Laserfiche WebLink
2.2 Determination of Ground Cover <br />Ground cover at each sample point was determined utilizing the point-intercept methodology as <br />illustrated on Exhibit 1. As indicated in this figure, Cedar Creek utilizes state-of-the-art instrumentation it <br />has pioneered to facilitate much more rapid and accurate collection of data. A transect of 10 meters <br />length was extended in the direction of the next sampling location from the flagged center of each <br />systematically located sample point. At each one-meter interval along the transect, a "laser point bar" <br />was situated parallel to, and approximately 4.5 feet vertically above the ground surface. A set of 10 <br />readings was recorded as to hits on vegetation (by species), litter, rock (>2mm), or bare soil. Hits were <br />determined at each meter interval by activating a battery of 10 low-energy specialized lasers** situated <br />along the bar at 10 centimeter intervals and recording the variable intercepted by each of the vertically <br />projected narrow (0.02'1 focused beams (see Exhibit 1). In this manner, a total of 100 intercepts per <br />transect were recorded resulting in i percent cover per intercept. (Second hits on understory vegetation <br />were not collected owing to the managerial nature of collected data.) All reclaimed area vegetation as <br />well as reference area vegetation (including both herbaceous and shrub strata) were subject to sampling. <br />This methodology and instrumentation facilitates the collection of the most unbiased, repeatable, and <br />precise ground cover data possible. <br />2.3 Sample Adequacy Determination <br />Sampling of the individual units was restricted to 10 samples (20 for reference areas) for cover due <br />to the managerial nature of collected data. However, for informational purposes, sampling adequacy <br />(nmin) has been calculated for each variable in each sampling unit in accordance with the Colorado <br />guideline (April 18, 1995) formula for sample adequacy when statistical testing is not required, as follows: <br />• nmin = (t2s2) / (0.1x)2 <br />• <br />Where: n = the number of actual samples collected with a minimum of 10 in each unit; <br />t = the 1-tailed value from the t distribution for 90% confidence with n-1 degrees of <br />freedom; <br />s2 = the variance of the estimate as calculated from the initial samples; <br />X = the mean of the estimate as calculated from the initial samples. <br />** Lasers utilized for this instrument are state-of-the-art and of specialized design to emit a unique electro-magnetic <br />• wavelength visible under full sunlight, a condition previously not possible with portable low-energy lasers. <br />• CEDAR CREEK ASSOCIATES, Inc. Page 8 Snowcap Coal Co. - 2008 <br />Revegetation Evaluation