IRRIGATION
Irrigation Systems
Frequency of watering for healthy growth of plants
Frequency of watering : depends on ability of soil to soak up the water the sprinklers are applying.
Frequency of watering depends on : plant water requirements and needs
Frequency of watering depends on : root zone depth
Frequency of watering depends on : recent rainfall
Frequency of watering depends on : soil moisture
Frequency of watering depends on : recent temperature extremes
Frequency of watering affects growth , fruiting and dormancy
To determine frequency of watering the soil permeability rate must be known:
sand loam / 1.7 inches / 12" sand loam per hour
silt loam / 1 inch / 12" clay loam per hour
clay / .2 inches / 12" clay per hour
sand / 1 inch / 12" sand per hour
irrigate 2 - 3 times per week in florida?
10 gallons of water per every 1" of palm tree caliper per week
irrigation is best at 4 am?
Turf root depth = 12"
Turf should only receive one inch of water per week (Florida)
1/2 inch to 3/4 inch of water every two to three days
when 30% | 50% of sod is wilting
when soil in root zone is dry and crumbly
nitrogen = 1.5 inches to 2 inches of water per week
Frequency of watering for healthy growth of plants depends on :
evapotranspiration rate in area
drought tolerance of plants
weather ( winds, rains, etc)
soils
VEGETABLE GARDEN
2 inches of water per week
PERENNIALS and ANNUALS GARDEN
1.5 inches to 2.0 inches of water per week
TREES GARDEN
1 inch to 1.5 inches of water per week
GROUND COVERS GARDEN
.5 inches to 1 inch of water per week
SHRUBS GARDEN
1 inch to 1.5 inches of water per week
Irrigation Heads
select heads by flow rate (GPM)
Irrigation systems typically run @ 60 psi / 90 psi max
Pop-Up spray head
RADII of 1 foot to 15 feet
high precipitation rate
shorter run time
Micro-sprays
Impact drive rotors
have to run five times as long as sprays to achieve equal precipitation rates
gear driven rotor
cover greater distances
large turf rotors
cover greatest distance
fixed spray heads
variety of patterns and throw radii
360 heads
3 gallons per minute
max throw 15 feet
emitters
porous pipes
efficient coverage is : mimicking rainfall for location by even water distribution by,
1. overlapping sprinkler spray patterns
2. head to head coverage
system zoned , efficient coverage irrigation system requires the following irrigation system components
1. (S) Main (source) / where the water comes from / how to get water? / how much is available? / how much pressure? / city main = static water pressure
2. (M) Meter
3. (BP) Backflow Preventer : AKA = check valve
4. (GV) Gate valve or ball valve
5. (SV) Solenoid Valve [ electronic source controller ]
6. (SH) Sprinkler Heads
7. (MLP) Main Line Pipe ( avoid CL 125 PVC pipe )
7a. (LP) Lateral Pipe ( avoid CL 125 PVC pipe )
8. (ES) Electricity Source
9. (MS) Moisture Sensor (over-ride switch)
10. (VC) Valve circuit
add THRUST BLOCK(s) on main lines and direction changes as a necessary construction component!
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++|||[ ]____[ ]_____[ ]_____water direction ---->
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(thrust block above)
irrigation hydraulics / 1 gallon = 3.785 liters / analysis
hydraulics is the study of the behavior of water both at REST and at MOTION
pressure is hydrolic energy
pressure is a principle by which energy is added to the fluid
pressure changes due to elevation change
each one foot of elevation change exerts .433 PSI
friction loss is a flow GPM characteristic
water volume : increase in water volume increases [ static pressure / design pressure ]
pumps are for increasing water pressure ( Force ) F-> in ( PSI )
use pumps when more force F-> in pressure is needed for irrigation
surge pressure is caused by water stopping suddenly in pipe causing shock waves called HAMMERING
water pressure at rest
static - psi - static
created by waters own weight
a force (psi) F->
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static water pressure with one foot of head exerts a force ( F-> ) of .433 psi
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static water pressure exerting a force ( F-> ) of one PSI will demonstrate 2.31 feet of head
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static water pressure is a force at a particular location caused by the weight of the water itself
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static pressure is the design pressure - design pressure PSI
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water pressure in motion
water moving is flow GPM
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velocity (speed) of water measured in FPS [ ft / sec ]
{ start }----------------{ flow rate GPM }---------{ ft / sec }
{ 0 feet }---------------------------------------------{ 10 feet }
maximum velocity ( speed ) of water in irrigation pipe is five feet per second <5FT/SEC> 5 FPS
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velocity = FPS
FPS = feet per second
working pressure (PSI) ----(SAME)---- dynamic pressure (PSI)
( IS )
( the pressure exerted by flowing moving water )
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The faster ( speed increase ) water moves, the more surge pressure and friction loss. Continuously added energy ( pressure ) increases speed ( velocity in FPS ) and speed ( velocity in FPS ) and speed ( velocity in FPS ) turns into pressure (PSI)
This pressure is the dynamic / working pressure in PSI
Friction loss is pressure loss
