2010-12-27_REVISION - C1981019 (2)

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be completed. In this manner, edge transects were retained entirely within the target unit by "bouncing" off the boundaries. 2.2 Determination of Ground Cover Ground cover at each sample point was determined utilizing the point- intercept methodology as illustrated on Figure 1. As indicated on this figure, Cedar Creek utilizes new state -of- the -art instrumentation it has pioneered to facilitate much more rapid and accurate collection of data. A transect of 10 meters length was extended in the direction of the next sampling location from the flagged center of each systematically located sample point. At each one -meter interval along the transect, a "laser point bar" was situated parallel to, and approximately 4.5 to 5.0 feet vertically above the ground surface. A set of 10 readings was recorded as to hits on vegetation (by species), litter, standing dead, rock ( >2mm), or bare soil. Hits were determined at each meter interval by activating a battery of 10 low - energy specialized lasers ** situated along the bar at 10 centimeter intervals and recording the variable intercepted by each of the narrowly focused (0.02 (see Figure 1). In this manner, a total of 100 intercepts per transect were recorded resulting in 1 percent cover per intercept. This methodology and instrumentation facilitates the collection of the most unbiased, repeatable, and precise ground cover data possible. Identification and nomenclature of plant species follows Weber and Wittman (1996) Colorado Flora: Western Slope. 2.3 Sample Adeauacv Determination Sampling within each managerial unit was conducted to a minimum of 15 or 30 samples per unit. From these preliminary efforts, the sample mean and standard deviation for total non - overlapping vegetation ground cover was calculated. For non - monitoring applications, the typical procedure is that sampling continues until an adequate sample, n m i,,, has been collected in accordance with the Cochran formula (below) for determining sample adequacy, whereby the population is estimated to within 10% of the true mean (p) with 90% confidence. When the inequality (n m i„ 5 n) is true, sampling is deemed adequate; and n mi „ is determined as follows: +` Lasers utilized for this instrument are state -of- the -art and of specialized design to emit a unique electro- magnetic wavelength visible under full sunlight, a condition previously not possible with portable low- energy lasers. CEDAR CREEK ASSOCIATES, Inc. Page 5 Colowyo Coal Company 2006 Phase II Evaluation (Updated Dec -10)