Laserfiche WebLink
be completed. In this manner, edge transects were retained entirely within the target unit by "bouncing" <br />off the boundaries. <br />2.2 Determination of Ground Cover <br />Ground cover at each sample point was determined utilizing the point- intercept methodology as <br />illustrated on Figure 1. As indicated on this figure, Cedar Creek utilizes new state -of- the -art <br />instrumentation it has pioneered to facilitate much more rapid and accurate collection of data. A transect <br />of 10 meters length was extended in the direction of the next sampling location from the flagged center <br />of each systematically located sample point. At each one -meter interval along the transect, a "laser point <br />bar" was situated parallel to, and approximately 4.5 to 5.0 feet vertically above the ground surface. A <br />set of 10 readings was recorded as to hits on vegetation (by species), litter, standing dead, rock <br />(>2mm), or bare soil. Hits were determined at each meter interval by activating a battery of 10 low - <br />energy specialized lasers" situated along the bar at 10 centimeter intervals and recording the variable <br />intercepted by each of the narrowly focused (0.02) beams (see Figure 1). In this manner, a total of 100 <br />intercepts per transect were recorded resulting in 1 percent cover per intercept. This methodology and <br />instrumentation facilitates the collection of the most unbiased, repeatable, and precise ground cover data <br />possible. Identification and nomenclature of plant species follows Weber and Wittman (1996) Colorado <br />Flora: Western Slope. <br />2.3 Sample Adeguacv Determination <br />Sampling within each managerial unit was conducted to a minimum of 15 or 36 samples per unit. <br />From these preliminary efforts, the sample mean and standard deviation for total non - overlapping <br />vegetation ground cover was calculated. For non - monitoring applications, the typical procedure is that <br />sampling continues until an adequate sample, n min , has been collected in accordance with the Cochran <br />formula (below) for determining sample adequacy, whereby the population is estimated to within 10% of <br />the true mean (u) with 90% confidence. <br />When the inequality (n mi „ <_ n) is true, sampling is deemed adequate; and n mi „ is determined as <br />follows: <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 Q CREEK ASSOCIATES, INC. Page 5 Colowyo Coal Co. Phase 11 Evaluation <br />