Irrigation System Flashcards
Goal of today’s irrigation designer
To produce a system that keeps the landscape green while conserving water and keeping costs down
Entire pipe, valve, control, monitoring, instrumentation, water emission device (sprinklers, emitters, bubblers), and related component package used to deliver water to the landscape
Irrigation system
Water emission device that throws water through the air with a predictable pattern and radius
Sprinkler
The distance a sprinkler will throw and still apply 0.1 inch in an hour at the outside extent of the radius
Effective radius of throw
The smallest orifice of the water flows through in a sprinkler irrigation system
Nozzle
Devices that would cause the sprinklers to operate fairly consistently, even if pressure varies; compensates for varying pressure within the lateral and causes the nozzle to flow at or near the nominal flow rate
Pressure compensating devices
Established by either the mechanical setting of the sprinkler itself, or, in the case of pop-up spray, the nozzle pattern
Arc
Synonymous with the rate that rain falls, the rate which is expressed as a depth of application in one hour or inchers per hour; the rate at which overlapping sprinklers apply water
Precipitation rate
Term used for sprinkler nozzles that have precipitation rates close enough to be used together on a single lateral
“Balanced”
Commonly used uniformity parameters to compare various sprinkler-pressure-nozzle combinations
Christiansen's coefficient of uniformity (CCU) Distribution uniformity (DU) Scheduling coefficient (SC) - most accepted
Water emission devices that tend to bubble water directly to the ground or that throw water a short distance, on the order of one foot, before water contacts the ground surface
Bubblers
Commonly applied in landscape shrub beds, and uses water emission devices called emitters, which have low flow rates, on the order of 0.5 to 2 gallons per hour; a system that employs a small-diameter polyethylene or flexible PVC hose with emitters
Drip irrigation
A control device that can be opened, either automatically or manually, thereby causing water to flow
Valve
Synonyms of an automated valve
Remote control valve
Solenoid valve
Electric valve
Automated control valve
A single remote control valve located at the water source; provides a safety feature and is opened only when other remote control valves in the system are programmed to open; wasted water from mainline failure can be prevented or minimized; if desired to be part of the POC assembly, it would be locate immediately downstream of the BPD
Master valve
A heavy-duty, bronze ball valve that is opened or closed by rotating the handle through 90 degrees; often used as the main shutoff valve for the system, and is located near the street curb
Curb stop valve
Area wherein valves are generally installed in, to protect them, and to make it easy to locate them over time
Valve box
An electric panel designed to apply 24-volt AC across a given station on the controller in order to open a valve or valves in a programmed sequence; powered by 110-volt AV but outputs 24-volt AC power to a terminal strip, and hence, to valves
Irrigation controller
Generally runs on a microcomputer and provides program changes and rain shutdowns from a central location using radio or telephone as a communication link
Central control system
The basic hardware required in the field, and at individual sites, to communicate back to the central control system
Satellite controller
The portion of the irrigation pipe network that is pressurized all or most of the time; the pipe network beginning at the water source and continuing downstream but upstream of the lateral remote control valve
Mainline pipe
The pipe network downstream of the remote control valve and delivering water to water emission devices; pressurized only when the it’s remote control valve is open
Lateral pipe
The flexible, black pipe that comes in rolls; connected using mechanical or threaded fittings
Polyethylene (PE) pipe
Rigid, white pipe that comes in 20-foot lengths; connected using glued or threaded fittings
Polyvinyl chloride (PVC) pipe
Isolating mainline pipe in logical subsections
Isolation gate valves
Often located on the mainline at point where incidental water may be needed for maintenance purposes; good to locate near other equipment and valve boxes
Quick coupler valves
A series of fittings and nipples designed to move so sprinklers can be set to grade initially and moved over time; protect against breakage due to heavy mowing equipment; used to attached sprinklers and other water emission devices to the lateral pipe
Swing joint
Factory-made swing joints
Prefabricated swing joints
A device or assembly to prevent particulate materials from passing
Filter
Type of filter for irrigation systems that are placed at the water source
Primary filtration
Type of filter for irrigation systems that are placed at individual laterals in the system
Secondary filtration
Device used to reduce water pressure to a desired, lower level
Pressure regulator
A component in a pressure regulator which describes how much water will flow through the regulator given the size of the regulator and the difference between upstream and downstream pressure
Pressure falloff curve
A device used to boost existing pressure in a pressurized irrigation system or to create a pressure from a surface water supply
Pump
Typically a centrifugal pump used to increase pressure (not flow) to the minimum appropriate to the irrigation system
Booster pump
A device, possibly a small diaphragm pump or a pressure differential arrangement, which is used to inject water-soluble chemicals into irrigation water at known rate
Fertilizer injector
