The words used in this chapter have the meaning set forth below:
"Application rate"means the depth of water applied to a given area, usually measured in inches per hour.
"Applied water"means the portion of water supplied by the irrigation system to the landscape.
"As-builts"means a set of reproducible drawings which show significant changes in the work made during construction and which are usually based on drawings marked up in the field and other data furnished by the contractor.
"Automatic controller"means a mechanical or solid state timer, capable of operating valve stations to set the days and length of time of a water application.
"Backflow prevention device"means a safety device used to prevent pollution or contamination of the water supply due to the reverse flow of water from the irrigation system.
"Conversion factor (0.62)"means a number that converts the maximum applied water allowance from acre-inches per acre per year to gallons per square foot per year. The conversion factor is calculated as follows:
(325,829 gallons/43,560 square feet)/12 inches = (0.62) |
325,829 gallons = one acre foot |
43,560 square feet = one acre |
12 inches = one foot |
To convert gallons per year to 100-cubic-feet per year, another common billing unit for water, divide gallons per year by 748. (748 gallons = 100 cubic feet.) |
means the portion of total precipitation that is used by the plants. Precipitation is not a reliable source of water, but can contribute to some degree toward the water needs of the landscape.
"Emitter"means drip irrigation fittings that deliver water slowly from the system to the soil.
"Established landscape"means the point at which plants in the landscape have developed roots into the soil adjacent to the root ball.
"Estimated applied water use"means the portion of the estimated total water use is derived from applied water. The estimated applied water use shall not exceed the maximum applied water allowance. The estimated applied water use may be the sum of the water recommended through the irrigation schedule.
"Estimated total water use"means the annual total amount of water estimated to be needed to keep the plants in the landscaped area healthy. It is based upon such factors as the local evapotranspiration rate, the size of the landscaped area, the types of plants and the efficiency of the irrigation system.
"ET adjustment factor"means a factor of 0.8, that, when applied to reference evapotranspiration, adjusts for plant factors and irrigation efficiency, two major influences upon the amount of water that needs to be applied to the landscape.
A combined plant mix with a site-wide average of 0.5 is the basis of the plant factor portion of this calculation. The irrigation efficiency for purposes of the ET adjustment factor is 0.625, therefore, the ET adjustment factor (0.8) = (0.5/0.625). |
means the quantity of water evaporated from adjacent soil surfaces and transpired by plants during a specific time.
"Flow rate"means the rate at which water flows through pipes and valves (gallons per minute or cubic feet per second).
"Hydrozone"means a portion of the landscaped area having plants with similar water needs that are served by a valve or set or valves with the same schedule. A hydrozone may be irrigated or non-irrigated. For example, a naturalized area planted with native vegetation that will not need supplemental irrigation once established is a non-irrigated hydrozone.
"Infiltration rate"means the rate of water entry into the soil expressed as a depth of water per unit of time (inches per hour).
"Irrigation efficiency"means the measurement of the amount of water beneficially used divided by the amount of water applied. Irrigation efficiency is derived from measurements and estimates of irrigation system characteristics and management practices. The minimum irrigation efficiency for purposes of this chapter is 0.625. Greater irrigation efficiency can be expected from well designed and maintained systems.
"Landscape irrigation audit"means a process to perform site inspections, evaluate irrigation systems and develop efficient irrigation schedules.
"Landscaped area"means the entire parcel less the building footprint, driveways, non-irrigated portions of parking lots, hardscapes — such as decks and patios and other non-porous areas. Water features are included in the calculation of the landscaped area. Areas dedicated to edible plants, such as orchards or vegetable gardens are not included.
"Lateral line"means the water delivery pipeline that supplies water to the emitters or sprinklers from the valve.
"Main line"means the pressurized pipeline that delivers water from the water source to the valve or outlet.
"Maximum applied water allowance"means, for design purposes, the upper limit of annual applied water for the established landscaped area. It is based upon the area's reference evapotranspiration, the ET adjustment factor, and the size of the landscaped area. The estimated applied water use shall not exceed the maximum applied water allowances.
"Mined-land reclamation projects"means any surface mining operation with a reclamation plan approved in accordance with the Surface Mining and Reclamation Act of 1975.
"Mulch"means any material such as leaves, bark, straw or other materials left loose and applied to the soil surface to reduce evaporation.
"Operating pressure"means the pressure at which a system of sprinklers is designed to operate, usually indicated at the base of a sprinkler.
"Overspray"means the water which is delivered beyond the landscaped area, wetting pavements, walks, structures or other non-landscaped areas.
"Plant factor"means a factor that when multiplied by reference evapotranspiration, estimates the amount of water used by plants. For purposes of this chapter, the average plant factor or low water using plants ranges from 0 to 0.3, for average water using plants the range is 0.4 to 0.6, and for high water using plants the range is 0.7 to 1.0.
"Record drawing" or "as-builts"means a set of reproducible drawings which show significant changes in the work made during construction and which are usually based on drawings marked up in the field and other data furnished by the contractor.
"Recreational area"means areas of active play or recreation such as sports fields, school yards, picnic grounds or other areas with intense foot traffic.
"Reference evapotranspiration" or "ETo"means a standard measurement of environmental parameters which affect the water use of plants. ETo is given in inches per day, month, or year, and is an estimate of the evapotranspiration of a large field of four-inch to seven-inch tall, cool-season grass that is well watered. Reference evapotranspiration is used as the basis of determining the maximum applied water allowances so that regional differences in climate can be accommodated.
"Run off"means water which is not absorbed by the soil or landscape to which it is applied and flows from the area. For example, run off may result from water that is applied at too great a rate (application rate exceeds infiltration rate) or when there is a severe slope.
"Soil texture"means the classification of soil based on the percentage of sand, silt, and clay in the soil.
"Station"means an area served by one valve or by a set of valves that operate simultaneously.
"Turf"means a surface layer of earth containing mowed grass with its roots. Annual bluegrass, Kentucky bluegrass, perennial ryegrass, red fescue, and tall fescue are cool-season grasses. Bermudagrass, kikuyugrass, seashore paspalum, St. Augustinegrass, zoysiagrass, and buffalo grass are warm-season grasses.
"Usable rainfall"means the portion of total precipitation that is used by the plants. Precipitation is not a reliable source of water, but can contribute to some degree toward the water needs of the landscape.
"Valve"means a device used to control the flow of water in the irrigation system.
(Ord. 488 § 1, 1992)