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New Haven Water Balance-Recharge Analysis-Manteca,California <br /> ETo Climate Zone 12; Manteca Rainfall,2010-2020 <br /> 1 2 3 4 5 6 <br /> Month Ave Precip. Average Runoff Available Precip. Potential Ero Actual ET Net Rainfall <br /> (in/month) Volume (in/month) (in/month) (in/month) Recharge <br /> Jan 2.42 0.00 2.42 1.24 0.37 2.05 <br /> Feb 2.08 0.00 2.08 1.96 0.58 1.50 <br /> Mar 2.31 0.00 2.31 3.41 1.01 1.30 <br /> Apr 1 1.47 0.00 1.47 5.10 1.52 0.00 <br /> May 0.44 0.00 0.44 6.82 2.03 0.00 <br /> Jun 0.1 0.00 0.10 7.80 2.32 0.00 <br /> Jul 0 0.00 0.00 8.06 2.40 0.00 <br /> Aug 0.01 0.00 0.01 7.13 2.12 0.00 <br /> Sep 0.11 0.00 0.11 5.40 1.61 0.00 <br /> Oct 0.69 0.00 0.69 3.72 1.11 0.00 <br /> Nov 1.67 0.00 1.67 1.80 0.54 1 1.13 <br /> Dec 2.61 0.00 2.61 0.93 0.28 2.33 <br /> Total 13.91 13.91 53.37 15.88 8.31 <br /> Notes: <br /> 1.Ave monthly precip for Manteca-San Joaquin County,National Centers for Environmental Information-2010-2020 <br /> 2.Estimated average monthly runoff volume;zero assumed,representing full onsite retention of rainfall on level site; <br /> 3."Available Precip"equal to ave monthly precip minus estimated runoff volume; <br /> 4.Reference ETo obtained from CIMIS for Zone 12,Eastside Sacramento-San Joaquin Valley;represents value for lawns and other uniform turf areas <br /> S.Actual ET adjusted based on site specific landscape/plant cover factor(fractional multiplier);see below for calculating"composite"factor,0.30 <br /> 6.Net rainfall recharge("deep percolation")equal to Available Precip(3)minus Actual ET(5);negative values set equal to zero <br /> Composite Eto Adjustment Factor for New Haven Elementary <br /> a.Key reference:University of Calif.Division of Agriculture and Natural Resources:Estimating Landscape Water Requirements(Table 1) <br /> https://ucanr.edu/sites/UrbanHort/Water Use of TurfRrass and Landscape Plant Materials/SLIDE Simplified Irrigation Demand Estimation) <br /> b.Site Development Conditions: <br /> Land Condition Fraction of Total Plant Factor* Product <br /> Impervious Area 0.37 0.05 0.02 <br /> Trees,shrubs,groundcover 0.05 0.5 0.03 <br /> Bare ground 0.30 0.1 0.03 <br /> Lawns(cool season) 0.28 0.8 0.22 <br /> Composite 1.00 0.30 <br /> •Per Table 1 for applicable landscape categories;for impervious areas assume nominal 0.05 to <br /> 0.10 to account for evaporation of rainfall retained on paved surfaces,gutters,puddles,etc.; <br /> assume 0.1 to 0.3 for for bare ground,related(inversely)to soil permeability. <br />