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8/13/2019 Bundscho Efficient Irrigation
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8/15/20
Irrigationbasicsforhomeand
smallscalemarketgardens
Or
HowmuchHowOften
and
Where?
Whydoweirrigateatall?
Foodproduction
Orchardsand
gardens
Waterconservation
Investmentin
technology
Terminology
SprayPopups,stationary
heads,microspray
RotorsImpact,geardriven,spiral
Drip Inlineemitters,soaker,
spotemitters
PartsandPieces
Tubing
Solid
Builtinemitters orspotemitters
EmittersandminispraysG PHrating
Fittings
Compressionvs.threaded
Controllers
Batteryoperatedhoseendvs.Fullyautomated
BackflowpreventerHomeownerliability
PressurereducersOptimum
operation
of
system
Homeownerorprofessional?
Licenses
Connectiontoapublicwatersystem
Liability
Contaminationofyourwatersupply
Privatewell
Ability
Complexityofsystem
Physicalrequirements
Notonesizefitsall
The need to customize irrigation
systems has led to the creation of
many methods and products.
Often combinations of several
products will be used in production
gardens drip , poly pipe, rotors,etc.
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Typicallayoutforbasicdrip TTapeandPolypipew/emitters
TTapeandplasticweedblock
Photo credit to www.davesgarden.com
TTapeandPolypipew/emitters
Emitter diagram slits go up!
Poly pipe and T-tape are
designed to emit a specific
amount of water at a
certain pressure simply
punching a hole in a
garden hose will not giveyou the same result.
Minirotors,spraysandspotspitters
In some applications the need to cover larger
areas such as ground cover or orchards can be
done with mini rotors and sprays. In certain
applications like potted plant shade houses
using Roberts spot spitters is a convenient
way to provide water just to the pots.
Pressurereduction, backflowandfilters
Licenses
Connectiontoapublic
watersystem
Liability
Contaminationofyour
watersupply
Privatewell
Ability
Complexityofsystem
Physicalabilities
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Pressurereduction
Pressure reducers are recommended for
drip irrigation systems they help to
provide the water at the rated pressure
which relates to the actual flow rate from
each emitter.
They are available in both hose end type
and pipe thread for more permanent
applications.
Backflowprevention
Backflow preventers are REQUIRED
for both hose bib type systems and
in ground irrigation systems
They prevent contaminated water from
being sucked into the drinking water
lines in your home or into the public
water supply.
Dripirrigationinlinefilters
In line filters are important to the
performance of your system
Supplying filtered water to the emitters
in both poly pipe and T-tape will help
prevent clogging and reduce sediment
buildup.
The filters are easily removed and
cleaned they can be either stainless
steel, or fine mesh plastic or media
disks. Usually the screens are
referred to as micron size or lines per
inch (mesh). 150 mesh screens are
the usual recommendation for drip
systems.
Timersandcontrollers
TurnitONorturnitOFFAutomaticvs.manual
Onceaweek?Insomecasesitmaybe
everyday
Itjustrained nowwhat?Raingauges
Placementandtype
Moisturesensors
Timersvs.Controllers
All irrigation timers or Controllers
are basically clocks. They can
be as simple or complex as you
wish.
Basic battery operated timers
that attach to hose bibs canoperate drip systems very
effectively.
They are available from 1 to 4
zones
Protection from the elements is
important . batteries do
corrode and go dead. Life
expectancy ???
Timersvs.Controllers
Irrigation controllers are used in
combination with zone valves
and do require wiring both for
the low voltage zone valves, and
also for the operation of the
controller.
They can accept rain or moisture
sensors and have great
flexibility for programming both
start times and run times.
Protection from the elements is
important . batteries are to
maintain program memory
110 VAC power is required. Life
expectancy many years.
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Wheredoesthewatergo?When we talk about irrigation,
we are talking about replacing
the water used by the plant.
