For the purposes of this chapter, unless otherwise apparent from the context, certain works and phrases used in this chapter are defined as follows:
"Landscaping"means vegetative plantings such as grass, trees, shrubs and vines and related improvements such as pools, walkways, rock work and sculpture which is of a design that will beautify and enhance a property and control erosion and reduce glare.
"Screening"means a masonry wall, board fence, screened chain link fence, hedge, berm or vegetative planting or combination thereof which is of a design that will provide a visual and audible barrier between land uses having different intensities of use.
"Shade tree"means trees of a variety approved by the city that will, under ordinary circumstances and growing conditions, provide shade upon reaching maturity.
"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.
"Check valve"means a valve located under a sprinkler head to hold water in the system so it minimizes drainage from the lower elevation sprinkler heads.
"Conversion factor (0.62)"means a number that converts the estimated total water use from acresinches per acre per year to gallons per square foot per year. The conversion factor is calculated as follows:
(325,851 gallons/43,560 square feet)/12 inches = (0.62) |
325,851 gallons = one acre foot |
43,560 square feet = one acre |
12 inches = one foot |
To convert gallons per year to one hundred cubic feet per year, another common billing unit for water, divide gallons per year by seven hundred forty-eight. (Seven hundred forty-eight gallons equal one hundred cubic feet.) |
"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 type of plants, and the efficiency of the irrigation system.
"Evapotranspiration"means the quantity of water evaporated from adjacent soil surfaces and transpired by plants during a specific time.
"Flowrate"means a portion of the landscaped area having plants with similar water needs that are served by a valve or set of valves with the same schedule. A hydrozone may be irrigated or nonirrigated. For example, a naturalized area planted with native vegetation that will not need supplemental irrigation once established is a nonirrigated hydrozone.
"Hydrozone"means a portion of the landscaped area having plants with similar water needs that are served by a valve or set of valves with the same schedule. A hydrozone may be irrigated or nonirrigated. For example, a naturalized area planted with native vegetation that will not need supplemental irrigation once established is a nonirrigated hydrozone.
"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. For the purpose of this chapter the following factors shall be used:
Spray heads (pop-up or riser) | 0.60 |
Rotor or impact heads | 0.70 |
Bubbler | 0.70 |
Drip | 0.76 |
"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(s) footprint, driveways, nonirrigated portions of the parking lots, hardscapes such as decks and patios and other nonporous 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.
"Mulch"means any material such as leaves, bark, straw or other materials left loose and applied to the soil surface to reduce evaporation.
"Nonpotable water"means water unfit for human consumption, such as treated or recycled waste water, untreated irrigation water or untreated groundwater.
"Overspray"means the water which is delivered beyond the landscaped area, wetting pavements, walks, structures or other nonlandscaped 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, use the following plant factors:
Low water using: | 0.1—0.3 |
Medium water using: | 0.4—0.6 |
High water using: | 0.7—0.9 |
These plant factors are based on the Water Use Classification of Landscape Species Project (WUCOLS). The project list is intended solely as a guide to help landscape professionals identify irrigation water needs of landscape species. It is not intended to be used as a required, mandatory, approved or master list. The WUCOLS Project is available from the California Department of Water Resources or from the Contra Costa water district.
"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-to seven-inch tall, cool season grasses that is well watered. Reference evapotranspiration is used as the basis of determining the estimated total water use so that regional differences in climate can be accommodated. (For historical ETo rates see Exhibit B attached to the ordinance codified in this chapter.)
"Runoff"means water which is not absorbed by the soil or landscape to which it is applied and flows from the area. For example, runoff 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 composition"means the classification of soil based on the percentage of sand, silt and clay in the soil.
"Sprinkler"means a device which sprays water through a nozzle.
"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 and its roots. This can be either a cool season or warm season grass. For example, Red Fescue and Tall Fescue are cool season grasses; Bermuda grass, Kikuyu grass, St. Augustine, Zoysia grass, and Buffalo grass are warm season grasses.
"Valve"means a device used to control the flow of water in the irrigation system.
(Ord. 893 § 2, 2011)