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Gypsum Loan Feasibility Outline <br />CWCB Water Project Loan Program <br />Page 18 of 33 <br />available but on average improved facilities should be able to avail themselves of <br />approximately this much water physically and legally available for diversion and storage <br />in the reservoir. <br />2.3.2 Water Su~lv Demands <br />a. Population Proj,ection. Based on information obtained from the U.S. Census <br />Bureau website, the population of the Town of Gypsum was about 1,750 according to the <br />1990 census. The nea~t census, in the year 2000 showed the Town's population to have <br />more than doubled to about 3,654. This increase corresponds to an average annual rate of <br />about 7.4% assuming continuously compounded exponential growth. The Census Bureau <br />estimates that in 2007 the Town's population was about 5,821, which corresponds to <br />continued growth at an average annual exponential rate of about 6.7%. As the 6.7% rate <br />is lower than the 7.4% rate from the previous period, the data demonstrate that the <br />Town's population growth has not sustained a constant exponential rate, instead <br />exhibiting a rate that diminishes with increasing population. This suggests that a logistic <br />trend, reflecting growth rate reduction as population size progresses toward capacity, ma.y <br />form the basis of an appropriate means of projecting future population size. A calibrated <br />logistic growth model using 1990 as the time of beginning was used to project the <br />Town's population size, resulting in an estimated population of about 37,000 in the year <br />2060. While this population size estimate could be high, local and national growth <br />patterns for the last two decades, and the continued projected regional growth <br />expectations in western states dictate a conservative approach. <br />b. Equivalent Water Service. On the same basis as the planning period population <br />projection, it is estimated that the Town's population is currently about 6,600. Drinking <br />water treatment facility diversion records show that wintertime (no irrigation) diversions <br />are currently running about 1.04 cubic feet of water per second of time (cfs), which <br />corresponds to 102 gallons per person per day. Although domestic water use constitutes <br />the vast majority of the winter flow demand, this figure also includes commercial usage, <br />system losses, and any other incidentals. It is worth mention that the current figures <br />show achievement of a 36% reduction in diversions per person since 2003, owing almost <br />exclusively to recent system improvements. Gypsum defines standard service <br />equivalence as one Equivalent Residential Unit (EQR) (equal to 350 gallons per day plus <br />lawn and garden irrigation water). Using this system, the Town of Gypsum is currently <br />serving an estimated 1,920 EQRs. <br />Some future demand reduction may be achieved through water conservation measures, <br />and the Town Code and water rates encourage conservation. However, reductions will <br />likely be most apparent in the summer months when conservation measures and <br />improved irrigation practices may be in effect. For this reason and based on the need for <br />conservative water supply planning to ensure adequa.te availability, the current ratio of <br />population to demand is deemed the most appropriate for use in demand projections. At <br />3.44 persons per EQR (6,600 / 1,920) the projected 2060 population of 37,000 will <br />demand an estimated 10,760 EQRs of potable water service. This is expected to require <br />