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perennial grasses, one was a native perennial grass, one was an introduced annual forb, <br />and the other a native perennial forb. <br />5.0 DISCUSSION AND CONCLUSIONS <br />5.1 2010 PRECIPITATION REGIME <br />Precipitation from October 2009 through May 2010 yielded total precipitation in the <br />amount of 8.18 inches based on Colorado State University records from the Paonia 1 SW <br />station. The CDRMS calculated "pre-growing season" precipitation mean for the <br />purposes of the historic record is 11.08 inches. For sampling purposes, "normal" years <br />were defined as those years with a "pre-growing season" precipitation total (as recorded <br />by the National Weather Service or their designee) greater than 8.45 inches and less than <br />13.71 inches. Based on this definition, the "pre-growing season" precipitation for 2010 <br />was determined to fall within the "dry" range. Vegetation parameter values from the <br />2010 growing season represent total vegetation cover, total herbaceous production, and <br />species composition from a defined "dry" precipitation year as specified in the historic <br />record concept for the West Elk Mine <br />5.2 PRECIPITATION REGIME DURING THE 2000-2010 PERIOD <br />In undertaking quantitative vegetation sampling at the Historic Record Study Area this <br />year, discussions between Mountain Coal and CDRMS concluded that finalization of the <br />revegetation success criteria for the West Elk Mine would be desirable. As sampling in a <br />"wet" year at the HRSA had not been conducted, nor were the last few years determined <br />to qualify as "wet" years, an agreement with CDRMS was reached to conduct sampling in <br />2010 and evaluate the data. One of the questions to be answered was whether there was a <br />reasonable expectation of encountering a "wet" year as defined in acceptance of the <br />HRSA approach in 1995. <br />Figure 4 depicts the values for pre-growing season precipitation for the last decade (2000- <br />2010), the average of those values, and the value of the historic mean for the pre-growing <br />season precipitation. The data reveal that only twice, in 2005 and 2007, did the <br />precipitation value exceed the historic mean value. During the remaining nine years, the <br />pre-growing season precipitation value was below the historic mean. Significantly, <br />during the last decade, no year qualified as a "wet" year as defined in the HRSA approach <br />(one with a pre-growing season precipitation total of 13.71" or more). <br />This precipitation record, while not predictive, suggests that prudence dictates the use of <br />the existing collected data from the HRSA to establish final revegetation success criteria <br />for the West Elk Mine sooner, rather than later. <br />5.3 CHANGES IN THE HRSA VEGETATION COMMUNITY: TRENDS <br />Vegetation sampling at the historic record study area in 2010 represented the fourth year <br />of data collection at the historic record vegetation community. The 2010 sampling is <br />separated from the initial three years of sampling by twelve years. Should significant <br />Mountain Coal Company, LLC Page 8 <br />Historic Record Study Area Vegetation Sampling Report: 2010