Irrigation System Components and Terminology, Exams of Water and Wastewater Engineering

Download Irrigation System Components and Terminology and more Exams Water and Wastewater Engineering in PDF only on Docsity!

Texas Irrigation Basics- Chapter 1 Exam

Review Questions and Answers

100%Pass

David Mungai [Date] [Course title]

Texas Irrigation Basics- Chapter 1

Exam Review Questions and

Answers 100%Pass

Absorption Rate The rate at which a soil will accept water. Rate decreases as soil "capacity" is reached. Affected by soil type, slope, run-off, etc. (Also called percolation rate, infiltration rate). Actual Head Pressure Operating pressure the base of the sprinkler head. Calculated by subtracting all pressure losses, between the head and the pressure source, from the static pressure at the source. Air Gap complete physical separation between the free flowing discharge end of a potable water supply pipeline and an open or non- pressure receiving vessel. Anti-siphon Device Any device that introduces air into the system to prevent "back siphonage". Application Rate. The rate at which water is applied by the irrigation system. It is usually measured in inches per hour. Often referred to as precipitation rate. The following formulas are used to calculate precipitation rate: Precipitation rate Arc.

An undesired reversal of the flow of water in a piping system. Caused by back pressure or back siphonage. Backflow Prevention. The mechanical prevention of reverse flow, or back siphonage, of non-potable water from an irrigation system into the potable water source. Backflow Prevention Assembly. Any assembly used to prevent backflow into a potable water system. The type of assembly used is based on the existing or potential degree of health hazard and backflow condition. Booster Pump. A pump that is installed on the water supply line and is designed to raise the operating pressure in the irrigation system. Bushing. A pipe fitting used to change to either a larger or smaller size. Check Valve. A valve that permits water to flow in one direction only. Class Pipe. A method by which PVC pipe is grouped according to the working pressure. Class 160, Class 200, Class 315 are examples of classes of pipe (Class 200 pipe can be used where pressures do not exceed 200 psi). Commission. The Texas Commission on Environmental Quality Consulting. The act of providing advice, guidance, review or recommendations related to landscape irrigation systems. Contour Line. A line of equal elevation drawn on a plan. For example, a contour line labeled "510" means that everywhere along that line is approximately 510 feet above mean sea level. Contour lines are usually accurate to plus or minus one-half of the contour interval. That is, when a contour interval of one-foot is indicated on a plan, a particular contour line will be acurate to plus or minus 6 inches. Control Wires.

The wire that transmits the signals from automatic controller to the automatic electric valves to open and close the valves. Controller. An automatic timing device, which may be electro- mechanical, digital or a combination of both, and signals the automatic valves to open or close according to a prescribed program. Council. The Texas Irrigation Advisory Council cross-connection An actual or potential connection between a potable water source and an irrigation system that may contain contaminates or pollutants or any source of water that has been treated to a lesser degree in the treatment process. Cycle. Refers to one complete operation of a controller through a watering program. Design. The act of determining the various elements of a landscape irrigation system that will include, but is not limited to, elements such as collecting site specific information, defining the scope of the project, defining plant watering needs, selecting and laying out emission devices, location system components, conducting hydraulics calculations, identifying any local regulatory requirements, or scheduling irrigation work at a site. Completion of the various components will result in an irrigation plan. Design Pressure. The pressure that is required for an emission device to operate properly. Design pressure is calculated by adding the operating pressure necessary at an emission device to the total of all pressure losses accumulated from an emission device to the water source. Direct Burial Wire. Any wire approved for direct underground burial without conduit. Distribution Uniformity (DU).

