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<br />CDM <br /> <br />Section 3 <br />Water Use and Forecasted Demands <br /> <br />Historical water use generally trended upward from 2001 to 2006, corresponding to a <br />growing population. However, water use decreased in 2003, following the 2002 <br />drought and remained lower than 2002 levels through 2004. This is attributable to the <br />following factors: <br /> <br />. Community response to regional drought awareness campaigns <br />. Community response to Erie's efforts to encourage conservation <br />. Relatively high precipitation in 2004, reducing the need for outdoor irrigation <br /> <br />Water use in 2004 through 2006 increased and as reflected in the demand projections <br />(see Section 3.3), demands will likely continue to increase (see Section 3.1.2). <br /> <br />In 1991, the last year of a 5-year drought, Southern California water agencies imposed <br />mandatory water conservation measures. There was also an extensive drought <br />education campaign in 1990 and 1991. This caused per capita water use to fall sharply <br />from 1990 levels. In 1992 and 1993, the drought subsided, but per capita use remained <br />low due to what is called drought memory effect. In the years following the drought, <br />customers gradually increased their per capita use after mandatory measures were <br />lifted. A similar pattern may be expected in Erie following the 2002 drought, and it is <br />possible that per capita demands could reach or exceed pre-drought levels if <br />permanent conservation measures are not employed. <br /> <br />3.1.2 Historical Per Capita Water Use <br /> <br />Figure 3-2 shows Erie's per capita water use from 2001 to 2006. As shown in the <br />equation below, per capita water use for the service area were estimated by dividing <br />the sum of potable system water use (including billed and unbilled water, see <br />Section 3.1.3), raw/lease (used for irrigation on the Vista Ridge Golf Course and Erie <br />Commons), and reclaimed water captured via exchange by the total residential <br />population. <br /> <br />H- t - I -t t Potable water + raw/lease water + relaimed water (gal/yr) <br />IS onca per capl a wa er use - <br />Total population x 365 days/yr <br /> <br />Figure 3-2 shows that the pattern of the annual per capita use is similar to the total <br />annual water use. Per capita water use decreased in 2003 and 2004, yet began to <br />increase in 2005 and 2006. Per capita demands may continue to increase as water use <br />behavior returns to more normal levels. Additional water conservation measures may <br />be employed to keep demands at or below pre-drought levels1. <br /> <br />1 As shown in the equation above, the per capita water use estimates include raw/lease water, <br />reclaimed water, and potable water (billed and unbilled). Billed potable per capita water use <br />is significantly less than the estimates presented in Figure 3-2. For example, the billed <br />potable per capita water use in 2006 is estimated to be 150 gpcd (assuming 15 percent of total <br />potable water usage consists of unbilled water). For purposes of this Plan, per capita water <br />usage includes potable (billed and unbilled) and non-potable water. <br /> <br />DRAFT <br /> <br />3-2 <br /> <br />\\DENSVR1\PROJECTS\9228 - ERIE\CONSERVATION PLAN\REPORT\DRAFT PRIOR TO PUBLIC REVIEW\CONNIE FORMATTED\SECTION 3.DOC <br />