the system
is a phenomenon in which water boils due to the reduction in water pressuere
cavitation
removal of excess water and salts in the area
drainage
soil drains naturally; rate of drainage depends on soil characteristics to the condition of the outlet
natural subsurface drainage
pipe system installed in subsurface
closed gravity drainage
used to collect seepage from canal, reservoir and other manmade facilities
interceptor
consist of parallel lateral drains
relief drainage
consist of the combination of deep lateral D to a series of shallow unlined mole drains
relief mole drainage
bullet-shaped object
moles
both clay and concrete
clay-tile
standard quality, extra and special quality
concrete tile
polyvinyl chloride (PVC) and polyethylene
plastic tubing
makes use of steady state condition
hooghoudt’s equation
the application of water tp soil for the purpose of supplying the moisture essential to plant growth
irrigation
the ration of the volume of voids to the total volume occupied by soil, water, and air
porosity
the percentage of volume of the soil not occupied by soil particles but occupied by water and air
pore space
ratio of wt of water to the dry wt of soil
MC on a dry wt. basis
ratio of dry wt of soil to the total soil volume
bulk density
ratio of dry wt of soil to the volume of soil particles
particle density
the ration of the weight of a single soil particles to the weight of a volume of water equal to the volume of the particle of soil
real specific gravity
the ratio of weight of a giver volume of dry soil, air space, to the weight of an equal volume of water
apparent specific gravity
equivalent depth of water in the soil at a given condition
DOW (present in soil)
to increase MC from an initial volume to final volume
DOW (needed)
the amount of water a soil profile will held against drainage by gravity at a specified time after through wetting
field capacity
the soil moisture content when plants permanently wilt
permanent wilting point
the difference in MC of the soil between the field capacity and permanent wilting point
available moisture
that portion of the available moisture that is most easily extracted by plants this is approximately 75% of the available moisture
readily available moisture (RAM)
the time rate at which water will percolate the soil
infiltration rate
the rate of infiltration from a furrow into the soil
intake rate
the velocity of flow into the soil caused by a unit hydraulic gradient in which the driving force is one pound per pound of water
permeability of the soil
the fraction of the irrigation water that must be leached through the root zone to control soil salinity at specified lebel
leaching req
is the sum of transpiration and water evaporated from the soil, or exterior portions of the plants where water may have accumulated from irrigation, rainfall, dew,…
evapotranspiration
the process by which water vapor escapes from plants, principally the leaves and enter the atmosphere
transpiration
sum of evapotranspiration and percolation losses
crop water requirement
the quantity of water, exclusive of precipitation, required to maintain desired soil moisture and salinity level during the crop season
Irrigation water req
the sum of irrigation req and farm ditch losses
farm water req
farm turn-out requirement plus conveyance losses in the main canal and lateral up to farm turn-out
diversion requiremenr
the ratio between the water delivered tp the farm to the water diverted from a river or reservoir expressed percent
water conveyance efficiency
ratio between water entered in the soil root zone during irrigation to the water delivered to the farm, expressed in %
water application efficiency
ratio between water beneficially used on the prroject, farm or field to the amount of water delivered to the farm, expressed in percent
water-use efficiency
the ratio of water stored in the root zone during the irrigation to the water needed in the root zone prior to irrigation, expressed in %
water storage eff
the ratio of the normal consumptive use of water to the net amount of water depleted from the root-zone soil
consumption use eff
the power theoretically required to lift a given qty of water each second to a specified height
water horsepower
water horsepower divided by pump eff, in dec
brake horsepower
the difference in elevation between the water surface in a pond, lake, or river which pumped water is taken…
static head
the sum of total static hand, pressure head, velocity hand, and friction head
total dynamic
the difference in elevation between the groundwater table and the water surface at the well when pumping
draw down
graphs that shows interrelations between speed, head discharge, and horsepower of a pump
characteristics curve
expresses the relationship between speed in rpm, discharge in gpm, and head in ft
specific speed
structural devices to retard velocity of flowing water
baffles
elevated land that confines waters of a stream to their natural channel in normal course of flow
bank
structure provided with a series of gates erected across a river to regulate water surface level and flow upstream
barrage
structural device designed to hold a pool of water to cushion the impact and retard the flow of falling water as from an overflow weir, chute, or srop
basin, stilling
a shelf pathway constructed on the slope of the canal bank
berm
temporary channel, constructed to divert stream flow, made during construction for purpose of dewatering the site…
bypass cannal
