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that the number of 90-degree days is between about 135 and 141 percent above normal. This <br />increase in 90-degree days potentially increases the amount of water removed from the soil or <br />shallow aquifer during the summer by either evaporation or plant transpiration. This increase in <br />90-degree days, in conjunction with the less than normal precipitation, also reduces the amount <br />of water available to plants, thus requiring additional or eazlier than normal imgation to sustain <br />normal, healthy plant growth. <br />Otu conclusions concerning the effects of less precipitation and increased summer temperatures <br />during 2000 and 2001 are supported by a recent article published in The Coloradoan, a local Fort <br />Collins newspaper, on November 23, 2001 which reported that the northern Colorado Front <br />Range azea was experiencing its second year of drought. Mr. Nolan Doesken, the Assistant State <br />Climatologist reported that "this was the first time we've had two years in a row with less than <br />13 inches of precipitation since 1977-1978." The article reported that the "past two years have <br />yielded precipitation totals of 12.67 inches in 2001 and 11.06 inches in 2000. These totals are <br />based on water years ending September 30. The average annual precipitation for the Fort Collins <br />area is 15.12 inches. Compounding the problem of lower than normal precipitation are two <br />record streaks of 90-degree days. There were 47 90-degree days in 2000 and 51 in 2001. The <br />annual average number of 90-degree days is 17." <br />3.2 Evapotranspiration <br />Reference evapotranspiration data obtained from the Colorado Climate Center for a Colorado <br />Agricultural Meteorological (CoAgMet) station neaz Fort Collins were also evaluated to <br />determine the annual reference evapotranspiration for 1995 through 2001. The compiled <br />reference evapotranspiration data are shown in Figure 4. This figure shows that reference <br />evapotranspiration was between 51 and 55 inches, averaging 53 inches, prior to 1998 and have <br />generally increased to as much as 67 inches, averaging 62 inches, since 1998. This nine (9) inch <br />increase in reference evapotranspiration is 17 percent higher than the average evapotranspiration <br />for 1995 through 1997 and reflects the increase in evaporation and plant transpiration during this <br />period. Increased evapotranspiration reduces the amount of available water stored in the soil and <br />removes water from the underlying shallow aquifer, thus potentially lowering the groundwater <br />levels. <br />5 <br />