A mechanical device used in drip irrigation to limit water flow to a drip or slow trickle. Discharge rate in gallons per hour rather than gallons per minute. Evaporation. The natural process of changing water into vapor. Evapotranspiration. The combination of evaporation and transpiration through plant material. It is often used as a measurement of the amount of water that should be replaced when irrigating plant material Flow. The movement of water in a piping system. Often expressed m gallons per minute or cubic feet per second. Flow Control Valve. A valve that can be mechanically adjusted to restrict water flow. Flow Restrictions. Physical restrictions in component parts of an irrigation system that affect the flow of water thus causing a pressure loss. Flush Flow. The higher initial momentary flow through a drip or trickle system required to flush emitters before pressure compensation occurs. Feet of Head (Foot-Head), A measure of pressure equivalent to .433 psi and equal to weight of 1 foot of water on a one square inch surface. Friction Loss. Pressure loss due to friction as water flows through the component parts of a system. Gate Valve. Manual valve capable of permitting straight-through, full open flow. The valve uses a wedge type metal-to-metal gate or disk for restricting partial flow. The gate valve is not recommended for use to throttle flow in an irrigation system. The gate valve is not recommended for use as a section valve for an irrigation system. Globe Valve. A valve that uses a rubber or composition plug against a valve body seat to restrict or stop the flow of water. Can be either

straight through or angle configuration. A globe valve is recommended for use as a section valve for an irrigation system. Gauge (Wire). Standards used for wire sizing. The larger the gauge number, the smaller the wire. Head to Head Spacing. The spacing of heads that is equal to the published radius. Health Hazard. A cross-connection or potential cross-connection with an irrigation systems that involves any substance that may, if introduced into the potable water supply, cause death or illness, spread disease, or have a high probability of causing such effects. Hydraulics. The science of dynamic and static water; the mathematical computation of determining pressure losses and pressure requirements of an irrigation system. Hydraulically Controlled. A system using water pressure through tubing to operate remote control valves. Inspector. A licensed plumbing inspector, water district operator, other governmental entity, or irrigation inspector who inspects irrigation systems and performs other enforcement duties for a municipality or water district as an employee or as a contractor. Insert Fittings A fitting that fits into pipe or tubing. Usually used on polyethylene pipe and tubing. Irrigation Plan. Plan. A scaled drawing of a landscape irrigation system which lists required information, scope of the project, and represents the changes made in the installation of the irrigation system. Irrigation System. An assembly of component parts permanently installed with and for the controlled distribution and conservation of water for the purpose of irrigating any type of landscape vegetation in any

Piping after the remote control valve not subject to constant main line pressure. Loop Mainline. A mainline designed to provide water to any valve from two or more directions. Mainline. That portion of the piping, normally under constant pressure, located between the water source and remote control valves or quick coupler valves. Maintenance Checklist. A document made available to the irrigation system's owner or owner's representative that contains information regarding the operation and maintenance of the irrigation system, including, but not limited checking and repairing the irrigation system, setting the automatic controller, checking the rain or moisture sensor, cleaning filters, pruning grass and plants away from irrigation emitters, using and operating the irrigation system, the precipitation rates of each irrigation zone within the system, any water conservation measures currently in effect from the water purveyor, the name of the water purveyor, a suggested seasonal or monthly watering schedule based on current evapotransipration data for the geographic region, and the minimum water requirements for the plant material in each zone based on the soil type and plant material where the sustem is installed. Manual System An irrigation system where control valves are operated manually. Master Valve. An automatic or manual valve installed at the supply point, which controls water flow into the system main line piping. If a master valve is installed, it must be installed after the backflow prevention device. Matched Precipitation.

All heads discharge varying amounts of water, combining to produce uniform coverage. Ex: If a full circle head discharges 4 gpm, a half circle head will discharge 2 gpm. Multiple Programming. The feature on some automatic controllers that allows more than one watering schedule or program. Non-Health Hazard. A cross-connection or potential cross- connection from a landscape irrigation system that involves any substance that generally would not be a health hazard but would constitute a nuisance or be aesthetically objectionable if introduced into the potable water supply. Non-Potable Water. Water not suitable for human consumption. Normally Closed Valve. An automatic valve through which no water will flow unless external influences are applied to open the valve. Most electric valves are "normally closed" type. Normally Open Valves. An automatic valve through which water will flow unless external influences are applied to close the valve. Almost all hydraulic valves are "normally open" type. Nozzle Tree. Refers to the interchangeable nozzle assortment, with different GPM and radiuses, provided with many rotor heads. Pass-Through Contract. A written contract between a contractor or builder and a licensed irrigator or exempt business owner to perform part or all of the irrigation services related to an irrigation system. Potable Water. Water suitable for human consumption. May be used for irrigation systems as long as approved backflow prevention is used to protect the water supply. Precipitation Rate.