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Our Objectives
Obtain site information and determine irrigation requirements.
Determine water capacity and pressure.
Select sprinklers and establish spacing ranges.
Establish sprinkler circuits and install valves.
Locate controllers and size wiring.
Prepare the final irrigation plan.
How can students read the site plan and interpret it to determine the irrigation requirements of the landscape? Climate is the major influence of the water needs of
plants
Evapotranspiration (ET)- the loss of water from plant tissue, soil, and soil surface Affected by: relative humidity, solar radiation, day length,
temperature, and even wind
Irrigation- supplying water to land through artificial means Usually clean enough to drink however, in some parts of the
country waste water is used for irrigation to conserve good water
Using Automated Irrigation
Irrigation allows you to use water in the most economical way
Being aware of weather, soil types, and plant knowledge assures correct usage of water
Using a site plan allows the landscaper to recognize the types of plants Allows for proper placement of sprinkler heads as well as
flow rate of h20
Automated systems save water because it applies only the amount of water needed
If pesticides/ fertilizer that are used are soluble they can be applied through the irrigation system saving time
How is the water capacity and pressure of a project determined? 1st we must know the GPM or gallons per minute and the PSI or
working pressure at the point of connection
Static water pressure- the PSI in a close system with no water moving Determined using a direct pressure gauge reading or calling the water
company
Most sprinkler heads need 3GPM to operate
Working water pressure- a.k.a. dynamic water pressure, PSI at any give point in a system as a given amount of water moves past Can be affected by gravity, friction of the inside of the pipes, length of
pip, grade changes, number of sprinkler heads
3 calculations should be made to determine PSI and GPM The pressure loss through a water meter should not exceed 10% of the
minimum static pressure
Maximum flow should not exceed 75% of the maximum safe flow of the meter
Water meter flow chart will be needed
Velocity of flow should not exceed 5- 7.5 feet per second
A loss chart for the type and size of piping will be need for this calculation
How can students select and locate sprinkler heads for maximum benefit and coverage?
Two main categories of irrigation: sprinkler and trickle
1. Sprinkler- when spray heads or rotating sprinklers are used to water plants
Sprinkler heads are determined based on: Size/ shape of area
Type of plant
Water pressure/ flow
Soil type
You want to use as few sprinkler heads as possible to save money
Two types of sprinkler; spray-head and rotating Sprayhead- emits a single or double fan type pattern of water
Used for small areas or targeted plantings and have a relatively short spray range
Example: greenhouse
Rotating- nozzles that rise and revolve to distribute water
Have a much larger spray range
Higher operating water pressure is needed
How can students select and locate sprinkler heads for maximum benefit and coverage? (cont.)
Two main categories of irrigation: sprinkler and trickle
2. Trickle irrigation- bubblers, emitters, or drip irrigation devices are used to water
• Used to conserve water
Placement of Irrigation Systems
Once equipment is chosen, proper spacing needs to be determined 3 major spacing patterns
Triangular patter- used where area has irregular boundaries
Square pattern- used when there are equal sides running between
Rectangular pattern- used to fit areas with defined straight boundaries and corner
Determining the Amount of Water Delivered Precipitation rate- water delivered to the landscape,
usually expressed in inches per hour, used to make sure necessary amount of water is deliver
Formula used is 96.3 X GPM
S X L
96.3 IS THE CONSTANT WHICH INCORPORATES THE INCHES PER SQUARE FOOR PER HOUR
GPM is the total gallons per minute applied
S is the spacing in feet between sprinkles
L is the spacing in feet between rows
How are sprinkler circuits set up and the required valves placed for an installation project?
Sprinkler circuits- add the GPM of each head together Each circuit is called a valve group
Cannot exceed the system flow limit
Valves should be located near the center of the sprinkler group to balance flow
Mainline- line from water source to the valve
Lateral pipe- line from valve to sprinkler head
How are sprinkler circuits set up and the required valves placed for an installation project? (cont.)
Backflow prevention device- prevents contamination of drinking water by not allowing the irrigation water to flow backward into the water supply
How are controllers effectively placed and suitable wiring sizes chosen?
Irrigation controllers- the electrical devices used to regulate and control the sprinkler system Controls which days it will water, how long it will water, and
what time it will water
When multiple controls are use, in is best to group them together for easier control
Station- a single electric switch in an irrigation controller Runs a solenoid valve on or off