2011-08-10_APPLICATION CORRESPONDENCE - C2010088 (2)

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Corey Heaps CAM Colorado LLC August 10, 2011 Pag 15 Division Response: The language used to describe the woody plant density standard is confusing and it is not clear if a reference area or technical standard will be used for comparison to show success. The Division suggests that CAM use only the approved greasewood reference area as a standard which achieves 90% woody plant density of the approved greasewood reference area sample mean at the 90% confidence level. CAM - Examination of the Greasewood Predisturbance Area shrub density data found in Table 2.04.10 -5, documents that the average shrub density of this area is 17.84 plants per 100 square meters or 721.98 plants per acre. Since a total of 13 of the 25 density transects sampled had shrub density values of less than 500 plants per acre or 12.35 plants per 100 square meters, CAM - Colorado LLC is proposing a shrub density success standard of 500 stems per acre at the time of final bond release. Permit page 2.05 -38 will thus be modified accordingly. Division Response: A reference area has been established and sampled. The Division questions the wisdom of switching the shrub density success standard from a reference area to a technical standard of 500 shrubs /acre. The advantage of a living reference area is to allow for changes through time that a technical standard does not account for. Please explain in further detail why CAM is requesting to have a technical standard for shrub density success over the reference area. 74a. A reference area is being used to determined the revegetation success on the reclaimed area. It has not been demonstrated by the operator as per Rule 4.15.7(3), that the reference area is statistically comparable to the disturbed area in terms of vegetative cover, herbaceous production and shrub density. Please submit a statistical demonstration that the reference area is equivalent to the proposed disturbed area. 75. For the diversity success standard, the Division believes it would be appropriate to also include a half -shrub and a perennial grass component. CAM Response: Please see revised seed mixes SM -1 and SM -2 in Exhibit 4. Division Response: In the baseline vegetation survey, inland saltgrass (Distichlis spicata) was the only species of grass that contributed to plant cover. The Division suggests adding inland saltgrass (Distichlis spicata) to the reclamation seed mix. For the diversity success standard, the Division believes that it is appropriate to include a native perennial grass. Please add to the diversity standard on page 2.05 -38 that one perennial grass will contribute at least 2% relative cover. CAM - Examination of the plant cover data collected from the Greasewood Predisturbance Area in 2010 and from the Elam Borrow Area in 2011, documents that of the 35 vegetation transects sampled for plant cover in these areas only four of the transects had any cover represented by this plant. The overall average cover of this plant across all of these areas was 0.17 percent. Furthermore, a careful examination of the naturally revegetated areas associated with the old refinery disturbances in the NE portion of the site and in the