2019-07-09_REVISION - M2004044 (35)

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2019 Wetland Delineation Report Tucson South Sand and Gravel Mine—Brighton, Colorado original survey area and was not field surveyed. A desktop analysis of the parcel was conducted and found one pond and no additional wetlands or other potential WOTUS. 3.1 Wetland Delineation Methods Wetland delineation for the Project followed Methods contained in the USACE Wetland Delineation Manual (USACE 1987) and the Regional Supplement to the USACE Wetland Delineation Manual: Great Plains Region (Version 2.0) (USACE 2010). The delineation process was utilized to document dominant vegetation, soils, and hydrology in the Project. For a site to be considered a wetland, there must be positive indication of dominance by hydrophytic vegetation, hydric soils, and characteristic wetland hydrology. In normal conditions, if a sample plot lacks any of these three criteria, it is considered upland. To determine these three variables, the field team typically designated paired sample plots, placed at discrete (typically less than 25 feet) distances from one another—one to represent wetland conditions, the other to represent uplands. Each sample plot featured a hand-dug soil pit averaging 20 inches in depth. The sample plot also included nested concentric sampling rings for vegetation cover and species identification, as follows: • Herbaceous vegetation was identified within a 5-foot radius of the sample plot center • Sapling/shrub vegetation was identified within a 15-foot radius of the sample plot center • Trees and woody vines were documented within a 30-foot radius of the sample plot center 3.1.1 Hydrophytic Vegetation The dominant vegetation at each sample plot was keyed to species level and each species was assigned a wetland indicator status using The National Wetland Plant List (Lichvar 2016). The field team used the Flora of Colorado(Ackerfield 2015) as the field taxonomic reference for keying unknown plant species. Hydrophytic vegetation, or plants that are indicators of wetlands, include those species designated obligate (OBL), facultative wetland (FACW), or facultative (FAC). As a general rule, hydrophytes dominate a sample plot when greater than 50 percent of the evaluated species are OBL, FACW, or FAC. Upland plants include those listed with facultative upland (FACU), or upland (UPL) status. Table 1 provides descriptions of these indicators. Table 1.Wetland Indicator Status Indicator Status Occurrence in Wetlands Obligate (OBL) Almost always occur in wetlands under natural conditions (estimated probability >99%). Facultative Wetland Usually occur in wetlands (estimated probability 67%-99%), but occasionally (FACW) found in non-wetlands (estimated probability 1%-33%). 4