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Friction loss (pressure loss) in irrigation systems come from the pipes, the valves and from elevation changes
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\/ Diameter Radius is Irrelevant
___
WATER ||
( WATER ) One foot deep ( 1 FOOT of Head)
WATER ||
| | | | ___
| | | |
\/ \/ \/ \/
Force ( F-> ) Static water pressure is .433 PSI
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\/ Diameter Radius is Irrelevant
___
WATER ||
( WATER ) 2.31 feet deep ( 2.31 FOOT of Head)
WATER ||
| | | | ___
| | | |
\/ \/ \/ \/
Force ( F-> ) Static water pressure is 1 PSI
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elevation changes seven ( 7 ) feet. [ 7 additional feet of head ] This increases the static water pressure ( F-> ) FORCE from Zero PSI to 3 PSI
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Four Main Sources of Water for Irrigation
1. municipal potable water
positive effects : available, drinkable, clean
negative effects : expensive, consumptive use, limited resource
2. well water
positive effects : reliable, cheaper overtime, clean
negative effects : electricity use, maintenance costs, aquifer depletion, cost of well
3. re-used treated effluent
positive effects : inexpensive supply, good way to use and treat effluent, irrigation
negative effects : expense of initial service main, some availability issues, pressure issues and water quality issues and dissolved salts
4. surface water
positive effects: natural
negative effects : pump maintenance, electric costs, water draw down, causing of aesthetic problems, quality and availability
IRRIGATION PIPE
+in irrigation systems pressure losses can happen because of irrigation pipe types (smoothness), because of the size of pipe, because of the water volume used, because of obstruction s such as 1. valves 2. backflow preventers 3. meters 4. abrupt pipe bends.
+schedule of pipe refers to wall thickness
+class of pipe is classified by sustainable pressure
+as schedule (type) nominal pipe size increases the PSI decreases
+maximum velocity that water should go through the pipe is FIVE feet per second
+schedule pipe has three categories of different wall thicknesses
+++++schedule (40) -------- (80) --------(120)
+thinner walls - SCH 40 6" Nom. DIA. (180 PSI)
+thicker walls - SCH 40 1/2" Nom. DIA. (600 PSI)
+class pipe is pressure rated : class 125 pipe holds 125 PSI / class 315 pipe holds 315 PSI
+schedule pipe and class pipe have different wall thicknesses
PUMPS
+water pressure ( FORCE F-> ) can be created with pumps. pumps are often needed with irrigation systems using 'pond water, well water, city supplied water.
+typical pumps can deliver not more than 20' of lift
1 PSI = 2.31 Feet of head
20 Feet (divided by) 2.31 feet of head = 8.65 PSI
+centrifugal pump ( DYNAMIC PUMP )
high volumes / low pressure
propeller or lifting action
volute, diffuser, turbine, propeller (pumps)
diffuser (pumps) : high pressure
volute (pumps) : lifting pumps
used to increase water pressure
radial flow
axial flow
mixed flow
single and double action impellars
most irrigation pumps are enclosed or semi-enclosed impellers
+turbine pump (DYNAMIC)
very large capacities
operated on the centrifugal principle
similar to submersible pump
+submersible pump
pump is submersed in water
can be turbine or centrifugal pumps
greater pressure for less pump
deep well pumps
+jet pumps (multi-stage)
high volumes
high pressures
special effects pumps
combination of a volute centrifugal pump and a nozzle-venturi arrangement
DRIP IRRIGATION
+drip irrigation water deliver options
1. emmitters for plants spaced apart
2. tubing and tape for intensive watering tape-type tubing
3. dripperline : ornamental settings. can be curved. soaker drip-line
4. mini-sprayers and mini-sprinkler for larger areas don't work well in heavy winds
+DESIGN : water the plants you want to water only - quality of source water is very important - all drip systems need a filter - drip systems need a pressure regulator - drip systms run on 10 - 25 PSI
+STEPS TO TAKE to design a drip irrigation systems
1. plan for future (leave 25% more water capacity available for future growth needs)
2. sketch areas to drip
3. locate water source
4. note location and size of plants and water requirements
5. find distances for tubing and required fittings
6. determine how many and what type of emitters / sprayers are required
7. determine how much water the system needs
8. add up total number of emitters and their flow rates
9. backflow prevention device / check valve
10. controller designed to water 2 hrs per station
11. determine soil type
+APPLICATION
hanging baskets (emitters or misters)
container plants (mini-sprayers)
ferns and rhododendrons (misters and mini-sprayers)
low growing ground cover (mini-sprayers or mini-sprinklers)
fruit and ornamental trees (soaker tubing / emitters / mini-sprinklers)
flower beds (soaker tubing or mini-sprayers)
drought tolerant plants (drip or emitters, 1-2 years then disconnect once established)
berries (soaker tubing or in-line emitters)
vegetable garden (soaker tubing or closely spaced emitters)
+UTILIZATION
healthier plants
better yields
great time saver
decreases the incidence of plant disease
water-soluble fertilizer can be applied though drip irrigation systems
reduces weed growth
15% less water evaporation
keeps water off buildings
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HIRE
Me, CONRAD!
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