Laserfiche WebLink
The vegetative sampling serves to confirm what can be observed in the field. The <br />revegetation at Colowyo is excellent and there is virtually no evidence of erosion <br />attributable to a lack of cover. In fact the herbaceous cover existing at Colowyo <br />meets or exceeds the premining condition and is undoubtedly providing <br />significant competition with the woody specie seedlings. There is certainly no <br />evidence that herbaceous cover values on the reclaimed areas should be set higher <br />than the herbaceous cover of the premine areas in order to achieve bond release. <br />Herbaceous Production <br />For both Pre-2008 and Post-2008 revegetation (targeting(and achieving) the rangeland <br />land use subcomponent of g azingland), herbaceous production of the revegetated area <br />will be considered adequate for final bond release if it is not less than 90% of the <br />herbaceous production, as determined from the reference areas with a 90% statistical <br />confidence utilizing a standard students statistical Mest comparison of the means. As <br />allowed under the rules promulgated on 9/14/05, these comparisons may utilize one of <br />three methods detailed under Rule 4.15.11 (2) [(a), (b) or (c)]. As allowed by Rule 4.15.7 <br />(4), either weighted-average or individual protocols will be followed. For grassland <br />testing the weighted average approach (Rule 4.15.7 (4) (b)) will be utilized where <br />reference area data and revegetated area data are "weighted" (each combined into single <br />values for comparison) based on the proportional acreage of pre-mine communities <br />within the disturbance area footprint. Testing will then follow procedures detailed under <br />Rule 4.15.11 (2) with preference being given first to subsection (a) [direct comparison], <br />second to subsection (c) [reverse-null testing], and third subsection (b) [classic t-test]. <br />For areas designated as Post-2008 sagebrush steppe revegetation (rangeland land use <br />subcomponent of wildlife habitat), herbaceous production success criteria will be <br />eliminated as a requirement should CDRMS rules change as expected in the near future. <br />In the meantime, for Post-2008 sagebrush steppe revegetation, herbaceous production of <br />the revegetated area will be considered adequate for final bond release if it is not less than <br />70% of the herbaceous production as determined from the reference areas with a 90% <br />statistical confidence utilizing a standard students statistical Mest comparison of the <br />means. If necessary, a reverse-null hypothesis testing procedure may be utilized in <br />accordance with procedures detailed in Rule 4.15.11 (2) (c). As inferred under Rule <br />4.15.8 (3) (ii), relaxation of the herbaceous production standard for areas targeting <br />wildlife habitat post-mining land uses is designed to compensate for revegetation <br />techniques (prescribed ecological reclamation approach) that must discourage grasses to <br />encourage shrubs in the post-revegetated community. Justifications for reduction to 70% <br />are identical to those presented for cover in the previous section. <br />Woody Plant Density - Pre-2008 Reve etation <br />Cedar Creek Associates, Inc.'s recent in-depth analysis of past "shrub conducive efforts" <br />(report dated April, 2007) attempted by Colowyo on older (pre-2008) reclamation has <br />4.15-19 Revision Date: 12/22/09 <br />Revision No.: TR-84