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theoretical maximum of an infinite series). Because we assume that irrigation return <br />flows cannot be captured, the reuse multiplier associated with this type of reuse scheme is <br />simply 1.0, or <br />reuse_multiplier_irr = 1.0 (3-11) <br />Since the model allows for a combination of recapture and exchange reuse (with the <br />combined reuse percentage not to exceed 100 %), a weighted average reuse multiplier is <br />calculated as: <br />net multiplier = reuse_multiplier_irr *(reuse_recap / total reuse) + (3-12) <br />reuse_multiplier exch * (reuse_exch / total reuse), <br />where <br />total reuse = reuse_recap + reuse_exch. <br />Equation 3-9 can therefore be written as: <br />(3-13) <br />demand = total use_annual - net multiplier *(Is` time reuse water). (3-14) <br />The lst time reuse water (AF) is calculated based on user-input percent reuse values and <br />the actual amount of water available for reuse. The amount of water available for reuse is <br />a function of the non-CU usage (only non-CU water can be reused) and the CU credits <br />associated with this non-CU water. Only water for which there is CU credit can be <br />reused. These calculations can be summarized as: <br />Is` time reuse water = total reuse * extra CU, <br />and <br />(3-15) <br />extraCU = percentCU source * demand - <br />percentCU annual * total use_annual. (3-16) <br />Equations 3-9 through 3-16 can be rearranged and easily solved for demand, according <br />to: <br />demand = total use_annual *(1 + net multiplier * total reuse * percentCU annual) <br />/(1 + net multiplier * total reuse *percentCU source), (3-17) <br />However, when the available consumptive use percentage (percentCU source) is less <br />than the percent CU of the demand (percentCU_annual), the water requirement is limited <br />by meeting the M&I consumptive use and there are no "extra" consumptive use credits <br />available for reuse. For this case, reuse = 0 and the demand is simply the total usage, or: <br />