Laserfiche WebLink
WORKSHEET INFORMATION & EQUATIONS <br />'Local monthly evapotranspiration rates are listed in Appendix D. <br />b The following table can be used for common plant factors: <br />Plant Factor <br />PF <br />_ <br />Very Pow water use plant <br />0.1 <br />Low water use plant <br />0.2 <br />Medium water use plant <br />0.5 <br />High water use plaint <br />0.8 <br />L.iw,n <br />0.8 <br />Pool" Spa, or other water feature <br />1.0 <br />`Irrigation efficiency is derived from measurements and estimates of irrigation system <br />characteristics and managenrent practices. The miniuuun average irrigation ef#iriency for <br />purposes of these Guidelines is tb. r I . The following irrigation e f ciencY may be obtained for the <br />lusted irrigation heads with an Irrr`gation Management Efficiency of 90 %: <br />Inigatiou 1klethod <br />IE <br />spraynozzles <br />71% <br />High efficiency spray nozzles <br />73`Yo <br />Multi streanrmulti trajectory <br />rotary CMSMT) nozzles <br />76% <br />Stream rotor nozzle <br />73% <br />Microspray <br />76% <br />Bubblers <br />77% <br />Drip emitter <br />81% <br />Subsurface. drip <br />81 °.0 <br />a Estimated Total Water Use (ETWU) is the annual gallons required <br />ETW'U = (ETo) x (0.62) x (ETAF x Area) <br />where, ETo = annual evapotranspiration rate in inches per year <br />0.62 = factor used to convert inches per year to gallons per square foot <br />ETAF = plant factor irrigation efficiency <br />Average ETAF for Regular Landscape Areas must be 0.55 or below for residential areas. and <br />0.45 or below for nonresidential areas. <br />r Maxinnem Allowed Water Allowance (MAWA) is the annual gallons allowed <br />MAWA = (ETo) x (0.62) x [(ETAF x LA) + ((I -ETAF) x SLA)] <br />where, ETo = annual evapotranspiration rate in inches per year <br />0.62 = factor used to convert incites per year to gallons per square foot <br />ETAF =plant factor= irrigation efficiency <br />LA = total (site wide) landscape area in square feet <br />SLA= total special landscape area <br />26 <br />