2008-03-13_REPORT - C1981019 ‎(2)‎

• Permit No: C1981019
• IBM Index Class Name: REPORT
• Doc Date: 3/13/2008
• Doc Name: 2007 AHR 2007 Revegetation Monitoring Report
• From: Colowyo Coal Company
• To: DRMS
• Annual Report Year: 2007
• Permit Index Doc Type: Hydrology Report
• Email Name: SB1
• Media Type: D
• Archive: No

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(Koe%ria macrantha) with 10.5%, 10%, 6.0%, 4.7%, and 2.9% average cover, respectively. With
regard to diversity, the Sagebrush Reference Area exhibited 5 perennial grasses and 1 perennial forb with
between 3% and 50% relative cover.
2.5.3 Improved Pasture Reference Area
The Improved Pasture Proposed Reference Area is comprised of approximately 11.1 acres of flat to
gently rolling vegetation (see Plate 3). This reference area is just external to the northwest corner of
the Collom study area, and can be located in the bottom of Morgan Gulch (see Map 2). A total of 8 plant
taxa were observed in this reference area (see Table AB-1). Current annual herbaceous production
across the area averaged 1,387.2 pounds per acre in 2007 with perennial grasses the dominant category
(see Table 1). Ground cover in the Improved pasture Reference Area (Table 8) consisted of 57.3% live
vegetation, 0% rock, 40.4% litter, and bare soil exposure of 2.4%. Perennial cover across the unit
averaged 56.1% with annual and biennial cover averaging 1.2%. The dominant taxon was smooth
brome with 52.3% average cover. With regard to diversity, the Improved Pasture Reference Area
exhibited 0 perennial grasses and 0 perennial forbs with between 3% and 50% relative cover. This area
has been selected as a reference area should the need arise for a Pastureland land use.
2.5.4 Target Grassland Reference Area
The Target Grassland Proposed Reference Area is comprised of approximately 27.7 acres of gently
sloping vegetation (see Plate 4). This reference area is located on a gently sloping ridge immediately
west of Collom Gulch (see Map 2). A total of 33 plant taxa were observed in this reference area (see
Table AB-1). Current annual herbaceous production across the area averaged 385.4 pounds per acre in
2007 with perennial grasses the dominant category (see Table 1). Ground cover in the Target Grassland
Reference Area (Table 8) consisted of 43.1% live vegetation, 1.4% rock, 33.4% litter, and bare soil
exposure of 22.3%. Perennial cover across the unit averaged 32.5% with annual and biennial cover
averaging 10.6%. Dominant taxa were western wheatgrass, Sandberg's bluegrass, snakeweed
(Gutierrezia sarothrae), and cheatgrass with 11.5%, 8.9%, 7.2%, and 4.0% average cover, respectively.
With regard to diversity, the Improved Pasture Reference Area exhibited 2 perennial grasses and 0
perennial forbs with between 3% and 50% relative cover. This area has been selected as a reference
area should the need arise to have a direct comparator for "grassland" targeted vegetation communities.
Rio Tinto Energy America/Colowyo Mine
Page 35 Revegetation Monitoring - 2007