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6.0 DISCUSSION & RECOMMENDATIONS FOR BOND RELEASE STANDARDS The current permit for Bowie's operations identified three major plant communities for which reference areas or technical standards have been established, as appropriate for future bond release comparisons. These are juniper woodland, mixed shrubland, and disturbed meadow. Effectively, there is no disturbed meadow within the proposed new WRDA, therefore, bond release comparisons would only involve the first two communities. With respect to the mixed shrubland and juniper woodland extant within the proposed new WRDA, the two current reference areas exhibit variable utility for future bond release comparisons. It must be noted that the mixed shrubland reference area exhibits perennial herbaceous cover that is nearly 10 times greater than the proposed new WRDA (24.1 % vs. 2.79'0) and production that is 6 times greater (600 vs 100 Ibs/acre). Based on site-specific observations, it is likely that these differences result from several factors. First, the reference area exhibits an east-facing aspect as opposed to south-facing. Second, the reference area does not appear to have suffered over-grazing impacts in the past, as has the proposed WRDA. Third, the reference area is approximately 1000 feet higher in elevation and exhibits a denser overstory of oak. Finally, underlying soils appear to be somewhat different between the two areas. With regard to the juniper woodland reference area, it is somewhat different from the woodland within the WRDA as well, however, the differences are not nearly so dramatic as with the mixed shrubland. Because of these differences (mixed shrubland reference area showing heavier veoetation cover) it is not possible to show statistical eouivalencv between the Drooosed disturbance area and the historic reference areas. However, past revegetation efforts in the area have shown an ability to outperform native areas by a substantial margin, therefore BRL will utilize the existing reference areas as follows. Success testing will follow a weighted evaluation protocol that complies with Colorado's °Guideline Regarding Selected Coal Mine Bond Release Issues" (April 18, 1995). Collected parameters from the two reference areas will be weighted based on acreage of each community type within the proposed WRDA. These weighted values will be compared to the entire revegetated WRDA as a single unit. Total WRDA disturbance is projected to be 36.8 acres. Juniper woodland acreage comprises 25.2 acres plus some old disturbance of 3.2 acres of juniper woodland for a total of 28.4 acres (or 77.2% of the WRDA). Mixed shrubland disturbance acreage is projected to be 8.4 acres or 22.8% of the WRDA. Therefore, when reference area data are collected, they will be weighted accordingly (.772 x JW variables, and .228 x MS variables) before the comparison with the overall revegetated area occurs. • •. • CEDAR CREEK ASSOCIATES, INC. Page 1fF Exhibi[ 5 -Bowie WRDA VEgetation Survey