channel or waterway artificially constructed or maintained for conveying water or for connecting two or more bodies of water
canal
artificially constructed embankments of a canal usually with designed top widths and side slopes
canal banks
ratio of vertical drop to horizontal distance of a given stretch of canal
canal grade
plan of the canal system in an irrigation project
canal layout
finished surface layer installed on the inside slopes of canal banks and on the bed of the canal to prevent excessive seepage…
canal lining
fixing of the traverse lines along which a canal is to pass
canal location
loss of water in a canal through effluent seepage
canal seepage
designed volume of flow or capacity of a canal
canal supply
contracted measuring weir in which sides of the trapezoidal weir have a slope of one horizontal to 4 vertical to compensate for end contraction
cipolleti weir
any temporary watertight structure constructed to shut off water from a construction site
cofferdam
small stream that serves as natural outlet for drainage of basins of nominal size
creek
top of a dam, dike, etc., frequently restricted to overflow portion
crest
instrument for measuring velocity of water by ascertaining speed at which the stream of water rotates the vane or wheel of the meter
current meter
any structure to reduce percolation of water under surfaces of a structure of through porous data
cutoff
barrier constructed to hold water back and raise its level
dam
reservoir where floodwater is stored for relatively brief period , part of it being retained until…
detention reservoir
canal or streams embankments to prevent overflow of canals and streams
dikes
waterway bordering fields of individual farmers as part of the distribution or drainage system
ditch
site where water is diverted in whole or in part from its natural channel to another channels…
diversion site
runoff from drainage area removed in 24 hrs expressed in unit of depth
drainage coefficient
system of drainage where the parallel lateral lines empty into a main line
gridirion
system used to drain fields that slope towards the center; shaped like the bones of a herring
herringbone
single drain line placed at the base of a hill to intercept the seepage flow from the hill
interceptor or cutoff
stream or river flowing into a larger river or lake; a tributary system
effluent
raised surface, such as dike, built up by filling with earth or other material
embankment
stream that flows only in direct response to precipitation, receiving no water from springs; its channel is at all times above the water table
ephemeral stream
plank of wood placed in canal structures to control the elevation and flow of water
flashboard
vertical distance between normal maximum operating level of a reservoir or of canal and top of dam canal bank, or between stage of the design flood and top of levee
freeboard
weir in which tail water is below the crest or flow is in no way affected by the elevation of the tail water; not a submerged weir
free weir
instrument for observing or recording the stage of a river, amt of rainfall, etc.
gauge
type of dam that depends mostly on its own weight for its structural stability
gravity dam
arrangement of boulders laid by hand where the interstices or joints between boulders are filled with cement grout; used as lining, erosion
grouted riprap
reservoir where water is stored for release when ordinary flow of the stream is insufficient to satisfy req
impounding reservoir
that portion of an irrigation structure through which water has to pass before actually flowing into the structure itself
inlet
divides the water into two main laterals
bifurcation
bridge oven an irrigation canal smaller than either a road or a thresher crossing
bull cart crossing
raises level of water surface in a canal
check gate
closed conduit used for conveying water across and under an elevated roadway
culvert
conveys water from a higher to a lower level
drop
passes water over depressions, low ground and roadways, drainage creeks, or a lower irrigation canal
flume
controls or regulates flow of irrigation water in a canal
head gate
small structure or opening with or without a gate from which a small canal takes water from a supply canal
heading
always inverted; water is conveyed underneath an obstacle such as roadway or another waterway
siphon
divides water into three main laterals
trifurcation
small outlet gate along a supply canal used for delivering water directly to rice paddies or to farm ditches
turnout
branch canal heading off from the main canal
lateral
dike or embarkment to protect land from inundation or to confine flow of stream
levee
principal or biggest channel of a distribution system that starts off from the main head gates or diversion works and from which smaller canals or lateral branch off
main canal
channel in which stream is not completely enclosed by solid boundaries and therefore has a free surface subjected to atmospheric pressure
open channel
stones or pieces of rock arranged and laid by hand on slopes
riprap
dam whose main body is a pile or filling of hard rocks
rock-filled dam
receptacle or structure in which the flow of water is retarded to allow deposition of sediment
settling basin
gate for controlling the passage pf water through the sluiceway
sluice gate
channel portion of a sluice
sluiceway
surface or underground stream that contributes its water either continuously intermittently, to another and generally larger stream
tributary
