WorldWide Drilling Resource

63 WorldWide Drilling Resource ® MAY 2015 Basic Irrigation Terminology Part 1 Adapted from Information by Rain Bird Corporation and Washington State University A Angle Valve - A valve configured so its outlet is oriented 90º away from its inlet. These valves are generally installed with the inlet at the bottom of the valve. Antisiphon Device - A type of backflow preventer which seals off the atmospheric vent area when the system is pressurized. It should be installed downstream of a control valve in a location at least 12 inch- es higher than the highest point in the lat- eral it serves. When system pressure drops to zero, the float and seal assembly drops, opening the vent to atmosphere and breaking any siphon effect. Antisiphon Valve - The combination of an angle valve and antisiphon device in one unit. The antisiphon device is located downstream of the angle valve. Application Rate - Measurement of the volume of water applied to landscape in a given time typically expressed as inches/ centimeters per week. Arc - The area a part-circle sprinkler irri- gates, expressed in degrees of a circle. For example, a 90º arc provides quarter- circle coverage, while an 180º arc pro- vides half-circle coverage. Audit - An irrigation audit consists of a detailed review of the irrigation system. This includes tests to determine overall system efficiency, identify problems areas needing correction, and determine an ideal watering schedule. Automatic Control Valve - Also called a remote control valve, this valve is activat- ed by an automatic controller using elec- tric or hydraulic methods. B Backflow - The unwanted reverse flow of liquids in a piping system. Backflow Preventer - A mechanical de- vice designed to prevent backflow. It is used to protect potable water supplies from becoming contaminated with irriga- tion water. Even if your area doesn’t require backflow prevention devices, it’s a good idea to use one. Best Management Practice - A practice which is economical and practical while assisting with water use reduction, water protection, and maintaining or improving crop production. C Check Valve - Used to prevent low head drainage, this valve allows water to flow in one direction only. Coefficient of Uniformity - A numerical expression which serves as an index for the uniformity of water applied to a given area within a specific geometric arrange- ment of sprinklers (e.g., square or tri- angular). Controller - Also refered to as a timer or clock, this is the brain of the sprinkler system which automatically opens and closes valves according to a preset schedule. An automatic controller is typically more water-efficient than oper- ating sprinklers manually. Coverage - The area watered by a sprin- kler or grouping of sprinklers. Check back next month for more Basic Irrigation Terminology ! " ; # 511-,(2 0) 20'5&43 %9 4+(3( ,/( $/5)$&452(23 ; 08 029'0/ # ! : : $8 $,- 3$-(3 *,6(/3,/4(2/$4,0/$- &0. "(% ,4( 777 *,6(/3,/4(2/$4,0/$- &0.