There are other considerations
that effect the plants ability to
use that water effectively.
Soil type and slope are just two
of the challenges that we have.
Deep sandy soils will not hold
water and irrigation has to be
scheduled more often.
Heavy clay soils will tend to
absorb water more slowly and
perhaps runoff before reaching
the root zone.
Raisedbedsandshape
Drip irrigation work best when it is
combined with raised beds and a
shallow bowl to hold the water
both from rainfall and irrigation.
Heavymulchanddripirrigation StriptillrowcropfarmingIt looks a little like raised bed
gardening plant the seeds, side
dress with fertilizer .. add T-tape
irrigation and youre ready to go.
Howmuch?
Whatdoes
ascrewdriver,
a
tuna
can,andyourfinger
haveincommon?
HowmuchdoIhavetospend?The easiest way to determine
the available water that you
have to run your drip system is
to measure the gallons per
minute at the source hose
bib or main water line after
all pressure reduction andfilters. Open the hose bib
completely or start the timer
place the 5 gallon bucket
under the water flow and
time how long it takes to fill the
bucket.
GPH = (3600 / Time in sec. X 60)
Volume in gallons
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Howmuchiseachemittersupplying?
You can trust the
suppliers published
rates or we can use
a simple catch cup andmeasuring device to
determine the actual
flow rates in gallons per
hour. Poly pipe is
usually .9 GPH per
emitter , T-Tape is
usually .27 GPH per
emitter.
GPH Flow rate = Volume in ounces / Time in minutes X 60
128 (Ounces per gallon)
HowmanyfeetoftubingcanIuse?Now that we know how much water
we have to spend and how
much each emitter uses and we
know the emitter spacing wecan calculate the total area or total
linear feet we can supply.
Example:
Emitter spacing 12
GPH per emitter 1
GPH available 600 (10 gpm.)
Total tubing in zone = 600 feet
Reducing this by 20% will provide a marginof safety in performance.
HowMuchdoIneedtowater?
Oneinchperweek?Rememberyourshadowinthegarden?
SoiltypeSoilstructure sand,clay,loam
Plantsweat ET(Evapotranspiration)Evaporation
Transpiration
Publishedvaluesforeachmonth TexasETnetwork(http://texaset.tamu.edu/index.php)
Formulasforcalculating
waterneeds
Squarefeetoftotalzone
Precipitationrateofsprayordripsystem
ETValueforyourlocation
Plantcoefficient basedonplanttype
Waterrequirements= ((ET/PR)*60)/30
ETdividedbyPrecipitationrate,times60minutes
dividedby30days givesyouhowmanyminutes
perday.
Letskeepitsimple
12
12
1
1 of water per square foot equals .62 gallons of water.
So to give your plants one inch of water a week
you need to apply .62 gallons of water per square foot of root zone.
In July, the average water requirement (ET) in Houston, Tx. is 6.57
inches of water. This is based on a cool season turf grass
vegetable crops will be different. This does not account for rainfall.
That means for every sq. ft. I need to apply 4 gallons of water per
month (6.57 X .62 = 4.07) or 400 gallons per 1000 sq. ft.
WhatcanIdotomakethemostofmywatering
efforts?
ConservationNativeandwelladaptedplants
MulchThinkoftheforestfloor
MinimizerunoffWhyarewewateringthestreetsandsidewalks?
CycleandSoak
PassiverainwaterharvestingSwagsandswales
Slowitdownusewhatyouaregiven
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Resources
TexasETNetworkhttp://texaset.tamu.edu/index.php
Dripworkshttp://www.dripworks.com/
TexasA&Mhttp://water.tamu.edu/
TexasA&Mpublicationforsoilmoisturesensorshttps://agrilifebookstore.org/publications_details.cfm?whichpublication=2411&orderby=pubnumber&SIMPLESEARCH%3Dirrigation&criteriastring=SIMPLESEARCH%3Dirrigation