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presents a summary of precipitation data collected from 1993 through 2004, wrresponding <br />. with the most recent vegetation monitoring. A review of the data illustrates that precipitation <br />is lowest during the late autumn and winter months (October through Mazch), peaks in April <br />through June, and tapers off gradually until late autumn again. The months with the highest <br />average precipitation are May and June. Based on the 1993-2004 data, average yearly <br />precipitation was calculated. <br />Calendar year 2004 precipitation levels were significantly lower than average levels. In <br />September 2003 no precipitation was recorded (compared with a average of 1.13 inches), and <br />October and November 2003 were 88% and 46% below average. Above normal amounts of <br />precipitation were recorded in December 2003, January 2004, and February 2004, though the <br />remainder of the precipitation for the season (April through July 2004) was significantly below <br />normal. March 2004 was the only normal precipitation month, registering the mean amount <br />of precipitation (1.b9 inches). <br />Total precipitation for the first eleven calendar months of 2004 was 9.59 inches. Cumulative <br />precipitation for the January-July 2004 period was 6.00 inches. Total cumulative precipitation <br />for the period from September 2003-July 2004 was 6.85 inches. Compared to their <br />corresponding averages, these values represent a 24.4 percent decrease from the yearly <br />precipitation mean (corrected for 2004 precipitation), and a 40.5 percent (September-July) <br />decrease from the corresponding period in 2003. The precipitation regime for this year <br />(2004) favored early gowth of cool season graminoids and annual forts. Drying conditions <br />from April through the growing season inhibited the growth of the warm season component of <br />. both the reclamation areas and the reference area. <br />4.2 VEGETATION COVER <br />Total vegetation cover values within the 1995 and 1997 reclamation areas were approximately <br />equal to their values in the corresponding areas in 2003 (Table 13). The 1998 interseeded or <br />reseeded areas and 1999 reclamation areas saw modest increases in their total vegetation <br />cover. The Osgood sand reference area saw a decrease in total vegetation cover of 37 percent <br />from 2003. These changes can be attributed to the precipitation distribution described above. <br />The lack of late summer and autumn precipitation in 2003 may have hampered moisture and <br />biomass production in the warm season component. March precipitation encouraged the early <br />cool season component gowth, but the lack of continued precipitation through the growing <br />season resulted in less vigorous growth by the later cool season and warm season component. <br />Interestingly, relative cover values for Bromus tectorum in all reclamation areas ranged from <br />equal to significantly less than relative cover values from 2003, while Bromus tectorum <br />relative cover increased 60 percent within the reference area (Table 14). The opposite was <br />true for the annual fort Kochia scoparia. This annual has never been recorded in the <br />reference area. In the reclamation areas this season, Kochia was widely distributed, with <br />changes in relative cover ranging from -25 percent (1999 Reclamation Areas) to +409 percent <br />(1995 Reclamation Areas) compared to 2003. <br /> <br />Coors Energy Company Page 17 <br />?A04 RevegetaUon Monitoring Report <br />