WILLAMETTE RIVER WATERBODY <br />1,700 lineal feet of the Willamette River OHW mark are located within the study area boundaries. An <br />additional 450 lineal feet of OHW were delineated outside of the study area using field notes combined <br />with hydraulic model and elevation data sets. The Willamette River described here is only partially <br />contained within the study area. <br />The OHWM was delineated at the site based upon shifts in vegetation community, soil character, and <br />topography. OHW corresponded to a vegetation community transition from sedges to upland species <br />including Himalayan Blackberry, English ivy, and snowberry (Symphoricarpos albus, FACU). Alder were <br />commonly found just upslope of OHW, and washed roots were observed in line with OHW. Vegetative <br />transitions were the primary indicator used, and were present throughout the study area. Soils upslope <br />had more developed horizons compared to sandy soil downslope, and this indicator was only present <br />at a few locations. A topographic slope break was also observed at the OHWM at several locations. The <br />OHWM was delineated at an elevation 406.5 feet at the middle of the study area and 407.4 feet at the <br />upstream end of the study area <br />F.Deviation from LWI or NWI <br />The US Fish and Wildlife Service maps wetlands and deepwater habitats based on Cowardin classes as <br />part of its National Wetland Inventory (NWI) program (Cowardin et al. 1979). NWI maps are produced <br />from aerial photographic and topographic map interpretation and are not meant to represent the extent <br />of jurisdictional wetlands (Dahl et al. 2015). No wetland types were mapped found within the study <br />area. Just outside of the eastern boundary of the study area, the Willamette River was classified as: <br />1ŵ4!'ȎɎ1¯¼«¸¯´«ȍɎ²µ½«¸Ɏ¶«¸«´´¯§²ȍɎ»´©µ´¹µ²¯ª§º«ªɎ¨µººµ³ȍɎ¶«¸³§´«´º²¿Ɏ¬²µµª«ª. The <br />Willamette River was mapped as this wetland type. <br />The absence of wetlands identified in this delineation is in agreement with the absence of mapped NWI <br />wetlands. The OHWM of the Willamette River as delineated in the field is in relative agreement with <br />the R2UBH boundary from NWI, however our field delineated OHWM was located landward of NWI. <br />Discrepancies between delineated and NWI OHW are most likely due to the quality and scale of data <br />used. This delineation used field indicators, detailed survey, and detailed field investigation to <br />determine wetland boundaries while NWI wetlands are mapped from aerial photos and topographic <br />maps and are therefore less precise. <br />A local wetland inventory (LWI) was completed for the project area by Pacific Habitat Services Inc in <br />2003. This LWI did not delineate any wetlands within the project area. <br />8 <br />