Laserfiche WebLink
Wetlands <br />Wetland plant communities, other than those associated with seeps, springs, and <br />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 />scouring typical of such channel gradients. Conversely, soils of the drainage channels <br />having more gentle gradients aze darker in color with chromas of less than 2 being <br />common. Wetland hydrology is provided by channel flooding, Iateral flow, and <br />subirrigation. Wetland/upland transition zones are typically narrow to abrupt as a <br />function of channel topography, though broad transition zones can be found in more <br />gently sloping azeas. <br />Wetland vegetation communities are comparatively simplistic in teens 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 tren:uloides) 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 tenuifolia), and red- <br />osier dogwood (Comus stolonifera). Wetlands typically include a mix of these species <br />although large, dense stands of willows or dogwood may be found in the more gently <br />sloping floodplains of Hubbard Creek. <br />1 Herbaceous species occurring within these wetlands are variable and have become <br />established in direct response to soil hydrologic 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 aze 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 Channels -The major drainages of the project azea are chazacterized by <br />straight to curved channel beds. Braided formations and meanders aze 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 azea have less well-defined beds and banks and are 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 />azea. 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 />