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KENNEY, KLEIN, AND CLARK <br />May 22: <br />August 1: <br />voluntary <br />mandatory <br />...- restrictions <br />•••-•-••--•-----•-•--- ....._............... <br />......... ....... ...................... ................ <br />restrictions <br />0.35 <br />- •-- •- -- -I•- <br />0 <br />-- <br />1 <br />w <br />0.26 <br />.0.2 <br />0.15 <br />-- — <br />0.1 <br />- •- sooxg.�aa <br />0.05.- <br />5+1+2002 51 8!29.2002 Gil 212002 6 <br />711012002 72412002 81vi2002 8121MD2 <br />Figure 1. Comparison of Actual and Expected Per Capita Water Use for the <br />City of Westminster From May 1 to August 31, 2002. <br />use" compares 2002 usage (deliveries) to the average <br />examples, the lower figure is calculated by subtract - <br />of 2000 to 2001 usage; "per capita use" translates net <br />ing 2002 use from 2000 to 2001 average use, while the <br />use to a per person value in order to account for popu- <br />higher number is calculated by subtracting 2002 use <br />lation growth; and "expected use per capita" is a com- <br />from the "expected" level of 2002 use. For the "Poten- <br />parison of actual per capita use in 2002 .with that <br />tial Savings" scenarios, the lower number is .2000 to <br />level of use anticipated in 2002 had water restrictions <br />2001 average use multiplied by the average savings <br />not been in effect and given the adverse climatic con- <br />under the "net use" method for a given scenario (i.e., <br />ditions associated with drought]. Essentially, the first <br />every three days, twice weekly, etc.), while the higher <br />metric evaluates water restriction effectiveness from <br />number is the product of the expected use in 2002 <br />the standpoint of the reservoir system, while the sec- <br />times the average savings under the "expected use" <br />and and third reflect the standpoint of the individual <br />method associated with the given scenario. These sav- <br />water user. The comparisons are for the exact corre- . <br />ings percentage values are shown in Table 3. For the <br />sponding dates in one of three time spans: the entire <br />scenario assuming "Mandatory Restrictions Employed <br />study period (May 1 to August 31), .the period of vol- <br />All Study Period" the percentage values used are city <br />untary restrictions (case specific), and the mandatory <br />specific. <br />restriction period (case specific). Thus, for example, <br />Although calculations for each city were conducted <br />the effectiveness of voluntary restrictions in Westmin- <br />in a standardized manner, cross -city comparisons <br />ster is based on a comparison of usage from May 22 to <br />should be done cautiously. Each city has unique cir- <br />July 31, 2002 (see Table 2), with the same periods in <br />cumstances, including the blend of residential to <br />2000 and 2001 and with the expected value during <br />other uses (industrial, commercial, agricultural), the <br />those same dates in 2002. These dates are different <br />size and age (and thus technology) of the water sys- <br />for each city and in some cases may comprise too brief <br />tem, the preexisting level of conservation programs, <br />of time periods to merit serious comparisons. <br />the mix of single family homes to multifamily <br />Table 4 provides estimated ranges of actual and <br />dwellings, average household size, and so on. Each of <br />potential water savings in volumetric terms, with <br />these factors can influence the effectiveness of water <br />the net use and expected use per capita methods as <br />restrictions. For example, Narayanan et al.'s (1985) <br />upper and lower boundaries. For the "Actual Savings" <br />study of drought in Utah found that the effectiveness <br />JAWRA 82 <br />JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION <br />