Ordinance No. 20414 - Laserfiche WebLink

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(NFIP). The NFIP requires that any modifications that cause a rise in the Base Flood Elevations (BFEs, which corresponds to water surface elevations associated with the 100-year flood event) must be approved by FEMA. The no-rise condition is also a requirement of ODOT for any bridge replacement project. Consistent with C.31, both Eugene and Springfield have adopted ordinances regulating construction within floodplains and floodways; City of Eugene FEMA "no-rise" certification for any construction or structures within floodways/special flood hazard areas; and City of Springfield Type I permit to allow any construction in the floodplains or floodways within Springfield. Comments from the Eugene Floodplain Manager note that a FEMA no-rise certificate would only be required through the City of Eugene for construction (fill) or structures within the floodway or floodplain that are outside of the right-of-way. The proposal includes temporary staging areas outside of the ODOT right-of-way; portions of the Whilamut Natural Area and Eastgate Woodlands, and ODOT and Lane County property both located southeast of 1-5 and the Willamette River. For these areas, prior to any fill or other development within the regulatory floodway, ODOT will be required to obtain a "no-rise" certification stating that the development will not impact the pre-project (before the temporary bridge) base flood elevation elevations, floodway elevations and floodway data widths. This certification must be signed by a professional engineer and supported by technical data consistent with current FEMA standards. Based on the preliminary modeling, the proposed pier location options would result in the following; Option A would result in an increase of 0.02 feet over existing conditions for the 100- year flood event and, Option B would result in a decrease of 0.54 feet for the 100- year flood event. Option B, including a decrease in base flood elevation, is consistent with the no-rise and Policies C.30 and C.31. Option A's preliminary analysis shows an increase of 0.02 base flood elevation, which does not meet the no-rise requirement. However, a detailed no-rise analysis has not been submitted and the modeling will be run again to meet the no-rise requirement when the design is refined for the permitting process. Furthermore, ODOT requires its bridges to meet the no-rise requirement. Therefore, in the context of a plan amendment, these policies are met. Specific construction and operational details will be appropriately addressed during local and state permitting processes, subject to applicable approval criteria and related standards. Regarding Policy C.32, as noted under Goal 7, portions of the project area proposed for temporary staging areas are identified as moderate hazard risk areas on the map identifying Relative Slope Instability Hazards in Eugene. However, while this information may guide the City in adopting code revisions, it does not apply directly to land use applications as it is not adopted as refinement plan or as codified land use criteria. Additionally, based on the earthquake hazard, geotechnical investigations can 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 can be constructed in a manner that reduces the potential for erosion or small landslides. Based on the findings above, in the context of a plan amendment, the proposed plan amendments are consistent with these policies. D. Willamette River Greenway. River Corridors. and Waterways Element Exhibit A ~ Findings Page 27