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Plantings in California and contains the calculations necessary for estimating the water <br /> requirements of the wastewater disposal area landscaping. It is assumed that the effluent from the <br /> Business Park will supply 100%of the total volume of water required by the landscape grass during <br /> the spring, summer and fall months. However, there may be a need for supplemental irrigation <br /> water during the hottest days of the summer. If additional irrigation water is needed, it must be <br /> applied and monitored carefully. <br /> Worksheet for Estimating Landscape Water Needs <br /> Step 1: Calculate the Landscape Coefficient(KL) <br /> KLformula: KL= ksx kdx kmc........................ <br /> ks=species factor <br /> kd=density factor <br /> kmc= microclimate factor <br /> ks= 0.8 (range= 0.1-0.9) (Turfgrasses=80%of Etc) <br /> kd= 1.0 (range = 0.5-1.3) (Complete canopy and single vegetation type) <br /> kmc=1.4 (range= 0.5-1.4) (Open area, with buildings, winds) <br /> KL=0.8x1.Ox1.4 = 1.12. <br /> (k.) (kd) (km.) <br /> Step 2. Calculate Landscape Evapotranspiration (ETA) <br /> ETLformula: ETL= KLx Et............................ KL= landscape coefficient <br /> ETo= reference evapotranspiration <br /> KL= 1.12 (calculated in Step 1) <br /> ETo=41.85 inches (For months April through September-Taken from CIMIS Website: California Irrigation <br /> Management Information Service) <br /> ETL= 1.12 x 41.85 =46.87 inches. <br /> (KL) (ETO) <br /> Step 3. Calculate the Total Water to Apply(TWA) <br /> TWA formula: TWA= ETA................................. ETA= landscape evapotranspiration <br /> IE .................................. IE = irrigation efficiency <br /> ETL=46.87 (calculated in Step 2) <br /> IE= 0.75 (Irrigation Efficiency estimate of 85%) <br /> TWA= ETL=46.87 inches =62.5 inches <br /> IE 0.75 <br /> The total water needed(in inches)to be applied to a deep-rooted grass planted over the filter bed <br /> disposal area during the months of April through September is calculated to be 62.5 inches. The <br /> total water needed to be applied(in gallons) over the filter bed area during the months of April <br /> through September = 62.5 in. x 1,600 ft2 x 0.62 gals/ft'-inch = 62,000 gallons. The irrigation <br /> requirement volume supplied by the effluent is approximately: 62,000 gals required for irrigation <br /> 160,000 gallons effluent generated18 mos of the yr = 38% of the effluent evapotranspired from the <br /> total theoretical volume of effluent generated. <br /> Page -12- <br /> Chesney Consulting <br />