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6.A. - Page 37 of 6$f, <br />Aareement for rueFoint Services Exhibit D — Water Budget Methodology <br />Variable <br />Definition <br />Default Values <br />Variable <br />CIMI5 weather stations. CIMIS weather data is accessed <br />requirement as a fraction of ETo. <br />Ks, <br />Type <br />ICS <br />Species or plant factor relating to a specific plant type's water <br />KsT or KSN or <br />CIMI5 weather stations. CIMIS weather data is accessed <br />requirement as a fraction of ETo. <br />Ks, <br />through the CIMIS Web API and REST Services more <br />KsT <br />Turfgrass water requirement default value. <br />0.8 <br />Constant <br />Ksr4 <br />Non -Turf water requirement default value. <br />0.4 <br />Constant <br />Ksw <br />Water Feature water requirement default value. <br />1.2 <br />Constant <br />ETo <br />Reference evapotranspiration (inches) equals the depth of <br />CIMIS Spatial <br />Source <br />water evaporated and transpired from a reference crop (4 to <br />ZIP: 940£3 <br />Variable <br />of year, and root zone depth. Effective Rain is calculated <br />7 inch tail fescue grass) with an abundant water supply. ETo is <br />separately for Turf and Non -Turf. <br />the "standard" measure of water needs from which other <br />= Min(Precip(d), (MSCI + ETo(d) - 5ST(d-1))) <br />Function <br />plant types are compared via KS. Redwood City uses ETo from <br />CIMI5 weather stations. CIMIS weather data is accessed <br />through the CIMIS Web API and REST Services more <br />information is available at http://et.water.ca.govl Redwood <br />City uses the CIMIS Spatial Network data source for ETo <br />collected by Zip Code. <br />ERain(d) <br />Effective rainfall for each day (d) in inches equals the depth of <br />rain effective in offsetting ETo for each hydrazone. Effective <br />rainfall varies widely with rainfall frequency, magnitude, time <br />of year, and root zone depth. Effective Rain is calculated <br />separately for Turf and Non -Turf. <br />ERainT(d) <br />= Min(Precip(d), (MSCI + ETo(d) - 5ST(d-1))) <br />Function <br />ERainNT(d) <br />= Min(Precip(d), (MSCNT+ ETo(d) - SSNT(d-1))) <br />Functions <br />NIR(d) <br />Net Irrigation Requirement: The amount of water required in <br />>= 0 Function <br />a hydroxone that is not provided by rainfall. NIR is calculated <br />for each day (d), based on weather data downloaded from <br />specified weather websites. NIR is calculated for both turf <br />and non -turf surfaces, since these surfaces have different <br />water storage characteristics, and thus differing requirements <br />for irrigation. NIR is a function of daily precipitation and daily <br />reference evapotranspiration. Should any calculated NIR <br />value be a negative a value of 0 shall be used for NIR. <br />NIRT(d) <br />NIRT is calculated for Turf using the logic below and the max <br />Calculated, Function <br />soil constant for turf minimized to 0. <br />>= 0 <br />=Max(0, ETo(d) - ERain(d) - S50-1)) <br />NIRNT(d) <br />NIRNT is calculated for Non -Turf using the logic below and the <br />Calculated, Function <br />max soil constant for non -turf minimized to 0. <br />>= 0 <br />=Max(4, ETo(d) - ERain(d) - SSNT(d-1)) <br />NIRDF <br />A default factor to be applied to NIR when historical NIR <br />1.25 Constant <br />values are used to calculate water budgets. This accounts for <br />REV: 04-23-19 PR <br />Page 33 of 64 <br />Water <br />Budget Methodology Page - 33 - <br />ATTYlAGR.2019.106lTruePoint TrueBill Utility Billing System <br />45 <br />