Introduction to Irrigation Design.ppt

7/25/2019 Introduction to Irrigation Design.ppt

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Introduction to Irrigation Design

Sprinklers uniform application over entire

area lawns


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Micro sprays Water uniformly over small

areas


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Drip Trickle specific area shrubs


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Plants need water for

Cooling evaporation and

transpiration use energy results ins

cooling plants Nutrient transport

Dispersion of plant expelled waste


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Site Information needed

Soil texture, profile and infiltration rate

ater source !uantity and pressure,

!uality, cost "ayout of site areas to #e irrigated,

elevations

Plants to #e irrigated $ainfall and %& rates

'udget


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ater Conservation

Pota#le to effluent

Irrigation sc(eduling


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Steps to develop plan)* +#taining site information

* Determining t(e irrigation re!uirement

-* Determining water and power supply

.* Selecting sprinklers and ot(er e!uipment

/* "ateral layout 0or 1circuiting2 sprinklers3,locating valves and main lines

4* Si5ing pipe and valves and calculating total

system pressure loss6* "ocating controllers and si5ing wire

7* Preparing t(e final irrigation plan


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Site plan "ocate all #uildings, walkways, driveways,

parking areas, lig(t or utility poles, retainingwalls

Indicate w(ere t(ere are slopes and in w(ic(

direction and (ow steeply t(e ground slopes* "ocate all trees and s(ru# areas and pinpoint

t(e plant material on t(e drawing*

soil type

"ocation of any new planting areas and t(e

types of vegetation t(at t(ese areas will contain*


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Available Soil Water

Soil a#sor#s and (olds water in muc( t(e sameway as a sponge*

8 given texture and volume of soil will (old a

given amount of moisture* &(e intake rate of t(e soil will influence t(e rate

at w(ic( water can #e applied*

&(e a#ility of soil to (old moisture, and amountof moisture it can (old, will greatly affect t(e

irrigation operational sc(edule


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Soil moisture

Hygroscopic water is moisture t(at is(eld too tig(tly in t(e soil to #e used #yplants*

apillary water is moisture t(at is (eld int(e pore spaces of t(e soil and can #eused #y plants*

!ravitational water drains rapidly fromt(e soil and is not readily availa#le to #eused #y plants*


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Source: ;S


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Source: ;S


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Source: ;S


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Source: ;S


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Source: ;S


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Soil moisture &(e permanent wilting point represents t(e

#oundary #etween capillary water and (ygroscopicwater*

'ecause (ygroscopic water is not usa#le #y plants,

continuous soil moisture levels #elow t(epermanent wilting point will result in t(e damage or

deat( of t(e plants*

"ield capacity represents t(e #oundary #etween

gravitational water and capillary water* It is t(eupper limit for soil moisture t(at is usa#le #y plants*


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Available Water

Soil Te#ture $ange Average

in%&in% in%&in%

'ery coarse(te#tured sands and

fine sands )%)*()%)+ )%),

oarse(te#tured loamy sands

and loamy fine sands )%),()%-) )%)+

Moderately coarse(te#tured

sandy loams and fine sandy loams )%-)()%-. )%-/

Medium te#tured very fine sandy loams0

loam and silt loams )%-/()%-1 )%-,

Moderately fine(te#tured sandy clay loams0

clay loams0 and silty clay loams )%-.()%2- )%-+

"ine(te#tured sandy clays0 silty clays0

and clay )%-/()%2- )%-3

$eference4 5SDA0 6$S0 Engineering Field Manual

Available for each soil group by soil hori7on from

6$S Soil Surveys


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Source: N$CS


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ater needs

Soil 8 0inc(es9foot or inc(es9inc(3 ? @ield

Capacity 0@C3 ilting Point 0P3

@or specific plant 8 0in3 ? 0soil 83 A

$ooting Dept(

$eadily availa#le water ? plant 8 A 8llowa#le

Depletion 0use /B if not provided3

Irrigation interval ? 8 A 8D9 usage per day %fficiency ? net water to root 5one9gross water

applied to system


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$eference 8vapotranspiration

8To or potential evapotanspiration represents a

well watered, fully developed plant suc( as

grass

$eference evapotranspiration is multiplied #y acrop coefficient to o#tain t(e %& rate for a

specific crop

&(e crop coefficient varies t(roug(out t(e

growing season

@or %xample Corn at B ? B*46 at /B?)


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%stimates of %&

ax and min temperatures

$elative (umidly

ind Net radiation

odified Penman to estimate 8To

; of isconsin we# site (ttp:99www*soils*wisc*edu9wimnext9et9miet*(tml


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Precipitation $ates

P ? !98

;nits M5ST #e consistent* @or:

P ? precipitation rate 0in9(r3

! ?flow onto area 0gal9min3

8 ? area 0ftE3P ? F4*- !98


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Precipitation $ate Importance

Do not want to apply water faster t(an

t(e soil can a#sor# it

e need to know t(e time re!uired toapply t(e correct amount of water


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Sprinkler Irrigation

;niform application #y overlapping

non=uniform wetting paterns

Sprinkler spray (eads no movingparts = small area pop up

icrosprays over(ead small area

$otary Sprinklers Impact or geardriven


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$otary Sprinklers uniform application

over entire area lawns


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Micro sprays Water

uniformly over small areas


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Drip Trickle specific area shrubs


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&ec(nical Information No55le = remova#le

controls velocity and flow +perating Pressure inc

pressure inc water flowand c(ange wetting

pattern $adius of &(row furt(est point

ater Distri#utionPatterns

&raGectory angle


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Spray >eads

&ec(nical Information operating

pressure, flow, radius of t(row, and

no55le options @ixed (ead

$otary otor=driven

$otary Impact

'u##les

Introduction to Irrigation Design.ppt

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