A mechanical assembly used to prevent potentially contaminated water from flowing out of the irrigation system, and back into a potable water system, due to back pressure or back siphonage; most cases, it is above grade
Backflow prevention device (BPD)
A mechanical device that uses a propeller or other means to measure the volume of water flowing through the pipe per unit of time
Water meter
A known point, available to the contractor, from which the irrigation system will be built; the term is contractual in many instances, as it defines the contractor’s starting point and the point from which the contractor can expect a minimum available flow and pressure; its size is dictated by the size of the “tap” into the water supply or the size of the water meter
Point of connection (POC)
A common POC with landscape irrigation systems
A cap or threaded connection immediately downstream of the project’s water meter
The inherent force of the water created by a pump or relative vertical position below a free water surface
Pressure
Pressure calculations for no-flow conditions; a good example is an irrigation system with all valves closed
Static hydraulics
Pressure calculations under flowing conditions
Dynamic hydraulics
The evaporation from the soil surface plus the transpiration through the plant
Evapostranspiration
A device monitoring system used to measure the evapotranspiration (ET) rate using a container closed at the bottom and with the top flush with surrounding grade and planted with turf
Lysimeter
Terms to avoid
Heads - sprinklers
Zones - laterals
Circuiting - lateral layouts
Clock - irrigation controller
Units of measure for flow
QGallons per minute (GPM)
Gallons per hour (GPH)
Units of measure for velocity
VFeet per second (FPS)
Unit of measure for precipitation rate
PRInches per hour (IPH)
Unit of measure for pressure
PPounds per square inch (PSI)
Unit of measure for evapotranspiration
ET Inches per day (IPD)
Basic components of a pressurized irrigation system (11 components)
Water sourcePump (if needed) Master valve Fertilizer injector (if needed) Filter Main pipe Lateral valve Controller Lateral pipe Pressure regulator Water emission device
Undesirable reversal of the direction of flow of water or other substances into the distribution pipes of the potable water supply from any source or sources caused by backpressure and/or backsiphonage
Backflow
Backflow caused by a pump, elevated tank, boiler, or pressure “head” in pipe, or any means that could create greater pressure within a piping system, than that which exists within the potable water supply
Backpressure
The reverse flow of water, mixtures, or substances into the distribution pipes of a potable water supply caused by negative or sub-atmospheric pressure in the potable water supply
Backsiphonage
An indicator of the probable influence the sodium ion has on soil properties; must be calculated to fully analyze and understand a water sample
Sodium absorption ratio (SAR)
The first valve; may require a special valve box key or valve key to fit and operate the valve itself; used only by the water purveyor when service is required within its system or when the water bill has not been paid by the customer
Water purveyor’s valve
The valve next to the first valve, generally for the entire system; a curb stop ball valve is generally used; it may be a stop and waste valve or may be a part of the backflow prevention assembly; may also be used to shut off the irrigation system for maintenance
Primary shutoff valve
Valves that are not necessarily needed, but larger syste,s have them so that some portion of the irrigation mainline can be closed off for maintenance purposes; often manually actuated
Isolated gate valves
Maximum distance between quick couplers
Two 50-foot host lengths or 100 feet
Two possible configuration for solenoid valves
Globe
Angle (less pressure loss)
In landscape irrigation, a pipe through which another pipe passes; generally installed on a project before the hard surface is installed
Sleeve
Type of sprinkler generally suitable for irregular areas
Pop-up sprays
Type of sprinkler suitable for large-radius applications and larger areas
Pop-up rotors
A device that can be used to measure pressure at the sprinkler nozzle under field conditions
Pitot tube
Term used when water flows between the sprinkler body and the stem; a small flushing action
Flow-by or blow-by
Nominal effective radius alternatives
10 , 12, and 15 feet
Commonly available arcs
1/3 (120°), 1/2 (180°), 3/4 (270°), and full (360°)
Percent that a pop-up spray sprinkler nozzle can be adjusted down to
30%
Special pattern nozzles (for narrow rectangular turf areas)
End strip
Center strip
Side strip
A valve that can be an added feature with pop-up sprays if there are elevation changes within the lateral
Check valves
Water draining from the lowest sprinklers on the lateral; undesirable drainage because water is wasted and excessive water can accumulate in low areas
Low head drainage
A rotor sprinkler that use a spring-loaded arm that strikes the water stream coming from the nozzle to cause rotation; exhibits the fewest problems under marginal (dirty) water conditions
Impulse or impact sprinkler
A rotor sprinkler that uses centrifugal force and the impact forces from two stainless steel balls to cause sprinkler rotation
Ball drive sprinkler
A rotor sprinkler that utilizes a diaphragm and piston, which together move the sprinkler a few degrees each time the piston finishes a stroke
Piston drive sprinkler
A rotor sprinkler that uses flowing water and a series of intricate gears for rotation
Gear drive sprinklers
Precipitation rate equation
(S) (L)
Precipitation rate equation for am equilateral triangle pattern
(S) (L x 0.857)
