2010-06-11_REVISION - C1981028 - Laserfiche WebLink

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weed according to the Colorado Noxious Weed Act, but is not considered mandatory for control. Weld County weed control district does not list Cheatgrass as a species requiring mandatory control. Coors Energy Company weed management efforts are acceptable. The Colorado Noxious Weed list, downloaded June 10, 2010 from the Colorado Department of Agriculture website, confirms that Bromus tectorum remains on the state Noxious weed list. Although productivity is not a condition of Phase II bond release, CEC provided results of productivity sampling for all three bond release blocks. Referral to the regulations and 1995 bond release guidelines also reiterates that annual and biennial species contribution to cover and production should not exceed 10 percent. "Annual or biennial cover or production in excess of this threshold should be deleted from the reclaimed area data prior to success comparison." And that, "under no condition will noxious weeds count towards the success standard. The cover and production component provided by the noxious weeds should be deleted from both the reference and reclaimed area data prior to success comparison for those parameters." CEC presents results of herbaceous production sampling in Table 3 for the 1998/1999/2000 reclamation block. Calculated herbaceous productivity standard was 135.07 g/m2 (using 13.71 inches precipitation for the x variable). The 2009 sampling of the 1998/1999/2000 reclamation block measured herbaceous productivity of 261.13 g/m2 biomass. CEC needs to assure the Division that noxious species (i.e. Bromus tectorum) were not included in the herbaceous productivity sampling. The 2009 sampling of the 1998/1999/2000 bond release block appears to have met the herbaceous productivity success requirement. This bond release block was sampled to adequacy for herbaceous productivity. Species Composition for BRB 1998/1999/2000: Species composition, or species diversity is not a requirement for Phase II bond release success, however CEC collected the data for the 1998/1999/2000 BRB in 2009, and the data helps the Division evaluate if the reclaimed bond release block is approaching final reclamation success criteria. Colorado Statute Section 34-33-120(2)(s) requires a "diverse, effective, and permanent vegetative cover of the same seasonal variety native to the land to be affected and capable of self-regeneration and plant succession...." on the reclaimed areas, which implies perennial species need to be established. The species composition success standard defined in the permit state that there shall be at least four perennial species, three of which are warm season perennial grasses and one a cool season perennial grass. No forbs are required for species compositions success. It is clear by the approved success standards in the permit that noxious species, prohibited species, or annual species do not count towards the species composition success. For the 2009 sampling event, 6 perennial species met the species composition requirements on the 1998/1999/2000 Bond Release Block. 6 perennial species > 3% rel. cover, but <40% relative cover Calamovilfa longifolia 31.17% rel.cov. Prairie Sandreed Perennial warm season native grass Ambrosia psilostachya 8.04% rel. cov. Ragweed Perennial cool season native forb Panicum virgatum 7.12% rel.cov. Switchgrass Perennial warm season native grass Western Pascopyrum smithii 6.56% rel. cov. wheatgrass Perennial cool season native grass Bouteloua gracilis 4.29% rel.cov. Blue grama Perennial warm season native grass Andropogon hallii 4.05% rel.cov. Sand bluestem Perennial warm season native grass The 2009 sampling event demonstrates that on the 1998/1999/2000 Bond Release Block there are four warm season perennial grass species, one cool season perennial grass, and one cool season forb that meet the species composition requirements. Although Ragweed is not considered a desirable range species, it is not considered a noxious weed, nor is it prohibited or toxic. Therefore, it contributes to the overall species composition on the reclaimed Bond Release Block. The 1998/1999/2000 Bond Release Block achieved the Species Composition standard for the 2009 sampling event. 2009 sampling for Reclamation Areas 23, 25, and 30: Reclamation areas 23 and 25 were reclaimed and reseeded in 2002, while Reclamation area 30 was reclaimed and seeded in 2006. Vegetation sampling was conducted between August5-6, 2009. Page 11 of the "2009 Vegetation Monitoring Areas 23, 25, and 30" provided calculation of the required samples necessary to achieve sample adequacy for cover on the 2002 and 2006 reclaimed parcels. The 2002 reclaimed parcels; Reclamation areas 23 and 25, required 16 sample transects to achieve statistical sample adequacy. Only ten transects were collected on these two reclaimed parcels. Reclaimed areas 23 and 25 were not sampled to adequacy in accordance with Rule 4.15.11(2). At a minimum fifteen sample transect should have been collected. Therefore the vegetation sampling data collected from reclamation areas 23 and 25 will not be included in the Phase II bond release evaluation. Keenesburg SL5 Memo 2 June 11, 2010