2015-10-13_REVISION - C1981014 (18)

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Shrub Density. Along each production transect sampled on all of the reclaimed areas with the exception of the Corley Reclamation, the number of woody plants, as defined in the CDRMS regulations, excluding half shrubs were counted by means of a belt transect 100 square meters in size. On the reference areas sampled a belt transect 100 square meters in size was used while on the New Portal and Old Portal reference areas a belt transect 10 meters in size was used to sample the woody plant densities on these areas. Statistical Methods. As required by the Division's regulations at Rule 4.15.11(2)c, it is not always necessary to achieve sample adequacy for reclamation monitoring for Phase III bond release sampling efforts provided that the success standard has been achieved, and/or the "reverse null" hypothesis is used and data has been collected from at least 30 transects. All of the data collected in this evaluation were analyzed for sample adequacy in order to determine whether the Division's sample adequacy requirements had been satisfied. The sample adequacy formula contained in the CDRMS regulations in Rule 4.15.10(2)(a) was used. Precision of 0.10 was used for plant cover and forage production and a precision of 0.15 was used for shrub density. The CDRMS has historically used difference sample adequacy formulas over the course of their regulatory program. Page 15 of the Vegetation Guideline says that with respect to the "t -value" which is to be used in the formula, that the "t -value" is to be "1.64(which is the t table value for a double -tailed t test with infinite degrees of freedom at the 90% confidence interval." Rule 4.15.10(2)(a) requires that the "t -value" in the formula consists of "the (alpha =0.10) t -table value for a 1 tail t-test, n-1 degrees of freedom..." Page 20 of the Bond Release Guideline says that the "t -value" in the sample adequacy formula is "the (alpha = 0.10) t -table value for a single tailed t- test with (n-1) degrees of freedom." Therefore, as used in this evaluation, the t -value for a one - tailed t-test was used in all statistical sample adequacy calculations. On all of the areas sampled in this evaluation, the data were analyzed for sample adequacy for both "total plant cover" and "allowable plant cover" to determine if sample adequacy was achieved prior to leaving the site. For plant cover and forage production sampling, a minimum of either 15 or 30 samples were collected and the data analyzed for sample adequacy before the "reverse null" approach was applied. According to the CDRMS regulations and previous written guidance received from Mr. Dan Mathews and Ms. Sandy Brown of the Division for other projects, if sample adequacy was achieved on both the reclaimed and reference area with the minimum number of transects, and the reclamation sample mean exceeds 90% of the revegetation success standard, no statistical testing is required and success can be demonstrated by direct comparison. If sample adequacy is not achieved for any of the areas sampled, but the reclaimed sample mean exceeds 90% of the approved standard, then the "reverse null" statistical hypothesis can be used. As explained on page 18 of the Bond Release Guideline: If the parameter sample mean for the bond release block is equal to or greater than 90 percent of the reference area or weighted reference area sample mean, or 90 percent of the approved technical standard, revegetation is considered successful for the parameter. Other than a demonstration of adequate sample size, no statistical calculations are required in this case to document success. If the parameter sample mean for the bond release block