Laserfiche WebLink
~~ -- <br /> <br /> Wetlands <br /> Wetland plant communities, other than those associated with seeps, springs, and <br />L! stockponds, are typically confined to the borders of creeks and drainage channels. The <br /> soils of the wetlands located in the major drainage channels may exhibit light-colored <br /> matrices with little evidence of hydric indicators due to the continuous flooding and <br />L.l scouring typical of such channel gradients. Conversely, soils of the drainage channels <br /> having more gentle gradients are dazker in color with chromas of less than 2 being <br />~' common. Wetland hydrology is provided by channel flooding, lateral flow, and <br />,-~ subirrigation. Wetland/upland transition zones are typically narrow to abrupt as a <br /> <br />' function of channel topography, though broad transition zones can be found in more <br />~~ gently sloping azeas. <br /> Wetland vegetation communities are compazatively simplistic in terms of diversity, <br /> typically being dominated by a few hydric species. The tree stratum, where it occurs, is <br /> dominated by narrow-leaf cottonwood (Populus angustifolia) and boxelder (Acer <br /> negundo) at lower elevations. Aspen (Populus tremuloides) is the common tree of <br /> wetlands occurring at higher elevations. Shrub species are essentially ubiquitous across <br /> the majority of the wetlands associated with creeks and drainage channels, although some <br /> small drainages located between narrowly spaced ridges do not support a shrub canopy. <br /> Dominant wetland shrubs include a variety of willows such as coyote willow (Salix <br /> exigua) and plane-leaf willow (Salix planifolia), thinleaf alder (Alms terruifolia), and red- <br /> osier dogwood (Comas stolonifera). Wetlands typically include a mix of these species <br />C although large, dense stands of willows or dogwood may be found in the more gently <br /> sloping floodplains of Hubbazd Creek. <br /> Herbaceous species occurring within these wetlands aze variable and have become <br />established in direct response to soiVhydrologic conditions reflecting soil depth, water <br /> holding capacity, and period of saturation. Along drainages where sandy soils and <br /> comparatively steep gradients predominate, few herbaceous species have become <br /> established to any degree. Wetland shrubs are the primary community component. <br /> Conversely, in more gently sloping drainages where soils have developed more fully and <br /> organic matter has accumulated, herbaceous species such as cow parsnip (Heracleum <br /> Janata), false Solomons-seal (Smilacina stellata), California false-helebore (Veratrim <br /> californicum), northwest cinquefoil (Potentilla gracilis), and a variety of sedge (Carex) <br /> and rush (Juncos) species have become established. <br />Other Waters of the U.S. <br />Drainage CLannels -The major drainages of the project area are characterized by <br />straight to curved channel beds. Braided formations and meanders are rare. The beds and <br />banks are well developed and have formed in response to topographic gradients. These <br />drainages exhibit gravel beds. Channel fines are typically sand-size. Smaller drainages in <br />the project area have less well-defined beds and banks and aze often vegetated to the <br />channel borders. These channel beds often have a higher percentage of fines mixed with <br />endemic gravels and cobbles. <br />`'~ Seeps, Springs, and Stockponds -These three features are common across the project <br />area. Seeps and springs are naturally occurring and are primarily associated with coal <br />seam outcrops at lower elevations and with sandstone lenses and colluviaUlandslide <br />8 <br />