2013-06-28_PERMIT FILE - C1981008A

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Reference Area Characterization The Reclaimed Irrigated Pastureland reference area is a typical irrigated pasture in the Nucla area. The reference area is adjacent to the mine and contains many of the same soils which are present in the reclaimed area. Vegetation is almost entirely herbaceous species, mainly introduced perennial pasture grasses planted for livestock forage. Flood irrigation results in uneven water application, and as a result the species composition within the reference area varies with soil moisture. On most of the reference area where soil moisture is moderate, at least 8 species of upland perennial grasses are dominant, with Kentucky bluegrass, tall fescue, wheatgrasses, and meadow fescue the most dominant (Attachment 2.05.4(2)(e) -5 shows production and cover summary data from 2007 vegetation sampling, and scientific names of plants). Desirable perennial forbs are much less common, and include mainly Alsike clover with minor amounts of dandelion. In shallow drainageways the soil is saturated during the growing season and wetland plants dominate primarily various species of sedge and rush with minor amounts of tufted hairgrass, buckhorn plantain, common plantain, and rarely cattail. In June 2007, mean cover of total vegetation measured at 15 transects was 71.9% (see Attachment 2.05.4(2)(e) -5). Most of the remaining cover was litter, with very little bare ground (3.5 %). Most of the vegetation is desirable (perennial grasses, grass -like plants, and forbs, excluding noxious weeds), comprising 68.6% cover. Of these, Kentucky bluegrass and tall fescue contribute nearly 48% relative cover (the fraction of total vegetation cover), and sedges, rushes, and wheatgrasses comprise 32% relative cover. Among life forms, desirable perennial grasses (including sedges and rushes) are dominant by far (64% cover, 89% relative cover), and desirable perennial forbs (primarily Alsike clover) are next (4.5% cover, 6.2% relative cover). Undesirable species together comprise total cover of 3.3% and relative cover of 4.6 %. These include shrubs (gumweed), a few weedy annual forb species, and the noxious weed field bindweed; each of these life forms contributes 1.5% or less total cover. Mean total production measured in June 2007 at 44 plots was 2,677 lb/acre for all vegetation, and 2,513 lb/acre for desirable vegetation. Perennial grasses (including sedges and rushes) contribute most of the production, at 2,436 lb/acre (97% of desirable production and 91 % of total production). Forbs made up most of the remaining plant production, with a minor contribution from shrubs (gumweed) and the noxious weed species field bindweed. (June 2013 MR 86) 2.05.4(2)(e) - 28 MR _N, f}POr "Wd g8 j' un "?01_3