Term
Irrigation Design Pipe Sizing |
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Definition
BASED ON VELOCITY OF WATER THAT WILL FLOW THROUGH IT IN FT/SEC PIPE DIAMETER AND MATERIAL AFFECT VELOCITY |
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Term
Irrigation Design Soil Properties |
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Definition
Infiltration rate (inches/hour): depth of water infiltrated after 1 hour Field capacity: volume of water soil will hold after gravity drains excess. Available moisture: % moisture in soil available to plants
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Term
Irrigation Design Infiltration Rate |
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Definition
Affected by soil type: coarse grained soils, high; cohesive soils low (sand >loam>clay) slope (steeper slope, less infiltration; easier for water to move along surface) antecedent moisture: dry soil, high initial rate; decreases as soil approaches saturation
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Term
Irrigation Design Field Capacity |
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Definition
Water held in soil by capillary action (attraction to soil particles) Fine particle soils (silts, clays) have greater surface area/volume and therefore higher field capacities High field capacity: hold larger volume, deeper and less frequent watering
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Term
Irrigation Design Available Moisture |
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Definition
Differs from field capacity. Plants must be able to suck up water. High field capacity soils (e.g., clay) may hold water tightly, therefore less available Expressed as % of field capacity
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Term
Irrigation Design Plant Characteristics |
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Definition
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Term
Irrigation Design Plant Characteristics: Root Zone Depth |
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Definition
Determines depth of soil profile for water calculations |
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Term
Irrigation Design Components |
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Definition
Water supply Delivery system Distribution devices
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Term
Irrigation Design Water Supply: Municipal |
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Definition
Usually requires only tapping existing line behind a water meter or connecting to main and installing new meter Volume of water available depends on supply line size and water meter size Commercial/institutional usually 1 inch service or larger
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Term
Irrigation Design Water Supply: Municipal |
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Definition
Pressure available at meter varies and depends on design of water distribution system. Field testing necessary. Test pressure more than once and at different times of day. Nighttime usually higher because lower water use period
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Term
Irrigation Design Water Supply: Wells |
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Definition
Best to have preliminary idea of volume of water expected as well as quality If found at reasonable depth (500' or less), can be very cost effective Requires pump and optional pressure system
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Term
Irrigation Design Water Supply: Wells |
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Definition
Pumps: self-priming centrifugal (shallow wells, low volume & pressure requirements) submersible: fit entirely into well casing; for deeper wells with higher volume & pressure req's. submersible turbine: high vol & pressure demands
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Term
Irrigation Design Water Supply: Wells |
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Definition
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Term
Irrigation Design Water Distribution System |
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Definition
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Term
Irrigation Design Irrigation Pipe & Fittings |
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Definition
Thermoplastics PVC (good all-purpose), Polyethylene (low pressure only), ABS (sprinkler bodies, nozzles, drip emitters, valve bodies)
Metals Cast Iron: most durable; protective rust layer Galvanized steel: deteriorates, not good for ground contact Copper: flexible, strong, chemical resistant but expensive
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Term
Irrigation Design Pipe Fittings |
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Definition
join lengths of pipe threaded: galvanized steel, thick-wall PVC bell & spigot: cast iron, large diameter PVC mechanical joint pipe (w/flange): cast iron, large diam. PVC slip fittings: copper pipe (soldering, sweating), small dia. PVC (solvent welding/chemical bond)
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Term
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Definition
used to control flow of water in system from supply to individual heads and to drain or maintain water in pipe manual valves: allow parts of system to be isolated for maintenance or repair while rest of system can still operate remote control valves: turn water on/off at specific points in system
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Term
Irrigation Design Manual Valves |
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Definition
Gate Valve: flow straight through; have machined seat that relies on tight fit to seal valve Globe valve: preferred for dirty water since washer and seat can be replace; less efficient hydraulically than gate valve
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Term
Irrigation Design Remote Control Valves |
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Definition
operated hydraulically or electrically available with plastic or brass bodies, with or without pressure reg devices. plastic good for valves up to 2 in. and water pressure up to 100 psi
