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4 <br /> <br />The right bank impact area is just above bankfull elevation and, while inundated by over-bank <br />flow this year, it is presently out of the zone of substantial sand deposition. Observations did <br />reveal silt and debris accumulation, which would be expected. Future channel adjustments may <br />allow sand to be deposited over this bankfull floodplain area. <br /> <br />2.5 Wetlands & Waters of the U.S. <br />Wetlands are poorly developed along the segment of the River on the project site due to instability <br />of the sandy substrate along the River, frequent channel changes, channel braiding, and periods of <br />sand deposition followed by erosion and then deposition in another area. Few wetland plants can <br />survive in such unstable conditions. <br /> <br />Figure 3 illustrates the general distribution of wetlands on the project site. Sandbar willows (Salix <br />exigua) with little understory vegetation occur along the edge of the River in topographically low <br />areas frequently flooded. Peachleaf willow (Salix amygdaloides), a small wetland tree, is <br />infrequently present on the edge of wetlands, and plains cottonwood (Populus deltoides) is <br />somewhat more abundant, but in upland areas. Understory herbaceous plants occur infrequently <br />in these sandbar willow wetlands, or are limited to undesirable weeds. <br /> <br />There is a large cattail (Typha latifolia, T. angustifolia) marsh in the southwest corner of the project <br />site. In the 1990's, Builders Aggregate Company removed 3-4 feet of overburden in this area in <br />order to mine the sand and gravel. However, before mining could commence, the River flooded <br />this area, creating conditions appropriate for an emergent wetland. Builders Aggregate Company <br />created a dam along the western edge of the excavation in the 1990's. However, the dam has <br />been breached and beaver have colonized the eastern edge of this wetland. There is also a <br />herbaceous wetland on the right bank of the River just east of the current mining pond (Figure 3). <br />Mining operations likely created a topography conducive to the development of this wetland. The <br />most abundant plants in the Herbaceous Wetland include the introduced and invasive canary <br />reedgrass (Phalaris arundinacea), common reed (Phragmites australis), a native grass, and cattails. <br />These species tend to form dense stands in areas that have been mined. Infrequently occurring <br />wetland plants include pinkweed (Persicaria amphibia). <br /> <br />Wetlands in the areas of fill and excavation on the east and west banks were delineated on July <br />20, 2009 according to the 1987 U.S. Army Corps of Engineers Wetland Delineation Manual and <br />the March 2008 Interim Regional Supplement to the Corps of Engineers Wetland Delineation <br />Manual: Great Plains Region. The wetlands were delineated based on the vegetation, hydrology <br />and soil criteria of these Manuals, and the boundaries marked with numbered pin flags. The <br />numbered boundary pin flags were surveyed by Steve Belz of Black Creek Hydrology, LLC. <br /> <br />It should be noted that the large cattail marsh on the west end of the project site and possibly the <br />Herbaceous Wetland, which was partially impacted, may not be jurisdictional. Part 328 – <br />Definition of Waters of the United States, Section 328.3(d) states, "For clarification, it should be <br />noted we do not consider the following to be 'Waters of the United States': <br />(e) Waterfilled depressions created in dry land incidental to construction activity and pits <br />excavated in dry land for the purpose of obtaining fill, sand, or gravel unless and until the <br />construction or excavation operation is abandoned and the resulting body of water meets <br />the definition of waters of the United States (see 33 CFR 328.3(a)." <br /> <br />2.6 Upland Vegetation <br />Upland habitats on the project site are highly disturbed and characterized by relics of the native <br />vegetation type and introduced annual and perennial weeds. Relics of the native grassland <br />include sandreed grass (Calamovilfa longifolia). Common perennial weeds include Canada thistle <br />(Cirsium arvense), wild licorice (Glycyrrhiza lepidota), and naked spike ragweed (Ambrosia <br />psilostachya). The most abundant annual weeds include giant ragweed (Ambrosia trifida), Canada