Laserfiche WebLink
2017 Wetland Delineation Report <br /> Tucson South Sand and Gravel Mine—Brighton,Colorado <br /> 3.1 Wetland Delineation Methods <br /> Wetland delineation for the Project followed Methods contained in the USACE Wetland <br /> Delineation Manual (USACE 1987) and the Regional Supplement to the USACE Wetland <br /> Delineation Manual: Great Plains Region (Version 2.0) (USACE 2010). The delineation process <br /> was utilized to document dominant vegetation, soils, and hydrology in the Project. For a site to be <br /> considered a wetland, there must be positive indication of dominance by hydrophytic vegetation, <br /> hydric soils, and characteristic wetland hydrology. In normal conditions, if a sample plot lacks any <br /> of these three criteria, it is considered upland. To determine these three variables, the field team <br /> typically designated paired sample plots, placed at discrete (typically less than 25 feet) distances <br /> from one another—one to represent wetland conditions, the other to represent uplands. Each <br /> sample plot featured a hand-dug soil pit averaging 20 inches in depth. The sample plot also <br /> included nested concentric sampling rings for vegetation cover and species identification, as <br /> follows: <br /> • Herbaceous vegetation was identified within a 5-foot radius of the sample plot center <br /> • Sapling/shrub vegetation was identified within a 15-foot radius of the sample plot center <br /> • Trees and woody vines were documented within a 30-foot radius of the sample plot center <br /> 3.1.1 Hydrophytic Vegetation <br /> The dominant vegetation at each sample plot was keyed to species level and each species was <br /> assigned a wetland indicator status using The National Wetland Plant List (Lichvar 2016). The <br /> field team used the Flora of Colorado(Ackerfield 2015)as the field taxonomic reference for keying <br /> unknown plant species. <br /> Hydrophytic vegetation, or plants that are indicators of wetlands, include those species <br /> designated obligate (OBL), facultative wetland (FACW), or facultative (FAC). As a general rule, <br /> hydrophytes dominate a sample plot when greater than 50 percent of the evaluated species are <br /> OBL, FACW, or FAC. Upland plants include those listed with facultative upland (FACU), or upland <br /> (UPL) status. Table 1 provides descriptions of these indicators. <br /> Table 1.Wetland Indicator Status <br /> Indicator Status Occurrence in Wetlands <br /> Obligate(OBL) Almost always occur in wetlands under natural conditions(estimated probability <br /> >99%). <br /> Facultative Wetland Usually occur in wetlands(estimated probability 67%-99%), but occasionally <br /> (FACW) found in non-wetlands(estimated probability 1%-33%). <br /> Facultative(FAC) Equally likely to occur in wetlands or non-wetlands(estimated probability 34%- <br /> 66%). <br /> Facultative Upland Usually occur in non-wetlands(estimated probability 67%-99%), but <br /> (FACU) occasionally found in wetlands(estimated probability 1%-33%). <br /> 4 <br />