Resolution No. 5303 - Laserfiche WebLink

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Eugene -Springfield Area Natural Hazards Mitigation Plan 2. Hazard Descriptions Land "within the 100-year floodplain" is not considered "suitable and available" under the buildable land definition. Due to State planning requirements, City floodplain development requirements, and the small number of dwelling units located in Special Flood Hazard Areas, the vulnerability of residential development to the flood hazard is low. Eugene and Springfield are in the process of identifying resources to update flood hazard information through new mapping. Once complete, a thorough quantification of vulnerable structures can be completed, provided the resources are available. The 2014 Regional Climate and Hazards Vulnerability Assessment found, while flood incidents have the potential to cause severe loss and damage in localized areas, flooding is not likely to result in significant damage to critical systems or systemic failures across multiple sectors. The reason vulnerability to this hazard is rated as moderate for riverine flooding relates to the primary impacts and potential inconvenience for many members of the population (transportation impacts, drain on emergency response resources, etc.). The area's capacity to respond to this hazard is moderate due to resources and the prolonged onset period of flood hazards. 2.6.7 Risk Assessment FEMA Flood Insurance Rate Maps (FIRMS) are the most comprehensive resource for identifying flooding hazards in the Eugene -Springfield area. The Eugene - Springfield area's most recent FIRMS became effective on June 2, 1999. It is common knowledge the Eugene -Springfield metro area flood maps are based on outdated information. The availability of LiDAR data and other technologies offers superior ability to project and map riverine flooding in the area. Eugene and Springfield are actively working with FEMA and the State of Oregon to identify resources needed to update the Eugene -Springfield regulatory floodplain maps. Notably, some areas within Springfield have recently been re -mapped. These include the Willamette River through the southern portion of Glenwood, as well as the confluence of the Middle Fork and Coast Fork of the Willamette River. Flood prone areas of the Eugene -Springfield area include the FEMA-mapped floodplains for major rivers including the Mohawk, McKenzie, and Willamette (including the Middle Fork and the Coast Fork). FEMA-mapped floodplains also include areas along Amazon Creek, Mill Race and several smaller creeks (mostly in the western portion of Eugene). Historical experience and hydrologic/hydraulic modeling suggest the most problematic areas for local stormwater drainage flooding in Eugene are the Amazon Creek, Willow Creek, and Laurel Hill basins in the South Hills. Drainage problems in these areas are exacerbated by relatively thin, impermeable soils. Vulnerability 2-37 January 2020