D.Methods <br /> <br />The wetland assessment was conducted on December 3, 2018. Wetland boundaries were primarily <br />established according to the Routine Onsite method described in the 1987 Corps of Engineers Wetlands <br />Delineation Manual (USACE 1987), and the Regional Supplement to the Corps of Engineers Wetland <br />Delineation Manual: Arid West (Version 2.0) (USACE 2008) (hereafter, referred to as the Manual). Areas <br />with high potential to support jurisdictional wetlands were identified prior to field work by reviewing <br />aerial photographs of the site, National Wetland Inventory (NWI) maps, United Stated Department of <br />Agriculture Natural Resources Conservation Service (USDA NRCS) soil maps, and LiDAR. All areas <br />within the study area were surveyed on foot. Notes concerning soil, vegetation, and hydrology were <br />recorded at each sample plot location. <br />No wetlands were identified at the site. The Willamette River Ordinary High Water (OHW) mark <br />shown in this report was delineated using field indicators using methodologies outlined in the Washington <br />Department of Eoclogy 2016 manual (Washington Department of Eoclogy 2016). The line was drawn in the <br />office using detailed field nots, aerial photographs, formal topographic survey, and hydraulic model results. <br />Field indicators included changes in soil character, vegetation community breaks, and topographic <br />breaks. Vegetative community shifts were the most obvious indicators for OHW, and are described in <br />detail in the following sections. <br />Wetland sample plot locations were determined through observation of topographic and vegetation <br />patterns, while periodic soil sampling ground-truthed our observations by determining the presence or <br />absence of hydric soils and wetland hydrology. Sample plots 1, 2, and 3 were sited near the river at low <br />spots on floodplain benches where wetlands were most likely to occur. Sample plots 4 and 5 were placed on a <br />similar floodplain bench feature, but adjacent to a stormwater/ tributary outfall. Sample plots 6 and 7 were <br />sited below a stormwater outfall pipe further up the slope to investigate the presence or absence of wetlands <br />in relation to these types of features. Sample plot 4 was sited below the OHW mark, and has been excluded <br />from the appendix for this reason. <br /> <br />6 <br />