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Term
Irrigation Design Special Valves |
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Definition
Check valve: allows flow only in one direction Drain valve: used to purge water from lines and pumps (often when subject to freezing temp) Pressure regulating valve: reduce pressure in selected parts of system (e.g., different zones, pump systems); needed to protect drip emitters from high pressure Master valve: remotely controlled, downstream of main water supply; turns supply off when irrigation system is off; also helps protect potable water supply from contamination
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Term
Irrigation Design Backflow Prevention |
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Definition
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Term
Irrigation Design Controllers |
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Definition
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Term
Irrigation Design Sprinkler (Spray) Heads |
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Definition
distribute water in uniform pattern, usually fixed as full or part of a circle commonly used for small turf areas, planting beds in residential and small commercial projects useful in low-pressure situations
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Term
Irrigation Design Types of Spray Heads |
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Definition
Pop-up: installed flush with grade rises above body when water pressure applied bodies available with riser hts. of 2 - 18 in. turf applications: 2 - 4 in ground cover & shrubs: >4 in usually plastic facilitate maintenance no safety/tripping hazard when retracted
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Term
Irrigation Design Types of Spray Heads |
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Definition
Shrub Spray Head: spray nozzle mounted on permanent riser nozzle usually fitted to normal pipe thread adapter mounted high enough to prevent foliage from interfering with spray pattern High rise pop up sprays recommended near walks
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Term
Irrigation Design Types of Spray Heads |
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Definition
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Term
Irrigation Design Drip Emitters |
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Definition
Single port: for single plants that will not increase in size Multiport: for trees/other plants that will get larger or for watering several plants made for installation on PVC or flexible polyethylene tubing Drip system must be actuated by valves that open/close at very low flows Zones must be protected against sand/small particles in water supply and high pressure
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Term
Irrigation Design Hydraulics |
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Definition
Pressure expressed as head measured in feet (ft) or pressure measured in pounds per square in (psi) column of water 1 foot high exerts uniform pressure of .433 psi change in elevation results in loss/gain of pressure equal to change in elevation expressed in feet of head
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Term
Irrigation Design Hydraulics: Operating Pressure |
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Definition
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Term
Irrigation Design Hydraulics: Radius |
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Definition
distance from sprinkler head to the outer rim of water distribution pattern as pressure goes up within operating pressure range, radius of throw will increase
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Term
Irrigation Design Hydraulics: Flow Rate |
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Definition
amount of water discharged from nozzle in gallons per minute (gpm) as pressure increases, flow rate increases
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Term
Irrigation Design Hydraulics: Velocity |
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Definition
rate of low measured in feet per second (fps) critical in determining pipe size as velocity increases, friction inside pipe increases, and pressure drops at high velocity, water scours pipes, erodes the seats in valves, and can break pipes due to surge pressure (water column meeting resistance in line due to change in direction/obstacle/end of line)
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Term
Irrigation Design Pipe Sizing |
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Definition
Irrigation Mains Irrigation Laterals runs of pipe that carry water between zone valves and heads/emitters usually smaller in size than mains only under pressure when zone is being operated
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Term
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Definition
Heads: uniform coverage over areas to be watered with minimal overspray onto streets & walks Head-to-Head Spacing: 50% of diameter of full circle head; ensures adequate overlapping to account for loss of depth with increasing distance from head Square spacing: slightly less efficient than triangular spacing with respect to uniformity of distribution but easier to control edges and overspray Triangular spacing: fewer heads needed to get uniform coverage, but harder to get uniform coverage at ends of rectangular areas. Most practical use is for large turf areas
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Term
Irrigation Design Precipitation Rate |
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Definition
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Term
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Definition
Velocity = feet/second (fps) Flow rate (volume from nozzle) = gallons/min (gpm) Pressure = pounds/sq. in (psi) or feet of head Infiltration rate (of soil) = inches/hour Precipitation rate (rate at which irrig. head applies water to soil) = inches/hour
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