bundscho efficient irrigation

8/13/2019 Bundscho Efficient Irrigation

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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

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