The basic pattern of a sprinkler that applies more water near the sprinkler and less waster as you move farther from the sprinkler
Distribution rate curve
Using this concept, nozzles are engineered and manufactured such that quarters, halves, and fulls all complement one another with flow rates proportioned to the arc, hence, precipitation rates can be identical
Matched precipitation rates (MPR)
An irrigation system commonly referred to as “trickle” or “low-flow” irrigation; its basic concept is to provide near-optimal soil moisture on a continuous basis while conserving water; a system that applies water directly to individual plants
Drip irrigation
Key devices within a drip irrigation system, as their hydraulic design affords flow rates of 1/2 to 2 gallons per hour; all should incorporate UV-inhibiting agent to prevent damage from solar radaitaion
Emitters
Two categories of emitters
Point source
Aerosol
An emitter type that drips water directly to the soil surface
Point source
An emitter type that throws through the air for some distance before water contacts the soil surface; a mini-sprinkler
Aerosol
The most common operating pressure range for pressure compensation
20 PSI to 50 PSI
A component of a typical drip irrigation system lateral; the portion between the remote control valve and the zone control valve; does not have emitters, but used to provide for operational flexibility and system adaptability
Lateral mainfold
A necessary component for every lateral end to facilitate periodic flushing to remove any suspended solids that have settled from moving water as the velocity drops
Flush plug
In a drip irrigation system later, a valve that is used to isolate selected portions of the lateral for maintenance purposes
Zone control valves
Typical burial depth of the lateral mainfold
8 to 14 inches
Often installed on the soil surface, but protected under mulch and staked at 6- to 10-foot intervals with wire stakes; should always have a flush plug at the end
PE or flexible PVC lateral pipe
A management tool for drip irrigation that monitors relative soil moisture levels
Tensiometers
A primary filtration device that is appropriate for suspended high-density solids, such as sand in the water; should be followed by a screen filter
Centrifugal separator
A common flow rate for a single drip emitter
1 GHP
Vertical elevation difference between some know point; the only factor required to determine various pressures within a static system
Datum
A common material for the mainline pipe, which has a relatively high working pressure rating, and is suitable for continuously pressurized service
PVC
Typical burial depth of mainline pipe
15 to 24 inches
Typical burial depth of lateral pipe
10 to 16 inches
The term that refers to a glued fitting
Slip
FIPT
Female iron pipe thread
MIPT
Male iron pipe thread
General PVC fittings used in irrigation
Schedule 40
General Schedule of nipples suitable for threading
Schedule 80
In piping (cast-iron, steel, some PVC, etc.), a rubber ring or other resilient material used in coupling together some types of pipes to prevent leakage
Gasket
Typical size of pipes using glued connection method; beyond this, gasketed connection methods are to be applied
Equal to or less than 3 inches
Anything that transfers water’s energy within a pipe system to the earth rather than to a joint; keeps gasketed and slip-pipe joints from coming part under pressure; most common material is concrete; applied to gasketed fittings that change in direction
Thrust block
A type of pipe wherein a constant pressure rating was achieved by increasing the wall thickness as the pipe increased
Classed pipe
Commonly used class pipes in landscape irrigation; with a working pressure rating of 160 PSI and 200 PSI, respectively
Class 160 and Class 200 PVC pipe
Contrary to classed PVC pipe, this type of pipe is manufactured with a constant wall thickness, thus, the pressure rating goes down as the size goes up
Copper pipe
Common material of a pipe used above ground to service the backflow prevention assembly; does not degrade in sunlight and takes on a characteristic tarnished appearance over time, which is aesthetically acceptable
Scheduled pipe
Frequently used pipe for POC assemblies that is greater than 3 inches
Ductile iron pipe
A union having an insulator between the two sides of the union; should be used between any dissimilar metal materials to avoid galvanic action
Dielectric union
Pipe or tube fittings that are inserted into pipes or tubes and are held in place by the friction created by the barbs or clamps over the pipes into which they are inserted; fittings typically available for use with PE pipe
Barbed fitting
A pipe fitting with inside or outside threads that allows it to be connected to another fitting or pipe with the opposite type of threads
Thread fitting
A common threaded sealant in landscape irrigation, which is available as a paste or a tape; the type is generally preferred, wrapped around threaded pipe, fittings, or equipment before screwing together to facilitate lubrication and a better seal
Teflon
A popular thread used in golf irrigation applications; uses a gasket to complete the connection, and provide a water-tight seal
Acme thread
The evapotranspiration rate of the unstressed plant material
Potential ET
The potential ET rate for a specific crop, most commonly for grass, and a specific set of surrounding, or advective, conditions
Reference ET
The soil moisture content immediately after wetting
Field capacity
Defined as the soil moisture content below which plants will wilt permanently
Wilting point or wilting coefficient
The movement or seepage of water from the surface to the subsoil or groundwater; normally expressed in terms of inches (or mm) per hour
Infiltration
