Ordinance No. 20414 - Laserfiche WebLink

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property from natural hazards such as floods, land slides, earthquakes and related hazards, tsunamis and wildfires. It is not subject to hazards normally associated with wildfires, or tsunamis. Consistent with this goal, the City of Eugene has adopted provisions regulating development in floodplains and floodways, and building codes regulations that address slopes and seismic concerns. To the extent that this is relevant to the proposed plan amendment, the existing detour bridge does not meet current seismic standards. Consistent with this goal, the proposed bridge replacement project will provide bridges that meet current seismic, safety and design standards. Additionally, regarding slopes, portions of the project area are identified on the map for Relative Slope Instability Hazards. The portions of the project site in the Whilamut Natural Area and Eastgate Woodlands, and the area southeast of 1-5 and the Willamette River are identified as moderate hazard areas. However, both of these areas are proposed for only temporary staging locations. The applicant has completed 10 borings on either side of the river as part of a geotechnical investigation related to the temporary detour bridge (three north of the river, seven south of the river). A geological report (which was not submitted for this application) indicates that geological resources in the project area consist of fill material, alluvium, and bedrock. The processes affecting these materials are man-made, such as excavation and grading, and natural. Since there is an existing bridge, impacts to geological resources would consist of relatively minor changes in topography, minor settlement of near-surface materials, possible increase in erosion, minor changes to the river flow regime and related sediment and related sediment transport, and potential changes in slope stability (from vegetation removal). These impacts would occur as a result of excavation, placement of structure and fills, and clearing and grading. Impacts related to construction would be temporary, localized changes to river flow regime; stability of partially constructed slopes; erosion; and resultant sedimentation. The highest risk to landslide would be slope failure into the Willamette River; however, considering the low height of the riverbank, such a failure would be limited to a small area relative to the width of the river. The applicant states that geotechnical investigations will also be completed during design to determine the best method to seat foundations and piers and to reduce effects related to hazards. Additionally, slopes will be constructed in a manner that reduces potential for erosion or small landslides. \) Therefore, the project would have no permanent effects on geological resources. In the context of a plan amendment, landslide and earthquake hazards are addressed consistent with this goal. Furthermore, specific construction details will be further reviewed during the local permitting processes, subject to applicable standards, such as, based on the earthquake hazard, geotechnical investigations should be completed prior to construction to determine the best method to seat foundations, piers, and bents to reduce effects related to earthquakes (e.g., lateral spread, liquefaction). In addition, slopes should be constructed in a manner that reduces the potential for erosion or small landslides. Regarding flooding, portions of the project area are located within the floodway and floodplain of the Willamette River. As previously stated, both Eugene and Springfield have adopted ordinances regulating construction within floodways and floodplains. Furthermore, in response to Metro Plan policies C.30 and C.31 below, which is incorporated herein by reference, because the 1-5 Willamette Bridge project is located within a FEMA designated regulatory floodway and Exhibit A - Findings Page 17